Deepwater Horizon Essay PDF

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Shay Stainsby PET 501 HW#2 Deepwater Horizon Essay Due: 10/04/2016

The Deepwater Horizon disaster had many factors effecting the outcome rather than just one. The first being that BP company men called off running a Cement Bond log test. Schlumberger had a team on standby to run a CBL to test the integrity of the cement seal around the annulus at the bottom of the well. This was not mentioned in BP’s executive summary of the incident but I found other reliable to sources to say this is true. The movie also did a decent job of depicting this incident. Secondly, the cement job at the bottom of the well is to blame. A foamed slurry of nitrified cement was used to seal the bottom of the well. A common theory on this is that nitrogen breakout and migration occurred creating channels in the cement from the reservoir to inside the casing. This would mean that both shoe track barriers failed. These include the cement in the shoe track and the float collar. This was mentioned in BP’s executive summary but was not mentioned in the movie. It was portrayed in the movie though because hydrocarbons were flowing freely through the wellbore. After reading other sources as well, I found that Halliburton was the company that supplied the cement and that the cement had failed multiple lab tests before passing other tests and being deemed fit for use. I am not 100% sure on this statement. Neither BP’s executive summary nor the movie portrayed this. Another source also said that BP was advised to use 21 centralizers and only ended up using six. This could have possibly made the tubing off center of the well bore not allowing the cement to fully encircle and seal off the bottom of the well. Neither the movie nor BP considered this an option. Running a CBL test would have given them the insight to know something was wrong with the integrity of the cement job.

Third, two negative pressure tests were run to ensure the integrity of the cement job because the CBL had not been run. During a negative pressure test the well is sealed, evacuated of drilling fluid, and filled with sea water to run underbalanced and controlled. Pressure readings and volume bled at the time of the negative pressure test indicated communication between the wellbore and the reservoir. After this the well was again filled with heavy weight drilling mud. This allowed hydrocarbons to flow up through the production casing and into the riser above the BOP. The rig crew did not recognize the influx and did not try to shut the well in until well after the time hydrocarbons started flowing rapidly up the wellbore. This was all stated in BP’s statement and partly portrayed in the movie. Although in the movie they showed the negative pressure test being run with drilling mud still in the well rather than sea water. This was incorrect. The second negative pressure test was run on the kill line. This was also shown in the movie. In the movie it shows the kill line being plugged giving a pressure reading of zero. This was the test the company gave the go ahead after. This was only portrayed in the movie and not mentioned in BP’s executive summary. After reading other sources I came up with another scenario. A very heavy LCM was on board the drilling rig and it needed to be used in order to be disposed of. Sources say they used the LCM pill as displacement fluid for the cement so it was still downhole and it being so heavy is why they didn’t see a kick in the initial negative pressure test. This was not portrayed in the movie nor in BP’s executive summary and I do not know if this is true or not. They should not have gone ahead because they didn’t have a good pressure test. Fourth, well control actions could have been done a little differently in order to buy some time. The fluids rushing out of the wellbore were diverted through the Mud Gas separator rather than to overboard diverter line. One flaw in this is that the MGS system allowed for the diversion to the MGS while the well was in a high flow condition. This overwhelmed the system and gas was being diverted directly onto the rig where it could much more easily find an ignition source. It is believed

the generators sucked in the gas causing them to over rev which gave an ignition source for the gas. This was portrayed in the movie very well. It was also mention in BP’s summary. Finally, the BOP was at fault. The blow out preventer did not seal the well. It is believed that explosions and fire disabled the emergency disconnect sequence that was supposed to disconnect the riser from the well. This was displayed in the movie as well as in BP’s report. A fault in one solenoid valve on the BOP and an insufficient charge on the other solenoid was also noted in BP’s report. This was only discovered after the incident but it is believed to have been present during the time of the incident. This was not shown in the movie. I also read from other sources that a crewman had accidentally pulled a significant amount of drill pipe through a closed annular some days before and they were finding chunks of rubber in the shakers. This would mean the annular preventer would not make a good seal. This was neither reported in BP’s executive summary nor displayed in the movie. Proper routine maintenance could have eliminated the BOP solenoid issue. In conclusion, I really enjoyed the movie and found it to be more factual than I originally expected. One thing I did not like was the emphasis it put on BP being at fault and making everyone else involved look completely innocent. Being 43 days behind on a well when the rig costs were $1.2 million/day had everyone involved cutting corners. There were multiple reasons the well blew out and not one company is at fault....