A rotary steerable drilling tool and a method according to which a universal joint is sealed. In one embodiment, the method includes providing the collar, the shaft, the universal joint, and first and second shoulders between which the universal joint is positioned; providing first and second self-energizing seals between the collar and the shaft on opposite sides of the universal joint; rotating the collar and the shaft; seating the first self-energizing seal against the first shoulder; and seating a second self-energizing seal against the second shoulder. In one embodiment, the universal joint includes a convex surface formed on the shaft; a first concave surface extending circumferentially about the shaft and adapted to mate with the convex surface to carry a first axial load; and a spacer ring defining a second concave surface adapted to mate with the convex surface to carry a second axial load.

Disclosed is a directional well trajectory control method based on drill pipe drive, the method including the following steps: parameters down-transmission, determining the offset vector, closed loop control of eccentric ring rotation angle, and well parameter closed-loop control; this method can achieve three-dimensional well trajectory control without frequent trips during drilling operations, and has a high penetration rate, good wellbore cleaning effect, well trajectory control accuracy, high flexibility, low tripping times, high borehole quality, high safety, etc., which is suitable for the development of special process wells such as medium-deep wells, ultra-deep wells, ultra-thin oil layer horizontal wells and unconventional oil and gas wells in China's complex oil and gas reservoirs. This method can also achieve precise control of well trajectory, and overcome the shortcomings of existing control methods that cannot achieve closed-loop control and cannot remove interference signals.

A piston for use in a rotary steerable system includes a body formed from a first material. A sealing surface extends around the circumferential wall of the body. The sealing surface is formed from a plurality of layers of a second material. The second material is harder than the first material. The piston can be within a downhole piston assembly that also includes a housing, and the piston being longitudinally movable in a bore in the housing. A method for producing a piston includes preparing a piston formed from a first material, with the piston including a first end. A sealing surface is applied to the piston using laser cladding, with the sealing surface including a second material harder than the first material. The sealing surface is finished to a sealing surface diameter.

The invention concerns compounds of Formula (I)

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or pharmaceutically-acceptable salts thereof, wherein R.sup.1, R.sup.2 and n have any of the meanings defined hereinbefore in the description; processes for their preparation, pharmaceutical compositions containing them and their use as anti-proliferative and/or cell-killing agents.

A directional core drilling includes an outer barrel assembly with at least one steering pad for orientating a drill bit within a hole and a drive barrel rotationally supported within the outer barrel assembly. An inner drive assembly is receivable within the outer barrel assembly and includes a torque latch assembly and an anti-rotation bearing assembly. The torque latch assembly includes latch arms configured to releasably couple a rotational drive input to the drive barrel. A core barrel is coupled to the anti-rotation bearing assembly and is rotationally fixed relative to the drive barrel.

A method that includes an electronic application identifying a downlink sequence for execution by a surface control system of a drilling rig, with the sequence including target output values of a mud pump system and/or a drive system. The method includes instructing the control system to operate in accordance with the sequence. The application receives measured output values of the mud pump system and/or the drive system and calculates differences between the target and measured output values. When the differences are within a level of tolerance, then the application identifies the control system as compliant; and when the differences are greater than the level of tolerance, then the application identifies the control system as non-compliant. The method also includes the application receiving data from a BHA of the drilling rig and determining, based on the data received, if a downlink to the BHA was successful.

Aspects of the disclosure relate to a system including an implement (e.g., a steering tool, a drill bit) tetherable to an equipment string (e.g., a drill string), where the implement includes a steering mechanism to steer the equipment string with respect to a wall of a tubular passage (e.g., a borehole). The system can also include a bearing housing for the equipment string (e.g., connectable to a drill pipe of the drill string), where the bearing housing is rotationally coupled with the implement and rotated. The system can further include an actuation mechanism coupleable between the bearing housing and the steering mechanism to actuate the steering mechanism based upon a rotational orientation of the bearing housing with respect to the steering mechanism.

An easy building-up hybrid rotary steerable drilling system includes a front supporting body, a weight-on-bit (WOB)-torque-on-bit (TOB) deflectable transmission joint and a deflection control system. The WOB-TOB deflectable transmission joint includes a universal joint. A front end of the front supporting body is fixedly connected to a drill bit, and a rear end of the front supporting body is fixedly connected to an outlet end of the universal joint. A front push-the-bit assembly is provided on a circumferential surface of the front supporting body. The deflection control system controls radial push-the-bit parts of the front push-the-bit assembly to push a borehole wall along a radial direction of the front supporting body, such that the front supporting body generates a deviation angle relative to an input shaft of the universal joint by taking a center point of the universal joint as a center, thereby controlling a drilling direction.

An illustrative dogleg severity (DLS) estimation method includes: retrieving dimensions of steering assembly; determining an initial DLS estimate; using the DLS estimate in combination with the steering assembly dimensions to determine node displacements for a shaft portion of the steering assembly; deriving a bit side force from the node displacements while accounting for elastic bending in a housing portion of the steering assembly; performing a DLS calculation based in part on the bit side force; adjusting the DLS estimate if the DLS calculation does not match; repeating said using, deriving, performing, and adjusting until a match is achieved; and storing the DLS estimate on a nontransient information storage medium.

The invention relates to a drill head and a device for drilling a bore in the ground, the drill head having a first unit coupleable with an inner drill pipe of a double drill pipe assembly and a second unit coupleable with the outer drill pipe of the double drill pipe assembly. By means of the inner drill pipe the first unit is rotatable about an axis of rotation relative to the second unit which is drivable by means of the outer drill pipe. The drill head has a sliding contact arrangement for establishing an electrical connection between the first unit and the second unit.