Title:How_to_Decommission_CUT_DOWN_5_Drill_Cuttings_FINAL_MASTER-_211216_
Duration: 3:35 minutes
Description:
The challenges and solutions for dealing with the drill cuttings associated with the decommissioning of the Brent platforms.
How_to_Decommission_CUT_DOWN_5_Drill_Cuttings_FINAL_MASTER-_211216_Transcript
[Background music plays]
Instrumental music with synthesised effects, at times with softer tones, at other times building to a stronger rhythm.
[Graphic]
Computer generated imagery of drill cuttings around the Alpha jacket footing at frame-left, 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]
Drill Cuttings
[Narrator]
When Brent’s wells were drilled, a mix of lubricants was used in the drilling process, some of which were oil-based. These, and the shards of rock that came out of the wells, were discharged into the sea.
[Video footage]
Bird’s eye footage of darkened platform topsides seen against blue ocean waters. Wide footage of workers wearing safety gear surrounding a drilling rig on a platform. Low angle close-up of the rising drill rigging, with lubricants pouring down the shaft. More footage of workers surrounding the drilling rig, placing a clamp into place around the shaft. High angle footage of an operator in the drilling control room, seated in front of a bank of screens, his hands on a joystick and other controls as he watches the screens.Underwater aerial footage of the drill cuttings on the seabed, small fish also swimming along the seabed.
Interview with Alistair Hope
[Title]
Brent Decommissioning Project Director
[Text displays]
Alistair Hope / Brent Decommissioning Project Director
[Alistair]
So around the old platforms in the North Sea, you have these things called cuttings piles, which are essentially little bits of rock and sand, but in there, there are some smaller quantities of oil based mud.
[Video footage]
Close-up of Alistair Hopeas he speaks, seen against the slightly out of focus background of an office environment.
[Animated sequence]
Computer generated imagery of a gravity base structure on the seabed with cuttings piles around and on top of the storage cells. A magnified image appears at frame-right, surrounded by a yellow line and linked to the cuttings piles with a yellow line graphic. The magnified image denotes the particles which make up the cuttings piles.
Interview with Duncan Manning
[Title]
Brent Decommissioning Asset Manager
[Text displays]
Duncan Manning / Brent Decommissioning Asset Manager
[Duncan Manning]
The drill cuttings comprise of around 2% hydrocarbon, so very low hydrocarbon content.
[Video footage]
Close-up of Duncan Manningas he speaks, seen against the slightly out of focus background of an office environment.
[Narrator]
The practice of discharging drill cuttings ceased in the 1990s. But for existing piles, the regulator requires operators to measure the level of oil diffusing from them.If it’s below a certain threshold, they recognize that leaving the piles undisturbed is the best option.
[Video footage]
Panning front view of a platform topside seen against a background of blue seas and sky. Underwater aerial footage of the drill cuttings on the seabed, small fish also swimming along the seabed.
[Animated sequence]
Computer generated imagery of a gravity base structure on the seabed with cuttings piles around and on top of the storage cells, zooming slightly to focus on the cuttings piles.
[Alistair]
So in the case of Brent, we've got cuttings piles next to the four platforms. And, of course, in the case of the concrete platforms, there are cuttings piles on tops of the cell tops.
[Video footage]
Close-up of Alistair Hopeas he speaks, seen against the slightly out of focus background of an office environment.
[Narrator]
Shell has worked with independent experts to assess Brent’s cuttings piles.
[Video footage]
Underwater aerial footage of the drill cuttings on the seabed around the base structures, small fish also swimming along the seabed.
Interview with James Blackburn
[Title]
Brent Decommissioning HSE Manager
[Text displays]
James Blackburn / Brent Decommissioning HSE Manager
[James Blackburn]
We have done some long-term fate modelling, to better understand what happens to those cuttings.
[Video footage]
Close-up of James Blackburn,as he speaks, seen against the slightly out of focus background of an office environment.
[James Blackburn]
And we have demonstrated that the hydrocarbon content from those original drill cuttings back in the 70’s will slowly degrade and recover.
[Video footage]
Close-up of a bearded man seated, with folded arms, at a desk and looking down, as the shot pans down, at something on the desk which is being pointed out by a hand at frame-right. Close-up of James Blackburn,as he speaks, seen against the slightly out of focus background of an office environment.
Interview with Mark Purcell
[Title]
Principal Consultant, Risk Advisory Services, DNV GL Oil and Gas
[Mark Purcell]
There’s quite a large volume of drill cuttings there.
[Video footage]
High angle close-up of diagrams on a desk, a man partially visible in rear view pointing down to the diagram with the pen in his left hand, as another hand also points in at the diagram from frame-left.
[Text displays]
Mark Purcell / Principal Consultant, Risk Advisory Services, DNV GL Oil and Gas
[Mark Purcell]
Our specialists looked at them, they’ve considered the environmental impacts and what was found was that at Brent Alpha and Brent Delta they were within OSPAR limits. Brent Charlie, they were fine at the seabed, but the cell tops exceed one of the OSPAR criteria in terms of the oil load released.
[Video footage]
Close-up of Mark Purcell as he speaks, seen against a glass panelled background. 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 in profile of the man at frame-right as he watches the displays. Close-up of Mark Purcell as he speaks, seen against a glass panelled background.
[Alistair]
The one pile that we have that is slightly above the threshold is on Brent Charlie, where there's a cuttings pile on top of the cells. So it comes up about nine metres above the cells. That one has a slightly higher leech rate of oil from it, because it's more exposed and prone.
[Video footage]
Another close-up of the diagrams on the desk and the hands pointing to them, cutting up to reveal the two men engaged in discussion, seated at the desk against the background of an open plan office environment and the large windows beyond.Close-up of Alistair Hopeas he speaks, seen against the slightly out of focus background of an office environment.
[Animated sequence]
Computer generated imagery of a low angle view of the gravity base structure on the seabed with cuttings piles around and on top of the storage cells, panning slowly upwards to focus on the cuttings piles.
[Narrator]
Shell used a comparative assessment process to assess the pros and cons of managing this cuttings pile.
[Video footage]
High angle rear view footage of the man seated at the left-hand side controls in the drilling control room, his eyes on the screens facing him. Underwater aerial footage of the drill cuttings on the seabed, small fish also swimming along the seabed.
[Alistair]
If you are to remove them, it is very much using almost like a giant vacuum cleaner to suck them up onto a vessel and then bringing them onshore. So it is a big, big operation, and there is this risk of putting oil into the water column whilst you do it, that's very hard to prevent.
[Video footage]
Close-up of Alistair Hopeas he speaks, seen against the slightly out of focus background of an office environment. Bird’s eye view of one of the Brent platforms and a vessel alongside, seen against the background of a glistening ocean and an evening sky. Close-up of Alistair Hopeas he speaks, seen against the slightly out of focus background of an office environment.
[Narrator]
Though they exceed the threshold, removing them could worsen their environmental impact.
[Animated sequence]
Computer generated imagery of a close-up of the cuttings piles on top of the storage cells of the gravity base structure, and a pipe descending to suck up the particles, causing a cloudy release of substances at the point that the cuttings piles are being disturbed.
[Mark Purcell]
If you disturb them, the disturbance itself will create pollution and release the oil.
[Video footage]
Close-up of Mark Purcell as he speaks, seen against a glass panelled background.
[Narrator]
Shell recommends leaving all the drill cuttings undisturbed, but continuing to monitor any impact they have on the environment. This is an option the UK regulator has approved before.
[Video footage]
Footage of the display screens in the darkened control room. Aerial footage of a yellow inspection vehicle being lowered into the water. Low angle view of the inspection vehicle being lowered back onto the platform by workers wearing hardhats and safety gear. Aerial black and white footage taken as from the inspection vehicle of the platform below as the workmen reach up to guide it back into place.
[Duncan Manning]
There is a requirement to conduct a monitoring operation to understand any impact of leaving the drill cuttings in place and understand that they are degrading in line with our expectations.
[Video footage]
Close-up of Duncan Manningas he speaks, seen against the slightly out of focus background of an office environment.
[Alistair]
Northwest Hutton, which is a BP platform they've just recently revisited their cuttings pile and indeed see the cuttings piles are naturally degrading, and their environment is recovering. And in fact it's happening a bit quicker than anticipated. So, it all points to, leaving in place and allowing natural degradation, is the best way forward.
[Video footage]
High angle close-up of diagrams on a desk, a hand visible at lower frame-right pointing to parts of the diagram. Close-up of Alistair Hopeas he speaks, seen against the slightly out of focus background of an office environment.Underwater panning aerial footage of cuttings piles on the seabed.Close-up of Alistair Hopeas he speaks, seen against the slightly out of focus background of an office environment. More underwater footage of the seabed and the small fish swimming along it.
[Text displays]
With thanks to ROVOP / Subsea 7
[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.
[Graphic]
Shell Pecten centred on a white background with text displaying below.
[Text displays]
© Shell International Limited 2016