The full catalogue of failures that led to the destruction of the Deepwater Horizon drilling rig and the subsequent oil spill in the Gulf of Mexico have been laid out by a final US government report.
The report was released today by the Bureau of Ocean Energy Management, Regulation and Enforcement (BOEMRE) — set up to replace the discredited Minerals Management Agency wound up in the wake of the disaster (see Nature’s special page for all news on Deepwater).
Investigators from BOEMRE and the US Coast Guard lay the blame for the accident on owners of the rig Transocean, contracting company Halliburton and ‘ultimate operator’ BP.
“The loss of life at the Macondo site on April 20, 2010, and the subsequent pollution of the Gulf of Mexico through the summer of 2010 were the result of poor risk-management, last-minute changes to plans, failure to observe and respond to critical indicators, inadequate well control response, and insufficient emergency bridge response training by companies and individuals responsible for drilling at the Macondo well and for the operation of the Deepwater Horizon,” they write.
The panel concludes that BP, Transocean and Halliburton all violated a number of federal regulations. (The full list is below the fold.)
Most of the details of the report will be familiar to those who have followed this incident, but taken together, they still paint a damning picture.
Among the causes of the accident were the use of only one cement barrier to plug the well, failure to use “industry-accepted recommendations” in the cementing, and the failure of the Deepwater Horizon crew to detect the unexpected ‘kick’ of hydrocarbons flowing from the well until it was too late, leading to a blowout. Transocean had previous admitted that the crew had “screwed up” by not catching a previous kick in a timely fashion; 10 of 11 crew from that incident were on duty when the rig was lost in April last year.
The new report estimates that five million barrels of oil leaked from the well before it was closed. Eleven people died in the disaster.
Federal Regulation Violations
BP failed to protect health, safety, property, and the environment by (1) performing all operations in a safe and workmanlike manner; and (2) maintaining all equipment and work areas in a safe condition.
BP, Transocean, and Halliburton (Sperry Sun) failed to take measures to prevent the unauthorized release of hydrocarbons into the Gulf of Mexico and creating conditions that posed unreasonable risk to public health, life, property, aquatic life, wildlife, recreation, navigation, commercial fishing, or other uses of the ocean.
BP, Transocean, and Halliburton (Sperry Sun) failed to take necessary precautions to keep the well under control at all times.
BP and Halliburton failed to cement the well in a manner that would properly control formation pressures and fluids and prevent the release of fluids from any stratum through the wellbore into offshore waters.
BP failed to use pressure integrity tests and related hole‐behaviour observations, such as pore pressure test results, gas‐cut drilling fluid, and well kicks to adjust the drilling fluid program and the setting depth of the next casing string.
BP and Transocean failed to conduct major inspections of all BOP stack components.
BP failed to perform the negative test procedures detailed in an application for a permit to modify its plans.
Image: Gas leaking from damaged well burning at the surface / photo by US Coast Guard Petty Officer 3rd Class Patrick Kelley.