Abstract: A drill string rotation controller includes an anti-torque balance module, a TC bearing retaining ring, an upper TC bearing, an upper thrust ball bearing, an upper Haval ring, a middle seal retaining ring, an upper mandrel, an upper shell, a rotary control cylinder, an upper spring, a spline shell, a spline sleeve, a spline mandrel, a lower shell, a spring push sleeve, a lower spring, a floating piston, a lower mandrel, a bulkhead, a lower thrust ball bearing, a lower Haval ring, a lower TC bearing, a conversion joint, an anti-drop joint, a lower joint, and a control pin. The rotary control cylinder causes the spline sleeve to switch the transmission relationship between the spline mandrel and shell. Therefore, the drill string rotation controller controls the conversion between the composite drilling mode and the directional drilling mode.

Abstract: A rotary steerable drill string (16) employs a drill bit (10) selected to positively contribute to underpressure in a preselected azimuthal segment of the borehole relative to an opposing azimuthal section. Generally, a high flow velocity of drilling fluid in the selected azimuthal segment relative to in other segments will result in a more pronounced underpressure in the selected azimuthal segment. Drill bit designs which locally enhance the drilling fluid flow velocity are proposed to be employed in the present rotary steerable drill string.

Abstract: A universal joint (U-joint) assembly transmits torque from a drive component to a driven component across an articulating joint. The U-joint assembly includes male and female U-joint members, a central ball joint, and a retaining device configured to secure the assembly in an assembled configuration. The female U-joint member includes a cavity extending into a receptacle end thereof. The cavity terminates in a circular receptacle and includes a plurality of rectangular channels extending radially outward from the cavity at equal intervals, each channel defined by three planar drive surfaces. The male U-joint member has a drive end with a plurality of corresponding rectangular extensions protruding from an outer periphery of the drive end, each extension including a plurality of axial angular surfaces. When assembled, each of the angular surfaces of the drive end opposes a corresponding one of the drive surfaces of the cavity. Other embodiments are also disclosed.

Abstract: An angular offset tool for directionally drilling an underground borehole is formed from a collar, a housing, and a wedge. The collar and the housing are joined by a ball-and-socket connection. An internal wedge is situated between the collar and the housing within the ball-and-socket connection such that the collar and housing are joined at a non-straight angle. At least one of the collar and the housing has a recess formed in an element of the ball-and-socket connection. The wedge is situated in the recess in contacting relationship with the collar and the housing. The wedge and the housing have interlocking features that prevent rotation of the wedge within the recess.

Abstract: An embodiment includes a downhole motor configured to operate a drill bit to drill a well into an earthen formation. The downhole motor includes a motor housing, a stator supported by an inner surface of the motor housing, a rotor operably coupled to the stator. The rotor is configured to be operably coupled to the drill bit. The motor housing includes an uphole portion, a bend, and a downhole portion that extends relative to bend away from the uphole portion in a downhole direction. The downhole motor includes an adjustment assembly that can guide the direction of drilling.

Abstract: 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.

Abstract: An example downhole motor may include a first housing and a second housing coupled to the first housing at a movable joint. A turbine may be within the first housing in selective fluid communication with a bore of the first housing. A biasing mechanism may be coupled to the movable joint and the turbine. The biasing mechanism may alter an angle between a first longitudinal axis of the first housing and a second longitudinal axis of the second housing by altering an orientation of the movable joint.

Abstract: Adjustment of the angle of a bent sub or other steering feature in a drill string relative to a reference angle of a downhole sensor is facilitated by a rotatable coupling between the bent sub and the sensor. The rotatable coupling may be rotated to align the high side with a reference indicium and locked at the set angle. Rows of ceramic balls retained in circumferential channels may be provided to permit rotation while carrying tensile and compressional forces. Calibration of the sensor is facilitated and opportunities for certain measurement errors are eliminated. An embodiment provides a mechanism for locking the rotatable coupling at a desired angle. The embodiment comprises a ring with teeth that engage a downhole portion of the coupling and depressions that engage an uphole portion of the coupling.

Abstract: A directional drilling system for use in drilling a wellbore can include a bit deflection assembly with a bit axis deflection mechanism which applies a deflecting force to a shaft connected to a drill bit. The deflecting force may deflect the shaft, without being reacted between the deflection mechanism and the drill bit. The deflecting force may deflect the shaft between the drill bit and a radial bearing which maintains the shaft centered in the bit deflection assembly. The deflection mechanism may both angularly deflect and laterally displace the bit axis in the deflection mechanism.

Abstract: A downhole system including a driving unit for driving an operational tool. The driving unit is provided in a first part of the system and the operational tool is provided in a second part of the system. The system further includes a release device for releasing the operational tool and the second part from the first part of the system.

Abstract: An apparatus for controlling the direction of drill bit within a wellbore. The apparatus comprises a first housing with a first housing axis therein, and wherein the first housing has a first threaded opening having a first threaded opening axis. The first housing has a helical end. A second housing is included, and the second housing contains a second housing axis, and a second threaded opening having a second threaded opening axis configured to engage with the first threaded opening. A collar is included that has a helical collar end that engages the helical collar end and wherein the helical collar end is configured reciprocal to the helical end, and rotational displacement of the first housing relative to the collar will angularly displace the drill bit axis. The apparatus may further include spline members for locking the collar in place relative to the first and second housing.

Abstract: A method of locking tubular components in end to end relation. A first tubular body is provided having a tongue with an outwardly facing groove protruding past one end along an interior surface that has a keyway. A second tubular body is provided having a tongue with an inwardly facing groove protruding past one end along an exterior surface. A split ring is positioned in the grooves to connect the bodies. The split ring has a tapered outer surface to permit removal by an axial force. A tubular insert carries a locking key which engages the axial keyway. When the tubular insert is fully inserted into the first tubular body, the key underlies the split ring and prevents the split ring from having sufficient clearance to be withdrawn.

Abstract: A rotating inner member is used to drive a downhole tool housed within the hollow outer member of a dual-member drill string. The downhole tool preferably will be adapted to receive rotational energy from the inner member. In a preferred embodiment, the downhole tool is an electric generator connected to a downhole electric device. In another preferred embodiment the downhole tool is a mechanical transmission that uses the rotational energy from the inner member to drive a non-electric tool, such as a downhole hammer. This invention will increase the consistency and efficiency of downhole energy production.

Abstract: A downhole apparatus permitting separation of one part of downhole equipment from another part thereof includes a first part connected to a second part by a connecting member which limits axial and rotational movement of the first and second parts and has first and second ends connected respectively to the first and second parts. The connecting member includes a cross bar extending between the first and second ends having an aperture therein that results in a region of weakness, a portion of the cross bar spaced from the aperture minimizing stress at the region of weakness when torque is transmitted in use between the first and second parts via the connecting member.

Abstract: A rotating inner member is used to drive a downhole tool housed within the hollow outer member of a dual-member drill string. The downhole tool preferably will be adapted to receive rotational energy from the inner member. In a preferred embodiment, the downhole tool is an electric generator connected to a downhole electric device. In another preferred embodiment the downhole tool is a mechanical transmission that uses the rotational energy from the inner member to drive a non-electric tool, such as a downhole hammer. This invention will increase the consistency and efficiency of downhole energy production.

Abstract: As a serial element of a drill string, the drill string is adjustably bent by rotating one end of the sub relative to the other end. The opposite ends rotate about a tilted center line such that in one rotational position the sub is straight. One half turn of one end relative to the other bends the sub to the maximum angle. Between straight and maximum bend, any angle can be achieved by control of the amount of the relative rotation between the opposite ends of the sub.

Abstract: A rotating inner member is used to drive a downhole tool housed within the hollow outer member of a dual-member drill string. The downhole tool preferably will be adapted to receive rotational energy from the inner member. In a preferred embodiment, the downhole tool is an electric generator connected to a downhole electric device. In another preferred embodiment the downhole tool is a mechanical transmission that uses the rotational energy from the inner member to drive a non-electric tool, such as a downhole hammer. This invention will increase the consistency and efficiency of downhole energy production.

Abstract: A device for connecting a tool to a mechanical drive contains as the coupling element a spring washer coupling or clutch, which is made in one piece from metal and at least in the rotation direction has a limited resilience. Use is made thereof for preventing torque peaks in the case of a sudden deceleration of the tool, e.g. if a screw strikes a wood surface.

Abstract: There is provided an adjustable housing for use with a drill string for controlled directional drilling of a well hole. The housing includes an upper sub and a lower sub each having a first portion extending along a primary axis and a second portion extending along a secondary axis offset from the primary axis by a predetermined angle. The second portions are rotatably mounted together such that the secondary axes of the respective upper and lower subs are coincident. The upper sub is thus rotatable in relation to the lower sub between a bent position wherein the primary axes of the upper and lower subs are misaligned and a parallel position wherein the primary axes of the upper and lower subs are parallel to each other. A locking member is slidably mounted on splines extending radially from the second portion of the upper sub such that the locking member is slidable between an engaged position and disengaged position.

Abstract: Opposite ends, or terminals, of the sub are connected by a tubular arbor with threaded pins on each end. The arbor is bent in the middle. A mating threaded box on the upper terminal is tilted an amount equal to the bend angle of the arbor and mates with the bent end of the arbor. If the arbor is rotated in the box, the centerline of the other threaded end describes a cone. One line on the cone is the axis of rotation of the upper terminal. If the lower terminal is locked in that position, the sub is in the straight configuration. Locked in any other rotational position, the sub is bent an angle that is a function of the amount of arbor rotation. To make the arbor adjustable from the outside, an indicator ring is mounted on splines on the arbor. The ring can slide axially on the arbor. The lower terminal can be tightened on the lower end of the arbor to jam the indicator against the upper arbor, locking the assembly for use.

Abstract: The present invention relates to an elevator (10, 134, 136, 150, 162, 186), particularly a single joint elevator, for supporting tubular members such as drill pipe (118), borehole casing and/or production tubing, for use in downhole operations. In a preferred embodiment of the invention, an elevator (10) is generally elliptical shaped, and comprises a housing (12), a lock (14), lifting eyes (16) and a hinge (18). The housing comprises first and second portions (20, 22), pivotally coupled via the hinge (18), which together define an upper ring, elliptical in cross-section, and a tapering, generally truncated cone-shaped lower portion. The tapered lower portion of the elevator (10) ensures that the elevator (10) does not become caught or fouled upon a Vee door, or a pipe discharge ramp (122), on to which the pipe (118) supported by the elevator (10) is to be discharged during, for example, the “running-in” of the pipe (118) into a borehole of an onshore or offshore well.

Abstract: In the invention a side tracking bit that has a flexible interface between the bit crown and the bit shank which greatly reduces the length of inflexible structure between the face of the bit and the flexible interface. The limiting of the length of inflexible structure between the face of the bit and the flexible point significantly increases the side tracking bit's angle in starting and drilling a curved hole from the vertical to the horizontal and significantly shorten the radius of the curved hole.

Abstract: The apparatus has a housing which is secured to the lower end of a drilling motor body and carries an arbor that is secured to the output shaft of the motor. The arbor has three segments serially connected by gimbals. The upper segment is axially fixed by the bearings of the motor and has a lower end that extends when actuated to push the center segment downward. Axial movement of the center segment actuates a cam to move it laterally. The lower segment extends from the housing as an output shaft. It is arranged to tilt relative to the housing and its upper end is moved laterally by the gimbal connected center segment. The resulting tilt of the rotating axis of the output shaft causes an attached drill head to drill a deflected well bore.

Abstract: A device for controlling the drilling direction of drills includes a cylinder-type housing 6, a first ring-formed component 11 which is located on an inner peripheral surface that is eccentric with respect to the cylinder-type housing 6, a second ring-formed component 12 which is located on the inner peripheral surface that is eccentric with respect to the circular inner surface of the first ring-formed component 11, and hollow-type harmonized reduction gears 13,14 which rotate the first and second ring-formed components 11,12 relatively around their respective centers. A resolver is positioned between the first and second ring-formed components 11,12 and the hollow-type harmonized reduction gears 13,14 to detect the rotating angular position of the first and second ring-formed components 11,12. A fulcrum bearing 8 of the rotating shaft 2 is located at a midpoint between the drill bit and the first and second ring formed components 11,12.

Abstract: A drill string orienting tool for insertion into a well bore includes a housing that has a plurality of inwardly projecting splines. A mandrel is disposed within the housing. The orienting tool has two operating positions, a running position, and an orienting position. The housing is longitudinally moveable relative to the mandrel between the running position and the orienting position. The mandrel and the housing define an annular chamber that is vented to the exterior of the housing. A flexible metallic coiled tube is disposed within the annular chamber and contains hydraulic fluid. The upper end of the coiled tube is coupled to the housing and is in fluid communication with the first fluid chamber. The lower end of the coiled tube is coupled to the mandrel. The mandrel has outwardly projecting splines that are engageable with a corresponding set of inwardly projecting splines on the housing when the orienting tool is in the running position. A piston is movably disposed within the housing.

Abstract: A directional drilling apparatus includes a two part tubular body including an upper section and a lower section adapted to rotate with respect to one another, the upper section including threads for attaching the apparatus to a drill string, the upper section including at its lower end portion a slot including a straight portion which is generally aligned with the axis of the upper section and an offset portion which is spaced laterally from an spaced radially from the vertical section, connecting teeth for forming a connection which rigidly affixes each of the upper and lower section with respect to each other so that they are prevented from rotating with respect to one another, and a sleeve carried by the lower section and slidably movable with respect to the upper section, the sleeve including a locking pin which extends into the slot, the pin being adapted to move longitudinally and laterally within at least a portion of the slot and into either the vertical or laterally offset a section thereof.

Abstract: A movable joint bent sub for attachment to a well conduit for use in deviated drilling of a well. An elongated housing is provided having one end for attachment to a well conduit, a mandrel is telescopically movable in the bore of the housing, and a movable body is pivotally connected to the mandrel and is longitudinally movable in the housing. Coacting cam surfaces on the body in the housing pivot the body to a desired deviation when the mandrel is telescopically moved in the bore. A releasable lock may be provided between the mandrel and the housing.

Abstract: A fitting for controlled trajectory drilling. This fitting comprises a downhole motor, a drilling tool, at least one stabilizer and a remote controlled variable angle elbow element.

Abstract: The sub, usable as a length element of a drill string which may include a drilling motor body, comprises three generally tubular members. Two members, each having means to attach to a continuing drill string, have threaded boxes positioned in opposition. A third member is a double ended threaded, shoulderless, pin threadedly extending into the boxes with box faces in contact when the sub is assembled. One box, and the mating pin end, have threads coarser than the finer threads in the other box and on it's mating pin end. Axial position adjustment of the pin causes the abutting box faces to change rotational relationship, thus changing the rotational relationship of axially spaced drill string elements separated by the sub. If the sub is to be used to deflect the drill string centerline, the double ended pin and the threaded boxes have a centerline tilted a small angle from the centerline of the first two members. In one configuration the assembly has, preferably, both end centerlines on one line.

Abstract: An orientatable adjustable bent housing consisting of a tubular inner housing which is telescopically received within a tubular outer housing. A sleeve is provided which has an angular offset end face. The sleeve is axially slidable along the inner housing between a coupled position wherein spline non-rotatably couple the sleeve with the inner housing and an orientatable position wherein the sleeve is disengaged from the spline permitting respective rotational positioning of the sleeve and the inner housing. In the coupled position the sleeve is further slidable between an inoperative position wherein the sleeve is spaced from the outer housing and an operative position. In the operative position the angularly offset end face of the sleeve is brought in face to face relation with an angularly offset end face of the outer housing thereby creating a bend the magnitude of which is dependent upon the relative rotational positioning of the outer housing and the inner housing.

Abstract: A method for directional drilling of a well with a motor and drill bit. A tubular housing is secured to the lower end of the motor with the housing having a first surface with an axis angularly disposed relative to the axis of the tubular housing. A second tubular housing has a surface engagable with the first surface and is angularly disposed relative to the axis of the second tubular housing with the extent of the engagement of the first and second surfaces determining the angular position of the axis of the second tubular housing relative to the axis of the first tubular housing. The extent of the engagment of the surfaces is selectively adjustable by shims. A first angular stabilizer is carried with a drill bit which is rotatably mounted with a drive means including universal joints. The apparatus is secured to a tubing string with a drill bit and lowered into the bore hole with the apparatus actuated by application of tubing weight with direction being controlled by rotation of the drill string.

Abstract: An adjustable bent housing for controlled directional drilling of well holes. The bend angle of the housing can be conveniently adjusted upon release of the locking nut which is threadably mounted to the motor casing. The locking nut engages an adjusting ring having splines to lockingly engage both the motor casing and the adjustment sub. The adjustment sub and motor casing are lockingly engaged against axial displacement by threads and a plurality of locking balls. An end portion of the outer surface of the motor casing and an end portion of the inner surface of the sub have an angle offset from the central axis to allow angle adjustment. The adjusting ring and locking nut are mounted to the coaxial portions of the components to simplify machining and ensure a clean locking engagement. Adjustment of the bend angle is accomplished by loosening the locking nut to disengage the adjusting ring and allow rotation of the motor casing relative to the universal housing sub.

Abstract: A bendable sub for use in the drilling string includes an elongated tubular mandrel with a threaded top end for mounting the mandrel at the bottom end of a drilling string, a lock nut threaded onto the body of the mandrel between the ends thereof for vertical movement, a coupler slidably mounted on the mandrel beneath the lock nut for movement between a release position and a locking position, the coupler being non-rotatable on the mandrel, a sleeve on the mandrel beneath the coupler with a tapering passage extending therethrough, a latch between the coupler and the sleeve for releasably connecting the coupler to the sleeve, and a retaining nut on the bottom end of the mandrel beneath the sleeve for retaining the latter on the mandrel, at least the bottom end of the coupler and the top end of the sleeve being inclined with respect to the longitudinal axis of the mandrel, whereby the sleeve can be tilted or inclined with respect to the mandrel to form a bend in the drilling sub.

Abstract: An improved directional drilling tool permits changing the downhole drilling assembly between straight and directional drilling configuration by manipulation of conventional drilling fluid flow controls at the surface. A housing, with stabilizer features, shrouds a shaft which functions as an extension of the drill string and attaches to a drill head. A drilling fluid flow rate responsive selector valve is situated in the shaft and responds to drilling fluid flow rate manipulations to change assembly configuration. In the straight configuration the shaft remains straight and is rotationally locked to the housing. In the directional configuration the housing is rotationally unlocked from the shaft, normally after directional orientation, so that the shaft can rotate through it. The same action transversely displaces the shaft midsection relative to the housing and the shaft and drill head below is angularly deflected by way of a hinge arrangement near the drill head end of the housing.

Abstract: A method of directionally drilling a borehole makes use of a drilling assembly including an apparatus having an upper section with a longitudinal axis I, and a lower section having a central axis II and including at least part of a rotary drill bit, said sections being interconnected by a universal pivot mechanism. The method comprises rotating the assembly in such a manner that the upper section rotates about said longitudinal axis I and the lower section rotates about said central axis II. During at least part of the drilling operations said central axis II is tilted and rotated in an orbital mode relative to said longitudinal axis I such that a plane containing said two axes is maintained in a predetermined orientation relative to a reference direction.

Abstract: The device comprises a variable-angle elbow coupling (14) interposed between the ends (12, 13) of two successive sections of a column. The coupling (14) comprises a first rectilinear tubular element (14a) and a second rectilinear tubular element (14b) connected to the element (14a) and mounted to be rotatable relative to the element (14a) about an axis (16). The axis of the tubular element (14) makes a non-zero angle with the axis (18) of the first section of the column. The end portions of the elements (14a, 14b) are radially offset relative to the axis (18) of the column and connected to the first section (12) and the second section (13) respectively by detachable rigid tubular elbow couplings (15a, 15b). The device of the invention is applicable to a drilling column.

Abstract: A drilling tool having a body that functions as a length of drill string and telescopes to shorten the body each time column load is applied by way of applied bit load. The telescoping action causes a cam turret in the body to change position to cause one of two possible conditions to exist while drilling. In one condition the body centerline is held straight while drilling. In the second condition the lower portion of the body is laterally deflected for changing the course of the well bore while drilling proceeds. Optional features cause a mud pressure signal to be generated, for detection at the surface, when selected elements in the apparatus are in preselected positions.

Abstract: Apparatus for effecting a change in the direction of a downhole rotary drilling tool comprises a bent housing disposed between the bottom end of a downhole motor and a tubular housing connected to the drilling tool. The bent housing is angularly adjustable relative to the motor housing and the connecting housing is provided with an eccentric external surface upon which an annular eccentric stabilizer is adjustably mounted. In a modification, a second annular eccentric stabilizer is mounted on the upper portion of the motor housing. Selective angular adjustment of the eccentric stabilizers relative to their mounting housings, coupled with angular adjustment of the bent housing effects any desired shift in angular position of the rotary drilling tool to effect a desired change in the direction of the drilling with a minimum of side wall interference.

Abstract: A body and driveshaft extension for down hole drilling motors to allow the down hole assembly to operate as part of a drill string responsive to selected manipulations of the drilling fluid flow rate, carried out at the earth surface, to assume either a straight hole drilling configuration or a directional drilling configuration by choice of the driller.In the directional drilling configuration, the drill head driving output shaft rotates about a centerline deflected from the motor general centerline. The point of deflection is between the drilling motor and the drill head.

Abstract: An orienting and circulating sub is disclosed for connection in an apparatus for angular drilling in the earth. The drilling apparatus comprises a drill string extending into a substantially vertical well bore in the earth supporting a fluid operated motor and drill bit at its lower end. The drill bit is supported for angular drilling by either using a bent sub for supporting the drilling motor or be using a drilling motor with a bent housing. A surveying tool is connected above the motor for determining and controlling the direction of drilling. A mule shoe keying sub is connected to the surveying tool for orienting the position of the motor in relation to said surveying tool. The orienting sub comprises a tubular housing formed in two sections threaded together with one end connected to the surveying tool by the mule shoe keying sub and the other end connected to the bent sub or to the bent motor housing.

Abstract: A directional drilling tool permits the control of the angle of drilling of a drill bit through the repeated placement or removal of a ball within the mudstream. The ball activates a clutch mechanism within the directional drilling tool. The clutch mechanism, upon activiation, locks the exterior of the directional drilling sub to a fixed angular orientation. Simultaneously, there is activated a deflection mechanism to deflect a drive shaft which is normally fixed in an aligned straight position within the tube body, so as to shift the normally straight aligned shaft to a deflected position, causing the bit and the sub to angle for drilling at a controlled angle of offset from the vertical. The unit is aligned and located using wireline measuring equipment of known design.

Abstract: The present invention relates to drilling a well with a bent bore. A bending device is inserted in a drilling string between a stabilizer and an active motor element. If the drilling string is rotated in one direction the bending device takes up a rectilinear configuration for ensuring rectilinear drilling, and if the drilling string is rotated in the opposite direction it takes up a bent configuration, thereby transforming itself into a bent coupling for curved drilling. The device comprises two superposed sleeves (1, 2) one of which is capable of rotating through a limited angle about a pivot (3) whose axis lies at the same small angle (A) to the axes (10, 10A) of both sleeves. The invention is applicable to drilling oil wells or geothermal wells.

Abstract: A connector housing for connecting a motor housing to a bearing housing, so that the angle between the longitudinal axis of the motor housing and the longitudinal axis of the bearing housing can be changed. The connector housing has a top housing, a center housing, and a bottom housing. The top and bottom housings have angles in their respective longitudinal axes aligned in the same direction. The center housing has a pair of angles in its longitudinal axis, the sum of which is equal to the sum of the angles in the top and bottom housings. The top and bottom housings are held against rotation relative to one another, but can be rotated 180 degrees relative to the center housing. A stabilizer holds the center housing as the top and bottom housings are rotated. Dogs limit the relative rotation between the center housing and the other housings to not more than 180 degrees.

Abstract: An improved directional drilling tool permits the control of the angle of drilling of a drill bit through the repeated placement or removal of a ball within the mudstream. The ball activates, clutch mechanism within the directional drilling tool. The clutch mechanism, controlled by the activated valve, locks the exterior of the directional drilling sub to a fixed angular orientation and activates a deflection cam to deflect a drive shaft so as to angle the bit, causing the bit and sub to drill at a controlled angle offset from the vertical. The unit is aligned and located using wire line measuring equipment of known design. Since the sub may be controllably set in a straight line drilling or an angle drilling position, it may be left permanently in position in a drill string significantly reducing the requirement to trip out the well bore during directional drilling and significantly increasing the flexibility available to the driller to deflect the direction of drilling while drilling is in progress.

Abstract: A variable angle directional drilling "sub" provides a shifting end portion which allows the sub to be rotated from a first, in-line, axially straight orientation with the drill string to a selected second, angled or "bent" position, which second position is normally assoicated with conventional bent "subs" which are permanently structured in the bent position. The tool provides a multiple choice of varying angles to the sub in its bent position to satisfy differing directional drilling situations. A first embodiment (FIGS. 1-7) is manually set and varied at the surface by positioning two angularly marked sections temporarily rotatable with respect to each other until the desired angle set is matched up, while a second embodiment (FIGS. 8-9) is motor driven to allow varying the angle direction while "down in the hole".

Abstract: A process for drilling spaced horizontal boreholes in a coal or other mineral deposit in excess of 1500 feet in length in a pattern determined to maximize gas removal. Directional guidance is provided by a continuous downhole survey tool connected to data display devices by an internal drill rod cable system. Directional drilling control is provided by a positive displacement motor positioned at the end of the drill string and operated by a flow of drilling fluid through the drill string from the drilling rig. The mineral strata surrounding the borehole is periodically hydrofractured to permit effective removal of the gas. The hydrofractionation is effected without removal of the drill string or survey instruments from the borehole. Upon completion of the borehole, the drill string is removed and gas which enters the borehole from the surrounding deposit is withdrawn.

Abstract: This invention relates to a device for selectively setting the axial alignment of sections of pipe from axial coincidence to an obtuse angle between the pipe sections.