DEEPWATER HORIZON CATASTROPHE

Deepwater Horizon was an ultra-deepwater, dynamically positioned, semi-submersible offshore drilling rig. The Deepwater Horizon oil spill (also referred to as the BP oil spill, the Gulf of Mexico oil spill or the Macondo blowout) is a massive ongoing oil spill in the Gulf of Mexico, now considered the largest offshore spill in U.S. history. Some estimates placed it by late May or early June as among the largest oil spills in the world with tens of millions of gallons spilled to date. The spill stems from a sea floor 10,000 foot deep oil gusher (MC252) that followed the April 20, 2010 Deepwater Horizon drilling rig explosion. The explosion killed 11 platform workers and injured 17 others.
Factors that contributed are: 1. The cement that seals the reservoir from the well; 2. The casing system, which seals the well bore; 3. The pressure tests to confirm the well is sealed; 4. The execution of procedures to detect and control hydrocarbons in the well, including the use of the BOP; 5. The BOP Emergency Disconnect System, which can be activated by pushing a button at multiple locations on the rig; 6. The automatic closure of the BOP after its connection is lost with the rig; and 7. Features in the BOP to allow Remotely Operated Vehicles (ROV) to close the BOP and thereby seal the well at the seabed after a blow out. A failure of the cement plug was found contributed to the blowing of an exploration. As far as the drilling processes going on a cement cork is placed at the bottom of the well in order to temporarily shut it off before pumping the oil out. As the cement is drying, mud is loaded to the top of the well to prevent a gas surge. Before removing the mud, pressure tests are carried out to ensure the plug is holding. The mud was removed – which led to a ball of gas rushing up the well and exploding at the surface.

The lost mud in reservoir when drilling the portion of the well at the bottom. It indicates good reservoir quality, an interval of lower pressure or both can result in an enlarged washout. It might have been difficult to create a good cement seal between the casing and the formation. It was impossible to ensure the effectiveness of the cement seal without running a cement-bond log, and this was not done. The cement contains some amount of nitrogen additive to lighten so that it flows more easily and fills better in the area between the casing and the lost circulation-washout zone. This also decreases its sealing effectiveness.

Gas from the reservoir may have further diluted the viscosity of the cement. All cement begins as a slurry with cement flakes and water. Contractors then add ingredients to make the cement set at the right time and to keep out gas and oil.

Halliburton is responsible for the Deepwater Horizon job, mixes in nitrogen to make its slurry more elastic. The nitrogen also helps create a light weight cement that resembles a gray foamy mousse and bonds better to the casing.

But the recipe also depends on the job, because cement must respond to varying pressures and temperatures. Cement contractors work closely with oil and gas companies on the formulas for individual wells. The oil and gas companies have the final say on what is used.

Once the consistency of the mix is decided on, it is pumped deep into the well, where it first sinks to the bottom and then oozes upward to fill the narrow spaces between the steel casing pipe and rock walls. When the cement sets, the casing and cement are supposed to form an impenetrable wall to keep gas or oil from pushing into the hole anywhere but the bottom, where its flow up the pipe can be controlled.

But if gas bubbles invade the setting cement, they can form a channel for pressurized gas and oil to surge uncontrollably up the well, usually around the casing. The cement must be strong enough to withstand up to 5,000 pounds of pressure per square inch, to keep the well walls from collapsing.

Many oil and gas companies will scrimp, though, if they don't think they need all the ingredients in the cement, he said. Cement is often squeezed in later to try to fill gaps, but Beck said the success rate of this remedial work is low.

And if cement was part of the cause of the Deepwater Horizon catastrophe, it also could be part of the remedy. Two relief wells are being drilled to intersect the leaking well and plug it with cement.

Halliburton was completing the final cement work on the exploratory well beneath Deepwater Horizon in the wee hours of April 20. It added an initial cement plug to the well to act as a cap until a later production phase.

Sea water is much lighter than drilling mud so there was less downward force in the wellbore to balance the flow of gas from the reservoir. The drilling supervisors knew that there was gas in the drilling fluid because a gas flare can be seen in photos probably coming from a diverter line in the riser. This, along with a steady increase in mud pit volume, suggests that surges of gas were entering the drilling fluid from a gas column below the wellhead, and outside of the 7-inch production casing. Gas had probably channeled past the inadequate cement job near the bottom of the well and, had reached the seals and pack-offs separating it from the riser at the sea floor.

A plan that does not include enough cement to overlap the final and previous casing strings and that does not require running a cement-bond log to ensure the integrity of the seal is a defective plan. The fact that there have not been blowouts on previous wells does not justify the approval and use of an unsafe plan.

The blowout was caused by a mismanaged well plan that did not include enough cement between the 7-inch production casing and the 9 7/8-inch protection casing. The blowout preventer failure is an important but secondary issue. The recent efforts to limit the flow with an insertion tube have apparently been effective. The blowout preventer was manufactured by Cameron. When the remote operating vehicles tried to operate shear rams, loss of pressure was found. Investigation was done by injecting dye into the hydraulic fluid and showed a large leak coming from a loose fitting. Second, the blowout preventer had been modified. The blowout preventer has an underwater control panel. A test ram had been connected to the socket that was supposed to activate the variable bore ram. The cutting capacity of the blowout preventer is not that powerful enough to cut through the joints in the drillpipe. The blowout preventer has two emergency controls. One is called the emergency disconnect system or EDS. EDS was activated on the drill rig before the rig was evacuated. It was believed the explosion on the rig destroyed the communications link to the blowout preventer before the emergency sequence could be completed. In other words, the emergency controls may have failed because the explosion that caused the emergency also disabled communications to the blowout preventer. The blowout preventer also has a switch which is supposed to activate the blowout preventer when all else fails. But there were multiple scenarios that could have caused the switch to remain deactivated. The switch may not have been enabled on the control panel before the BOP was installed on the ocean floor. It won’t work if the batteries are dead and is connected to two separate control pods on the blowout preventer. Both rely on battery power to operate. When one of the control pods was inspected after the spill, the battery was found to be dead. And one appears to be a design problem. The deadman switch activates only when three separate lines that connect the rig to the blowout preventer are all severed: the communication, power, and hydraulic lines. Cameron believes the power and communication lines were severed in the explosion, but it is possible the hydraulic lines remained intact, which would have stopped the deadman switch from activating. There are more failure scenarios that could cause the malfunction of the blowout preventer. Steel casing or casing hanger was ejected from the well and it blocked the operation of the rams. The drill pipe dropped from the rig could break the seal. Also the operators on the rig tried to activate the shear rams by pushing the shear ram control button. This would have closed the rams, but it failed. The shear rams do not have enough power to cut drill pipe unless they are activated through the emergency. Congressional hearings, testimony, investigations, reports, primary documents made available by Congress, and other federal or state reports. Congressional hearings held earlier heard that key safety tests carried out as the well was being dug may have been inconclusive. Congressional hearings are the principal formal method by which committees collect and analyze information in the early stages of legislative policymaking. Whether confirmation hearings — a procedure unique to the Senate — legislative, oversight, investigative, or a combination of these, all hearings share common elements of preparation and conduct. Hearings usually include oral testimony from witnesses, and questioning of the witnesses by members of Congress. George B. Galloway termed congressional hearings a goldmine of information for all the public problems of the United States. Instructions included spill remediation activities but specifically talked about their ongoing program to seal the well, including continued efforts to activate the BOP; using a containment and riser system to collect the oil still leaking; drilling two relief wells; and looking at a “top kill” where the well will be re-entered at the top and sealed around the area of the BOP. Their analysis of the failure of the well is focused on the failure of the BOP. The purpose of this joint investigation is to develop conclusions and recommendations as they relate to the Deepwater Horizon MODU explosion and loss of life on April 20, 2010. The facts collected at this hearing, along with the lead investigators' conclusions and recommendations will be forwarded to Coast Guard Headquarters and MMS for approval. Once approved, the final investigative report will be made available to the public and the media. No analysis or conclusions will be presented during the hearing. Together with the Department of the Interior (DOI), we are conducting an interagency investigation into the causes of the explosion and spill, and we held the first formal public proceedings of that investigation last week. In addition, DHS is working along with Interior and the Department of Justice to ensure that all records and evidence that may be relevant to the ongoing investigation to identify the cause of the well blowout and any future litigation are preserved, including monitoring the removal of equipment and debris from the spill site. A confidential government report on the unfolding spill disaster in the Gulf makes clear the Coast Guard now fears the well could become an unchecked gusher shooting millions of gallons of oil per day into the Gulf.

Reports are absolutely central to the way we regulate industry activity, and that’s true across regulatory contexts. The SEC, FCC, FEC (etc) regulatory agencies each collect public information, not as a byproduct of their work, but as a central approach to doing their jobs.

The basis for most federal regulation is the Outer Continental Shelf Lands Act (OCSLA), 18 which provides a system for offshore oil and gas exploration, leasing, and ultimate development. The OCSLA provides broad five-year planning periods for offshore leasing across the U.S. OCS as well as processes for leasing, development, and production. The OCSLA also authorizes the administration of health and safety requirements. All of these are administered by MMS. The Minerals Management Service (MMS) and the U.S. Coast Guard (USCG) are the primary regulators of drilling activity. The Environmental Protection Agency (EPA) has multiple responsibilities as the vice-chair of the National Response Team and Regional Response Teams. The Federal Emergency Management Administration (FEMA) has responsibilities with respect to the economic impacts of the spill; its role so far has been primarily that of an observer, but that may change once the scope of impacts can be better understood. MMS is also the lead regulatory authority for offshore oil and gas leasing, including collection of royalty payments. MMS regulations generally require that a company with leasing obligations demonstrate that proposed oil and gas activity conforms to federal laws and regulations, is safe, prevents waste, does not unreasonably interfere with other uses of the OCS, and does not cause impermissible harm or damage to the human, marine, or coastal environments. Regulations to implement federal statutes are promulgated by numerous federal authorities and vastly outnumber federal statutes. The bases for relevant federal regulation in this instance are, among other statutes, the Outer Continental Shelf Lands Act (OCSLA)49 and the Oil Pollution Act of 1990 (OPA). The sheer number of regulations from these statutes and from other federal laws complicates the description of the regulatory framework. Frequently, case law, international measures, or other legal actions define the regulatory parameters that apply to the Deepwater Horizon events. How the regulators manage the OCS is described below by outlining the roles of the lead federal regulators in the national response efforts, the Minerals Management Service and the U.S. Coast Guard.

References
Best, R.A. (16 January 2003). The Intelligence Community and 9/11: Congressional Hearings and the Status of the Investigation. Retrieved from fas.org: http://www.fas.org/irp/crs/RL31650.pdf
Deepwater Horizon Investigation. (n.d.). Retrieved from gcaptain.com: http://gcaptain.com/maritime/blog/tag/deepwater-horizon-investigation/
Hagerty, C.L. & Ramseur, J.L. (27 May 2010). Deepwater Horizon Oil Spill: Selected Issues for Congress. Retrieved from scribd.com: http://www.scribd.com/doc/33206527/R41262-Deepwater-Horizon-Oil-Spill-Selected-Issues-for-Congress
Out, H. (16 June 2010). BP’s Deepwater Oil Spill – An Update on Collection, Evaluating The President’s Speech and Open Thread. Retrieved from theoildrum.com: http://www.theoildrum.com/node/6612#more