Offshore oil spill prevention and response

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Inspector on offshore oil drilling rig Offshore oil drilling inspection.jpg
Inspector on offshore oil drilling rig

Offshore oil spill prevention and response is the study and practice of reducing the number of offshore incidents that release oil or hazardous substances into the environment and limiting the amount released during those incidents. [1] [2] [3]

Contents

Important aspects of prevention include technological assessment of equipment and procedures, and protocols for training, inspection, and contingency plans for the avoidance, control, and shutdown of offshore operations. Response includes technological assessment of equipment and procedures for cleaning up oil spills, and protocols for the detection, monitoring, containment, and removal of oil spills, and the restoration of affected wildlife and habitat. [4]

In the United States, offshore oil spill prevention contingency plans and emergency response plans are federally mandated requirements for all offshore oil facilities in U.S. Federal waters. [5] Currently administered by the Minerals Management Service (MMS), these regulatory functions were ordered on May 19, 2010 to be transferred to the United States Department of the Interior's newly created Bureau of Safety and Environmental Enforcement. [6] Oil spills in inland waters are the responsibility of the Environmental Protection Agency (EPA), while oil spills in coastal waters and deepwater ports are the responsibility of the U.S. Coast Guard. [7]

Unlike the Best Available Technology (BAT) criteria stipulated by the Clean Air Act and the Clean Water Act, the Outer Continental Shelf Lands Act amendments of 1978 stipulated that offshore drilling and oil spill response practices incorporate the use of Best Available and Safest Technologies (BAST). [8] [9] While the Technology Assessment and Research (TAR) Program is tasked with research and development of such technologies through contract projects, human factors are also highly relevant in preventing oil spills. As William Cook, former chief of the Performance and Safety Branch of Offshore Minerals Management for the MMS, expressed it: "Technology is not enough. Sooner or later, it comes face to face with a human being. What that human being does or does not do, often ensures that the technology works as it was intended--or does not. Technology -- in particular -- new, innovative, cutting edge technology must be integrated with human and organizational factors (HOF) into a system safety management approach." [10]

Top 10 largest oil spills in history

RankDateCauseSourceLocationSpill Volume
1.Jan. 23–27, 1991Deliberate act by IraqOil Tankers10 miles out of Kuwait240–460 million gallons
2.April 20, 2010ExplosionDrilling rig Deepwater HorizonGulf of Mexico, 50 miles off the coast of Louisiana210 million gallons
3.June 3, 1979Well blowoutOil well Ixtoc 1Gulf of Mexico140 million gallons
4.March 2, 1992LeakOil wellFergana Valley, Uzbekistan88 million gallons
5.July 19, 1979Collision of tankersAtlantic Empress and the Aegean CaptainTrinidad & Tobago87 million gallons
6.Sept. 8, 1994Dam burstOil ReservoirRussia84 million gallons
7.April, 1977Well blowoutEkofisk oil fieldNorth Sea81 million gallons
8.Feb. 4, 1983CollisionNowruz Field PlatformPersian Gulf, Iran80 million gallons
9.May 28, 1991ExplosionTanker ABT SummerOffshore of Angola78 million gallons
10.Aug. 6, 1983Fire on tankerTanker Castillo de BellverCape Town, South Africa78 million gallons

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Regulations and consequences

Because of treatment and disposal requirements for drilling and production, wastes are likely to become ever more stringent. Bans on land disposal will pose even greater challenges, especially for remote oil and gas operations. The significant costs to oil and gas producers complying with this new wave of regulation will be outweighed only by the even more significant costs of non-compliance. The federal Environmental Protection Agency (EPA) in the United States and similar bodies globally as well as many state and local agencies have greatly increased both their enforcement capabilities and activities. Most environmental laws carry criminal charges. Because of this many operations personnel and members of senior management of large companies have found themselves on the wrong side of environmental enforcement actions through ignorance to the increasingly complex requirements and the severe consequences of violating environmental laws. [11]

International treaties, like the International Convention for the Prevention of Pollution from Ships (MARPOL), administered by the International Maritime Organization and implemented in many countries as legislation (such as the US Oil Pollution Act of 1973) place mandatory restrictions, recording, and penalties for the spilling of oil from ships.

In 1967, the Torrey canyon incident off the coast of Britain leaked massive amounts of oil into the ocean. One of the many issues this incident highlighted was the issue of economic compensation, as the existing laws did not allow the British and French government to sue the responsible corporation for adequate compensation. Today, there are several regulations, such as the clean water act, and International Convention on Civil Liability for Oil Pollution Damage (CLC) that provide a framework for how to deal with the issue of compensation. The regulations aim to identify who is the responsible party, what are damages they must compensate for, and which parties should receive compensation.  There are also non-government organizations that deal with oil spill compensation claims, like the international tanker owners pollution federation Limited (ITOPF), a non-profit organization. [12] Though international regulations, like CLC exists and are widely adopted, they do not apply everywhere. The U.S for example, have contributed to the creation of the CLC, but is not a signatory of the CLC because they have extensive national regulations, like the clean water act and oil pollution act that they rely on instead, while China only has implemented parts of it. [13]

Technologies

Hydrocarbon producing wells are designed and managed on the basis of the 'barriers' in place to maintain containment. A 'dual barrier' philosophy is typically used whereby two independently verified barriers to the hydrocarbon reservoir and the environment are required at all times. The failure of a single barrier would not lead to a hydrocarbon release. During the different phases of drilling, production, workover and abandonments, many different pieces of equipment will be used to maintain control of the well fluids and pressures.

Drilling blowout preventers

Figure 1. Of the shear rams tested, 50% failed under pressures expected in deep sea drilling. MMS455d barchart shear ram failures.png
Figure 1. Of the shear rams tested, 50% failed under pressures expected in deep sea drilling.
Figure 2. In a shear ram, the two blades are driven hydraulically to cut the thick steel drill pipe. MMS463a shear ram forces.png
Figure 2. In a shear ram, the two blades are driven hydraulically to cut the thick steel drill pipe.
Figure 3. Sheared end of a drill pipe. 455 sheared pipe.png
Figure 3. Sheared end of a drill pipe.

The primary safety control devices for well drilling are blowout preventers (BOPs), which have been used for nearly a century in control of oil well drilling on land. The BOP equipment technology has been adapted and used in offshore wells since the 1960s. The inspection and repair of subsea BOPs are much more costly, and the consequences of failure potentially much worse. There are two variations of offshore BOP in use; the sub-sea blowout preventer which sits on the ocean floor, and the surface blowout preventer which sits between the riser pipe and the drilling platform. The surface unit is smaller, lighter, less costly, and more easily accessed for routine tests and maintenance. However, it does not prevent blowouts involving a broken riser pipe. [14]

Blowout Preventers often contain a stack of independently-operated cutoff mechanisms, so there is redundancy in case of failure, and the ability to work in all normal circumstances with the drill pipe in or out of the well bore. The BOP used in the Deepwater Horizon , for example, had five "rams" and two "annular" blowout preventers. [15] The rams were of two types: "pipe rams" and "shear rams". If the drill pipe is in the well, the pipe rams slide perpendicular to the pipe, closing around it to form a tight seal. The annular preventers also close around the pipe, but have more of a vertical motion, so they loosen slightly if the drill pipe is being pushed downward, as might be necessary in a "snubbing" or "well kill" operation. [16] Shear rams may be used as a last resort [17] to cut through the drill pipe and shut off everything, including whatever might be coming up inside the drill pipe.

Studies done for the Minerals Management Service have questioned the reliability of shear rams in deep-water drilling. Figure 1 shows the result of a 2002 study on offshore oil rigs. This study was designed to answer the question “Can a given rig’s BOP equipment shear the pipe to be used in a given drilling program at the most demanding condition to be expected?” [18] Seven of the fourteen cases in this study opted not to test, another had insufficient data to draw a definitive conclusion, and three failed to shear the pipe under realistic conditions of expected well bore and seawater pressure. In each case of failure, increasing the pressure on the rams above its design value, successfully sheared the pipe. [18] A follow-up study in 2004 confirmed these results with a much larger sample of drill pipes and typical blowout preventers from three different manufacturers. [17]

In addition to insufficient ram pressure, a New York Times investigation of the Deepwater Horizon oil spill listed other problem areas for deepwater blowout preventers. If one of the threaded joints between pipe sections is positioned within a shear ram, the ram would probably not cut through it, because the joints are "nearly indestructable". [19] Requiring two shear rams in every blowout preventer may help to avoid this problem and to avoid some types of "single-point failure". [19] Other technologies that might improve the reliability of BOPs include backup systems for sending commands to the BOP and more powerful submersibles that connect to the BOP's hydraulics system. [19]

Well casings

Figure 4. Typical well casings during the final tests before shut in. Undersea well casing.png
Figure 4. Typical well casings during the final tests before shut in.

Casing of offshore oil wells is done with a set of nested steel pipes, cemented to the rock walls of the borehole as in Figure 4. Each section is suspended by a threaded adapter inside the bottom end of the section above. [20] Failure of either the casings or the cement can lead to injection of oil into groundwater layers, flow to the surface far from the well, or a blowout at the wellhead. [21]

In addition to casings, oil wells usually contain a "production liner" or "production tubing", which is another set of steel pipes suspended inside the casing. The "annulus" between the casing and the production liner is filled with "mud" of a specific density to "balance" the pressure inside the casing with the "pore pressure" of fluids in the surrounding rock "formations". [16]

To ensure that the cement forms a strong, continuous, 360-degree seal between the casing and the borehole, "centralizers" [16] are placed around the casing sections before they are lowered into the borehole. Cement is then injected in the space between the bottom of the new casing section and the bottom of the borehole. The cement flows up around the outside of the casing, replacing the mud in that space with pure, uncontaminated cement. Then the cement is held perfectly still for several hours while it solidifies. [20]

Without centralizers, there is a high risk that a channel of drilling mud or contaminated cement will be left where the casing contacts the borehole. These channels can provide a path for a later blowout. Even a thin crack can be pushed open by the enormous pressure of oil from below. Then erosion of the cement can occur from high-velocity sand particles in the oil. A hairline crack can thus become a wide-open gushing channel. [22]

Another cause of cement failure is not waiting long enough for the cement to solidify. This can be the result of a rushed drilling schedule, or it could happen if there is a leak causing the cement to creep during the time it is supposed to be setting. A "cement evaluation log" [16] can be run after each cement job to provide a detailed, 360-degree check of the integrity of the entire seal. Sometimes these logs are skipped due to schedule pressures.

Cement is also used to form permanent barriers in the annulus outside the production liner, and temporary barriers inside the liner. The temporary barriers are used to "shut in" the well after drilling and before the start of production. Figure 4 shows a barrier being tested by replacing the heavy mud above it with lighter seawater. If the cement plug is able to contain the pressure from the mud below, there will be no upward flow of seawater, and it can be replaced with mud for the final shut in.

There are no cement barriers in the annulus in Figure 4. While there is no requirement for such barriers, adding them can minimize the risk of a blowout through a direct wide-open channel from the reservoir to the surface. [23]

Human factors

See also

Related Research Articles

<span class="mw-page-title-main">Ixtoc I oil spill</span> Oil spill disaster in the Gulf of Mexico

Ixtoc 1 was an exploratory oil well being drilled by the semi-submersible drilling rig Sedco 135 in the Bay of Campeche of the Gulf of Mexico, about 100 km (62 mi) northwest of Ciudad del Carmen, Campeche in waters 50 m (164 ft) deep. On 3 June 1979, the well suffered a blowout resulting in the largest oil spill in history at its time. To-date, it remains the second largest oil spill in history after the Deepwater Horizon oil spill.

<span class="mw-page-title-main">Casing (borehole)</span>

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<span class="mw-page-title-main">Wellhead</span> Component at the surface of a well that provides the structural and pressure-containing interface

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<span class="mw-page-title-main">Blowout (well drilling)</span> Uncontrolled release of crude oil and/or natural gas from a well

A blowout is the uncontrolled release of crude oil and/or natural gas from an oil well or gas well after pressure control systems have failed. Modern wells have blowout preventers intended to prevent such an occurrence. An accidental spark during a blowout can lead to a catastrophic oil or gas fire.

<span class="mw-page-title-main">Blowout preventer</span> Specialized valve

A blowout preventer (BOP) is a specialized valve or similar mechanical device, used to seal, control and monitor oil and gas wells to prevent blowouts, the uncontrolled release of crude oil or natural gas from a well. They are usually installed in stacks of other valves.

<span class="mw-page-title-main">Coiled tubing</span> Long metal pipe used in oil and gas wells

In the oil and gas industry, coiled tubing refers to a long metal pipe, normally 1 to 3.25 in in diameter which is supplied spooled on a large reel. It is used for interventions in oil and gas wells and sometimes as production tubing in depleted gas wells. Coiled tubing is often used to carry out operations similar to wirelining. The main benefits over wireline are the ability to pump chemicals through the coil and the ability to push it into the hole rather than relying on gravity. Pumping can be fairly self-contained, almost a closed system, since the tube is continuous instead of jointed pipe. For offshore operations, the 'footprint' for a coiled tubing operation is generally larger than a wireline spread, which can limit the number of installations where coiled tubing can be performed and make the operation more costly. A coiled tubing operation is normally performed through the drilling derrick on the oil platform, which is used to support the surface equipment, although on platforms with no drilling facilities a self-supporting tower can be used instead. For coiled tubing operations on sub-sea wells a mobile offshore drilling unit (MODU) e.g. semi-submersible, drillship etc. has to be utilized to support all the surface equipment and personnel, whereas wireline can be carried out from a smaller and cheaper intervention vessel. Onshore, they can be run using smaller service rigs, and for light operations a mobile self-contained coiled tubing rig can be used.

<i>Deepwater Horizon</i> Former offshore oil drilling rig

Deepwater Horizon was an ultra-deepwater, dynamically positioned, semi-submersible offshore drilling rig owned by Transocean and operated by BP. On 20 April 2010, while drilling at the Macondo Prospect, a blowout caused an explosion on the rig that killed 11 crewmen and ignited a fireball visible from 40 miles (64 km) away. The fire was inextinguishable and, two days later, on 22 April, the Horizon sank, leaving the well gushing at the seabed and causing the largest marine oil spill in history.

<span class="mw-page-title-main">1969 Santa Barbara oil spill</span> Oil platform blow-out fouled the coast of California resulting in environmental legislation

The Santa Barbara oil spill occurred in January and February 1969 in the Santa Barbara Channel, near the city of Santa Barbara in Southern California. It was the largest oil spill in United States waters at the time, and now ranks third after the 2010 Deepwater Horizon and 1989 Exxon Valdez spills. It remains the largest oil spill to have occurred in the waters off California.

Oilfield terminology refers to the jargon used by those working in fields within and related to the upstream segment of the petroleum industry. It includes words and phrases describing professions, equipment, and procedures specific to the industry. It may also include slang terms used by oilfield workers to describe the same.

<i>Q4000</i>

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<i>Deepwater Horizon</i> oil spill Oil spill that began in April 2010 in the Gulf of Mexico

The Deepwater Horizon oil spill was an industrial disaster that began on 20 April 2010 off of the coast of the United States in the Gulf of Mexico on the BP-operated Macondo Prospect, considered to be the largest marine oil spill in the history of the petroleum industry and estimated to be 8 to 31 percent larger in volume than the previous largest, the Ixtoc I oil spill, also in the Gulf of Mexico. The United States federal government estimated the total discharge at 4.9 MMbbl. After several failed efforts to contain the flow, the well was declared sealed on 19 September 2010. Reports in early 2012 indicated that the well site was still leaking. The Deepwater Horizon oil spill is regarded as one of the largest environmental disasters in world history.

<i>Deepwater Horizon</i> explosion 2010 oil disaster in the Gulf of Mexico

The Deepwater Horizon drilling rig explosion was an April 20, 2010 explosion and subsequent fire on the Deepwater Horizon semi-submersible mobile offshore drilling unit, which was owned and operated by Transocean and drilling for BP in the Macondo Prospect oil field about 40 miles (64 km) southeast off the Louisiana coast. The explosion and subsequent fire resulted in the sinking of the Deepwater Horizon and the deaths of 11 workers; 17 others were injured. The same blowout that caused the explosion also caused an oil well fire and a massive offshore oil spill in the Gulf of Mexico, considered the largest accidental marine oil spill in the world, and the largest environmental disaster in United States history.

<span class="mw-page-title-main">Cameron ram-type blowout preventer</span>

The Cameron ram-type blowout preventer was the first successful blowout preventer (BOP) for oil wells. It was developed by James S. Abercrombie and Harry S. Cameron in 1922. The device was issued U.S. Patent 1,569,247 on January 12, 1926. The blowout preventer was designated as a Mechanical Engineering Landmark in 2003.

The following is a timeline of the Deepwater Horizon oil spill. It was a massive oil spill in the Gulf of Mexico, the largest offshore spill in U.S. history. It was a result of the well blowout that began with the Deepwater Horizon drilling rig explosion on April 20, 2010.

Following is a Timeline of the Deepwater Horizon oil spill for May 2010.

Efforts to stem the Deepwater Horizon oil spill were ongoing from the time that the Deepwater Horizon exploded on April 20, 2010 until the well was sealed by a cap on July 15, 2010. Various species of dolphins and other mammals, birds, and the endangered sea turtles have been killed either directly or indirectly by the oil spill. The Deepwater Horizon spill has surpassed in volume the 1989 Exxon Valdez oil spill as the largest ever to originate in U.S.-controlled waters; it is comparable to the 1979 Ixtoc I oil spill in total volume released.

Oil spill governance in the United States is governed by federal law.

Arctic Challenger

Arctic Challenger is a barge which has been converted by Superior Energy Services for use in the Arctic drilling operations of Shell Oil Company. This barge is designed to function as a "novel engineering solution" which they refer to as an Arctic Containment System to respond should a blowout event occur at drilling sites in the Beaufort or Chukchi Seas. According to testimony provided to Senator Mark Begich on 11 October 2012, Coast Guard Rear Admiral Thomas Ostebo said the certification for the Shell spill barge Arctic Challenger to operate in Alaska was given on the 10th of October at the Bellingham, Washington shipyard where it was constructed. Ostebo is commander of the Coast Guard's 17th district, which covers Alaska.

The Deepwater Horizon investigation included several investigations and commissions, among others reports by National Incident Commander Thad Allen, United States Coast Guard, National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling, Bureau of Ocean Energy Management, Regulation and Enforcement, National Academy of Engineering, National Research Council, Government Accountability Office, National Oil Spill Commission, and Chemical Safety and Hazard Investigation Board.

HWCG LLC is a not-for-profit consortium of deepwater oil and gas companies. HWCG maintains a comprehensive deepwater well containment response model that can be activated immediately in the event of a US Gulf of Mexico subsea blowout. It comprises oil and gas companies operating in the Gulf and incorporates the consortium’s generic well containment plan. HWCG has a healthy mutual aid component whereby HWCG members will respond and support another member’s incident.

References

  1. ↑ Oil Pollution Act of 1990
  2. ↑ Federal Water Pollution Control Act
  3. ↑ Oil Spill Prevention and Response Advisory Group, Terms of Reference Rev3, UK Oil & Gas
  4. ↑ Ornitz, Barabar E.; Michael A. Champ (2002). Oil Spills First Principles: Prevention and Best Response. Elsevier Science, Ltd. ISBN   0-08-042814-2.
  5. ↑ "Spill Prevention and Response". Energy Tomorrow, American Petroleum Institute. Retrieved 2010-06-15.
  6. ↑ Straub, Noelle (20 May 2010). "Interior Unveils Plan to Split MMS Into 3 Agencies". The New York Times. Retrieved 2010-06-15.
  7. ↑ "Oil Spills: Emergency management". Environmental Protection Agency. Retrieved 2010-06-15.
  8. ↑ "MMS Technology Assessment & Research (TA&R) Program". Mineral Management Service. Archived from the original on 2010-05-28. Retrieved 2010-06-15.
  9. ↑ The use of Best Available and Safest technologies (BAST) during oil and gas drilling and producing operations of the Outer Continental Shelf (OCS). Reston, Virginia: U.S. Geological Survey. 1980.
  10. ↑ Cook, William S (March 1997). "Technology Alone is Not the Answer". All Days. SPE/EPA Exploration and Production Environmental Conference. doi:10.2118/37895-MS . Retrieved 2010-06-15.
  11. ↑ Jones, Stephen C.; O'Toole, Patricia (1989). "Increasing Environmental Regulation of Oil and Gas Operations". pp. 209–215.
  12. ↑ Marchand, Pauline (2017). "The International Law Regarding Ship-Source Pollution Liability and Compensation: Evolution and Current Challenges". 2017 International Oil Spill Conference. 2017 (1): 193–210. doi:10.7901/2169-3358-2017.1.193 – via JSTOR.
  13. ↑ Yang, Yuan (2017). "Liability and Compensation for Oil Spill Accidents: International Regime and Its Implementation in China". Natural Resources Journal. 57: 465–492 – via JSTOR.
  14. ↑ Risk Analysis of Using a Surface Blow Out Preventer (BOP) Archived 2010-06-12 at the Wayback Machine , Marine Computation Services, Inc., April 2010, project 640 for U.S. Minerals Management Service.
  15. ↑ Diagram of BOP used in Deepwater Horizon well from U.S. Dept. of Energy, Open Government program.
  16. 1 2 3 4 Schlumberger Oilfield Glossary is an excellent source for definitions and simple explanations.
  17. 1 2 Shear Ram Capabilities Study Archived 2010-06-12 at the Wayback Machine , West Engineering Services, Sept. 2004, Project 463 for U.S. Minerals Management Service.
  18. 1 2 Review of Shear Ram Capabilities Archived 2010-06-03 at the Wayback Machine , West Engineering Services, Dec. 2002, Project 455 for U.S. Minerals Management Service.
  19. 1 2 3 Barstow, David; Laura Dodd; James Glanz; Stephanie Saul; Ian Urbina (20 June 2010). "Regulators Failed to Address Risks in Oil Rig Fail-Safe Device". The New York Times. Retrieved 2010-08-15.
  20. 1 2 Casing a Well, Heading Out (Dave Summers), The Oil Drum, 3 May 2010.
  21. ↑ BP Decisions Set Stage for Disaster, Ben Casselman, Russel Gold, Wall Street Journal, 5/27/2010.
  22. ↑ See discussion of centralizers in the Schlumberger Oilfield Glossary
  23. ↑ Shell Oil presentation Archived 2010-07-27 at the Wayback Machine "Drilling for Oil: A Visual Presentation of How We Drill for Oil and the Precautions Taken Along the Way", Joe Leimkuhler, John Hollowell, Aspen Ideas Festival, July 2010.
  1. U.S. Coast Guard and Environmental Protection Agency, Oil Spill Prevention, Control, & Countermeasure Regulations
  2. American Petroleum Institute, Oil Spill Prevention and Response
  3. NOAA, 2002. Oil Spill Prevention and Response: A Selected Bibliography on the Exxon Valdez Oil Spill
  4. Offshore Technology Resource Center. 2001. Comparative Risk Analysis for Deepwater Production Systems
  5. Oil & Gas UK, Oil Spill Prevention and Response Advisory Group (OSPRAG)
  6. International Oil Spill Conference (IOSC), 1969–present. Archives of over 3,000 papers and full-text conference proceedings covering spill prevention, planning, response and restoration processes, protocols and technology.

oil spills are bad

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