Abstract: A directional casing drilling system including a casing string for rotation of a drill bit, a shaft coupled to the casing string, and a sleeve having pads that are hydraulically extensible. The sleeve may be positioned about a portion of the shaft. The invention may also include a tube connecting the sleeve to the drill collar, the tube adapted to conduct drilling fluid, and a valve system adapted to operatively conduct at least a portion of the drilling fluid to the pads whereby the pads move between an extended position and a retracted position.

Abstract: A method for downlink communication with a downhole tool having a mud-powered downhole motor that includes receiving a sensor signal related to a rotational speed of a rotor in the mud-powered downhole motor, and interpreting the sensor signal to derive a downlink signal.

Abstract: A downhole pressure compensation system includes a seal housing disposed in a downhole tool, a dynamic seal disposed on the seal housing, wherein the dynamic seal seals around a part that is allowed to move relative to the seal housing, and a flexible membrane disposed in a sidewall of the seal housing proximate the dynamic seal.

Abstract: The present invention provides a method and apparatus for casing while drilling without the use of an underreamer. In one aspect, the invention provides a flexible drill collar that enables drilling of a large enough borehole for passage of the casing string therethrough.

Abstract: In one aspect, the present invention provides an apparatus to drill a borehole with a casing string. The casing string has affixed thereto a directional drilling assembly and a bi-centered cutter assembly. The bi-centered cutter assembly has a first cutting surface and a second cutting surface that are spaced apart by an offset. The bi-centered cutter assembly is configured to drill the borehole at a gauge diameter.

Abstract: A directional casing drilling system includes a casing string, a mud motor operatively coupled to the casing string, a rotary steerable system operatively coupled to the mud motor, and a drill bit operatively coupled to the rotary steerable system.

Abstract: A directional drilling system, including a casing string, a casing latch disposed inside the casing string proximate a lower end of the casing string and coupled to the casing string, a rotary steerable system disposed inside the casing string and coupled to the casing latch, and a drill bit coupled to the rotary steerable system.

Abstract: A method and apparatus is provided to support a gyroscope within a downhole drilling tool. A packaging system is positioned within a drill collar of the drilling tool and includes a housing for the gyro and at least one centralizer supporting the housing within the drill collar. The system may also be provided with a down-hole end cap, an up-hole endcap and a loading device. A gyro compression mechanism that is capable of holding wires may also be included to provide power and communication while compressing the gyro to isolate it from shock or vibration.

Abstract: A directional casing drilling system including a casing string for rotation of a drill bit, a shaft coupled to the casing string, and a sleeve having pads that are hydraulically extensible. The sleeve may be positioned about a portion of the shaft. The invention may also include a tube connecting the sleeve to the drill collar, the tube adapted to conduct drilling fluid, and a valve system adapted to operatively conduct at least a portion of the drilling fluid to the pads whereby the pads move between an extended position and a retracted position.

Abstract: A method and apparatus is provided to support a gyroscope within a downhole drilling tool. A packaging system is positioned within a drill collar of the drilling tool and includes a housing for the gyro and at least one centralizer supporting the housing within the drill collar. The system may also be provided with a down-hole end cap, an up-hole endcap and a loading device. A gyro compression mechanism that is capable of holding wires may also be included to provide power and communication while compressing the gyro to isolate it from shock or vibration.

Abstract: A system is disclosed for generating and transmitting data signals to the surface of the earth while drilling a borehole, the system operating by generating pressure pulses in the drilling fluid filling the drill string. The system is designed to maximize signal strength while minimizing the probability of jamming by drilling fluid particulates. The system uses a rotary valve modulator consisting of a stator with flow orifices through which drilling fluid flows, and a rotor which rotates with respect to the stator thereby opening and restricting flow through the orifices and thereby generating pressure pulses. The flow orifices with the stator in a “closed” position are configured to reduce jamming, and to simultaneously minimize flow area in order to maximize signal strength. This is accomplished by imparting a shear to the fluid flow through the modulator, and minimizing the aspect ratio and maximizing the minimum principal dimension of the closed flow area.

Abstract: A sensor protection system for use with an MWD tool includes a tubular body having lesser and greater diameter portions, antennas mounted in grooves in the lesser diameter portion, shield sleeves covering the antennas and being locked in place against longitudinal and rotational movement, and a wear band on the greater diameter portion to provide a standoff for the shield sleeve, the wear band also being locked against movement in the longitudinal and rotational directions. The locking mechanism also can be used to fix a sleeve-type stabilizer on the tubular body.

Abstract: An apparatus for sealing a first pressure environment from a second, lower pressure environment, includes a plug having a desired cross section for insertion into a barrier wall aperture shaped to receive the plug. The barrier wall has a first pressure environment on its outside surface and a second environment on its inside surface. A bearing surface on the plug bears against the wall of the aperture. A flexing member, subject to and reactive to the first pressure environment, has an outer surface providing at least a portion of the bearing surface. The flexing member, in reacting to the first pressure environment, flexes at least a portion of the bearing surface to bear more tightly against the wall of the aperture and tends to seal the first pressure environment from the second pressure environment and maintain the seal under a variety of mechanical loads. A chassis is secured within the barrier wall.

Abstract: Measurement-while-drilling apparatus includes a 14 MeV neutron accelerator, a near-spaced neutron detector which primarily senses source neutrons and whose output is proportional to source strength, one or more intermediately-spaced epithermal neutron detectors eccentered against the drill collar wall and primarily responsive to formation hydrogen concentration, and a third far-spaced radiation detector, either gamma ray or neutron, primarily responsive to formation density. The intermediately-spaced and far-spaced detector outputs, normalized by the near-spaced detector output, are combined to provide measurements of porosity, density and lithology and to detect gas. A thermal neutron detector and/or a gamma ray detector may also be provided at intermediate spacings to provide additional information of interest, such as standoff measurements and spectral analysis of formation composition. Tool outputs are related to the angular or azimuthal orientation of the measurement apparatus in the borehole.

Abstract: A stabilizer to be mounted on a collar of a well drilling string including a circumferentially continuous tubular body having several outwardly extending blades thereon, the tubular body having an inner dimension such that it can be slid onto a drill collar, and radially energized components which positively fix the stabilizer on the collar including dies mounted in the blades, and having serrations on their inner faces, and drive elements to cause the serrations to bite into the collar and thereby fix the stabilizer thereon in a selected longitudinal and rotational position.

Abstract: A retrievable radiation source carrier assembly for a logging while drilling tool is disclosed. The carrier includes a solid rod or member of high strength and low elastic modulus that connects the housings of at least two radiation sources. In a preferred embodiment, the carrier includes a sheath of high performance thermoplastic that covers the rod from the upper source to the lower source. The sheath provides the carrier with a smooth outer surface and a substantially constant diameter that resists the accumulation of mud particulate buildup thereon. The sheath also provides a low friction surface which allows improved ease of insertion and removal of the radiation source carrier into and from the internal source passageway of the LWD tool.

Abstract: An elongated body member having a plurality of crank arms pivotally attached thereto, such crank arms disposed generally symmetrically around the perimeter of the body member. At a first end of each crank arm is a contact pad for maintaining substantial contact with the sidewalls of a borehole. The second end of each crank arm is pivotally coupled to a drive link which is in turn attached to a piston which is longitudinally slidably mounted within the body member. Longitudinal movement of the piston within the body member will result in a corresponding generally lateral movement, either extension or retraction, of the crank arms and thereby of the contact pads attached thereto. A mechanism is provided for allowing the piston to traverse a limited range of longitudinal movement within the body member, a force being exerted upon the piston such that the piston is urged to the bound of such travel which will yield the maximum lateral extension of the contact pads.

Abstract: Measurement-while-drilling apparatus includes a 14 MeV neutron accelerator, a near-spaced neutron detector which primarily senses source neutrons and whose output is proportional to source strength, one or more intermediately-spaced epithermal neutron detectors eccentered against the drill collar wall and primarily responsive to formation hydrogen concentration, and a third far-spaced radiation detector, either gamma ray or neutron, primarily responsive to formation density. The intermediately-spaced and far-spaced detector outputs, normalized by the near-spaced detector output, are combined to provide measurements of porosity, density and lithology and to detect gas. A thermal neutron detector and/or a gamma ray detector may also be provided at intermediate spacings to provide additional information of interest, such as standoff measurements and spectral analysis of formation composition. Tool outputs are related to the angular or azimuthal orientation of the measurement apparatus in the borehole.