Independent Review Group (IRG)

Twenty seventh meeting – 29th – 30th November 2016

This was a private meeting of the IRG with the main purpose of discussing outstanding points in the draft Final Report of the IRG and to agree the responsibilities for the remaining drafting. A brief discussion by telephone took place with Shell to enable the IRG to understand the latest position with submission of the Decommissioning Programme to BEIS.

The opportunity was taken to review outstanding actions and to discuss the way in which the IRG Final Report would need to be worded to cover those that were still outstanding at the time the IRG wished to submit the final version to Shell. The text for the IRG web site covering the 22^nd – 26^th meetings was also discussed.

Twenty sixth meeting – 26th – 28th September 2016

Professor Shepherd welcomed everyone to the meeting, which he thought could well be the last formal meeting with Shell; the IRG may need one further private meeting to complete its Final Report.

Shell reported that the Alpha ACTM & Crane recycling had been completed with the replacement Crane commissioned. Alpha P&A start-up had commenced, with mobilisations and rig testing. P&A on Bravo was onto the last four wells. The Brent Field Benthic Survey analysis was ongoing and Shell was waiting for final reports, which would be shared with the IRG as soon as they are received.

The AllSeas test lift and load-in had been completed successfully and planning for remaining lifting arms commenced. Able Quay piling and concrete had been completed with the front wall, cofferdam and grounding bed works ongoing.

All the Technical Documents and the Decommissioning Programme had been updated by Shell to incorporate detailed comments received. Two sessions had been held with BEIS (formerly DECC) to discuss the Environmental Statement (informed by the Environmental Impact Assessment) and the draft Decommissioning Programme. Subsequently, the Decommissioning Programme (DP) had been submitted informally to BEIS and comments on a section by section basis are expected from the beginning of October onwards.

Shell advised formal submission would be likely late October/early November, when it will also become available to the public. The IRG had a major concern in that while the draft IRG Final Report should also be ready during October, it may not be able to include any new information from the final versions of the Decommissioning Programme or Technical Documents.

Despite this difficulty with sequencing, it was agreed that a first draft of the IRG Report would be sent to Shell for fact-checking as soon as possible. Similarly, the review process for other supporting documentation is unlikely to be completed before submission of the Decommissioning Programme and the IRG also sees this as a problem.

Shell agreed to share documentation sent to BEIS with the IRG at the same time. There is a further concern with the Environment Statement (ES) and the IRG asked when it will be available in final format. Shell reported that BEIS wish to see the ES as a supporting document and will review it during formal consultation. BEIS had also asked Shell to consider the Environmental Statement “branding”, to ensure that Shell’s responsibility is clearly documented.

DNV-GL was continuing with its final updates of the Environmental Impact Assessment/Environmental Statement.

The IRG had a concern about the weighting that Shell had used to perform Comparative Assessments, providing the basis for a number of significant decisions. The IRG had reviewed a report assessing these weightings and its draft comments were used as the basis for discussion.

Shell had asked Catalyse to extend the predictions and showed a series of graphs that the weighting for environmental matters would have to change from the current level of 6.7% to approximately 30% before any option other than “leave in place” became the better performing option. Shell agreed to send this report to the IRG. The discussion that followed revolved around changes in various weightings, the results being demonstrated using a spreadsheet to show any changes in the best option.

Various criteria were changed by significant amounts as suggested by the IRG but the preferred option (for an example selected from pipeline decommissioning) did not change. The IRG felt that the spreadsheet was an excellent way of exploring the importance of the weightings and demonstrating the overall effect. Shell will consider at what level the Comparative Assessment report might be made available, the initial thought being that this might be a level 2 document (comparable with the TDs).

Shell had sent a paper to the IRG prior to the meeting that described its initial thinking on the two options for the GBSs. The IRG also had a concern about the proposed “rolling programme” for reassessment of safety risks. The IRG accepted it as a useful suggestion but was concerned that it did not necessarily ensure a feasible option in the event of the structure becoming unsafe due to degradation.

The IRG was concerned that the structure could become a hidden reef just below the sea level. Once major degradation had occurred, it would be more difficult and possibly dangerous if any remedial action was required. Shell’s current view was that degradation would inevitably take place but the consequent risk from vessel collision remained acceptably low.

Other scenarios that the IRG felt should be included are the possibility of a near miss, for which data is sparse; also the responsibility for the legacy needs to be made clearer. Shell considered that it had proposed mitigation measures for two scenarios and was unlikely to consider any others as the range of future scenarios cannot be defined.

The IRG observed that there is an IMO Guidance Note that relates to providing or not inhibiting safe passage; it considered that the Shell proposal may not comply with this in the long term although it is mentioned briefly in the Decommissioning Programme. The IRG felt that it would be difficult to justify leaving the legs in place when any action that may need to be taken in a future critical situation may be far more difficult than removing the legs before they degrade.

Some provisional conclusions of the IRG were discussed that might eventually lead to a number of industry-wide programmes of research. Shell reported that equipment developed during the Brent decommissioning project is being made available throughout the industry.

It was agreed that the IRG will endeavor to produce the draft of its Final Report in mid-October 2016. This will be sent to Shell to check for any inaccuracies. The IRG intention is that it will be available in its final form at about the same time that Shell submits the DP to BEIS for formal consultation.

Stakeholder Meetings were on hold and there were no plans for any more meetings until the result of the consultation process became clearer. Shell hoped to submit the Decommissioning Programme for formal consultation at the beginning of November, when BEIS will trigger a 60 day window for public comments. Since this includes the Christmas period, Shell may suggest the period is extended by a further 14 days.

hell had programmed a 3 month period to respond to any comments received. The Decommissioning Programme will then be submitted to OSPAR for consideration, during which time, Shell will prepare the documentation necessary for derogation.

Shell suggested that contractual provision should be made for the IRG to respond to any comments on its Final Report or to give its views to BEIS if required.

Twenty fifth meeting – 20th – 22nd July 2016

The IRG thanked Shell for getting a great deal of the information back to the IRG but, since much of it had arrived just prior to the meeting, the IRG was still dealing with the various responses.

The IRG noted that recent information relating to cost and safety estimates had been mainly internal estimates from Shell and questioned how much external verification there had been. Shell commented that the costs had been scrutinised by an internal department and Shell’s partner, Exxon Mobil so there was good confidence in the figures used. The IRG suggested that Shell should document the process to avoid any later criticism as this appeared to have been picked up in the Stakeholder report. Also, there was very little information about estimates of uncertainty throughout the Technical Documents.

In reply to a question about figures for PLL, Shell reported that the figures used were based on estimates that are widely accepted by the industry. The IRG also commented that Shell should consider the presentation of too many significant figures to avoid giving a false impression of accuracy.

Recent Press coverage of the project was discussed, which Shell felt was a fair representation of the views expressed at the meetings in London and Aberdeen.

Shell reported that further good progress had been made with the preparations for decommissioning the Brent Delta topside, the highlights being the installation of the shear restraints, cutting the legs, completion of the cellar deck strengthening and module sea-fastening, removal of caissons and clearance of electrical equipment in the utility leg. The Attic Oil Recovery project trials had been completed, involving coring, pumping, injection of demulsifier, sonar measurements and water sampling. As a result of completing all this work Brent Delta was de-manned on 17th July 2016.

The AllSeas testing of lifting arms was ongoing and the Able safe piling and quay build continued. The Brent Alpha Crane replacement had been completed with the commissioning ongoing. The NASA probe had been deployed into Bravo cell and provided sonar results successfully. Top quartile P&A performance on Bravo had also been achieved. Brent Field Benthic Survey analysis was ongoing and results from Brent South had been shared.

The Topsides, GBS, Cuttings and Alpha Jacket Technical Documents had all been updated and reissued. The Environmental Statement had been updated and issued by DNV for internal and IRG review.

A number of Stakeholder 1:1s had been held, together with the IMechE-hosted Stakeholder events in London & Aberdeen.

Twenty fourth meeting – 31st May – 2nd June 2016

The IRG noted that a large number of reports and responses had been received from Shell in the previous two weeks and that the IRG would only be able to make preliminary comments during the meeting in most cases. Two teleconferences with Shell had been held on 20th March 2016 and 6th May 2016 at which the outstanding actions had been discussed and clarified where necessary.

Shell reported that for Brent Delta the shear restraints had been installed, the West drilling leg cut was complete and the cellar deck strengthening was 99% complete. The gas export line had been flushed, isolated & cut and the caisson removal was 70% complete. The module sea fastening was 65% complete, the utility leg electrical clearance was 60% complete.

The Brent Delta Dismantlement Safety Case had been approved by the HSE, covering the leg cutting, topside lift and post topside lift phases. Attic Oil Recovery project was on-going with 24hr pump runs; water breakthrough had been observed. Safe piling and quay build continues at Able UK and AllSeas testing of lifting arms ongoing. Brent Alpha P&A enabling works (compression module removal and Crane replacement) was progressing.

Reports on the Technical Feasibility and Environmental plenaries had been issued and Data Reconciliation was complete.

Modelling had been completed for an increased hydrocarbon concentration in cuttings on the Brent Charlie cell top. A predicted oil leach rate >10t/yr had prompted Shell to prepare a formal Comparative Assessment as part of an OSPAR Stage 2 assessment with the outcome that leaving undisturbed cuttings to remain in place and degrade naturally was the Shell recommended option.

BMT modelling reports had been revised and issued to the IRG. Comments had been received from DECC for the Alpha Jacket, Cuttings and GBS Technical Documents.

The Brent Field Benthic Survey analysis was ongoing and the results for Brent Delta had been issued in May 2016.

The Brent Field Decommissioning Programme had been drafted (pre data reconciliation) and issued to the IRG in March 2016 for information/comment but not for formal review.

The current position with IRG Reviews of the reports issued was discussed and the necessary actions agreed.

Shell reported that the Stakeholder Engagement Report is being finalized. Meetings have been planned for 4^th July at IMechE, London and 7^th July 2016 at RGU, Aberdeen, at which Shell will present the overall story of Brent Decommissioning and the Decommissioning Programme. Invitations have been sent to a wide range of interested parties.

The IRG initial view was that these meetings were a useful exercise but not a good substitute for special Stakeholder Meetings as the audience is likely to be haphazard. It was also concerned about the number of one to one meetings between Shell and Stakeholders, which did not give any opportunity for interactive discussion between Stakeholders.

Shell reported that the feedback that had been received was that there was little appetite for another group meeting but that Stakeholders were looking forward to the public consultation. Since the IRG ToR require the IRG to take account of the Stakeholders views, the IRG would have preferred to be involved and interact with Stakeholders at a Group Meeting rather than attending a formal lecture.

Twentythird meeting – 21st-23rd March 2016

Since this was the first meeting with Shell since the 21st IRG meeting (September 2015), the CMSTG meeting and the Technical Feasibility and Environmental Scoring Plenary Sessions were discussed. The IRG will review the relevant reports once received.

Shell reported that good progress had been made with preparing the Brent Delta topsides for lifting off. The underdeck lift points were all complete, cellar deck strengthening progressing and utility leg electrical clearance progressing. The oil export line had been pigged, flushed, isolated and cut, the gas export line flushed, isolated and cut. Shear restraint preparatory work was progressing in drilling legs.

The Attic Oil Recovery project re-mobilisation was commencing and Brent Delta celltops had been cleared from fresh storm damage. Preparation of the Dismantlement Safety Case was ongoing and Shell hoped for approval mid/late April 2016 ahead of first cut.

Safe piling and quay build continues at Able UK and AllSeas testing of lifting arms on Pioneering Spirit was ongoing.

The Brent Field Benthic Survey analysis was ongoing and the Delta results were due very soon. The BMT modelling reports were being revised in line with IRG comments and the Charlie cell top (increased concentration) modelling had been completed. Cell GBS & Cell Contents TDs were issued for review

The Comparative Assessment data reconciliation was ongoing and reports on the Technical Feasibility and Environmental plenaries had been completed. The Decommissioning Programme had been drafted (pre data reconciliation) and would be issued very soon after internal review.

In addition, Shell showed video taken during recent sampling operations and a computer simulation of the Pioneering Spirit lifting off the Brent Delta topsides.

The current position with IRG Reviews of the reports issued was discussed and the necessary action agreed.

Shell reported that a number of one to one Stakeholder meetings were expected to take place from April onwards and that there were no current plans for further Stakeholder Meetings in London and Aberdeen. CMSTG activities were complete and the findings would be incorporated into the overall Stakeholder report. Shell anticipated that the following actions would be taken:

One to one meetings with highly-engaged Stakeholders would be held to share and discuss the outcomes of the Comparative Assessments
The overall response would be gauged to indicate whether further plenary sessions would be helpful, possibly in June 2016.

Shell had contacted approximately 100 Stakeholders and 58 had responded, mostly wanting information rather than a dialogue. Their main concerns had been around the big picture, including jobs, the supply chain, innovation and the environment.

Twenty second meeting – 5th-6th January 2016

This meeting had been planned to be with Shell but the IRG members noted that Shell did not appear to have made the progress it had expected with documentation for the IRG. Consequently, the IRG held a Private Meeting in order to review the current position. It was agreed to prepare a comprehensive list of outstanding items to inform Shell and to note that the IRG was unable to make progress with its Final Report until the documents had been seen and reviewed.

IRG members had attended the CMSTG Plenary Meeting in November 2015 and it was reported that it had been very much like previous meetings and those present expressed satisfaction that water and sediment samples from the Brent Delta storage cells had been obtained and that the results of the analysis can be used as a basis for the EIA.

The CMSTG meeting did not consider there to be a strong argument for further sampling as it would not have a significant effect on the EIA. However, the IRG considered that it should express a concern about the possible variability of amount and composition of cell contents between platforms and recommend that further sampling on other platforms should be carried out.

The IRG representatives had felt some disappointment with the Stakeholders attending the CMSTG meeting as only about 10% of them had spoken., particularly since, as far as they knew, nobody from Greenpeace had attended.

The IRG was uncertain about the level of real understanding of the modelling outputs among the participants in view of the few questions at the meeting about the differences between the models. However, feedback at the end of the meeting indicated that participants were satisfied with the information that had been presented. Whilst it had been agreed that the IRG members would attend as observers, Shell had asked for an IRG presentation during the meeting.

IRG members had also attended the Technical Feasibility Plenary in December 2015. The meeting discussed 28 activities for which scoring by sub-groups had been generated prior to the meeting.

The intention for the meeting was to rationalise all the ratings for the different activities. It appeared that cutting the legs of the GBSs was feasible, based on an Olaf Olsen report and concern was expressed about the collapse mechanism over time. It was reported that another Anatec report is in preparation, which would be sent to the IRG. The IRG representatives considered that some of the scales appeared to be rather artificial as a result of leaving in options that are really infeasible.

The action to be recommended for pipelines is still very much in question as it appeared as though Shell/Exxon would like the appropriate contractors to advise on the optimum final procedure. Removing the Brent Alpha footings was also considered to be feasible with internal cutting being rated more highly than external cutting. Cleaning of the mini-cells was rated as highly infeasible as it would be difficult to remove any waste and the quantity is very small.

The previous separation between feasibility and cost seemed to be blurred at this meeting and there was a feeling that an option would be considered to have failed if the cost over-ran by 10 – 20%. The IRG was waiting for a paper explaining the relative weightings of major criteria. The IRG suggested that it should be given the opportunity to review a report of the meeting

The IRG considered the current position on its Review Comments and would ask Shell for the timescale when each action was expected to be completed.

Twenty-first Meeting - 23rd-25th September 2015

Shell reported that preparations for cut and lift of the Brent Delta topsides were progressing well. All the cruciform pads were in place and being welded to the MSF. Testing of the lifting arms by Allseas was progressing and the first operational use was likely to be the Yme platform topsides in Spring 2016.

The weight to be lifted is approximately half that of the Brent Delta topsides so will provide good experience. Preparation work at the Able yard was on schedule for completion in February 2016.

Preparations for recovery of the attic oil were also progressing well and all the equipment was being mobilised.

The Dismantlement Safety Case was being prepared and work had started on the ESHIA (Environmental and Societal Health Impact Assessment), the Envid (Environmental Identification) having been completed. Shell had contracted an external specialist, AECOM, to do this work, building on that of DNV.

The benthic survey beyond 50 m from the Brent Delta platform and Brent South had been completed and the scope for a further survey within 50 m was being finalised. Images of the top of a tricell had been obtained from an ROV. There appeared to be a concrete top slab with a central circular hole (rather than a triangular aperture) and unidentified debris. An attempt would be made to probe a tricell to determine the depth of drill cuttings.

The Technical Document for the Brent Alpha Jacket had been sent to DECC and was the subject of “informal” Review. Reconciliation of the Comparative Assessment data had commenced. The Technical Documents for the GBS and GBS Contents were being updated and should be issued to the IRG in late October.

It was still intended to attempt to use the NASA sonar probe on Brent Bravo to estimate sediment volume in the cells.

Shell had received a total of 3084 comments from the IRG on the many documents it had reviewed. Shell had now responded to most of these.

The meeting considered the latest position on review comments and agreed on the outstanding actions.
The IRG updated its current views on various aspects of the Brent Decommissioning project as follows:

Platforms
- Brent Alpha; the IRG considers that good progress has been made with the additional studies on footing removal (re. internal and external cutting of steel piles). It was not the role of the IRG to approve the Shell preferred option but to ensure that the range of options examined had been subjected to sound scientific and engineering assessments.
- GBS Prospects for refloat and removal (BB, BC and BD); nothing has changed with respect to BB and BD as far as the IRG is concerned. Shell reported that it is reconsidering some of the previous work on BC in the light of the proposed removal of the modular support frames from the GBS. The evidence that the risk levels were very high for the refloat of BB and BD had previously been recognised by the IRG but the IRG looked forward to the new analyses for BC which has still to be finalised.
- GBS in place: legs up/down (BB, BC and BD); Shell reported that this is now covered in the TD but will send the relevant feasibility report to the IRG for early review.

Contaminants and Modelling
- Surveys (marine and seabed); these had been discussed as part of the outstanding reviews.
- Drill Cuttings; the IRG would like to see deeper cores being obtained wherever possible and encouraged Shell to investigate this further.
- GBS Cell Contents; the IRG would still like to see more samples obtained as & when this is practicable and to check that the few cell samples available and the proxies (from separators etc) are representative.
- Modelling – Drill Cuttings and Cell Contents; the IRG considered that additional analyses/interpretation and possibly modelling particularly for the high level cell content release scenarios was still required.
- Cumulative Impact discussions: Shell showed a first attempt at a version of a diagram to illustrate the possible cumulative effect of releases of hydrocarbons from a decommissioned platform up to 1500 years. There was considerable discussion of the variability of the various components of the graph and the IRG was not convinced that conflating episodic and sustained releases in the same figure provided a sufficient representation of the available information, except in a very general way.
- Attic Oil; the IRG notes that Shell is committed to removing attic oil and interphase , and is currently mobilizing to use a platform based ROV. Thereafter Shell will revert to vessel based recovery once the topside has been lifted, as per the original Project plan.
Pipelines; the IRG has no reservations about the proposed remedial actions.
Other Outstanding Issues for which the IRG is waiting for the final reports from Shell:
- Environmental Impacts and Statement
- Long Term Issues (Monitoring, Maintenance and Liability)
- Comparative Assessment Process: awaiting outstanding narrative around PLT justification of scales etc.
- Decommissioning Programme (Possibly Q4 2015 or Q1 2016).

Shell introduced the newly-appointed External Relations Manager for Decommissioning who reported that Shell has been holding one-to-one meetings with individual members of the CMSTG since July, giving them an update on the samples obtained and presenting the physical and chemical properties measured.

Shell also presented an assessment of the 5 options available; the stakeholder reactions varied broadly from “OK to go forward” to “not enough information yet”. All the members of the CMSTG were keen to have a final meeting after receiving all the details and discussing them within their organisations. Shell was content with the material available and has made arrangements for the final meeting.

Shell had also met Resources for Change to plan the meeting, including the pack of information to be sent to participants, the meeting objectives and format. The meeting would consist of a summary of the events to date, table discussions to prioritise any outstanding issues and a presentation of the work that Shell has done with BMT Cordah and DNV.

Shell anticipates that this will enable a formal closure of the work of the CMSTG but this will depend on the feeling of the meeting. It was agreed that representatives from the IRG would attend this meeting as an observers but would be able to comment on the results of sampling as to ‘whether or not the process has been robust”, although not in a formal presentation.

Shell gave an update on its activities with Stakeholders; a number of one-to-one meetings has been held and these would be broadened prior to final meetings from January 2016 onwards; members of the IRG would participate as observers depending on availability.

Twentieth Meeting - 13th-15th April 2015

The IRG met in private initially to discuss the current position for a number of reviews and Shell’s responses in order to facilitate the discussions with Shell that followed. Since a teleconference on March 11th, the IRG had cleared most of its outstanding actions and Shell thanked it for doing so.

Shell reported that the Brent Delta benthic survey would be carried out in June 2015 and hoped that the timing would enable the IRG to see the report in October. The IRG suggested that Shell should endeavour to obtain samples from deeper into the cuttings pile to counter the lack of information with respect to modelling of the long term exposure.

Shell indicated that the attic oil removal project on BD would commence in August 2015 using new and smaller equipment to drill 3 inch holes for access, operated by ROV prior to topside removal, to amalgamate oil into one cell. Post topsides removal the oil would then be pumped to a vessel and the holes plugged when the operation is complete.

Shell did not expect the results of sampling the cell sediment to change the Comparative Assessment. From the sampling and survey programme, the depths of sediment in the cells sampled were in fact very close to the working assumption and would update the studies accordingly.

The IRG queried statements relating to the shear strength/bearing capacity and expressed surprise at the low levels of bacteria, noting that H2S was not detected on the samples using the gas detector; the implication being either that large amounts of biocide had been used or there may be nutrient depletion and this needed to be double-checked.

Shell had attempted to deploy the NASA probe but had experienced problems and intended to try again in 2016 on Brent Bravo.

Proposals for the cell top debris removal had been approved by DECC subject to minimum disturbance of the drill cuttings.

Shell reported that planning work with Pioneering Spirit was progressing with smaller lifts being programmed to test systems prior to lifting the BD Topside, expected to take place mid-2016. Work was also progressing at the Able Yard, mainly quay strengthening work. Other work planned for Summer 2015 included work to secure the pipework and conductors in the BD legs and sampling of the tri-cells. A survey of debris had suggested that the BD cells do not have as much drill cuttings on top as previously thought.

Shell were currently preparing formal responses to comments on the BD Topside DP and were hoping to achieve approval from DECC by June 2015. In addition, Shell reported the schedule for completion of the remaining Technical Documents which they anticipated could all be closed out by the IRG and an updated Decommissioning Programme sent to the IRG by Autumn 2015.

Shell’s interaction with Stakeholders had been very low-level during the public consultation period for the Topside DP but a number of one-to-one sessions and a CMSTG meeting were planned later in 2015.
The meeting considered the latest position on review comments and agreed on the outstanding actions.
The IRG summarized its current views on various aspects of the Brent Decommissioning project as follows:

Platforms
- Brent Alpha; the main concern for the IRG is the possibility of complete removal and how this is considered in the Comparative Assessment. Shell reported that DECC have verbally requested separate CAs are performed with and without the presence of the drill cuttings. At present, the IRG does not feel that the possibility of internal cutting & removal has been fully considered.
- GBS Prospects for refloat and removal (BB, BC and BD); additional information was requested by the IRG on the difficulties likely to be encountered with a BC refloat.
- GBS in place: legs up/down (BB, BC and BD); the IRG requested more information on the issues associated with the cutting of the concrete legs and, if cut, their disposal. The IRG is still concerned about the use of standard (Gaussian) statistical distributions for extreme event calculations, e.g. vessel impact on legs up (low probability/high consequence).

Contaminants and Modelling
- Surveys (marine and seabed); the IRG would still like Shell to try to obtain deeper samples from within the drill cuttings. It was pleased to note that pipeline surveys would include habitat surveys and ground-truthing.
  The IRG was pleased to hear that Shell is considering how the contents of the tri-cells can be estimated. This would include looking back at drilling records and material unaccounted for.
  The IRG is still concerned that the hydrocarbons estimates for the BC cell-top drill cuttings appear to be inconsistent with those in the drill cuttings on the sea bed. Shell agreed to re-examine this and consider whether these can be either discounted or included in the modelling to obtain a revised figure for the release of hydrocarbons from the cell tops and the sea bed.
- GBS Drill Cutting and Cell Content modelling; with respect to cell content and discussions with the IRG, Shell intends to do additional modelling work for a range of release scenarios from collapsing cells and compare the results with the previous cell sediment sea bed modelling so as to identify a possible ‘worst case’ situation. With respect to the drill cuttings, the IRG considered that it may be necessary to re-examine the BC situation.

Pipelines; the IRG did not have any outstanding issues.
Environmental Impacts and Statement; the IRG was not comfortable with the demonstration of the rigour of the overall exercise and Shell will ask DNV to rationalise all the assessments to make sure all the parts of the facilities have been assessed appropriately to enable the overall comparisons to be made. The IRG suggested that DNV should be asked to identify the specialists who made the assessments, and state their qualifications.
Long Term Issues (Monitoring, Maintenance and Liability); the IRG would like to be informed of Shell’s intentions when these are available, which is likely to be when all the TDs have been completed. These will be considered by DECC but it is not clear how the results of any monitoring programme would be assessed in future, and used to initiate any necessary remedial action.
Comparative Assessment Process; the IRG was still concerned about the justification for selections of weights and scaling and problems that might arise over the inclusion or exclusion of various options. It was waiting to see the high-level narrative from Shell that should make this clear.
Decommissioning Programme; the IRG looked forward to receiving the draft Decommissioning Programme.

Nineteenth Meeting – 4th-5th February 2015

The main purpose of this IRG private meeting was to discuss the review comments for a number of reports but a teleconference with Shell was held to receive an update on the current state of the decommissioning project. Shell informed the IRG that preparations for the removal of Brent Delta topsides from the platform and reception in the Able Yard were proceeding. The Brent Delta topside Decommissioning Programme had been sent to DECC for issue in mid-February for a 30 day public consultation period.

The IRG noted that there were several instances where review comments had attracted a substantive and helpful response from Shell. The IRG considered that such responses, where appropriate, should be included in the final documents.

Following a discussion on the technical aspects of Re-injection of Cell Sediments, it was concluded that it would not be reasonable to inject cell contents into the Brent formation although re-injection into a higher formation using new sub-sea wells remote from the platforms could be successful. However if this approach was to be considered further, considerably more work would be needed.

The IRG also met to discuss its work with Mrs. Audrey Banner – Head of DECC Decommissioning North Sea.

Eighteenth Meeting – 20th-22nd October 2014

Shell reported that operations in the Brent Field had currently been Lost Time Incident free for 417 days, with only one minor First Aid injury during that time. Plug and Abandonment for Brent Delta had been completed in June 2014 and monitoring of the last two wells was continuing.

Drilling and sampling of the three GBS cells had been completed in September 2014 and the analysis of the samples was proceeding; Shell would compare the results with the recent cell contents modelling and with the environmental impact assessments generated as part of the Environmental Statement. Preliminary results showed similar orders of magnitude for quantity and composition as those used for modelling.

Test cutting of concrete with a similar thickness to the cell walls (2m) had been successful. The IRG again requested copies of the reports on the concrete cutting trials, as these had not yet been made available. The SLV Pioneering Spirit (formerly Pieter Schelte) would arrive in Europe in Q4 2014 and plans were being made for the Brent topsides to be lifted off in 2016.

Shell had made a decision to separate submission of the Decommissioning Programme (DP) for the Brent Delta topside from the remainder of the Field DP. Provided that Shell could show that the removal of the Delta topside would not have a negative impact on the remainder of the decommissioning activities, DECC would accept submission of two DPs, each with separate public consultation periods. The IRG noted that securing internal structures within the legs would be necessary before the topsides were removed if cutting the legs was to be considered at a later date.

It was agreed that Shell would send the argument for not impacting on later decommissioning operations to the IRG. Shell now expected to submit the GBS Technical Document, including the assessment of the Technical Feasibility of options (i.e. the Legs up/Down Decision paper) for IRG review later in 2014 or early 2015. Shell now expected to submit a proposal to leave the legs of the Brent platform in place.

The IRG was not yet able to prepare its draft Final Report as there were major reports still to be reviewed. It was also noted that the IRG felt that some elements of the case for not refloating Brent Charlie still needed to be strengthened.

Shell had used its Project Leadership Team (PLT) to select the criteria and weightings to be used for Comparative Assessments and then considered the sensitivity of the results to each choice. Consequently, Shell regarded the revised TDs as more robust and close to the final versions.

The IRG commented that the raw data had not been made available to the IRG and that the evidence had not been supplied for the IRG to be convinced that the support for the decisions made was adequate. Shell was considering the suggestion that a facilitated meeting should be held to discuss the weightings, but to inform not to control. A further meeting of the PLT would be held early in November 2014 for further discussion. It was agreed that the proposed action and subsequent record thereof should provide an adequate evidence base.

Shell then outlined the process of data collection, using 12 providers, identifying the maximum and minimum points and collating on a spreadsheet to define the global scales. From this, the values in the range 0 – 1 were assigned and the calculations would be checked to confirm that this process was robust. The results would then be used to compare the decommissioning options for all of the Brent facilities. The best-performing options would then be subjected to sensitivity check of the weightings, with a difference chart aiding the final narrative and recommended option

The IRG considered that the process sounded good and that it was pleased to hear about the checks. However, without having the detail, it was difficult to be fully confident. At present this would be a cause for concern for the IRG until it was convinced that the process was indeed robust. Shell intended to freeze the process following this meeting and the weightings after the PLT meeting. Discussions with DECC had indicated that the process was acceptable.

The meeting then discussed progress with the production and review of the TDs. The question of drilling out grout in the piles of the Brent Alpha Jacket to enable internal cutting was discussed. The IRG requested Shell to provide any information it had on the level of grout in the piles.

Shell reported that this would not affect a decision to remove or leave some of the footings in place so further study was not considered economically worthwhile. The IRG commented that the reasons for omitting this as an option needed to be contained in the TD and the IRG would consider whether a clear and convincing case had been made adequately.

Shell responses to the IRG comments on a number of the cell content release modelling reports had been received and were being considered by the IRG.

Shell reported that preliminary results from the GBS cell content sampling were available and would be reported to the IRG in the near future.

Shell reported that two people had been appointed to work with Stakeholders, an Upstream UK Communications Manager for Shell and a Stakeholder Project Manager. Since the last meeting of the IRG, there had been continuous Stakeholder engagement, mainly through one-to-one teleconferences.

The content of the conversations had mainly been to explain the decision to submit the Decommissioning Programme for the Brent Delta topsides, followed by the main Brent Delta DP. Shell had also carried out public sensing activities in London and Middlesborough, followed by Edinburgh and Dundee (avoiding Aberdeen because of the close links with the oil and gas industry).

The two Stakeholder Meetings in London and Aberdeen, planned for December 2014, would now be rearranged in late January/February 2015 (note: subsequently further postponed).

Seventeenth Meeting – 20th-22nd May 2014

Shell reported that the Cell Sampling Project baseplates had been installed at Brent Delta on 3 cell tops, ready for deployment of the survey and sampling equipment in June/July 2014. All the preparatory work was proceeding well and it was hoped to obtain first samples early in August.

Technology had also been developed in conjunction with NASA to deploy sonar probes down the oil export lines directly into the cells. Trials had been partially successful and redeployment on Delta was imminent after further development work. Shell was looking at developing this process and being able to repeat the deployment on Bravo.

Plug and Abandonment was almost complete for the wells on Delta and would be followed by partial removal of the conductors. A contract for removal of the topsides and Brent Alpha jacket using the new SLV Pieter Schelte had been awarded to Excalibur Marine Contractors SA and the necessary testing and reviews were being undertaken. A contract for the onshore dismantling had been awarded to the Able UK Limited yard and preparation of the site had been started.

Pre-submission CMSTG and Stakeholder events were planned for late November/early December 2014. Although the schedule was very tight, it was still planned to submit the Consultation Draft DP to DECC by the end of December 2014 to initiate the 60 day public consultation process.

Shell reported that the earlier draft recommendation that the GBS concrete legs should be partially removed to -55m had been reviewed in the light of recent trials on cutting compressed concrete. Consequently, the TD would be revised to recommend that the legs should be left standing and submitted for further review by the IRG.

The IRG requested the background reports on the concrete cutting trials. The IRG observed that the reports on the risk to mariners would remain particularly significant and the IRG review comments might need to be reconsidered; the IRG was concerned that the time available to review this revision and to identify other reports that might be affected was now extremely short.

The IRG referred to a suggestion it had made at an earlier meeting that leg removal would be a very suitable topic for a JIP; the IRG observed that the development in the technology was unlikely to occur unless incentivised through the initiative of a JIP. At this stage, the IRG considered that there are still gaps in the evidence that support a decision to leave the legs in place.

Shell had considered the advice offered by the IRG on Comparative Assessment (CA) methodology and thought that it would be preferable to carry out sensitivity analysis to identify the main differentiating factors, rather than asking Catalyze to carry out a more detailed Multi-Criteria Decision Analysis (MCDA).

The IRG did not consider the current approach to be easily defensible and felt that Shell should either do a numerical analysis that weighted all criteria explicitly, or there should be a narrative assessment (for example to identify the least worst or most positive combination of attributes).

Shell reported that the decision on the approach to take had been made as a result of a presentation of all CA methods that had been used by the industry in the past.

The DECC guidelines are not specific on the approach required but do state that company reputation can be referred to but should not be used as a weighted criterion in a CA.

Shell agreed that, although it would require a substantial rewrite of one chapter in the report, an approach would be considered that identified all the relevant main criteria together at an early stage in the report, consider the options against these criteria in a structured but narrative assessment and, if a numerical assessment was to be used, to undertake a sensitivity analysis on the weighting attached to these criteria.

The IRG agreed that it would not be necessary to revise the generic CA report as long as the alternative approach was used consistently for all the TDs. Shell felt that a short document outlining the revised approach would be useful for discussion with DECC, and would also be in line with its internal procedures for document control.

Shell reported that the laboratory procedures for analyzing cell samples were being finalized, including the possibility of using some samples for analysis of several parameters where possible.

The IRG confirmed that it strongly recommended replicating samples if possible although Shell reported that the time required to obtain each complete suite of samples, which involves considerable testing for safety reasons for each deployment, is in the region of 6 hours. The IRG also strongly recommended that, for the sediments, the main effort should be to obtain undisturbed samples if at all possible.

The IRG noted that not all the laboratory tests required the samples to be kept pressurized; the earlier concern about the limitation on the total number of samples that might be caused by a shortage of pressure containers might be avoided by using alternative unpressurised containers.

Shell was concerned that this could cause confusion on board during the sampling operation but it was agreed that this could be avoided by a detailed field sampling and sample handling protocol, which would be required in any case. The IRG agreed to comment on the parameters and test methods that were to be proposed by Shell.

In response to requests for clarification of certain parameters for contaminant modelling, the IRG suggested that the most appropriate option to obtain values for the currents would be to identify the year that is most typical for the bottom currents and use this year for modelling at all depths. The bioturbation depth of 25 cm had been queried previously by the IRG and it had been suggested that a shallower depth of 5 cm would be more appropriate.

The IRG suggested that the model should be re-run for one typical case for both depths; if there was no significant difference, it would not be necessary to re-run all the cases. The IRG was concerned that the proposed ways in which the particle size distribution was being modelled would not produce a credible outcome.

The IRG stressed that it was trying to be helpful by suggesting appropriate ways forward, but that any suggestions would be advisory and should be considered by Shell and the modellers at BMT after taking appropriate expert advice if necessary.

Shell had produced a number of reports on modelling of cell contents that were being reviewed by the IRG and the position for each was discussed. The IRG was concerned that, for the latest report as for earlier ones, the modelling contractor had not provided any interpretation of the raw data, contrary to earlier remarks by the IRG that this sort of report was not suitable to be reviewed.

In addition, the IRG suggestions had clearly been taken as a statement of Shell’s requirements; the IRG reminded Shell that its Terms of Reference (ToR) are to provide comment and guidance and it is Shell’s responsibility to accept the suggestions and to pass them on to the contractor or to reject them.

Shell outlined the work that had been undertaken on reinjection and the conclusions of the work to extend the results for Brent Delta to Bravo and Charlie. It had been concluded that existing Bravo and Charlie platform wells were unsuitable for Cell Contents injection because structural integrity reduced the number of viable wells, existing wells were located at close lateral separation distances at the injection horizon and the separation distances decreased at the shallower confinement formations.

A review of cement logs of those Bravo wells that had already been permanently plugged indicated a general lack of along-hole hydraulic isolation and there was a risk that the sole identified Bravo injection well would also have inadequate along-hole hydraulic isolation.

As a result, Shell recommended that, as per the Delta review, the only feasible option for Bravo and Charlie would be to re-inject into a higher level formation above the Brent formation using a purpose-drilled new subsurface well remote from the platform.

The IRG review comments for the Brent GBS Decommissioning TD were being prepared and would be sent to Shell. It was not intended that this review would be closed out until a number of other contributing factors such as the CA process had been finalised.

The IRG was concerned with the timings surrounding the changeover of the Stakeholder Manager. It hoped the replacement would be announced shortly to ensure minimal impact at such a sensitive time in the project and hence continue the positive public perception of the importance that Shell places on its relationship with Stakeholders and their views on the various impacts that the Brent field decommissioning will have. The IRG were surprised that the present incumbent’s departure could not be delayed slightly until the replacement had fully taken over the responsibilities.

Shell outlined the plans for the final CMSTG meeting to be held at the end of November and for final Stakeholder meetings to be held in London and Aberdeen early in December. However, both these meetings would have to be postponed if the sampling programme was delayed.

Sixteenth Meeting – 13th-15th January 2014

Shell reported that the work to obtain samples from the cells was about to deploy offshore to fit baseplates on 3 Brent D cells; surface preparation might involve disturbing a small amount of drill cuttings on the cell tops, which had been accepted in the work approval documentation. Actual sampling would be carried out after Plug and Abandonment had been completed, probably in May 2014.

Provided this schedule was achieved, the sample analysis would be available prior to submission of the draft Decommissioning Programme, then planned to be in October 2014. There would also be an opportunity to deploy a probe through existing pipework, intended to give volumetric information but with the option of being modified to obtain a small grab sample.

Lifting of the topsides of Brent Delta was still planned for Summer 2015 but would depend on the availability of the new single lift vessel (SLV) “Pieter Schelte” and could be postponed to 2016. Removal of conductors on Brent Delta was planned for May/June 2014.

Revision 5 of the Environmental Statement was being prepared and would be sent to the IRG as soon as available. The argument for leaving the GBS legs up or cutting them has now been incorporated into the GBS Technical Document that the IRG is currently reviewing.

Shell was hoping that the draft Decommissioning Programme would be ready in September 2014 for consideration at Stakeholder Events, having been made available to the IRG possibly as early as April/May 2014.

The meeting of the CMSTG in June 2013 was intended to be the last one and Shell did not intend to rerun the Catalyze weighting exercise. [Note: Catalyze are a third party contractor specialising in multi criteria decision analysis modelling]. Shell had circulated the final Catalyze report for the IRG to review, bearing in mind that Shell did not intend Catalyze to do any further work on improving the model.

The IRG commented that this is an elaborate process for dealing with a limited amount of information and asked how much change might be expected from any new information. It considered that the main uncertainty was the volume and composition of the cell contents and the outcome might change significantly when new information became available.

Shell acknowledged that most options were very close together but this did give confidence that the chosen solution would be acceptable; Shell did have the ability to rerun the existing model when new information became available.

Shell wished to extrapolate the results obtained for reinjection of cell contents from Brent Delta to Bravo and Charlie on a platform by platform basis rather than the well by well basis used previously and a scoping document to outline this approach was being prepared.
The IRG commented that reinjection had not been offered as one of the options to the delegates at the Stakeholder meeting; Shell explained that there was a need to complete this work for submission to DECC before being discussed more widely.

The IRG noted that the preferred option within the draft Brent GBS TD was to take the legs down and considered that there were many advantages with this option compared with that for ‘legs up’. However, more information on the options could be presented in the TD.

Shell had discussed the option of toppling the legs and leaving them on the seabed but considered that this was unlikely to be acceptable to the regulatory authority. Although the range of options for reuse of the legs was likely to be very limited, this had not been considered to date.

Shell reported that it was not possible to remove the Brent Alpha jacket footings using an SLV as the footprint was wider than the barge that would be required to transport them but it would consider other footing removal options in the TD on Brent A.

The modelling results for the estimated GBS cell contents (sediment and water) were discussed. The IRG considered that the sensitivity of the results should be tested. Shell agreed to further model runs to examine biodegradation, agglomeration, particle size and density variations in the sediments.

It was also agreed that an alternative (and possibly more realistic) cell sediment release at a high level (approx. 20m above sea bed, rather than a static cone of sediment on the sea bed) would be modelled.

Shell reported that they were pleased with the breadth of representation at the Stakeholder Meeting held in November 2013; the discussion had been a good test of the emerging recommendations, which are expected to be to leave drill cuttings in place and a mixture of trenching, removal and rock dumping for pipelines.

There had been almost overwhelming acceptance of these recommendations. Overall, there had been stronger acceptance for the GBS legs to be partially removed rather than left standing. The option of toppling was discussed and Shell considered that DECC would not find leaving them on the seabed acceptable. There had been a general view that cell sediment could be left in place with capping; however, the meeting had considered that leaving in place and doing nothing was the least acceptable option.

Fifteenth Meeting – 3rd-5th June 2013

Shell reported further personnel changes planned as the project moved into another phase of its development. A new timescale for obtaining a sample from the cells anticipated installing a new baseplate in September 2013, deploying tooling to drill a 3.6 inch access hole in October 2013 with equipment then deployed to survey the cell contents and obtain a sample using a suction technique.

A letter of intent for removal of topsides for 3 platforms (Alpha, Bravo and Delta) had been issued and there would now be a period of working through the engineering details. Three UK shipyards had been identified as potential locations for disposal and first lift was still planned for 2015. Discussions were being held with DECC to determine whether the full Decommissioning Programme has to be approved before first lift can take place.

The question of whether GBS legs should be left up or down had been discussed by the Shell Executive Committee and the project team was reviewing the technical feasibilities and costings. The IRG recognised that the technology required to remove the legs probably does not exist at present, although contractors appear to be confident that this is feasible.

The alternative of leaving them in place indefinitely does not appear to the IRG to be an acceptable long term solution. The IRG suggested that a possible compromise solution would be to leave the legs in place initially, with any necessary work undertaken to secure internal structures, and for Shell to take an active part in a Joint Industry Project (JIP) to develop the technology for removing the legs in the future, before deterioration and uncontrolled collapse occurred.

Shell reported that a good response had been received to invitations to the next Cell Management Stakeholder Task Group (CMSTG) meeting, to be held in Aberdeen on 17/18th June 2013. Presentations were planned on the long term fate of the GBSs, the toxicological assessment for cell water and sediments and the Environmental Impact Assessment.

Shell’s intentions for the meeting were to firm up or remove some of the assumptions in the model, review the weightings in light of new work and communicate how the outcome of the CMSTG will be worked into the overall internal decision-making process. Several IRG members will be present as observers.

The IRG had received a number of responses from Shell on its reviews of reports on cell remediation. These were considered by the IRG on the final day in order to respond to Shell as quickly as possible. The IRG was awaiting Shell’s response to the IRG review comments on reports on the contaminant modelling of cell contents and drill cuttings. A teleconference had been held since the previous meeting to discuss modelling the water phase using the DREAM model and the outcome was discussed.

Specialists from Shell and the three additional members of the IRG joined the meeting through a teleconference link to discuss re-injection. The IRG had been satisfied with the reports it had seen prior to the meeting but still had to consider the overarching report. It was noted that the subject of reinjection is still at a feasibility stage and it would be necessary to obtain approval to proceed before a high precision seismic survey would be undertaken.

Shell intended producing a paper on a possible extension of the results for Brent Delta to Bravo and Charlie and this would be reviewed by the IRG. The overall impression was that there is adequate capacity in the Frigg/Skade formations to take the sediment from all 3 platforms.

A number of reports on the refloat of the three GBSs had been closed out by the IRG but within these close out statements, some issues had been identified that required further information/explanation from Shell. A review of such outstanding issues would be timely.

The IRG was particularly concerned about the uncertainty that will arise as a result of deterioration at the waterline if the legs are left in place; a Shell report on legs up/down would be incorporated into a Technical Document that the IRG would review when available.

The IRG review of the draft Environmental Statement had produced a lot of comments; the IRG recognised that the report had been sent in a preliminary format but had taken the view that, once the comments had been recorded, it was thought that they would be helpful to the report’s authors and it had been decided to send them.

The overall view of the IRG was that the report was not as well-founded as the IRG had expected it to be. In certain areas, the report was seen as being unduly simplistic, e.g. the eventual collapse of the legs was dealt with in a short statement with no consideration of the consequences.

Further reports on the Brent Alpha jacket and pipelines were also discussed. The IRG noted that it is possible that it could be technically feasible to remove the entire Brent Alpha jacket without any disturbance to the drill cuttings.

A draft report on the proposed procedure for Comparative Assessments methodology was being reviewed by the IRG. At first sight, it appeared to be based principally on the approach to be adopted for pipelines and the IRG considered that this approach may not be transferable without modification to all other decommissioning areas.

Fourteenth Meeting – 4th-6th March 2013

This was the first meeting attended by the additional members of the IRG whose responsibility was to consider the subject of cell content re-injection. At an early stage of the decommissioning project, re-injection had been regarded as a preferred option of the Decommissioning Programme and had been considered to be important by the IRG, DECC and Stakeholders at that time.

Subsequently, it had been regarded less favourably by Shell and the IRG had recommended a further study, leading to the reports reviewed that would be discussed later in the meeting. The new studies appeared to have produced a credible alternative for consideration in the Decommissioning Programme and a useful basis for the final decision regarding disposal of the cell contents.

Shell reported that no sample from the cells had been obtained in 2012 and that the equipment seen by the IRG during the 12th meeting was no longer being developed; Shell was in discussion with another contractor who would be developing alternative equipment.

The target for obtaining a sample assumes deployment of the equipment in September 2013 with the intention of using industry-proven techniques to give information on the liquid and sediment present in cells 9, 17 and 18 of Brent D. Shell considered that the delay in obtaining a sample would not be expected to delay removal of the topsides (as there is no credible method for dealing with the sediments using the topsides equipment).

Mr Blackburn reported that Shell intended submitting a draft of the Decommissioning Programme in 2013 for informal consideration leading to formal approval in April 2015, in time to meet the 2015 window for removing topsides modules. Shell reported that the Cell Management Stakeholder Task Group (CMSTG) will meet in June 2013 with some IRG members present as observers. Stakeholder engagement meetings in autumn 2013 are being considered at which the draft Decommissioning Programme would be presented. Shell outlined the events expected to lead up to the Stakeholder meetings.

The IRG had reviewed a number of reports on cell content re-injection and, in addition to commenting on the reports, had sent a number of generic questions focusing on re-injection feasibility either before or after topsides removal. These were discussed and it was accepted that existing wells are not suitable for re-injection and drilling new wells from the platforms is not a credible option because the existing wells give little room for new ones.

Suitable formations can be reached by drilling new wells from a mobile drilling rig remote from the platforms but detailed engineering will not be undertaken until Shell has made a decision on the preferred option for disposal of cell contents. Shell mentioned the possibility that some Stakeholders may oppose re-injection.

The question of transporting the cell contents to the re-injection site has not been considered in any detail but the IRG suggested that preliminary scoping studies of the transportation options would be helpful. A separate meeting between Shell’s specialists on re-injection and the three additional members of the IRG was held to discuss the relevant reports in more detail.

Contaminant modelling was discussed in some detail. There were three activities to be considered; modelling the dispersion of the cell sediment (if left in place) and cell water as they escaped from the degrading cells, and modelling the drill cuttings. The IRG had reviewed a number of reports on these activities prior to the meeting and had received responses from Shell in some cases. The IRG continued to have reservations about the modelling of contamination from cell contents and considered that additional modelling work may be needed.

The preliminary view of the IRG was that a clear case for leaving Brent Bravo and Delta GBSs in place had been made but the leave in place case for Brent Charlie was less convincing. Shell considered that the case for Brent Charlie was made but accepted that the issues may need to be presented more clearly and would look at this.

The IRG had reviewed a number of reports on leg removal for Brent Bravo, Brent Charlie and Brent Delta. Shell had recently responded to these and the IRG would consider these responses. Several studies on leg removal were in hand and the reports, once available, would be reviewed.

An early draft of the Environmental Statement had been made available to the IRG and this would be reviewed with other reports on environmental issues.

Thirteenth Meeting – 23rd-24th October 2012

Shell reported that a number of personnel changes would take place during the next two months as the project moved into another phase of its development. Shell had reviewed the programme for submission of the Decommissioning Programme and a decision had been taken to delay this until late 2014. This would enable the Plug and Abandon work to be completed and give more time for sampling of the cell contents. The baseplates for the cell sampling equipment had not been installed as programmed for 2012 and Shell would be reviewing the options available.

Shell considered that the later submission of the Decommissioning Programme would mean that it would be more robust and consequently less likely to be subject to delays during the consultation process. The delay would not affect the programme to remove the first modules in 2015.

Shell will arrange the final Stakeholder meeting when the Decommissioning Programme is substantially complete so that a full overview of the proposed actions can be given. Reviews of reports and Shell’s responses for a number of subjects were discussed, including options for refloat, GBS derogation, removal of legs from the concrete platforms, long-term fate modelling, environmental impacts and pipelines.

Shell also outlined its current work on reinjection and the programme for reports to be issued for review by the new members of the IRG.

Twelfth Meeting – 23rd-25th July 2012

Shell reported that submission of the Decommissioning Programme had been delayed to 2nd Quarter 2013 to ensure that wells could be abandoned in a safe condition based on the latest Plug and Abandon Strategy. One consequence is that the pressure had been taken off the sampling programme but submission of the Decommissioning Programme would not be conditional on obtaining a sample.

Stakeholders had been informed of the decision to move the submission of the Decommissioning Programme to 2013 and that there had been no serious objections. The plans for the final Stakeholder event will be rescheduled next year at the appropriate time.

It appeared that most refloat options had been discussed during the Brent Decommissioning GBS Peer Review Follow-up Session (19/20th June). Overall, the IRG observers considered that it had been a very good workshop that formed a basis for making the required decisions.

The IRG observed that Shell has insufficient confidence in the current technology to justify taking the legs down at this time without trials. The IRG considered that this did not rule out leg removal at some time in the future if a proven technology became available. There were clear advantages in leg removal. The prospect of leaving cut leg sections on the sea bed should also be examined.

In view of the large number of platforms that will be decommissioned in the next few years and require similar decisions to be made about leg removal, the IRG considered that it may be appropriate for an industry study to be undertaken.

The IRG observers were concerned that the Stakeholders present at the Shell Brent Cell (Contents) Management Stakeholder Task Group (CMSTG) were more concerned with effects on fishing stocks and mammals and there had been no-one present with an understanding of the lower trophic levels; this may distort the outcome in that there may be a failure to recognise how the higher organisms will be affected in the longer term. Shell felt that there had been a good management outcome in that Stakeholders had developed an understanding of the wider implications.

Shell reported that there had been delays in the activity on Cell Content Reinjection but it was now hoped to arrange the first meeting between Shell and the additional newly appointed IRG specialists in September/October 2012.

Shell arranged an IRG visit to Geoprober to view the equipment to obtain a sample from the cells. Members of the IRG were impressed with the progress made and noted that dock side testing was to be undertaken at Invergordon later in the year.

Shell’s plans for dealing with the remaining pipelines were discussed. The IRG had already seen and reviewed the reports on pipeline degradation. Other reports are being prepared to study the risk to the fishing industry associated with the range of options being considered for decommissioning the pipelines.

It was noted that to date the IRG had received more than 150 substantial reports relating to the decommissioning of the Brent Field; following an iterative process between the IRG and Shell, almost all the report reviews had been ‘closed out’.

Eleventh Meeting – 30th-31st May 2012

Shell reported that progress with the cell sampling project had been further delayed and was unlikely to go offshore until August 2012. The base plate for the sampling equipment needed to be redesigned. Shell recognised that a sample had to be obtained from the cells in order to characterise the residue but considered that this can be done more easily once the topsides and drawdown have been removed.

Shell considered the most recent meeting of the Cell (Contents) Management Stakeholder Task Group (CMSTG) to have been useful. Weightings for all the top criteria had been developed but the IRG questioned how the model will cope with a lack of consensus among the participants’ views.

Shell expected the reports on Cell Content Reinjection from the platform to be available by the end of July 2012 and would like the review to be completed by the end of August 2012. The IRG suggested that, in view of the high priority that had been given to reinjection and in particular by DECC, the IRG should seek additional expertise in the field of reinjection; Shell agreed with this proposal.

The IRG would delay its comments on the Refloat of Brent B and C and COWI risk reports until after the Brent Decommissioning Peer Review on 19/20th June 2012. Three IRG Members would be present as observers at this meeting. The IRG had agreed with the rationale for the Shell decision not to refloat Brent D but felt that the case for not refloating Brent B & C had not so far been made as convincingly.

The IRG had discussed a number of reports containing information on deposits from various sources that Shell considered gave a reasonable indication of the cell contents and provided the input data for Long Term Fate Modelling. The IRG identified a number of questions and asked to see a synthesis of the value of the various results, i.e. how consistent they were in predicting the cell contents and how they have been used by Shell or contractors for, e.g., modelling studies.

Shell intended that the planned Stakeholder event in September would be the final one before submission of the Decommissioning Programme but reported that the Stakeholder meeting might have to be postponed as a result of work still to be completed.

Nevertheless, Shell is still working towards submission of the Decommissioning Programme at the end of September 2012 but this will be reviewed at a meeting of the Shell Decision Review Board in 2 weeks time; Shell agreed to inform the IRG if any decision was taken to change the target date for submission. The IRG would not object to some delay as there was still some new work to be reviewed before it could prepare its final report.

The IRG commented that it had not been wholly happy with the rating process used to gauge the level of stakeholder concern on various proposals in the Stakeholder events in 2011. This was because the first Stakeholder to commit to an opinion tended to influence all the others; this aspect is being discussed with the Environment Council. In particular, there appeared to have been a clear preference in earlier meetings for the legs of the GBSs to be taken down.

Shell had noted that there was a wider spread of opinions among the Stakeholders and that opinions were more divided on this than for some other options; the results do not give a clear indication either way.

Tenth Meeting – 19th-21st March 2012

The IRG had reviewed the four field Concept Select Reports and subsequently asked to see additional reports referenced that it had not seen previously, to provide justification for the conclusions contained in the Concept Select Reports. The IRG observed that many of the additional reports had been produced a considerable time before but had not been made available until specifically requested. Shell reported that it expected the Environmental Impact Assessment to be finalised by the end of July 2012. Shell wished the IRG to comment on the draft Decommissioning Programme in July 2012 before it received wider circulation.

It had proved to be impossible to obtain a sample from the cells in 2011. Shell now hoped to be able to mobilise the sampling equipment offshore in August 2012. Shell would prefer to delay sampling until the topsides have been removed so that measurements could be made in more cells to characterise the residues. The IRG expressed its concern that this would not meet Stakeholder expectations.

Recent Shell studies of the options for reinjecting cell contents suggested that this may have a low chance of success and other options for disposal were being reconsidered. The IRG commented that the removal of what had been presented as one of the most favourable options would almost certainly attract critical scrutiny by the Stakeholders. The IRG suggested that it should appoint two specialists in sediment reinjection to give it advice. Shell accepted this approach. Timing of any report or review would be crucial.

Shell informed the IRG of the progress of its current work on leg removal, modeling of the fate of drill cuttings and modelling cell contents. The IRG expressed concern about possible partial leg collapse creating a future shipping hazard if derogation is granted to leave platform legs in place.

The IRG had been represented at both the Stakeholder meetings in September 2011 and as observers at the Cell Management Stakeholder Task Group. A further Stakeholder meeting was being planned for September 2012, by which time, it was expected that a preliminary version of the Decommissioning Programme would be available for discussions with Stakeholders.

Ninth Meeting - 28th - 29th June 2011

Before the 9th meeting with Shell, the IRG held a Private Meeting attended by Mr Richard Brooke, DECC; it was agreed to maintain a continuing dialogue between the IRG and DECC. The IRG prepared a list of issues on remediation that it considered important, similar to a previous list on refloat of Brent D GBS; this approach had been found to be helpful on the earlier occasion.

Shell reported on the internal review that had taken place and which had involved Professor Shepherd. One of the urgent issues identified had been the remediation process, for which Shell had prepared a decision model that was discussed later in the meeting. Whilst this led to Shell’s decision to undertake a sampling project in September/October 2011 and a further programme in 2013, the IRG remained concerned that knowledge of the cell contents was essential for a convincing argument to be made to support whichever option is finally selected.

Shell also reported on its proposed approach to the Decommissioning Programme and agreed to describe the basic structure to the IRG before the Stakeholder Meeting in September 2011. Technical Risk Assessments for Brent B and C were to be sent to the IRG at the same time.

Good progress had been made with finalising review comments on Shell documentation. It was agreed that progress with review comments on modelling of drill cuttings would be resolved more satisfactorily by a meeting between selected members of the IRG and the modeling contractors. The specific actions required for outstanding reviews on this subject, environmental matters and cell remediation were discussed and agreed. The question of monitoring issues for the long term was also discussed; Shell intends this to be a part of the Decommissioning Programme and will send relevant technical reports to the IRG for review.

The IRG were sceptical about the Shell intention to propose Decommissioning Programmes for Brent A, B and C on the basis of the work undertaken for Brent D. The IRG considered that there are a number of significant differences.

The meeting discussed the arrangements for the Stakeholder Meeting in September 2011 and the various communication activities being undertaken by Shell. It concluded with a review of the future work expected for the IRG, which will include consideration of the H2S management strategy, review of the four field Concept Select Reports and reviews of a future study of cutting the GBS legs, pipelines, a comparative assessment for the Brent A jacket and a design study for capping.

A teleconference was held on 14th September 2011 in place of the planned meeting as there was insufficient new material to discuss; the main purpose was for Shell to appraise the IRG of the latest status of the project.

Eighth Meeting - 15th - 16th November 2010

The eighth meeting opened with a review of the Stakeholder meetings held on 29th June and 1st July 2010 (attended by Professors Bakke and Clauss in Aberdeen and Professor Wilkinson in London). The IRG reported that it had been pleased to see very open discussions that reflected many of the review comments that it had made to Shell. Stakeholders’ strong concern with the need for sampling of cell contents was noted.

The IRG made a presentation at both the Stakeholder meetings. It had received a draft written response to all but one of the 13 Brent D refloat issues raised with Shell at the fifth meeting. On the basis of these responses and the other extensive evidence presented in both the contractors’ and Shell reports it considered that it was in a position to offer a statement at the July 2010 Stakeholder meeting as follows:

The IRG accepts that the uncertainties on crucial issues (including especially the structural integrity of the platform) are very large and that the risk of serious failure should refloat of Brent D be attempted is therefore very high.

Professors Shepherd and Wilkinson had met Mr Mayo and Mr Brooks of DECC during August 2010. The meeting was very useful and they reported that DECC wished to remain in contact with the IRG and to be kept informed of progress.

The subject of cell contents and the sampling strategy for Brent D was discussed. The IRG considered that for Shell to make an informed decision on cell remediation, it will be necessary to obtain volume information on cell sediments and to determine sediment composition. Shell had prepared a decision tree using estimated parameters as inputs to investigate the various sensitivities of a range of remediation options.

The outcome of this exercise was that the benefit of obtaining a sample in 2011 in order to make a final remediation selection was limited since extensive sampling would be required later anyway. The counterbalance to this was that full provision would have to be made for recovery and reinjection of cell sediments including sub-surface preparations and installation of any topsides equipment required. The ‘leave sediment in place’ would be the fall back option if recovery and re-injection proved to be non-viable. A convincing case would need to be made to sceptical Stakeholders.

Shell commented that the key value of the Concept Select Report – Remediation is its concentration on two main options – to remove and re-inject sediments or ‘leave in place’ and cap. The IRG would prepare and send its review comments on the Concept Select reports to Shell.

A number of other reports that the IRG had reviewed were discussed; it was expected that each of these would be ‘closed out’ in the near future.

Seventh Meeting – 11th-12th May 2010

The seventh meeting opened with a brief account of an internal workshop on 17th and 18th November 2009, organised by Shell on issues associated with refloat of the three Brent GBS platforms. Two IRG members (Professor Dover and Professor Clauss) had attended as observers. They found it to be an informative meeting with good discussion of the refloat options as well as the associated difficulties.

The role of the IRG at the planned Stakeholder meetings in June/July 2010 was discussed.

A number of reports on Brent D had been reviewed by the IRG and Shell had responded to the review comments. These were discussed and it was expected that each could be ‘closed out’ in the near future. Shell hoped to issue the Concept Selection Reports for the refloat option and cell remediation for IRG review by the end of June 2010. All IRG reviews of Decision Papers and consultants’ reports on Cell Remediation had been sent to Shell before the meeting. The reviews of the main Decision Papers were discussed with the intention of clarifying points as necessary.

It was agreed that the IRG should seek a meeting with DECC officers who have responsibility for platform decommissioning.

Sixth Meeting - 2nd - 3rd February 2010

At the start of the sixth meeting, the IRG members expressed the view that Shell was not interfacing with the IRG as well as it should. The IRG had been presented with some 40 reports on cell content remediation to examine over a very short time. The IRG had insufficient time to examine these in any detail before the meeting. They appeared to be final reports already approved by Shell. It seemed therefore that any comments to be offered by the IRG in its reviews would not change Shell’s position.

Shell explained that the 40 reports comprised 8 to 9 draft decision papers for cell content remediation options supported by the principal contractors’ reports on which the decision papers had been based. There were two considerations for the IRG, namely:

Is the basic evidence sound, i.e. the quality of science, technology etc in the contractors’ studies?
Is the basic synthesis sound, i.e. has the evidence been properly carried forward by Shell into the decision making process?

Consequently, it was agreed that the IRG would review both the contractors’ reports and the Shell Key Decision papers and for these reviews to be completed in time for Shell to consider the comments before the planned Stakeholder meeting in July 2010, at which remediation would be the main topic of discussion.

At its previous meeting, the IRG had posed 13 questions on the Brent D refloat option to which it considered Shell needed to have answers. Shell had prepared responses to all but two of the questions and presented these verbally at the meeting. A written response would be sent to the IRG before its next meeting. The IRG had provided a detailed review of the draft Refloat position paper but had received no response. Shell expected that an overview paper would be available before the next IRG meeting.

The IRG had received a proposal for additional modelling and considered the approach of examining the sensitivity of model outputs to a range of parameters to be worthwhile; the IRG would suggest parameters that it would expect to see used.

Other reports promised at the last meeting had not been received but were expected within the next 4 weeks.

Fifth Meeting - 17th - 18th September 2009

The fifth meeting was postponed from March to September 2009 and opened with an overview by Shell of the current state of the project. The IRG had reviewed a number of reports submitted by Shell before the meeting; members of the IRG presented their individual comments verbally; the formal IRG consensus review would be provided to Shell at a later date.

Two members of the IRG had attended Stakeholder meetings on 28th and 30th April 2009 (Professor Bakke – London and Professor Rullkötter – Aberdeen) and the main points arising were discussed. Shell reported that there would be a major Stakeholder meeting in mid-2010. Shell’s intention at this meeting was to report on the whole process and conclusions prior to submitting its decommissioning proposal for all four platforms to DECC.

The reports discussed during this meeting of the IRG covered the areas of refloat possibilities for Brent D, subsequent deconstruction inshore or onshore and environmental matters, including mathematical modelling to assess the fate of drill cuttings in the longer term (hundreds of years). As a result of the discussions, the IRG identified thirteen major issues in relation to the refloat option for Brent D and submitted these as questions to Shell.

It suggested that Shell needed to provide considered responses to these questions in order to ensure that sufficient knowledge would be available when the decision on whether to refloat Brent D was made. Shell agreed to prepare a response to this request.

Shell noted that a number of reports would become available to the IRG at the end of 2009 and the beginning of 2010 and the next meeting was planned for February 2010 to discuss the IRG reviews of these reports.

Fourth Meeting - 30th September - 1st October 2008

Very little had happened to involve the IRG between December 2007 and September 2008. Shell responses to IRG reviews of a number of reports were not received until early September 2008. Shell reported that, as a result of the decommissioning end-dates being extended, the opportunity had been taken to pause and reflect on the scope of the project.

The conclusion was that it is more complex than originally envisaged and a number of personnel changes had taken place to accommodate this. Shell reported on the current state for each of the study areas before a draft version of the Brent Feasibility Study was discussed.

The IRG was concerned that there should be an audit trail to show how its comments had been addressed in later versions of reports and Shell agreed to put this in place.

Three members of the IRG had attended the Stakeholder Workshops held since the third meeting of the IRG (Professor Wilkinson and Professor Bakke – London, Professor Dover - Aberdeen) and the IRG discussed the main issues that arose.

Shell described the study structure and concept decision process, stating that it expected the IRG to be closely involved at each Shell Value Assurance Review. It was agreed that the IRG would work from the bottom up, i.e. firstly considering the supporting studies which would be used in the development of higher level policy documents.

The IRG restated its intention to finally sign off reports with a ‘close out’ statement that the studies have provided adequate knowledge to make informed decisions and that the data base used to develop the knowledge is reliable but also to note areas where agreement with Shell had not been reached.

It was noted that, as Brent D was likely to be the first platform to be decommissioned, Shell would focus its studies on Brent D in the short term. Various studies were due to be completed before the end of the year and Shell expected to be in a position to know whether refloating of Brent D would be a possible option by April 2009. Consequently, the next meeting of the IRG was planned for March 2009.

Third Meeting – 11th-12th December 2007

For the third meeting, members of the IRG had reviewed the remaining reports from the feasibility stage of Shell’s study.

In addition, Professor Bakke had attended the Stakeholder meeting held in London on 29th December 2007 and reported on the views expressed there. Professor Dover had presented a paper at the International Seminar on Offshore Platform Decommissioning, Rio de Janeiro, Brazil on 10th July 2007, which described the work of Independent Review Groups for both the BP North West Hutton project and the Brent project.

Shell considered that the completion of the feasibility phase had provided a good understanding of the main issues and challenges. However, there was still a high level of uncertainty over the feasibility of some of the proposed options. These would be considered in the subsequent phases.

Second Meeting - 14th - 15th May 2007

Prior to the second meeting, members of the IRG had reviewed a first tranche of reports prepared for Shell by a range of contractors and which covered all the main aspects of the decommissioning programme for the four Brent platforms. Many of these were essentially feasibility studies intended to enable Shell to make informed decisions on the most appropriate path to follow. The IRG’s initial comments were discussed in detail with members of Shell’s decommissioning study team.

At the end of the meeting, the IRG suggested a list of issues, unknowns and concerns for Shell to consider.

First Meeting - 30th - 31st January 2007

The main purpose of the first meeting was for the IRG members to receive a comprehensive presentation on the rationale for the decommissioning study and the process that Shell anticipated would be necessary.

Prior to the meeting, members of the IRG had attended two Stakeholder meetings (Professor Shepherd on 16th January 2007 in Aberdeen and Professor Wilkinson on 18th January 2007 in London) to acquire an understanding of the issues that the wider community considered to be important.

The first IRG meeting concluded with the IRG expressing its initial view on outstanding areas of concern that had been identified and that it was happy with the proposed process. The agreed review process was for the IRG to examine contractors’ and Shell reports on the key engineering, scientific, environmental and health and safety issues etc. relating to the decommissioning options.

The IRG would then prepare formal comments to which Shell and/or the contractors would respond; this may involve iteration.

Finally the IRG would prepare a ‘close out’ statement on each review indicating that either the IRG comments or suggested actions had been satisfactorily addressed or noting areas where agreement with Shell was not reached.

Independent Review Group (IRG)