In accordance to an aspect a connection to attach a first downhole tool to a second downhole tool includes an externally threaded member positioned about the first downhole tool and an internally threaded member disposed with the second downhole tool to threadedly mate with the externally threaded member, wherein threadedly connecting the externally threaded member with the internally threaded member interconnects the first downhole tool and the second downhole tool with a defined tensile force and a compressive force at an interface between a hard shoulder of the first downhole tool and a hard shoulder of the second downhole tool.

An example downhole motor may include a first housing and a second housing with first and second portions characterized by non-parallel longitudinal axes. The second housing may be rotatably coupled to the first housing, and the first portion of the second housing may be arranged in a fixed, non-parallel longitudinal orientation with the first housing. A drive shaft may be at least partially within the first housing, and the motor may further comprise a selectively engageable torque coupling between the drive shaft and the second housing, positioned within the first housing.

A downhole motor for directional drilling includes a driveshaft assembly including a driveshaft housing and a driveshaft rotatably disposed within the driveshaft housing. In addition, the downhole motor includes a bearing assembly including a bearing housing and a bearing mandrel rotatably disposed within the bearing housing. The bearing mandrel has a first end directly connected to the driveshaft with a universal joint and a second end coupled to a drill bit. Further, the downhole motor includes an adjustment mandrel configured to adjust an acute deflection angle between the central axis of the bearing housing and the central axis of the driveshaft housing. The adjustment mandrel has a central axis coaxially aligned with the bearing housing, a first end coupled to the driveshaft housing, and a second end coupled to the bearing housing.

The present invention relates to drilling lateral wells or sidetrack wells from a primary wellbore to enhance the efficiency and productivity of oil and gas wells.

Systems and methods are presented for drilling a wellbore with a portion having a short radius of curvature. The systems include a drill assembly having a motor and a tubular housing. An actuator is at least partially disposed within the tubular housing and couples the motor to the tubular housing. The actuator is configured to selectively articulate the drill assembly between a straight configuration and a bent configuration. At least one torque anchor is fluidly-coupled to a trailing end of the drill assembly. Methods are presented for selectively articulating the drill assembly to form the wellbore, including the portion having short radius of curvature. Other systems and methods are presented.

An apparatus including a housing, a shaft rotatably extending through the housing, and a rotary seal assembly contained within the housing for providing a seal between the housing and the shaft. The shaft is capable of an amount of tilting within the housing about a tilting focal point which is axially located along the housing at an axial focal point position. The rotary seal assembly is axially located along the housing at an axial rotary seal position. The axial rotary seal position is substantially axially coincident with the axial focal point position.

A method and related apparatus for forming a wellbore in a subterranean formation includes forming a drill string that has a drill bit at a distal end, a drilling motor configured to rotate the drill bit with a drive shaft; a joint coupled to the drive shaft; and an actuator assembly displacing the drive shaft between a first and a second deflection angle, the drive shaft being movable at each of the deflection angles until a predetermined weight is applied to the bit. The method also includes conveying the drill bit through the wellbore and fixing the drive shaft in at least one of the first and the second deflection angles by applying a predetermined weight on the bit.

A motor includes: a rotor including an undulated surface; a rod disposed about the rotor; and a coil disposed about the rod to induce shape changes in the rod, which in turn impart forces to the undulated surface to rotate the rotor.

According to aspects of the present disclosure, systems and methods for controlling the direction of a drilling assembly within a borehole are described herein. An example system may include a housing 201 b (FIG. 2B) and a variable flow fluid pathway 203 (FIG. 2B) within the housing 201b. A fluid-controlled drive mechanism 209 (FIG. 2C) may be in fluid communication with the variable flow fluid pathway 203. Additionally, an offset mandrel 212 may be coupled to an output of the fluid-controlled drive mechanism 209. The offset mandrel 212 may be independently rotatable with respect to the housing 201b. The system may also include a bit shaft 216 pivotably coupled to the housing 201b and coupled to an eccentric receptacle of the offset mandrel 212.

A valve for subterranean whipstock service has a side port and a through passage with a biased movable sleeve to shift between circulation mode into the annulus and flow through mode for setting an anchor and then feeding window mill nozzles. The valve is run in when in circulation mode to allow operation of a measurement while drilling device. When the whipstock is properly oriented the pressure is increased to break a shear pin to allow a spring to bias the sleeve to the flow through position. The shifting of the sleeve opens a bypass passage around the restriction orifice that was first used to build pressure to break the shear pins that let the sleeve move under spring bias. As a result the spring can hold the sleeve in position despite high flow rates needed to remove cuttings from the mill as the window is opened.