Abstract: A directional drilling device for drilling a borehole having a borehole wall, the device including an outer housing and a driveshaft selectively rotatable with respect to the housing and including an axial flow bore and a through port formed in the driveshaft wall. The device also includes one or more borehole engagement members rotatable with and radially moveable with respect to the outer housing toward engagement with the borehole wall to urge the directional drilling device in a radial direction with respect to the borehole. The device further includes a mud pressure actuation system. The mud pressure actuation system controls fluid flow through the through port to control hydraulic pressure on a piston device and thus movement of the borehole engagement members into engagement with the borehole wall to maintain a rotational position of the outer housing and the corresponding radial direction in which the device is being urged.

Abstract: A directional drilling device for drilling a wellbore having a wall, the device including an outer housing, a driveshaft located at least partially within and selectively rotatable with respect to the outer housing. The device also includes extendable members moveable to extend radially outwardly from the outer housing and so as to apply a force onto the wellbore wall and move the device off-center in the wellbore in a direction. The device further includes a hydraulic actuation system operable to control hydraulic fluid to extend and retract of the extendable members. The rotational orientation of the extendable members is controllable by rotation of the outer housing by the driveshaft and the rotational orientation of the extendable members and the outer housing and thus the direction may be maintained by extension of the extendable members into contact with the borehole to restrain the outer housing from rotating.

Abstract: A directional drilling device for drilling a borehole having a borehole wall, the device including an outer housing and a driveshaft selectively rotatable with respect to the housing and including an axial flow bore and a through port formed in the driveshaft wall. The device also includes one or more borehole engagement members rotatable with and radially moveable with respect to the outer housing toward engagement with the borehole wall to urge the directional drilling device in a radial direction with respect to the borehole. The device further includes a mud pressure actuation system. The mud pressure actuation system controls fluid flow through the through port to control hydraulic pressure on a piston device and thus movement of the borehole engagement members into engagement with the borehole wall to maintain a rotational position of the outer housing and the corresponding radial direction in which the device is being urged.

Abstract: A directional drilling device for drilling a wellbore having a wall, the device including an outer housing, a driveshaft located at least partially within and selectively rotatable with respect to the outer housing. The device also includes extendable members oveable to extend radially outwardly from the outer housing and so as to apply a force onto the wellbore wall and move the device off-center in the wellbore in a direction. The device further includes a hydraulic actuation system operable to control hydraulic fluid to extend and retract of the extendable members. The rotational orientation of the extendable members is controllable by rotation of the outer housing by the driveshaft and the rotational orientation of the extendable members and the outer housing and thus the direction may be maintained by extension of the extendable members into contact with the borehole to restrain the outer housing from rotating.

Abstract: An example slip-ring interface may include a first section and a second section rotationally independent from the first section. At least one conductor path between the first section and the second section may be selectively associated with and dedicated to the transmission of signals with a first signal type. At least one conductor path between the first section and the second section may be selectively associated with and dedicated to the transmission of signals with a second signal type. If error conditions occur, the signal types associated with one or more of the conductor paths may be changed so that signals of both the first and second signal types are transmitted across the interface.

Abstract: A control mechanism for a drill string tool is configured to activate the drill string tool by hydraulically actuated movement of the switching element to an activated position, with drilling mud serving as actuating medium. Movement of the switching element to the activated position is automatically regulated, so that tool activation is conditional upon application of above-threshold downhole drilling fluid conditions for at least a predetermined switching duration. A switch regulator that regulates movement of the switching element to the activated position can be configured to regulate a rate of movement of the switching element such that a substantially constant switching duration is maintained regardless of fluctuations in the magnitude of an actuating pressure differential during above-threshold downhole drilling fluid conditions.

Abstract: An example slip-ring interface may include a first section and a second section rotationally independent from the first section. At least one conductor path between the first section and the second section may be selectively associated with and dedicated to the transmission of signals with a first signal type. At least one conductor path between the first section and the second section may be selectively associated with and dedicated to the transmission of signals with a second signal type. If error conditions occur, the signal types associated with one or more of the conductor paths may be changed so that signals of both the first and second signal types are transmitted across the interface.

Abstract: A well tool apparatus comprises a control arrangement configured to control response of the downhole tool by varying a bore-annulus pressure difference. The control arrangement includes a valve piston longitudinally slidable in a generally tubular controller housing that is in operation substantially co-axial with the wellbore, to open or close a valve port to a fluid flow connection between the drill string's interior and the tool. A latch mechanism is configured to latch the valve piston against movement in one axial direction, keeping the valve piston in an open or a closed condition. Unlatching of the valve piston requires displacement thereof in the other axial direction to a mode change position. A stay member is automatically displaceable under hydraulic actuation responsive to bore-annulus pressure differences above a trigger threshold value, to obstruct movement of the latched valve piston under hydraulic actuation to the mode change position.

Abstract: A control mechanism for a drill string tool is configured to activate the drill string tool by hydraulically actuated movement of the switching element to an activated position, with drilling mud serving as actuating medium. Movement of the switching element to the activated position is automatically regulated, so that tool activation is conditional upon application of above-threshold downhole drilling fluid conditions for at least a predetermined switching duration. A switch regulator that regulates movement of the switching element to the activated position can be configured to regulate a rate of movement of the switching element such that a substantially constant switching duration is maintained regardless of fluctuations in the magnitude of an actuating pressure differential during above-threshold downhole drilling fluid conditions.

Abstract: A method for forming a controllable bend angle in a drill string in a wellbore comprises attaching an upper housing to a drill string. At least, one drive motor is anchored in the upper housing. A middle housing is operably coupled to the at least one drive motor. A lower housing is operably coupled to the at least one drive motor. The at least one drive motor is controllably operated to rotate the middle housing by a first rotation angle with respect to the upper housing, and to rotate the lower housing by a second rotation angle with respect to the upper housing, to generate a desired bend angle between the middle housing and the lower housing at a target toolface orientation between the bend angle and the upper housing.

Abstract: A well tool apparatus comprises a control arrangement configured to control response of the downhole tool by varying a bore-annulus pressure difference. The control arrangement includes a valve piston longitudinally slidable in a generally tubular controller housing that is in operation substantially co-axial with the wellbore, to open or close a valve port to a fluid flow connection between the drill string's interior and the tool. A latch mechanism is configured to latch the valve piston against movement in one axial direction, keeping the valve piston in an open or a closed condition. Unlatching of the valve piston requires displacement thereof in the other axial direction to a mode change position. A stay member is automatically displaceable under hydraulic actuation responsive to bore-annulus pressure differences above a trigger threshold value, to obstruct movement of the latched valve piston under hydraulic actuation to the mode change position.

Abstract: A method for forming a controllable bend angle in a drill string in a wellbore comprises attaching an upper housing to a drill string. At least, one drive motor is anchored in the upper housing. A middle housing is operably coupled to the at least one drive motor. A lower housing is operably coupled to the at least one drive motor. The at least one drive motor is controllably operated to rotate the middle housing by a first rotation angle with respect to the upper housing, and to rotate the lower housing by a second rotation angle with respect to the upper housing, to generate a desired bend angle between the middle housing and the lower housing at a target toolface orientation between the bend angle and the upper housing.