Key findings of federal Deepwater Horizon oil spill probe

A joint investigation report by the U.S. Coast Guard and the Interior Department’s Bureau of Ocean Energy Management, Regulation and Enforcement spreads blame for the deadly Deepwater Horizon rig disaster and makes a number of key recommendations and findings for improving offshore safety in the Gulf of Mexico.

Among the report’s key findings:

  • A series of failures on the part of BP, rig owner Transocean and Halliburton contributed to the initial blowout of BP’s Macondo well.
  • In BP’s case, those include problems where the oil giant chose to set pipe-like production casing in the well; its failure to establish additional well barriers while pumping cement; its decision to set the float collar across the hydrocarbon of interest, instead of at the bottom of the shoe; its failure to place cement on top of the wiper plug; and its failure to inform contractors of all known risks, as well as BP’s failure in adequately analyzing risks at Macondo.
  • BP and Halliburton’s failure to perform the production casing cement job in accordance with accepted industry recommendations was also contributed to the deadly blowout, the report said.
  • Other possible contributors include the failure of BP’s well site leaders and Transocean crew members aboard the Deepwater Horizon to recognize risks tied to problems with cementing operations beginning the day before the blowout and various decisions by BP and Halliburton with respect to planning and conducting the Macondo production casing cement job.
  • Rig personnel with BP, Transocean and Halliburton should have detected an influx of hydrocarbons into the well before the oil and gas crossed the well-sealing blowout preventer on the sea floor.
  • “The overall complacency of the Deepwater Horizon crew was a possible contributing cause of the kick detection failure.”
  • BP’s failure to perform all necessary well pressure tests that might have signaled problems with the well and its failure to investigate or resolve pressure issues that arose in a first test.
  • Transocean’s ambigous well control procedures and lack of training for serious well blowouts was also cited as a contributing cause of the response failure.
  • The most likely ignition source was one of the engine rooms aboard the rig, but design flaws with rig equipment may have contributed to the deadly explosions.
  • The force of the blowout itself likely led to buckling of drill pipe in the well, which prevented the blowout preventer from shearing the pipe and sealing off the well.
  • BP’s “cost or time saving decisions without considering contingencies and mitigation” contributed to the blowout.

Here are some of the panel’s key recommendations for new federal regulations:

Strengthen the design of offshore wells

  • Requirements for negative pressure testing of certain wells.
  • Mandating at least two barriers — one mechanical and one cement — for any well that is undergoing temporary abandonment procedures. And according to the panel, float valves and collars designed to prevent cement from u-tubing back into the work string should not be considered a mechanical barrier.
  • Adding new detail to current regulations that cite the potential problems of lost and partial returns of drilling fluids. At the Macondo well, there were some lost returns — where material pumped into the well went unaccounted for and probably escaped into the reservoir. But current regulations do not define what qualifies as “lost returns.”

Improve how kicks and other problems are detected and combatted

  • Better reporting to the federal government of well kicks, or undetected influxes of hydrocarbons, which can precede a dangerous loss of well control. Under current regulations, offshore operators are only required to report “losses of well control,” but not less severe well control events such as kicks.
  • Regulators and industry should develop a standardized procedure for conducting and interpreting negative pressure tests. According to the joint investigation team, “if interpretation guidance had been provided to the rig crew, the early signals of the well flowing may have been detected and the blowout averted.”
  • More research on how quickly kicks can be detected, depending on water depth. In deeper wells, it is possible that influxes of hydrocarbons might not be detected until the oil and gas is in riser pipe, above a blowout preventer stack designed to help with well control.
  • New guidance for rig crews on when to divert flowing muds and other fluids from wells overboard, using mud-gas separator systems.
  • Better analysis by federal regulators of well activity reports to ensure offshore operators are accurately reporting significant anomalies at their drilling sites, including lost returns and well control failures.
  • Clarify who on a drilling rig is ultimately responsible for monitoring wells whenever they are unsecured by blowout preventers or mechanical and cement barriers. Current federal regulations say this is the responsibility of “the toolpusher, operator’s representative or a member of the drilling crew,” but that is “too broad,” the panel said.

Beef up blowout preventers

  • Issue a safety alert to offshore operators recommending that blowout preventers contain equipment (other than the annular preventer) designed to centralize drill pipe, increasing the odds that it will be successfully sheared in case of an emergency. This issue should also be further researched.
  • Require better remote, rig-based monitoring of batteries used for activating a blowout preventer via an automatic mode function or deadman switch. If the battery is weak, the system may not function as designed.
  • Research whether acoustic triggers should be required for blowout preventers. This would ensure a completely independent system for activating the devices in case lines to the blowout preventer are damaged.
  • Consider whether there needs to be more standardization of how remote operating vehicles interact with blowout preventer controls underwater. “On the Deepwater Horizon, numerous attempts were made to activate the BOP using multiple ROVs,” the panel noted.
  • Study how a flowing well can affect the ability of subsea blowout preventers to shear pipe. There are concerns that flowing oil and other sediment can create forces too great for shear rams to overcome.

Step up well control training

  • Regulators should work with industry organizations to ensure that employees understand all of their options for controlling deepwater wells and recognize the importance of monitoring the flow of fluids at the sites.
  • Better training by industry groups and individual companies should also include instructing offshore workers on how and when to use mud-gas separators and other equipment in case well control is lost.
  • Ensure offshore workers consider the emergency disconnect function as one of their well-control options when problems arise. At Macondo, “by the time the hydrocarbons reached the rig floor, it might have been too late to attempt to control the flow,” the panel said. “A better option in these cases, may be to . . . immediately activate the emergency disconnect function to disconnect from the well and stop further hydrocarbon flow.”
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