Deepwater Horizon Disaster

Transcription

1 Deepwater Horizon Disaster Professor Satish Nagarajaiah Dept. of Civil & Env. Eng., Dept. of Mechanical Eng. & Material Sc. Rice University, Houston, TX, USA Member, Deepwater Horizon Study Group (DHSG) Univ. of California, Berkeley Dedicated To The Men and Women Who Serve Our Country And To Those Who Lost Their Lives Doing Their Duty Invited Lecture, ASCE Houston Chapter, June 15, 2010 Disclaimer: This study is meant to be purely technical documentation of events and causes. It is not meant to place blame on any individual or company or industry or government.

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3 Space Shuttle Columbia Disaster

4 Space Shuttle Columbia Disaster Source: CAIB

7 Source: CAIB

8 World Trade Center, September 11, 2001

9 Chevron Typhoon TLP in 2000 ft of Water: 40,000 barrels/day and 60 million CFT of natural gas. Was upended by Hurricane Rita in 2005, but no leak!! and things worked fine. The platform turned into a natural reef. Before After: The Platform and Derrick Underwater Source: Chevron

10 Shell Mars TLP in 3250 ft of Water: 220,000 barrels/day and 220 million CFT of natural gas. Badly damaged in Hurricane Katrina No leak!! and things worked fine. The Mars platform is back in operation. Restored Platform and Derrick Damaged Platform and Derrick Source: Shell

11 Outline Deepwater Horizon Disaster April 20, 2010 Unfolding Environmental Disaster Impact of the Oil Spill Oil Spill Response and Containment Measures Ongoing g Investigations Concluding Remarks

12 Deepwater Horizon Rig Source: MMS and BP

13 April 20, 2010 At approximately 10 pm Horizon Rig disaster started Initial explosion due to Gas/Oil/Mud surge and ignition upon entry into the engine room Fire starts and power failure Violent vibrations that t shook the entire rig reported Second explosion Rig evacuated and fire/containment response and rescue begins by nearby vessels

14 Horizon Rig April 20/21/22, 2010 Source: MMS/AP/flickr

15 Collapse / Oil Spill Source: NYT/AP/flickr

16 Horizon Before/After Collapse Ocean Surface Horizon Drill Rig 21 Riser 5000 ft BOP Stack Wellhead ft Reservoir Source: Live Science

17 Containment Response (ROV - BOP Shr Ram) April 24 - several days Source: MMS/BP

18 Containment Response (Riser Insertion Tube) May 15 Source: BP

19 Containment Response (Top Kill/Junk Shot) May 26/27 Source: BP

20 Containment Response (Riser Cut & LMRP Cap) May 29 Source: BP

21 Containment Response (Riser Cut & LMRP Cap) May 29 Source: BP

22 Surface/Subsurface Containment Response Source: BP

23 Containment Response (Largest Ever) Source: BP

24 Containment Response (Largest Ever) Source: MMS/BP/flickr

25 Containment Response (Relief Wells) Mid August Source: BP

26 Source: NYT Environmental and Ecological Impact

27 ce: NYT Sourc Environmental and Ecological Impact

28 Cementing Procedure Figure Source: NYT

29 Source: MMS/DHSG As Drilled Well

30 Cement Seal Lacking Source: DHSG/Halibo orton Well Design

31 Blow Out Preventer (BOP) Riser Adapter Flex Joint Control Pod with Upper/Lower Annular Ram Behind Riser Connector Kill Line Blind Shear Ram Casing Shear Ram Pipe Ram Pipe Ram Test Ram Choke Line Stack Connector

32 U.S. House of Representative Energy and Commerce Committee Investigation ( g p p Excerpts from the Letter dated June 14, 2010, from Senate Energy and Commerce Committee to Mr. Tony Hayward, CEO, BP The Committee's investigation israising i serious questions about the decisions i made by BP in the days and hours before the explosion on the Deepwater Horizon. On April 15, five days before the explosion, BP's drilling engineer called Macondo a "nightmare well." In spite of the well's difficulties, BP appears to have made multiple decisions for economic reasons that increased the danger of a catastrophic well failure. In several instances, these decisions appear to violate industry guidelines and were made despite warnings from BP's own personnel and its contractors. In effect, it appears that BP repeatedly chose risky procedures in order to reduce costs and save time and made minimal efforts to contain the added risk. Source: U.S. House of Representatives - Energy & Commerce Committee

33 U.S. House of Representative Energy and Commerce Committee Investigation ( g p p Excerpts from the Letter dated June 14, 2010, from Senate Energy and Commerce Committee to Mr. Tony Hayward, CEO, BP At the time of the blowout, the Macondo well was significantly behind schedule. This appears to have created pressure to take shortcuts to speed finishing the well. In particular, the Committee is focusing on five crucial decisions made by BP: (I) the decision i to use a well design with few barriers to gas flow; (2) the failure to use a sufficient number of "centralizers" to prevent channeling during the cement process; (3) the failure to run a cement bond log to evaluate the effectiveness of the cement job; (4) the failure to circulate potentially gas-bearing drilling muds out of the well; and (5) the failure to secure the wellhead with a lockdown sleeve before allowing pressure on the seal from below. The common feature of these five decisions is that they posed a trade-off between cost and well safety. Source: U.S. House of Representatives - Energy & Commerce Committee

34 BP Internal Investigation BP investigation team s work thus far shows that this accident was brought about by the failure of a number of processes, systems and equipment. There were multiple control mechanisms procedures and equipment in place that should have prevented this accident or reduced the impact of the spill: the investigation is focused on the following seven mechanisms. 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. Source: BP

35 BP Internal Investigation Before, during or after the cement job, an undetected influx of hydrocarbons entered the wellbore The 9 7/8 casing was tested; the 9 7/8 casing hanger packoff was set and tested, and the entire system was tested After 16.5 hours waiting on cement, a test was performed on the wellbore below the Blow Preventer (BOP) During this test, 1400 psi was observed on the drill pipe while 0 psi was observed on the kill and the choke lines Following the test, hydrocarbons were unknowingly circulated to surface while displacing the riser with seawater As hydrocarbons rose to the surface, they expanded, further reducing the hydrostatic pressure. The well flowed and witness account suggest that the Annular Preventer in the BOP and the Diverter were activated An explosion occurred, followed by a power failure Witness accounts suggest that the Emergency Disconnect System was activated Source: BP/U.S. House Energy and Commerce Committee

36 BP Internal Investigation The rig was evacuated The BOP system failed to work as intended. Flow was not contained and the Lower Marin Riser Package did no disconnect Modifications have been discovered in the BOP system Leaks have been discovered in the BOP hydraulics system BP launched an investigation which is ongoing INVESTIGATION THEMES Cementing design and execution Casing design and installation Casing Hanger Design and Installation BOP Configuration, maintenance and Operation Source: BP/U.S. House Energy and Commerce Committee

37 Current State: June 15, 2010 The updated flow group spill estimate is 35,000 to 60,000 barrels/day. The flow has doubled due to two reasons: (1) "Top kill" operation by connecting to the choke and kill lines on the blow out preventer (BOP) and pumping 30,000 barrels of mud into the well has increased discharge. It appears that instead of clogging the pipe (remember Junk Shot was supposed to bridge the BOP) the top kill operation has made the discharge much more rapid (i.e., cleared the pipe of all obstruction including whatever cement plug was holding; the exact opposite of what it was supposed to do). (2) The riser cut has increased the flow dramatically the th kink k was much more severe than originally estimated. In this I must say that I was taken in by the response team's estimate of 20%. Obviously I wish I had access to the kink photographs p to examine more closely. Unfortunately there are no good photographs of the kink. Only the response team and flow measurement team has access to this information. In essence the flow has doubled from before due to the aforementioned reasons.

38 Current State: June 15, 2010 The flow measurement team has more accurate sensor data based on pressure and flow sensors that BP has installed at the leak point. They estimate the flow to have doubled from their previous estimates of 25,000 to 30,000 barrels/day. So here is the updated version of my current estimate 23,000* x2.0 = 46,000 barrels/day which turns out to be nearly the average of (35, ,000)/2 = 47,500 barrels/day. Hopefully BP can start capturing much more than 15,000 barrels/day. More BP assets are on the way (unfortunately ships take time to cross the high seas) and should help in capturing significantly more leaking oil/gas. An important point to remember is that BP will capture a mixture of oil/gas and sea water. So when BP says they will be able to capture 80,000 barrels/day it means they will get most, but not all. So relief well is the only permanent solution. * My earlier estimates from May 20, 2010 put the leak at 23,000 barrels/day (visit

39 Concluding Remarks Worst Environmental and Ecological Disaster Ever in the United States August September by the time this is all over and recovery begins White House Panel to Investigate the Deepwater Horizon Disaster Deepwater Horizon Study Group to conduct its own investigation MMS and regulatory structure expected to undergo significant changes More stringent safety and redundancy requirements likely The oil industry will weather this storm, but come out significantly safer but changed for good