A new tool enables variable bore rams and shear rams to be tested in one run, cutting rig time significantly. Developing a well-specific subsea-capping contingency plan involves assessing the feasibility of deploying a capping stack from a floating vessel, determining the weight and stability, and performing dynamic-flow simulations of closing the capping stack outlets. Despite multitier safeguards, blowouts occur. When such accidents happen, rate estimation is an important and daunting task.
Diniz Brandão Rocha, Leandro (Ocyan) | de Almeida Campos, José Eugênio (Ocyan) | Venâncio Xavier, Cristiano (Ocyan) | Visser, Thijs (Ocyan) | Freitas, Felipe (Stress Engineering) | Stahl, Matt (Stress Engineering) | Cruse, Greg (Oil States Industries)
This paper presents a case study of how a drilling contractor handled the implementation of Managed Pressure Drilling (MPD) equipment on 4 (four) drilling rigs, with focus on the impact on Well Control equipment and emergency disconnect while performing FMCD (Floating Mud Cap Drilling). The paper considers the effects of the rapid inflow of seawater from the bottom of the riser (water rush-in) during a possible emergency disconnect. Additionally, this paper discusses concerns about the subsea equipment when the drilling fluid level is close to the subsea BOP stack or below the seabed. Such scenarios can expose the drilling riser, riser adaptor, flexible joint, BOP annular preventer, BOP seals and gaskets to an inward-acting pressure differential. Restrictions that this inward-acting differential pressure may impose on the conventional equipment currently aboard the drilling units were taken into consideration to determine the feasibility of FMCD operations. This paper highlights the non-conventional considerations as well as challenges associated with this operation for the offshore drilling industry. Those challenges have also motivated technology innovation such as a reduced-friction, next-generation subsea flexible joint, which will operate equally in conventional or MPD conditions.
A proprietary design using a pyro-mechanical, electrically initiated, kinetic energy enabled shearing action has safely and reliably delivered on the promise of "Shear Anything" and seal successfully.
The kinetic blowout stopper (K-BOS) will shear anything in the well above the bit thus eliminating non-shearables from the oil & gas lexicon. Further a superior clean fish with minimal deformation is produced by the kinetic shearing action. The K-BOS will shut-in full flow and pressure blowouts in milliseconds with its simple protected hermetically sealed construction for unparalleled post–shearing sealing performance and dramatically reduce extremely deadly and damaging flammable and/or toxic gas releases. With unrivalled confidence and reliability with best-in-industry control system monitoring and function testing and actuation techniques, the K-BOS requires virtually zero maintenance because of its simple construction where the working components are not wetted by wellbore fluids until actuation, meaning lower costs and reduced NPT and downtime. Like the automotive air bag, the K-BOS is self-contained and meets US and International deregulation requirements regarding safety and logistics of pyrotechnic devices.
Starting with ballistic modeling technology developed for the military, the models were adapted to the K-BOS application and predicted the outcomes of shearing tests with different common tubulars including traditional "unshearables." A testing regime has been conducted to validate the models, demonstrate repeatability of the results, and demonstrate that a post shear seal could be achieved.
More than 30 test serials with the K-BOS 4-1/16″ prototype including empty well-bore tests, shear tests ranging from 5/16″ wireline to 3-1/2″ Drill Collar with a 1″ Wall Thickness. All tests to date have sheared the target tubular without failure. Multiple materials and configurations have been tested.
In all the shearing tests, the K-BOS successfully sheared the target while achieving all safety objectives. The shear test program has validated the models and has also provided validation data allowing for adjustments to the modeling technology for this specific application and resulting in a high level of accuracy and precision in design and shear performance expectations. The shear testing also showed that the K-BOS can shear without damaging the seals and provides an adequate sealing surface after shearing.
The K-BOS has successfully met technical readiness level 5 (API 17N scale) and is ready to move on to in the field scale shear and seal testing. These results and the continuation to continuing development further the prospects of ensuring the K-BOS achieves its mission to strengthen the industry's social license to operate.
This paper describes the planning, execution, improvements, and results from a multi-well fishing campaign using a snubbing unit on pressurized H2S wells for a national oil company (NOC) in the Middle East. A suitable blow out preventer (BOP) stack is shown for fishing coiled tubing, wireline tools, and milling along with the contingencies considered and how these were incorporated into the design of the stack. The challenges encountered during the execution phase are explained along with the solutions implemented. The key performance indicators used and how these improved the operational efficiency during the campaign are discussed. The well problems, desired results, and actual results of the interventions on the wells completed to date are shown.
This paper describes a new type of piston accumulator which uses a solid propellant gas generator to pressurize hydraulic fluid. It is a self-contained device in that both the power source and hydraulic fluid are packaged together in single accumulator. The device rapidly supplies high pressure and high flowrate hydraulic fluid on-demand much like an airbag system for automobiles. It is particularly suited for emergency applications such as closing of subsea BOP shear rams, closing pipeline valves, etc. A conventional piston accumulator can be easily retrofitted with a gas generator cartridge with only minor cap and piston modifications. Retrofitting a conventional compressed gas accumulator with a gas generator cartridge increases the performance of the accumulator by nearly 10X in terms of usable fluid, reliability, weight, and volumetric footprint. Additionally, the gas generator equipped accumulator requires essentially no maintenance and has a service life of more than 10 years. In DMAS applications it can be used in a "Direct-To-Hydraulics" mode by connecting the accumulators directly to the shear rams without the need for any valves other than a check valve. It also eliminates the hydraulic delay system in the DMAS with an electronic delay between CSR and BSR activation, and does not need a complex control system.
Well integrity and well barriers have been part of the exploitation for oil and gas for nearly a century, with the introduction of the blowout preventer (BOP) in the 1920s. The concept of creating well barrier schematics was inaugurated in Norway in 1992, long before the accidents on the Montara platform in 2009 and the Deepwater Horizon rig in 2010 elevated the global focus on well integrity. Yet there are large variations in the industry's perception of well integrity and well barriers, despite the daily use of these terms by drilling and well engineers. Well integrity is defined by the Norsok Standard D-010 (Rev. The definition is so broad that engineers might prefer something that lends itself to a more practical, hands-on description.
Some offshore drillers and equipment makers are betting that a cooperative, long-term relationship will reduce the cost of deepwater well control equipment. Contracts signed over the past the past year by Diamond Offshore Drilling and Transocean, covering a total of 20 offshore drilling units, give GE Oil & Gas and Schlumberger more responsibility, and some risk, for maintaining well control equipment. Intense pressure to both reduce costs and improve reliability and safety is pushing drillers and equipment makers to change. "The unit of measure on this is definitely not hours, days, weeks, or months," said Chuck Chauviere, president of Drilling Systems for GE Oil & Gas. "It is more accurately charted against quarters and years."
BOP Technologies has designed a blowout preventer (BOP) that it says is simpler, more efficient, and, most importantly, can deliver enough power to shear anything that goes into a well. After 3 years of work, the small Houston company is showing off models and pictures of a new compact, cylindrical design that it says can drive a shearing ram with 5 million pounds of force--more than 60% greater than what is now available--and that will be able to cut through drill collars that cannot be cut by currently available BOPs. That is where they come up short," said Jay Read, the inventor of the device and founder of BOP Technologies. The big problem now facing BOP Technologies is "we have got to prove it," Read said. The company needs to raise millions of dollars to build a BOP big enough to show what it can do to actual steel tubing. But based on his long experience building BOPs for the biggest makers in the industry, he said he is looking forward to it, adding, "I can't wait."
Expectations and requirements for subsea-well emergency response preparedness were stepped up as a result of the Macondo blowout and oil spill that began 20 April 2010 in the US Gulf of Mexico. A key change is the requirement to have subsea capping stacks ready to be deployed that are capable of handling the specific blowout scenarios projected for each GOM well, no matter how challenging. It is very important to distinguish between a subsea blowout preventer (BOP) and a subsea capping stack. The name of each piece of equipment gives some useful clues. As the names implies, a BOP is a safety device meant to prevent a blowout from occurring--that is, to prevent an uncontrolled flow of liquids and gases from reaching the surface.
NOV's pressure control research and development (R&D) laboratory is in a tall factory building with a row of large, thick-walled booths used to test how blowout preventers (BOPs) perform at extreme temperatures and pressures. During a tour, NOV's R&D Lab Manager Roger "Dale" Brown made a point of stopping to open a small electrical box. Nearly all of the 24 slots inside were filled with cartridges, each about the size of a deck of cards. The circuits inside them allow engineers to gather whatever sort of data they need from BOP tests and send it along to NOV's central data recorder. The box is a tangible sign of the industry's growing appetite for data as it seeks ways to reduce risk, increase efficiency, and pare costs.