FEATURES
 

DEEPWATER HORIZON

Deepwater Horizon - What Have we Done to Deserve This
Deepwater Horizon - After the BP Report
Deepwater Horizon - The Investigation
The Deepwater Horizon and the Late MMS.
The Deepwater Horizon - PR and Politics
The Deepwater Horizon - Forces at Work
The Deepwater Horizon - Where Are We Now?
ROVs, Risers and Mud
The Deepwater Horizon - Later
Something about the Deepwater Horizon Accident
Channelling the Oil Leak
Preventing Fires and Explosions on Offshore Installations

OTHER ACCIDENTS
The Costa Concordia Grounding
The Loss of the Normand Rough
The Bourbon Dolphin Accident
The Loss of the Stevns Power
Another Marine Disaster
Something About the P36
The Cormorant Alpha Accident
The Loss of the Ocean Express

OPERATIONS
The Life of the Oil Mariner
Offshore Technology and the Kursk
The Sovereign Explorer and the Black Marlin

SAFETY
Safety Case Development
The ALARP Demonstration
PFEER, DCR and Verification
PFEER and the Dacon Scoop
Human Error and Heavy Weather Damage
Lifeboats & Offshore Installations
More about PFEER
The Offshore Safety Regime - Fit for the Next Decade
The Safety Case and its Future
Jigsaw
Collision Risk Management
Shuttle Tanker Collisions
A Good Prospect of Recovery

TECHNICAL
The History of the UT 704
The Peterhead Connection
Goodbye Kiss
Uses for New Ships
Supporting Deepwater Drilling
Jack-up Moving - An Overview
Seismic Surveying
Breaking the Ice
Tank Cleaning and the Environment
More about Mud Tank Cleaning
Datatrac
Tank Cleaning in 2004
Glossary of Terms

CREATIVE WRITING
An Unusual Investigation
Gaia and Oil Pollution
The True Price of Oil
Icebergs and Anchor-Handlers
Atlantic SOS
The Greatest Influence
How It Used to Be
Homemade Pizza
Goodbye Far Turbot
The Ship Manager
Running Aground
A Cook's Tale
Navigating the Channel
The Captain's Letter

GENERAL INTEREST
The Sealaunch Project
Ghost Ships of Hartlepool
Beam Him Up Scotty
Q790
The Bilbao OSV Conference

THE DEEPWATER HORIZON - FORCES AT WORK

It is now the middle of June nearly two months after the loss of the Deepwater Horizon, and there seems to be a subtle change in the  direction of the public statements which relate to the official line on the sinking of the rig, the death of eleven of the crew and the subsequent massive release of oil into the Gulf of Mexico. It now seems that the well is pumping an almost unbelievable 40,000 bbls of oil per day into the sea. What bad luck we would think, in other circumstances, that BP should find probably the most productive single well in the Gulf of Mexico and then fail to keep hold of it. No wonder it was being difficult.

What seems to be happening is that BP are gradually gaining the experience necessary to deal with a problem which no-one has faced before, and are succeeding in the operations currently in place, and have plans for improving the recovery process and for providing redundancy. By 11th of this month the Discoverer Enterprise had recovered over 100,000 bbls of crude oil using the LMRP system described in the previous article. The ship is positioned over the well using GPS and a dynamic positioning system and is connected by a rigid pipe to the LMRP and then to the top of the Deepwater Horizon BOP. In order to discharge the current cargo and hence make space available for further oil, the tug/barge combination Massachusetts was loaded with 115,000 bbls of crude and sent off to a refinery for discharge. It says something for their confidence in the weather that  this tug/barge combination was sent fifty miles offshore and must have lain alongside the Discoverer Enterprise to be loaded.

Meanwhile the Q4000 is being, or has been, connected up to the choke and kill lines of the Deepwater Horizon by means of probably the same system as was used to attempt the well kill earlier. It also appears that the whole of the product recovered to this rig is being burnt off rather than stored and sent to the shore. This will be being done by the use of multiple well test burners, which are traditional bits of oilfield equipment and will probably successfully dispose of up to 20,000 bpd (barrels per day), the only problem being the possibility of melting bits of the rig if the water curtain is not efficient. 

As well as the Q4000, a dynamically positioned semi-submersible, there are currently on the location three construction vessels which provide most of the ROV services. These are the Skandi Neptune, the Viking Poseidon and the Ocean Intervention III, all of them incidentally Norwegian, but apparently able to work in the Gulf because they are not carrying cargo. There are also numerous smaller vessels at the wellsite engaged in skimming oil from the surface. And there are now plans, according to a letter from BP to Rear Admiral James Watson of the American Coastguard, for the whole system to be upgraded into a more or less conventional FPSO/shuttle tanker operation. This is principally to provide a means of continuing with the recovery process as the hurricane season approaches. It appears from the letter that a suction pile has been installed, and to this a flexible line (riser) is to be attached terminating in a subsea buoy. From this buoy a connection will be made to the Toisa Pisces which is a well testing vessel, and so already has the processing equipment on board. Apparently it is still being modified, one assumes so that it can be connected by flexible to a shuttle tanker. The Hilex Producer, another well testing vessel is to be similarly modified and there are three shuttle tankers coming from Europe, including the recently commissioned Loch Rannoch.

This is a photograph of the Toisa Pisces, taken in 2004 by Ron Jansen.

BP's letter describes the possible problems with their plans including the difficulties which may result from having all these vessels in quite a small area. I'm not sure whether they have missed it or if the system has already been tested elsewhere, but traditionally there are possible problems in the operation of dynamically positioned shuttle tankers, and as far as I am aware there have never been offtake operations which involved two dynamically positioned vessels. However there are almost continuous operations between  moored FPSOs and DP tankers, and one of the problems is "yo-yoing" where the connection between the two vessels tightens up, and in addition the DP system also registers loss of position and propels the ship forward. Of course it ends up too close and the DP system goes into reverse - and so on. How will this go with two vessels in DP mode?

Meanwhile the investigation into the events before the accident are beginning to uncover exchanges between the BP engineers who appear to have made changes to the well plan but "expect that it will all be OK in the end". And the senate committee questioning five top men from the oil industry are suggesting that BP have remained more interested in trying to limit their liability than in sorting out the problem. From our distant view across the Atlantic we'd be bound to say to those who administer the most litigious country in the world  "Well whose fault is that?"

Vic Gibson 15th June 2010.

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