Deep Vision, Inc.

Baker Hughes Corporation

James W Macfarlane

Roger W Fincher

Peter Fontana

Larry A Watkins

Roland May

The present invention provides drilling systems for drilling subsea wellbores. The drilling system includes a tubing that passes through a sea bottom wellhead and carries a drill bit. A drilling fluid system continuously supplies drilling fluid into the tubing, which discharges at the drill bit bottom and returns to the wellhead through an annulus between the tubing and the wellbore carrying the drill cuttings. A fluid return line extending from the wellhead equipment to the drilling vessel transports the returning fluid to the surface. In a riserless arrangement, the return fluid line is separate and spaced apart from the tubing. In a system using a riser, the return fluid line may be the riser or a separate line carried by the riser. The tubing may be coiled tubing with a drilling motor in the bottom hole assembly driving the drill bit. A suction pump coupled to the annulus is used to control the bottom hole pressure during drilling operations, making it possible to use heavier drilling muds and drill to greater depths than would be possible without the suction pump. An optional delivery system continuously injects a flowable material, whose fluid density is less than the density of the drilling fluid, into the returning fluid at one or more suitable locations the rate of such lighter material can be controlled to provide supplementary regulation of the pressure. Various pressure, temperature, flow rate and kick sensors included in the drilling system provide signals to a controller that controls the suction pump, the surface mud pump, a number of flow control devices, and the optional delivery system.

Subsea wellbore drilling system for reducing bottom hole pressure

A tubing handling for subsea oilfield tubing operations, includes an isolation tube to mechanically and/or chemically protect the drill string and improved passage of the drill string and fluid return line to the drilling vessel that further protects them during drilling use. In addition, the improvements include an automatic safety apparatus to hold against unintended movement of the tubular members under extreme length and weight conditions as well as against human error at the rig. Further, the invention includes multi-segment coiled tubing drill strings that can be adapted to drilling requirements in a deep wellbore.

Tubing handling for subsea oilfield tubing operations

The present invention provides apparatus and method for killing or suppressing a subsea wellbore. The system includes a pressure intensifier adjacent the wellhead. The output of the pressure intensifier is coupled to a &ldquo;kill&rdquo; inlet at the wellhead equipment. Power is supplied from the surface to the pressure intensifier, which increases the pressure by a known multiple, usually 3 to 5, and supplies the high pressure fluid to the wellbore. A control unit at the surface controls the operation of the pressure intensifier in response to the predefined criteria or programmed instructions. One or more sensors provide measurements to the control unit of the wellbore conditions, which are used to determine the timing of activation of the pressure intensifier.

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Katy, TX, United States of America

James W Macfarlane