Speaking in Houston, BP Chief Executive Officer Tony Hayward pointed out that deep water exploration has been taking place for over 20 years, and this is the first time an incident of this type has occurred. “There is an enormous amount of learning going on here, because we are doing it for real, for the first time. This learning will have profound implications for the industry...and will be extensive and inform what needs to happen in the future,” he said.

Many readers will be aware that the incident began on 20 April with an explosion and the tragic deaths of 11crew on Transocean’s Deepwater Horizon drilling rig, following a gas surge from the exploration well as it was being shut-in pending future development. The drilling rig eventually sank, during which the 21 inch diameter, 1.5 km long steel riser pipe, which had been attached to the blowout preventer (BOP), became detached from the vessel and collapsed onto the seabed. It is from this broken riser pipe that the oil and associated gas from the well is currently leaking.

A rapidly convened US Congressional investigation has begun to look into the incident and its origins, and it has become clear that the BOP failed to operate correctly. The reason for this is presently unknown, although one of the avenues of investigation will focus on the use of high strength pipe for the riser, and the ability of the BOP to completely shear the riser and therefore make the necessary seal. The increased strength of the riser pipes needed for deep water operations means that the BOP’s shear rams (used as a last resort to regain pressure control of a flowing well) have to be commensurably increased in strength, and this has been found not always to be the case.

As far back as 2002, in its Mini Shear Study for the US Minerals Management Service, West Engineering points out that the “limited data set from the latest generation of rigs paints a grim picture of the probability of success when utilising this final tool in securing a well after a well control event. While modifications, such as boosters or increased control system pressure, are available, demonstrative evidence that the installed shear rams will shear is often lacking.” An example of this was the 1979 blowout on the Ixtoc 1 oil rig off Mexico’s Yucatan Peninsula, where the BOP failed to sever the drill pipe because a high strength collar was at the location of the shear rams.

BP’s subsea source control and containment efforts continue to focus on stopping the flow of oil from the well by intervention through the BOP and, secondly, to contain the flow of oil to reduce the amount reaching the surface. These efforts are being carried out in conjunction with US government authorities and other industry experts. Testifying to this, US Interior Secretary Ken Salazar, has echoed Mr Hayward’s point that “the best minds in the world have been brought [to Houston]” to devise ways of resolving the situation. All of the techniques being attempted or evaluated to contain the flow of oil on the seabed involve significant uncertainties because they have not been tested in these conditions before. Among the most recent is a pipe-insertion plan, in which a 6 inch diameter pipe has been installed into the broken 21 inch diameter riser, the annulus sealed with a rubber collar, and the escaping oil allowed to flow under its own pressure to a tanker on the surface. At the same time, two relief wells are also being drilled, which will intercept the damaged well at around 3.9 km below the seabed, and allow the oil flow to be effectively sealed off at its source. These wells, however, are expected to take up to two more months to complete.

There are clearly many unanswered questions associated with this incident, and it will undoubtedly take a considerable time after the oil has stopped flowing for the industry and the public to understand what happened and how it can be prevented in the future. It is likely, however, that just as the Piper Alpha disaster in the North Sea in 1987 gave rise to both new regulations and the requirement for huge investment by operators when installing emergency shut-down valves on all pipelines, a similar outcome will emerge in the Gulf of Mexico concerning BOPs and deepwater drilling.