Following the Deepwater Horizon incident in 2010, a group of leading oil companies came together to form Marine Well Containment Company (MWCC), an independent company tasked with developing, owning and maintaining a system to respond to a deepwater well control incident. The capping stack is the centerpiece of this well containment system. MWCC’s Charlie Miller explains. The capping stack creates a connection and seal to prevent well fluids from escaping. The assembly contains a suite of adapters and connectors to interact with various interface points for the variety of well designs and equipment used by oil and gas operators in the US Gulf of Mexico. Capping stacks and their corresponding system equipment now safeguard the US GOM, providing a sound response solution and peace of mind for both regulators and industry.
As of August 31, 2013, 119 permits to drill have been approved by the regulator that cite MWCC’s system. AN INTERIM SYSTEM FOR THE GOM Formally established in December 2010, MWCC provides containment technology to respond to a well control incident in the deepwater US Gulf of Mexico. Today, the company is composed of ten members, all active in the GOM. MWCC’s containment system is available to any company planning to drill in the deepwater GOM, either as a member or as a non-member on a per well basis. As a company whose purpose and mission is to be continuously ready to respond, the cappingstack is at the core of our response system.
MWCC has two capping stacks designed for use in the GOM, and is currently building a third which will be delivered in 2014. The capping stack is an integral part of our overall containment system, and has come a long way since 2011. The first capping stack is rated at 15,000 psi and weighs 100 tons. It provides a dual barrier for containment – a blowout preventer ram, plus a containment cap. This massive piece of equipment is about 30ft tall including the necessary lifting gear, and 14ft wide. When first introduced in 2011, the capping stack could function in 8,000ft of water, but was later confirmed capable of capping a well in up to 10,000ft and cap and flow a well in up to 8,000ft. The system has the capacity to handle up to 60,000 b/d of liquid, and handle up to 120MMscf/d of gas.
However, as our members looked for new and deeper sources of hydrocarbons, we made additional enhancements to these initial capabilities to keep pace with their needs. For example, in August 2011, procedures were developed to provide containment operations for deepwater drilling wells under floating production facilities (TLP/SPAR). These procedures were necessary to be able to install well containment equipment under floating structures. Additionally in September 2012, the capping stack was upgraded for use at well temperatures up to 350 degrees and pressures up to 12,750 psi; for higher pressures up to 15,000 psi, the temperature rating remains at 250 degrees.
In July 2012, at the direction of the Department of the Interior (DOI), MWCC initiated mobilization of its interim containment system, including a physical deployment of the capping stack. Working with member company, Shell Oil Company, MWCC successfully conducted the demonstration on a simulated well in the Walker Ridge block in the deepwater GOM. The demonstration included deployment to a simulated wellhead in 6,900ft of water using the heave compensated landing system. All necessary functions were completed, and pressure testing confirmed the ability to control a well. This capping stack demonstration validated that the right equipment and processes are in place to safely and effectively cap a well.
In January of this year, MWCC introduced a smaller 10,000 psi capping stack with a dual ram that is designed to reach deepwater areas where well casing and riser systems are closely spaced. This smaller capping stack can cap a well in depths up to 10,000ft. The completion of the 10,000 psi capping stack – which stands 25ft tall including the necessary lifting gear and weighs approximately 50 tons – is an example of our collaboration with our members, listening to the needs and, in turn, meeting them. Its 9ft by 9ft frame makes it easier to maneuver where wells are closely spaced such as tension leg platform (TLP) applications where wells are beneath a floating production facility. This 10,000 psi capping stack is another example of the evolution of containment technology and the ongoing enhancements to the overall system.
AN EXPANDED SYSTEM WITH GREATER FLEXIBILITY
As mentioned above, an expanded system is under development. Building on current system capabilities, an expanded containment system (ECS), which represents an investment of more than US$1 billion by the members of MWCC, is currently being built. The ECS will provide greater flexibility to accommodate varying member needs, including greater containment capacity and use in deeper water depths. The expanded system will build on current capabilities to cap and flow a well in up to 10,000ft and can handle up to 100,000 b/d of liquid, and handle up to 200MMscf/d of gas.
This system required a number of firsts for the industry including the deepest production risers (reaching 10,000ft water depths) and the shallowest free-standing adjustable risers (reaching 2,000ft depths) ever built. Additionally, the subsea flexibles are the deepest ever supplied for production. The system will also offer new technological enhancements to the capping stack including the ability to allow operators to function valves and chokes remotely via an umbilical. Moreover, the umbilical, which is the deepest ever built, will function in 10,000ft water depths and provide continuous, real-time pressure and temperature data to the modular capture vessels (MCVs) on the surface. Should the response require a cap and flow scenario, the expanded system flowlines will allow the MCVs to be up to 5,000ft from the wellhead to decrease vessel congestion at the site.
The capping stack connects with two capture vessels – which are modified Aframax tankers each with up to 700,000 bbl of liquid storage capacity – through the riser assembly which directs the flow from the subsea components of the system. The MCVs can process, store and offload liquids to shuttle tankers, which can then safely take the liquids to shore for further processing. The vessels’ turret also allows for a quick disconnect should the MCVs need to move away from the incident site due to a storm in the Gulf. These MCVs are the first of their kind and part of MWCC’s dedicated equipment offering that will be available to operators in the US GOM as part of our expanded system.
As our members continue to look for new and deeper sources of oil, MWCC will continue to advance well containment technologies – including the capping stack – to keep pace with their needs. The next step in these efforts will be the delivery of our expanded containment system, and after that; time will tell. The operating environment in the US GOM encourages technology development to meet the evolving needs of operators. The need to move to deeper depths and greater pressures may not be too far off the horizon. When those needs come to reality, MWCC will be there to lead the industry with its containment systems and continue to deliver upon its mission to be continuously ready to respond. OE Review
Charles A. Miller serves as chief technology officer for Marine Well Containment Company. His responsibilities include development of MWCC capabilities to accept and operate the expanded containment system as well as enhancements to the interim containment system in response to members’ needs. Most recently, he served as vice president of production for Shell Brazil Ltda., where his responsibilities included management of production activities in offshore Brasil and onshore Argentina. A seasoned oil and gas professional, Miller has 35 years of experience in the upstream industry, including 20 years of offshore experience. Miller holds a B.S. in Mechanical Engineering from Oklahoma State University.
Image Caption (top): Marine Well Containment Company’s 15,000 psi capping stack was successfully deployed offshore in the deepwater GOM to a simulated well site at a depth of 6900ft subsea.
Photo: MWCC.
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