Bp & the Gulf of Mexico Oil Spill

BP & The Gulf of Mexico Oil Spill

1a) A fact that the decision-makers should have considered in assessing whether or not the cement job would be successful in preventing a blow out would be the stability of the cement mixture. If the cement mixture is not stable it could become porous and permeable thus leading to a lost circulation event or leaks. Decision-makers should also consider if the recommended number of centralizers were in place to ensure that the casing is placed at the centre of the wellbore. Centralizers are important to ensure that cement forms a solid column outside the casing. If the casing is not centred properly the cement can contain gaps through which hydrocarbons could escape. Conversion of the float valve system to unidirectional flow should also be considered, this process ensures that the cement flows down the casing and into the desired space rather than back up the casing. Decision-makers should also consider the fact that BP used lightweight cement which meant less pressure on the geologic formation. This can be detrimental as not enough pressure can lead to a kick or blowout. The results from the negative pressure test should also be considered as it tests the integrity of the cement job. Lastly, it should be considered that BP specified that the cement should be pumped slower than normal to prevent another lost circulation event. This speed requested is not recommended as it could result in an uneven cement job that might allow hydrocarbons to escape the surface. All of these facts were found pertinent to a successful cement job and should be considered in assessing if it can prevent a blow out.

1b) The overall primary technical difficulty experienced at the Macondo well was the lost circulation events. BP had lost approximately $15 million of drilling mud, was overbudget by $58 million, and drilling had taken nearly six weeks longer than expected due to these difficulties. The prolonged project had taken a toll not only financially but also on the employees on site. This resulted in many decisions being made with the goal of completing the project as quick as possible and/or preventing another lost circulation event rather than following proper processes. For example, before cementing, a  “bottoms up” process is used to circulate the mud which raised the likelihood that the cementing would run smoothly. Normally, approximately 2760 barrels of mud would be circulated through the system to ensure mud at the bottom of the well would return to the rig but only 350 barrels was circulated on April 20, 2010 at Macondo.

1c) BP chose not to conduct the Schlumberger casing test based on the assumption that the cement job had gone smoothly. This decision allowed BP to save roughly ten hours of time and $128,000 fee for the test.

2. BP was largely at fault for the accident. As they had many difficulties with the Deepwater Horizon Rig, there was various lost circulation events and BP was $58 million over budget, they made many decisions that may not have been the best practice but saved time. BP should have followed proper oil drilling and safety protocols to ensure each step of the process was conducted properly. Negligence by their staff was seen at various stages leading up to the blowout that could have been corrected which may have prevented the blowout from happening. For example, the choice of using six centralizers instead of 16+ as BP had originally planned was made so that they did not have to wait for more centralizers to be available. Halliburton warned BP that this may raise the probability of a severe gas problem but the BP engineer had the works completed wanting to save time. In the same manner, many of BP’s staff made decisions to save time rather than choosing the lower-risk option that was available, faults that had built upon one another resulting in the blowout. A small portion may be accredited to the flawed design of blowout preventer. The pipe had bent due to explosion at Deepwater Horizon, the shears of the blowout preventer were only made to cut through straight pipe. As a result, when the shears were activated they were stuck less than two inches apart leaving a gap which oil could still escape from. This is one flaw in design that should be considered although the fault of the accident fell mainly on BP.