A method of drilling a subterranean well bore comprising, monitoring the well bore for influx of formation fluid into the well bore, and, on detection of an influx, a) stopping any pump pumping fluid into the well bore, b) operating a first blow out preventer so that it closes within a first period of time, c) operating a second blow out preventer so that it closes within a second period of time, the second blow out preventer being located below the first blow out preventer, the second period of time being longer than the first period of time, d) circulating the influx out of the well bore via a flow line extending from below the second blow out preventer.

An underreamer for increasing a diameter of a wellbore. The underreamer may include a body having an axial bore extending at least partially therethrough. An electromagnetic activation system may be disposed at least partially within the bore of the body. A valve may be disposed within the bore of the body and coupled to the electromagnetic activation system. The valve may include a mobile element and a static element. The mobile element may be coupled to the electromagnetic activation system and move from a first position where the mobile element obstructs fluid flow through the valve to a second position where the mobile element permits fluid flow through the valve. A cutter block may be movably coupled to the body and move radially-outward as the mobile element moves from the first position to the second position.

An offshore well-processing system includes a mobile offshore drilling unit and a remote well-processing device configured to be positioned on an offshore platform different from the mobile offshore drilling unit, the mobile offshore drilling unit defining at least one well center and comprising at least one primary drill rig including at least one drill floor and at least one hoisting system for raising and lowering tubular equipment through the at least one well center from/into a well in the seafloor. The mobile offshore drilling unit and the remote well-processing device are configured to be operationally coupled to each other; and the mobile offshore drilling unit is configured to assist in performing concurrent well-processing tasks on respective wells, including the first well processing task performed by the remote well-processing device on a first well and a second well-processing task concurrently performed by the offshore well-processing system on a second well.

An offshore well-processing system includes a mobile offshore drilling unit and a remote well-processing device configured to be positioned on an offshore platform different from the mobile offshore drilling unit, the mobile offshore drilling unit defining at least one well center and comprising at least one primary drill rig including at least one drill floor and at least one hoisting system for raising and lowering tubular equipment through the at least one well center from/into a well in the seafloor. The mobile offshore drilling unit and the remote well-processing device are configured to be operationally coupled to each other; and the mobile offshore drilling unit is configured to assist in performing concurrent well-processing tasks on respective wells, including the first well processing task performed by the remote well-processing device on a first well and a second well-processing task concurrently performed by the offshore well-processing system on a second well.

In another embodiment, a method of drilling a wellbore includes running a drilling assembly into the wellbore through a casing string, the drilling assembly comprising a tubular string, an underreamer, and a drill bit; injecting drilling fluid through the tubular string and rotating the drill bit, wherein the underreamer remains locked in the retracted position; sending an instruction signal to the underreamer via modulation of a rotational speed of the drilling assembly or modulation of a drilling fluid pressure, thereby extending the underreamers; and reaming the wellbore using the extended underreamer.

In another embodiment, a method of drilling a wellbore includes running a drilling assembly into the wellbore through a casing string, the drilling assembly comprising a tubular string, an underreamer, and a drill bit; injecting drilling fluid through the tubular string and rotating the drill bit, wherein the underreamer remains locked in the retracted position; sending an instruction signal to the underreamer via modulation of a rotational speed of the drilling assembly or modulation of a drilling fluid pressure, thereby extending the underreamers; and reaming the wellbore using the extended underreamer.

An underreamer for increasing a diameter of a wellbore. The underreamer may include a body having an axial bore extending at least partially therethrough. An electromagnetic activation system may be disposed at least partially within the bore of the body. A valve may be disposed within the bore of the body and coupled to the electromagnetic activation system. The valve may include a mobile element and a static element. The mobile element may be coupled to the electromagnetic activation system and move from a first position where the mobile element obstructs fluid flow through the valve to a second position where the mobile element permits fluid flow through the valve. A cutter block may be movably coupled to the body and move radially-outward as the mobile element moves from the first position to the second position.

A method of assembly is for a string of drilling elements for deepwater drilling. Each drilling element includes an axial through hole, through which drilling mud can flow, and two connection portions for connecting it in series in the string. The method includes assembling a lower portion of the string, assembling a first drilling element with other drilling devices to create a first section of the string. These steps are repeated until the lower portion is proximate the blowout preventer or the bottom. Assembly of second drilling elements begins while executing a drilling cycle for creating at least a second section of the string. The assembly step is repeated until the second section extends equal to a desired drilling depth. After assembling the lower portion and before assembling the first drilling element, a third drilling element is assembled, which includes an obstruction element for preventing backflow in the string.

A method of assembly is for a string of drilling elements for deepwater drilling. Each drilling element includes an axial through hole, through which drilling mud can flow, and two connection portions for connecting it in series in the string. The method includes assembling a lower portion of the string, assembling a first drilling element with other drilling devices to create a first section of the string. These steps are repeated until the lower portion is proximate the blowout preventer or the bottom. Assembly of second drilling elements begins while executing a drilling cycle for creating at least a second section of the string. The assembly step is repeated until the second section extends equal to a desired drilling depth. After assembling the lower portion and before assembling the first drilling element, a third drilling element is assembled, which includes an obstruction element for preventing backflow in the string.

A retrievable module assembly can be used to install and/or de-install a blowout preventer (BOP) module from a BOP subsea where the BOP comprises one or more corresponding BOP module receivers. The retrievable module assembly typically comprises a frame configured to house and support the subsea BOP module; and a modular storage unit disposed at least partially within the frame. The modular storage unit further comprises a storage area configured to removably accept the subsea BOP module; a rotator configured to attach to and rotate the subsea BOP module, the rotator disposed at least partially within the frame; a rotator mover, slidably mounted in the frame and operatively in communication with the rotator; and a power connector operatively connected to the rotator and rotator mover and configured to interface with a power source.