摘要:
A system for steering the direction of a borehole advanced by cutting action of a rotary drill bit by periodically varying action of a drill bit while continuously rotating a drill string to which the drill bit is operationally attached. The steering system comprises a bit perturbation device cooperating with a bent housing subsection and operationally connected to the drill string and to the drill bit. Drill bit action is varied by periodic varying the rotation speed or rate of penetration of the drill bit. Periodic drill bit action results in preferential cutting of material from a predetermined arc of the borehole wall which, in turn, resulting in borehole deviation. Action of the drill bit can be varied independent of the rotation rate of the drill string
摘要:
A pressure orienting swivel arrangement including a weight assembly and a pin adapter reactably interengagable with the weight assembly to orient the pin adapter to the weight assembly. A pressure orienting swivel arrangement including a housing, a spring compression mandrel within the housing, a spring disposed about the spring compression mandrel, a weight assembly rotatably supported in the housing, and a pin adaptor rotatably supported within the housing and reactably interengagable with the weight assembly to accept a torque from the weight assembly. A method for orienting a downhole tool.
摘要:
A bottom hole assembly 10 for drilling a deviated borehole includes a positive displacement motor (PDM) 12 or a rotary steerable device (RSD) 110 having a substantially uniform diameter motor housing outer surface without stabilizers extending radially therefrom. In a PDM application, the motor housing 14 may have a fixed bend therein between an upper power section 16 and a lower bearing section 18. The long gauge bit 20 powered by the motor 10 may have a bit face 22 with cutters 28 thereon and a gauge section 24 having a uniform diameter cylindrical surface 26. The gauge section 24 preferably has an axial length at least 75% of the bit diameter. The axial spacing between the bit face and the bend of the motor housing preferably is less than twelve times the bit diameter. According to the method of the present invention, the bit may be rotated at a speed of less than 350 rpm by the PDM and/or rotation of the RSD from the surface.
摘要:
A bottom hole assembly connected to coiled tubing to create an acid tunnel in a wellbore formation. High pressure acid is pumped down the coiled tubing and out a nozzle located at the end of the bottom hole assembly. The bottom hole assembly includes a first reversible knuckle joint and a second reversible knuckle joint to properly position the nozzle against the wellbore and to allow the assembly to adjust its angle as it initiates and moves through the lateral tunnel. The two reversible knuckle joints increases the radius of curvature of the bottom hole assembly while providing a sufficient attack angle for the nozzle against the wellbore. The two knuckle joints may be adjusted in response to loads applied on the assembly as the assembly moves through the lateral tunnel.
摘要:
A drilling rig for drilling an underground borehole (5) into a seam (4) uses coiled metal tubing (8) fed by a tractor unit (11) from a drum (7) to provide a thrust force to a drilling head. The drilling head has a bent-sub assembly giving an angle of deviation which is controlled by rotating the coiled metal tubing in the borehole by way of rotation of the drum (7) in the frame (12) about the axis of the tube in the borehole (5).
摘要:
An orienting apparatus including at least one housing element configured to couple with a drill string; an actuator disposed inside the at least one housing element; a nozzle coupled to the actuator; a torque generator coupled to the actuator and extending axially downward through the at least one housing, wherein the torque generator is configured to rotate in a first direction as it moves downward; a mandrel coupled to the torque generator; and a stroke adjuster at least partially disposed in an upper end of the mandrel, wherein rotation in the first direction is caused by an increase in differential pressure is disclosed.
摘要:
A drill bit for drilling a borehole in an object, the drill bit having a central longitudinal axis and comprising: a pilot section for drilling a pilot bore section of the borehole in the object; an under-reaming section in a following position with respect to the pilot section, the cutting diameter Du of the under-reaming section being larger than the cutting diameter Dp of the pilot section; a connecting shaft extending between the pilot section and the under-reaming section; and a stabilising section located between the pilot section and the under-reaming section, wherein the stabilising section fits inside the pilot bore section and is capable of laterally stabilising the drill bit relative to the object while allowing rotation of at least the pilot section relative to the object.
摘要:
In one aspect of the invention a drill bit assembly has a body portion intermediate a shank portion and a working portion, the working portion having at least one cutting element. A shaft is supported by the body portion and extends beyond the working portion. The shaft also has a distal end that is rotationally isolated from the body portion. In another aspect of the invention, a method for steering a downhole tool string has the following steps: providing a drill bit assembly attached to an end of the tool string disposed within a bore hole; providing a shaft extending beyond a working portion of the assembly; engaging a subterranean formation with a distal end of the shaft; and angling the drill bit assembly with the shaft along a desired drilling trajectory.
摘要:
A general housing encloses a drilling motor that can be disabled to permit optimum rotary drilling practice. A mode selector responds to manipulation of the drilling fluid flow rate and permits activation of the drilling motor to drive a drill bit. The general housing is a two part arrangement that is connected by a deflection arrangement that is activated by start-up of the motor. A one-way clutch allows the lower housing to drive the drill bit when the motor is disabled and the clutch, with drill bit rotation resistance, changes the deflection arrangement for straight rotary drilling when the drill string is rotated.
摘要:
The drill string is fitted for drilling activity in the formation expected, including a jet nozzle equipped drill head, and a near bit kick sub. The drill string is deflected to change the progressing well bore to a preferred direction. After the change in well bore direction is accomplished by jetting, the kick sub is straightened and drilling proceeds along the new well bore center line. Ideally, the kick sub responds to direction from the surface and produces a change in drilling fluid pressure at the surface to indicate which mode, straight or deflected, is being carried out down hole.