Brent field cell contents
There are 64 storage cells in the Brent Field which sit around the legs anchoring the GBS to the seabed. Over the years, 42 of the cells have been used for oil storage and separation.
How to Decommission Brent: Cell Contents
Title: How to Decommission CUT DOWN 3 Cell Contents FINAL MASTER 211216
Duration: 5:48 minutes
Description:
The challenges and solutions for decommissioning of the storage cells of Brent’s three gravity base structures.
How to Decommission CUT DOWN 3 Cell Contents FINAL MASTER 211216 Transcript
[Background music plays]
Instrumental music with synthesised effects, at times with softer tones and at other times building to a stronger rhythm.
[Graphic]
Computer generated imagery of the outline of a gravity base structure at frame-left with a pipeline extending towards frame-right, seen against a dark greenish background with lighter streaks descending from top of frame representing rays of light piercing the dark underwater environment, the shadows and sunlight dappling the seabed.
[Text displays]
Cell Contents
[Narrator]
When Brent’s 3 gravity base structures were built in the 1970s, there was no pipeline in the North Sea that could export oil or gas to shore. So the GBS were constructed with cells at their bases to temporarily store oil, before it was offloaded into tankers.
[Video footage]
Low angle panning footage of the legs of the gravity base structure of one of the Brent platforms under construction, seen against the background of a pale blue sky. Bird’s eye view of a vessel in the North Sea against a background of grey waters and skies. Another low angle view of the concrete legs of the gravity base structure under construction. High angle view of wet cement pouring into a mould.
Panning aerial view of the cluster of storage cells, still under construction. Low angle view of the storage cells under construction. High angle view of the ocean and towing vessels below, as from the point of view of the tops of the legs, the storage cells of the base structure visible below.
Interview with John Gillies
[Title]
Brent Decommissioning Execution Manager
[John Gillies]
So this is a model of Brent Delta gravity base structure. You can see at the bottom there are 16 storage cells.
[Video footage]
Mid-view of John Gillies, as he speaks and points to a model of the base structure to his right, visible at frame-left. Low angle close-up of John, panning to a close-up of the storage cells of the model as he points to them.
[Text displays]
John Gillies / Brent Decommissioning Execution Manager
[John Gillies]
And this is a cross section through one of these 16 cells. It’s a reinforced concrete structure. The concrete is around one metre thick.
[Video footage]
Mid-view of John Gillies, as he lifts a cross-section of one of the storage cells. Close-up of the cross section as he points to various parts while explaining the structure.
[Narrator]
There are 64 cells across the whole field, each is 60 metres high and 20 metres in diameter. Before Shell could recommend a method of decommissioning, the team needed to investigate their contents.
[Video footage]
Vertically panning footage of the model of the base structure, cutting to a panning close-up of the tops of the storage cells. Rear view close-up of a man facing a computer screen which displays graphics related to the storage cells. Front view of the man seated at his workstation, cutting back to a close-up of the graphics on his computer screen.
Interview with Alistair Hope
[Title]
Brent Decommissioning Project Director
[Text displays]
Alistair Hope / Brent Decommissioning Project Director
[Alistair Hope]
When we set up this project back in 2006, one of the really big challenges we had, right from the outset, was to be able to get into the cells and sample them. So that's taken us several different attempts and in the summer of 2014, we actually got into the cells on Brent Delta.
[Video footage]
Close-up of Alistair Hope as he speaks, seen against the slightly out of focus background of an office environment. Aerial footage of equipment being lowered into the water alongside the platform. Underwater footage showing a mass of bubbles as something is lowered into the grey waters.
[John Gillies]
We drilled through the concrete at the top of 3 of the cells and lowered a series of liquid sampling and sediment sampling tools, all the way down so that we could capture physical samples.
[Video footage]
Rear view footage of two workers seated in front of control panels and a bank of screens in a drilling control room, cutting to a close-up of a hand on a joystick, controlling the drilling. Underwater aerial black and white footage of drilling taking place on the top of one of the storage cells. More footage of the screens and an operator in the drilling control room.
Close-up of John Gillies as he speaks, still holding the cross-section of the storage cell at frame-left. More rear view footage of two workers seated in front of the controls and screens of the drilling control room, cutting to a close-up of one of the screens.
[Narrator]
An unlikely partnership also helped the team better understand what it was dealing with.
[Video footage]
Rear view footage of Roddy MacFarlane as he walks between workstations in an open plan office space, cutting to a close-up of a kit bag he is carrying in his right hand, which he is then shown to place on the floor alongside a workstation. Mid-view footage of Roddy MacFarlane lifting the sonar sphere onto the counter of a workstation against the background of a now slightly out-of-focus office environment.
Interview with Roddy MacFarlane
[Title]
Brent Decommissioning Business Improvement Manager
[Roddy MacFarlane]
This is a sonar sphere, which we developed in conjunction with NASA.
[Video footage]
Mid-view footage of Roddy MacFarlane holding the sonar sphere as he speaks, seen against the background of an open plan office environment. Close-ups of the sonar sphere Roddy is holding on the countertop.
[Text displays]
Roddy MacFarlane / Brent Decommissioning Business Improvement Manager
[Roddy MacFarlane]
And what we were able to do with this is to put it down through the cell fill lines and into the storage cells.
[Video footage]
Close-up of Roddy MacFarlane as he speaks, seen against the background of the office environment.
[Roddy MacFarlane]
And on the front we have a small sonar, which is what we used to characterise the volume of sediment that was in the base of one of the cells.
[Video footage]
Footage of the sonar sphere moving through the cell fill lines.
[Narrator]
The sampling and sonar revealed there was about 4 metres of sediment, in 42 of the cells. This material was independently analysed.
[Video footage]
Close-up of particles in motion and of the build-up of sediment. Rear view footage of a man in a white coat and wearing safety googles, standing in front of a computer screen in a laboratory environment, cutting to a close-up of his face as he looks down at the computer screen.
[Alistair Hope]
The samples for the sediment certainly showed that the material was more benign than we thought.
[Video footage]
More close-up footage of particles in motion, cutting back to an extreme wide view of the laboratory environment as previously described. Close-up of Alistair Hope as he speaks, seen against the slightly out of focus background of an office environment.
[Narrator]
The cells’ contents were revealed to be 25% oil, 25% sand and 50% water.
[Video footage]
Wide-view of the man conducting tests in the laboratory environment, cutting to a close-up of liquid in a beaker and another close-up of particles in motion. Close-up of the man conducting the tests, cutting to an extreme close-up of his face and the syringe and vial he holds in front of it.
Interview with Duncan Manning
[Title]
Brent Decommissioning Asset Manager
[Text displays]
Duncan Manning / Brent Decommissioning Asset Manager
[Duncan Manning]
To all intents and purposes, it's relatively understood, and biodegradable.
[Video footage]
Close-up of Duncan Manning as he speaks, seen against the slightly out of focus background of an office environment.
[Narrator]
Shell recognised people’s interest in the cell contents, so it set up a task group of interested parties, including academics, scientists and environmental organisations.
[Video footage]
Wide view of a modern office building seen against a pale blue sky. Footage of a model of a Brent platform displayed in a window. A woman walks past the window outside the building as the shot cuts to her shaking hands with Duncan in the reception area before he ushers her through and beyond the reception area. Wide view of a glass fronted building, several flying flags and the landscape beyond reflected in the glass.
[Duncan Manning]
This 16-member body was formed in 2011, to really focus on the options for the cell contents and to ensure that we understood what the thoughts and views of our stakeholders were.
[Video footage]
Wide footage of Duncan and others seated around a large table, cutting to a rear-view close-up of John Gillies and a large screen against the wall beyond him. Close-up of Duncan Manning as he speaks, seen against the slightly out of focus background of an office environment.
[Narrator]
Shell assessed various options: some for leaving the sediment in place and others for removing it.
[Animated sequence]
Computer generated imagery of the storage cells on the seabed, panning down to show a cross section of one of the storage cells with a yellow pipe reaching down into the cell and demonstrating the proposed actions on the brown layer of sediment in the cell.
[Duncan Manning]
Removing the contents of the cells is a very demanding operation, it would require cutting a hole into the cell itself, so, kind of, penetrating that nearly metre thick reinforced concrete. It would probably need to be quite a large, sizable hole to put dredging equipment into the cells.
[Video footage]
Close-up of Duncan Manning as he speaks, seen against the slightly out of focus background of an office environment. High angle footage of a man seated at the controls in the drilling control room, cutting to footage of his colleague seated in the chair to his right, his hand on the joystick as he looks at the screens in front of them.
[Narrator]
If this could be achieved, the sediment could either be shipped to shore by a fleet of tankers, or re-injected into the reservoir via a series of new wells…
[Animated sequence]
Computer generated imagery of vessels in the ocean in the area of a base structure which is shown below the surface of the water, resting on the sea bed. A yellow line graphic extends from the vessel above, down into the sediment visible in a cross section of one of the storage cells. A second yellow line graphic then extends downwards from the other vessel at frame right and penetrates the sea bed, continuing belowground.
[Alistair Hope]
It’s an enormous operation it’s a multi season campaign, we think on balance this isn’t the right option.
[Video footage]
Close-up of Alistair Hope as he speaks, seen against the slightly out of focus background of an office environment.
[Narrator]
The team also considered options for leaving the sediment in place. They worked with specialists at DNV GL to identify and assess any risks, and predict potential environmental impact.
[Video footage]
High angle close up of fingers on a computer keyboard, cutting to a close-up of a computer screen displaying graphics related to the storage cells. Wide footage of James Blackburn, Mark Purcell and a female colleague, seen in profile, seated alongside each other at a long table in a conference room, their attentions on the laptop screens in front of them.
Close-up of a computer screen, a hand pointing a pen at information on the screen. This cuts to a close-up of the female colleague at the furthest end of the table. Close-up of James’ fingers tapping on the keys of his laptop, and panning up to a close-up in profile of his face, his colleagues faces forming part of the out-of-focus background.
Interview with Mark Purcell
[Title]
Principal Consultant, Risk Advisory Services, DNV GL Oil and Gas
[Text displays]
Mark Purcell / Principal Consultant, Risk Advisory Services, DNV GL Oil & Gas
[Mark Purcell]
We’ve had marine toxicologists, marine eco-toxicology, an under-water noise specialist.
[Video footage]
Close-up of Mark Purcell as he speaks, seen against a glass panelled background.
[Narrator]
They considered injecting additives into the cells to attempt to reduce the amount of contaminant.
[Animated sequence]
Computer generated imagery of the storage cells on the seabed, showing the cross section of one of the storage cells with a yellow pipe reaching down into the cell and demonstrating the proposed actions on the brown layer of sediment in the cell.
[Mark Purcell]
While this had benefit, it was limited in its benefit because the cell sediment could be four metres thick but the nutrients will only really affect the top layer of that, maybe 10, 20 centimetres.
[Video footage]
Close-up of particles in motion. Close-up of Mark Purcell as he speaks, seen against a glass panelled background.
[Alistair Hope]
Physics and chemistry aren't really helping us here, because the temperatures are very low, at most eight degrees – sometimes, in the winter, a lot cooler than that. So, rates of reaction are very, very slow.
[Animated sequence]
Computer generated imagery of the storage cells on the seabed, showing the cross section of one of the storage cells with a yellow pipe reaching down into the cell and demonstrating the proposed actions on the brown layer of sediment in the cell.
[Video footage]
Close-up of Alistair Hope as he speaks, seen against the slightly out of focus background of an office environment. Underwater footage of the seabed.
[Narrator]
They also looked at capping the sediment with a protective layer of aggregates.
[Animated sequence]
Computer generated imagery of the storage cells on the seabed, , showing the cross section of one of the storage cells with a yellow pipe reaching down into the cell and demonstrating the proposed actions on the brown layer of sediment in the cell.
[Duncan Manning]
The additional complexity associated with the capping option was that the sediment itself had a very low bearing capacity, and therefore any capping layer you put on top would likely fall into the sediment.
[Animated sequence]
Continuing computer generated imagery of the storage cells on the seabed, showing the cross section of one of the storage cells with a yellow pipe reaching down into the cell and demonstrating the proposed actions on the brown layer of sediment in the cell.
[Video footage]
Close-up of Duncan Manning as he speaks, seen against the slightly out of focus background of an office environment.
[Narrator]
To address this, a gravel filler would need to be submerged into the sediment, so the capping layers could then sit on top.
[Animated sequence]
Continuing computer generated imagery of the storage cells on the seabed, showing the cross section of one of the storage cells with a yellow pipe reaching down into the cell and demonstrating the proposed actions on the brown layer of sediment in the cell.
[Alistair Hope]
Cumulatively, we're talking about an enormous volume of material, transferring that all offshore, gravel and then sand and then putting that in each cell. So, all of that requires a large fleet of vessels, multi-year campaign, all the associated hazards of doing that; risks to people, environmental footprint, etc.
[Video footage]
Close-up of Alistair Hope as he speaks, seen against the slightly out of focus background of an office environment.
[Narrator]
Specialists predict that when the cells eventually degrade and sediment is released, any effects will only impact the local environment. So, Shell recommends leaving the cell contents undisturbed.
[Video footage]
Wide footage of James Blackburn, Mark Purcell and a female colleague seated abreast of each other at a table in a conference room, their attentions on Mark’s laptop screen. Close-up of a hand pointing a pen to information on the laptop screen. Extreme wide shot of the three seated at the long conference table. Rear view close-up of Mark Purcell, panning down to the data displaying on his laptop screen. More close-up footage of particles in motion.
[Duncan Manning]
It sounds slightly counter intuitive, but on balance it makes more sense to leave the sediment to degrade naturally as it is, entombed within the cells.
[Video footage]
Close-up of Duncan Manning as he speaks, seen against the slightly out of focus background of an office environment. More close-up footage of particles in motion.
[Text displays]
With thanks to NASA / ROVOP
[Text displays]
Shell.co.uk/BrentDecomm
The Brent Field’s equal partners are Shell UK Ltd and Esso Exploration and Production UK Ltd
[Audio]
Shell jingle.
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Shell Pecten centred on a white background with text displaying below.
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© Shell International Limited 2016
What are Cells
Three of the four Brent platforms were built using steel reinforced concrete and comprise large concrete legs, between 150m and 165m tall, which are anchored to the seabed by a concrete base. They are called gravity base structures (GBS), because they stay in place thanks to their sheer size and weight – each structure weighs around 300,000 tonnes.
Each base comprises a cluster of storage tanks called cells. There are 64 cells in total, which were designed for oil storage, most of which are 60m high and 20m in diameter, taller than Nelson’s Column. They are made of concrete, just under 1m thick, reinforced with steel bars.
What were the Cells used for
Whilst the cells were designed for oil storage, over the operating life of the field only forty-two of the sixty four cells were used for oil storage and separation at some point during production activities. The storage cells provided operational flexibility to allow the platform to produce and store oil when maintenance or other activities prevented direct export of oil to market via pipeline or tanker.
They also served as a means of primary separation of oil and produced water. Those cells not used for oil storage contain water for ballast or cooling. All of the cells provide structural support to the legs and additional ballast to secure the platform to the seabed.
During the first 20 years of production, Brent primarily produced oil with associated gas. From the mid-1990s the field was redeveloped to produce mainly gas with associated fluids (water and oil). During this latter phase of operation the storage cells served as a means to settle out produced sediment and again for separation of oil from the produced water. When production at Delta and Bravo stopped, seawater was pumped into the cells to replace the oil during final bulk export runs.
What do the Cells contain
After more than 30 years of production, the cells used for storage now contain (from top of the cell to bottom):
- a layer of crude oil called attic oil, estimated to be 1m deep at the top of most of the cells where attic oil is present;
- a 1m thick layer of stable emulsion of oil and water called interphase material;
- a large intermediary layer of water;
- a layer, 4m on average, of sediment at the bottom of each cell, this is a mixture of oil, sand particles and water;
- a 1m concrete baseplate supporting the layer of sediment; and
- typically a 19m layer of sand ballast.
How do we know what is in the Cells
One of our commitments to stakeholders was to sample the sediment prior to submitting our decommissioning programme. We had previously estimated the volume and composition of the cell contents from our historical operating records and computer modelling studies, but wanted to be able to confirm our assumptions about volume and composition with sediment samples.
Cell Sampling Process
Taking samples within the cells had never been done before. The technologies and know-how did not exist. It took eight years to develop the techniques and expertise to overcome the inherent complexity associated with this challenging task. Thousands of man hours were devoted to the sampling project and multiple concepts examined and tested. Two ideas progressed beyond the drawing board to become offshore projects in 2008 and 2012, but eventually both had to be abandoned due to feasibility challenges.
In 2014 another attempt to obtain samples was made offshore. Crucially this concept was based on creating a new subsea access point in the top of the cell, and integrating five different technologies which had been tested extensively onshore. Three storage cells on Brent Delta were chosen for sampling as they could be accessed using the topside crane.
Working at 80 metres depth, divers first installed base plates on each of the three cells and bolted them onto the concrete surface. Phase two was carried out from the Brent Delta topside using the platform cranes, supported by a platform-based, remotely-operated underwater vehicle (ROV). A drilling tool was attached to the base plate so it could core into the 0.9m thick concrete tank tops and a sampling tool was subsequently deployed to collect the samples.
In August 2014, during a period of calm weather, we were able to collect between one and three kilogrammes of sediment from each of the three cells accessed – as well as water samples. A 3D sonar device was also successfully launched in each cell to measure the sediment volume and its surface topography.
Independent analysis
In order to give extra assurance, the samples were collected in controlled conditions, with the offshore operation witnessed throughout by independent observers, Bureau Veritas, a global leader in testing, inspection and certification. Each sampling canister was temperature controlled, sealed and signed to ensure it could not be compromised before onshore analysis.
Once back onshore, a specialist independent laboratory carried out chemical and physical analyses of the sample. The results were shared with the Cell Management Stakeholder Task Group, a group of 15 stakeholders brought together to look specifically at the cell sediment issue.
The analytical programme was very comprehensive. It was approved by Shell and Esso and reviewed by the Independent Review Group. Stakeholders were also asked to contribute to the analytical programme which resulted in the inclusion of alkylated phenols, and other phenol compounds, in to the cell sediment sample analysis.
The programme tested for 156 chemical compounds and analysed six physical parameters for each sediment sample.
What do the samples reveal
As a result of the sampling, we were able to confirm the average volume of sediment per cell to be 1,044 m3 versus our assumption of 1,080m3.
Chemically, the sediment contains no significant amounts of non-biodegradable compounds. Trace levels of naturally occurring radioactive materials and heavy metals were found, but no traces of polychlorinated biphenyls, glycols or organotins. This is positive and in line with our assumptions.
Physically, the upper layer of sediment is a viscous mixture of about 50% water, 25% oil and 25% sand. The higher shear strength detected indicates the sediment is harder to mobilise and therefore will take more effort to recover or conversely is less likely to spread if it comes into contact with the surrounding marine environment.
The findings were mostly in line with the assumptions used throughout the fate modelling. However the water within one of the cells contained a higher hydrocarbon content than expected. Additional water samples taken from different cells since then were below our assumptions. As such, we are continuing to investigate why the hydrocarbon content in water differs between cells and as part of the process to recover the attic oil on Delta, we will carry out further water sampling.
What Are The Decommissioning Options For The Contents Of The Cells
Option 1: Remove the contents and re-inject into subsea wells
The cell contents would be pumped out of the cells into tankers and transported to an offshore location where they would be injected into specially drilled waste disposal wells.
The advantage of this option is that the sediment and contents would be removed from the cells and hence the risk of sediment entering the marine environment when the GBS start to disintegrate, several hundred years from now, would be eliminated. There are however numerous disadvantages. Technically, it would be very challenging to cut a large hole into the 1-metre thick concrete cell top 120m below the surface of the North Sea and safely extract the contents.
Option 2: Remove to shore for treatment and disposal
The cell contents would be pumped out of the cells into tankers and shipped to an onshore waste treatment plant capable of handling large volumes of hydrocarbon slurry. There the slurry would be separated into oil, water and solids. The solids would be treated and disposed of in a landfill, the water would be cleaned and returned to the sea, and the oil reused.
The pros of this option are the same as with removing the contents and re-injecting it into subsea wells: the contents would be removed from the cells and the risk of hydrocarbon slurry impacting the marine environment when the GBS disintegrate would be eliminated. On the negative side, the technical challenges and risks of accessing the cells and transferring the slurry from the cells into tankers, and from the tankers to the waste treatment plant are high with only a minor benefit in terms of legacy environmental impact.
Option 3: Leave in place with bioremediation
Bioremediation is a treatment that uses naturally occurring organisms to biodegrade and reduce the amount of organic substances in the sediment. At Brent it would mean adding nutrients to stimulate natural bacteria to break down the oil. Because of the low temperature and the limited amount of available nutrients, the bacteria would not be very active.
Treatment by this method is only likely to affect the surface of the sediment, as the nutrients cannot diffuse much deeper than 20 to 30 cm into the sediment. Overall, this option would require substantial quantities of nutrients to be added, but only affect the upper layer of the sediment; it would also take a long time and have no guarantee of success.
Option 4: Leave in place capped
Capping material, such as sand, would be deposited into the cells to form an inert layer, approximately 1 metre thick, on top of the sediment. This would form a protective barrier between the sediment and the sea when the GBS start to disintegrate. Chemicals would also be added to the cell water to promote the biodegradation of hydrocarbons within the water. This option could be challenging to execute; due to the lack of bearing capacity of the sediment (75% of the sediment are fluids it would therefore likely require a structural agent such as gravel to be injected into the cells to support the capping material).
This structural agent would need to be added in higher volume than the capping agent itself. The capping material would also only provide a limited amount of protection when the GBS eventually collapse. The technical challenges and cost associated with implementing this option are assessed as disproportionate to the limited benefit from an environmental legacy standpoint.
Option 5: Leave in place
The GBS will continue to provide physical containment to the cell sediment as the legs and caisson slowly degrade so one of our options is, to leave the cell contents in place, untouched and untreated, but effectively contained within the structure. The GBS are expected to remain largely intact on the seabed for hundreds of years. Eventually, they will start to disintegrate or collapse. Studies show that when this happens and the sediment slowly but progressively comes into contact with the marine environment, the impact on the environment is likely to be restricted to a small area close to the cells.
Independent scientific analysis of the legacy impact of the cell water and sediment on the marine environment found it would be unlikely to induce any measurable effects at the population level. Effects on the water column would be restricted to local and transient effects close to the release point. A worst case sediment release would result in an impacted area around each platform that is a little larger than the area already impacted around each platform by the historic drill cuttings.
Furthermore the impact of low levels of bio accumulating substances would also be localised and so are not expected to induce any measurable effects at the population level in the area surrounding the Brent Field.Compared with the technical challenge of removing the contents and either injecting them in waste disposal wells or transporting them to shore for treatment, the potential impact of the leave in place option is minor and transient.
Which option does our comparative assessment recommend?
The option recommended by our Comparative Assessment for the cell content is to leave the sediment in place, effectively protected by the GBS.
Although removing the cell content would create jobs in the short-term, this is not an area of the decommissioning industry with much capacity for growth given the limited number of similar structures – just 9 GBS are operational in the UK and 27 in the wider OSPAR region compared to 470 installations overall in UK waters.
As we have seen, there are significant technical difficulties involved with removing the cell sediment and this type of operation on such a scale has never been attempted before. All removal options would also carry increased safety risk to personnel.
The cost of removing the cell sediment for onshore treatment and disposal is disproportionate to any environmental legacy benefit. Modelling shows that protection of the sediment will be provided from the cells. This outer structure is predicted to last for hundreds of years.
Our long-term fate modelling studies and environmental impact assessment – both of which were undertaken by independent organisations – show that little will happen to the sediment if it is left untreated inside the cells. Any exposed cell sediment would disperse very slowly into the marine environment, with no significant effect on marine organisms or risk to higher trophic levels or people, and the sediment has a higher shear strength than expected, which means that its ability to flow and spread would be limited.
Studies show the impact of the cell water on the environment will be small, gradual and local. Some of the water will rise to the surface and form a short-lived film, while a third of it will evaporate. We feel that we have applied a high level of conservatism to our modelling.
In arriving at the Comparative Assessment recommended option we carried out sensitivity tests by increasing the weighting of each of the five Department of Business, Energy and Industrial Strategy (BEIS) – formerly the Department of Energy and Climate Change – criteria (Safety, Environmental, Technical Feasibility, Societal and Economic) in turn to see if it would impact the score. It didn’t. Even when we removed cost as a criterion the overall outcome remained the same, with leave in place ahead as the best option.
In addition to the comparative assessments, which form the basis of the evaluation for the decision making process, we also consulted extensively over several years with representatives of our Cell Management Stakeholder Task Group (CMSTG). While some continue to prefer removal, on balance we believe the technical difficulties associated with removal, treatment and disposal are disproportionate to any environmental legacy benefit of removal.
Who Are The Cell Management Stakeholder Task Group
Collaborating with NASA
Since 2010, Shell has been working with NASA to develop a technique to access the cells to gain images of the content. NASA specially designed “sonar spheres” – a bowling ball-sized satellite – to access the cell through existing pipework.
The sphere took sonar images of the cell sediment so that Shell could identify its physical characterisation. Images were successfully obtained from Brent Bravo in May 2016.
More in Brent Field Decommissioning
Brent Field Recommendations
Learn more about the Brent Field recommendations
Brent Field Gravity Base Structures
Decommissioning the GBS