Abstract: A method determining a tool face angle of a downhole drilling assembly in a well bore including the steps of determining an apparent tool face angle, measuring torque at least at one downhole axial location along the drillstring in the well bore, correlating a change in the apparent tool face angle relative to a change in the torque so as to produce a graphical curve of the correlation, and identifying a slope discontinuity along the graphical curve. The slope discontinuity is indicative of a contact resistance between the drillstring and the well bore. This method further includes the steps of determining a differential twist angle from the graphical curve and inferring a true tool face angle by subtracting the differential twist angle from the apparent tool face angle. The step of determining the apparent tool face angle includes measuring the inclination angle and azimuth angle of the well bore. The torque is measured at substantially the same axial location as the apparent tool face angle.

Abstract: A method of directional drilling including the steps of affixing a bit, a motor housing, a MWD, and a sub to an end of a drillstring, forming a hole in the earth by rotating the bit as the drillstring lowers into the earth, actuating the sub such that the MWD is stationary as the drillstring rotates, and measuring a position of the bit as the MWD is stationary and as the drillstring rotates. The motor housing and the MWD are connected to the drillstring such that the MWD rotates in correspondence with the motor housing. The step of measuring includes measuring an inclination and an azimuth of the hole at the location of the MWD in the hole. A tool face orientation is adjusted relative to the position of the bit within the hole. The sub has a first portion connected to the drillstring and a second portion connected to the motor housing. The step of actuating includes indexing a gear member within the sub such that the first portion rotates independently of the second portion.

Abstract: An apparatus for steering a forward end of a drill string having a motor. The apparatus includes a shaft connected to the motor. The shaft has a thickened portion. Drilling fluid having an operating mass flow rate, and a housing are provided. A piston is enclosed within the housing, and is displaceable by a mass flow of the drilling fluid. The piston has a central opening for the passage of the drilling fluid and has the shaft extending therethrough. The piston includes a displaceable sleeve within the housing, a first spring urging against the sleeve and the housing, and a displaceable piston part coaxial with the sleeve within the housing.

Abstract: A downhole drilling subassembly for use with a pressurized fluid carrying drill string extending from a well head down to a bottom of a bore hole. The drill string includes upper and lower sections disposed at an angle relative to each other and having respective upper and lower longitudinal axes. An upper subassembly portion is adapted to couple to the upper section of the drill string. A lower subassembly portion is rotatably carried by the upper subassembly portion and is adapted to couple to the lower section of the drill string. The upper and lower subassembly portions are hollow so as to permit the pressurized fluid to pass therethrough. An assembly responsive to raising the drill string off the bottom of the bore hole and lowering the drill string back onto the bottom of the bore hole is provided for rotating the upper and lower subassembly portions with respect to one another between first and second relative angular positions.

Abstract: The invention relates to a directional drilling tool for use in controlled directional drilling. The drilling tool comprises two parts which are moveable relative to each other either in the horizontal or vertical planes. Cam surfaces are provided between the two parts for adjustments to the drilling direction in the vertical plane. A slot and groove mechanism is provided between the two as an example of adjustments in the horizontal plane. In each case hydraulic pressure is the preferred means of controlling the adjustments said controlling means being independent of the other well operations.

Abstract: A drilling head for making a borehole along a predetermined underground path is formed by a tubular body having a guidable rotary drilling sub normally axially mounted in the body by means of a sleeve bearing journalling a drill bit equipped rotary drilling string sub joint moveable with and within the sleeve for disposing the drilling bit on a predetermined angle in a predetermined direction relative to the longitudinal axis of the body by means of diametrically opposite superposed pairs of wedges interposed between respective end portions of the sleeve bearing and the inner periphery of the body.

Abstract: A bottom hole drilling assembly connectable to coiled tubing comprises a downhole motor to rotate a drill bit, articulated sub for causing the drill bit to drill a curved bore hole when a second portion thereof is bent from coaxial orientation with a first portion, steering tool for indicating the attitude of the bore hole, thruster for providing force to advance the drill bit, and orientating tool for rotating the thruster relative to the coiled tubing to control the path of the bore hole.

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: An adjustable bent housing consisting of three tubular members arranged in end to end relation. Each of the tubular members has an interior bore. A first tubular member has a first axis. A second tubular member has a second axis. A central tubular member is centrally disposed between the first tubular member and the second tubular member and has a third axis. An internal tubular member extends into and engages the interior bores of the three tubular members thereby maintaining the tubular members in end to end relation.

Abstract: A steerable motor system with integrated formation evaluation logging capacity is presented. The device comprises a housing, a formation resistivity logging tool, a surface signaling device, a density logging tool, a porosity logging tool and a downhole motor and drill. The formation resistivity logging tool is located below the downhole motor and is mounted within the housing wherethrough a drive shaft, extending from the downhole motor, is disposed. Power and signal cables are located within an outer shell of the housing and connect the surface signaling device with the resistivity logging tool. In an alternate embodiment, the resistivity logging tool is located between a motor stabilizer and the drill bit. The present invention allows for increased drill angle during wellbore drilling and formation evaluation.

Abstract: A downhole adjustable blade stabilizer is disclosed for varying the position of stabilizer blades to provide an increased ability to control the direction of drilling. The adjustable blade stabilizer includes a plurality of blades mounted in an angled track to permit axial and radial movement of the blades. The blades are driven by a piston in response to a pressure differential created by a sufficient flow of drilling mud through the stabilizer. The stabilizer blades are retracted by a spring when the pressure differential is eliminated. A positioning piston limits blade extension to a desired position. The positioning piston moves in response to a command signal, and remains in place until a new command signal is received. By maintaining the positioning piston in a locked position, the position of the blades can be reset to the prior position after the loss of pressure differential. A measuring device is provided in association with the positioning piston to enable precise measurement of blade position.

Abstract: An orientation mandrel rotatable in an orientation body for providing rotational orientation and actuated by a hydraulic piston controlling the position of a helix. A thruster may be connected to the orientation mandrel and is adapted to hydraulically engage the well bore by plurality of elongate gripping bars. An annular thruster piston is hydraulically and longitudinally movable in the thruster body for extending the thruster mandrel outwardly from the thruster body. However, the orientating tool and thruster may be used separately.

Abstract: A fitting for controlled trajectory drilling. This fitting comprises a downhole motor, a drilling tool, and a variable geometry stabilizer.

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 downhole adjustable orienting sub is included in a directional drilling tool string that is run into the borehole on coiled tubing. The bent housing of the tool string defines a bend angle and a bend point, and the bend point is oriented about the center of the bore by operating the orienting sub. The level of the reactive torque applied to the bent housing as the bit drills on bottom is controlled by selecting the amount of the weight of the coiled tubing that is applied to the bit. The orienting sub can be indexed downhole to provide different orientations of the bend point by temporarily reducing and then increasing the mud flow rate.

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: There is described an adjustable bent housing comprising a cylindrical housing having an uphole and a downhole end and a bore formed therethrough, the bore being divided into uphole and downhole portions axially offset to one another, and a tubular mandrel having an uphole and a downhole end, the ends being axially offset to one another. The downhole end of the mandrel is receivable along a portion of its length into the uphole portion of the bore in the housing for rotational movement relative to the cylindrical housing for varying the angle of bend between the mandrel and the cylindrical housing. Also provided is a locking mechanism comprising outer and inner concentric sleeves disposed annularly about the mandrel.

Abstract: The present invention discloses a universal, adjustable pipe joint which permits a wide variety of possible adjustments with simple means in well drilling technology. In principle, the joint disclosed in this invention can be readily used for joining articles of all types which included tubular, pipe-like, projections.

Abstract: Drilling fitting equipment is disclosed, comprising a drilling motor, a member to be actuated, an information detection unit and a power unit for controlling the member, the motor comprises an energy transformation zone for rotating a drilling tool, the zone having an upper end, the equipment comprising a flow of drilling fluid through the drilling fitting, wherein the member to be actuated and at least one of the elements of an assembly formed by the detection unit and the power unit are situated on opposite sides of the upper end.

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 adjustable bent sub for a down hole drill is disclosed consisting of a hollow housing and a hollow mandrel shaped to fit within the housing. A jam nut is positioned on the end of the mandrel to retain it within the housing by abutting a shoulder provided on the inner surface of the housing. A 1 degree off-normal face is machined on the shoulder and on the abutting face of the jam nut. By positioning the mandrel/jam nut assembly at different angular positions with respect to the housing, a linear deviation of 0 to 2 degrees is possible through the length of the sub.

Abstract: In accordance with an illustrative embodiment of the present invention, a downhole adjustable apparatus for creating a bend angle in a drill string includes a mandrel mounted for rotation between first and second angular positions within a housing, the mandrel being telescoped into the housing on an axis that is inclined with respect to the principle axial centerline of the housing, so that in one rotational position of the mandrel the housing is axially aligned with the centerline of a drilling motor and in another rotational position that is 180.degree. from the initial position the housing is slightly inclined with respect to the centerline of such drilling motor to establish a bend angle. Further manipulation of the mandrel is used to return the members to their original positions for straight-ahead drilling.

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: The present invention discloses a universal, adjustable angle, pipe joint which permits a wide variety of possible adjustments with simple means in deep well drilling technology. In principle, the pipe joint disclosed in this invention can be readily used for joining articles of all types which include tubular, pipe-like, projections.

Abstract: An orientatable adjustable bent sub having a tubular member in the form of a adjustment sleeve, with a first and offset to a primary axis, telescopically receives the first end of the tubular member. By rotation of the adjustment sleeve the offset portion of the adjustment sleeve is adjusted in relation to the offset portion of the tubular member to produce a bend of desired magnitude. The adjustment sleeve is axially moveable between an engaged position and a disengaged position. In the disengaged position the adjustment sleeve is rotatable in relation to the tubular member permitting an adjustment to be made. An orientation sleeve telescopically receives the second end of the tubular member. By rotation of the tubular member within the orientation sleeve the bend created by the positioning of the offset portion of the adjustment sleeve in relation to the offset portion of the tubular member is orientated in a desired direction.

Abstract: A steerable mole for making a hole in the ground has a round tubular body, a guidable drilling instrument mounted in front on this body via a ball and socket joint, a device mounted in the body in order to guide the drilling instrument in relation to the body. The ball of the ball and socket joint is fixed to the drilling instrument, while the device for guiding the drilling instrument has a steering element situated in the body which turns round the longitudinal axis of the body of which the front is directed obliquely at this longitudinal axis of the body and works together with the back of the ball of the ball and socket joint. Another device rotates the steering element around the longitudinal axis of the body.

Abstract: An actuator for an appliance associated with a ducted body, through the duct of which flows an incompressible fluid, includes a differential piston axially moveable within the duct and operatively connected to the appliance. The piston has a tubular shape and a central bore which includes a first profiled throttling portion the minimum internal diameter of which is smaller than the internal diameter of the duct. A protruding profiled element secured in the duct body is disposed coaxially with the piston and cooperates therewith for selectively increasing the loss of head of the incompressible fluid as it flows in the direction of circulation. A spring is arranged between the piston and part of the drill-string for biasing the piston in a direction of movement opposite the direction of circulation of the incompressible fluid. A measurement device is provided for measuring the pressure of the incompressible fluid at the first end of the drill-string.

Abstract: A bottom hole assembly is described having a bit driven by a downhole motor and stabilizers located above the motor on the drill string. A subassembly is also provided for controlling the bit trajectory that is operational on demand at the rig site. The subassembly comprises an underreamer located directly above the bit. The underreamer is hydraulically actuated to retract and extend the cutters.

Abstract: An adjustable bent housing consisting of an inner housing telescopically received within an outer housing. A sleeve is provided having an angularly offset clutch face. Spline non-rotatably couple an interior surface of the sleeve with an exterior surface of the inner housing. The sleeve is axially slidable along the exterior surface of the inner housing between an inoperative position wherein the sleeve is spaced from the outer housing and an operating position. In the operative position the angularly offset clutch face of the sleeve engages an angularly offset clutch face on the outer housing thereby non-rotatably coupling the inner housing and the outer housing in a bent position 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 method and apparatus for drilling highly deviated wells is disclosed. A drilling assembly is attached to a drill string. The drilling assembly includes a bent sub, a pony collar attached to the bent sub, a motor with a bent housing, and a bit. Improved survey collars and bits are also disclosed.

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: Steerable mole for making a hole (31) in the ground (30), which drilling mole has a round tubular body (1), a guidable drilling instrument (2, 3) mounted in front on this body (1) by means of a ball and socket joint (4, 5) and means (7-9) mounted in the body (1) in order to guide the drilling instrument (2, 3) in relation to the body (1), characterized in that the ball (4) of the ball and socket joint (4, 5) is fixed to the drilling instrument (2, 3), while the means (7-9) for guiding the drilling instrument (2, 3) have a steering element (7) situated in which turns round the longitudinal axis of the body (1) the body (1) of which the front is directed obliquely at this longitudinal axis of the body (1) and works together with the back of the ball (4) of the ball and socket joint (4, 5) and means ( 8, 9) to rotate the steering element (7) round the longitudinal axis of the body (1).

Abstract: A system of apparatus for the controlled directional drilling of a deviated well bore into the earth has a fluid operated drilling motor and drill bit secured on the bottom end of a drill string. The drill bit is supported for angular drilling relative to a substantially vertical well bore by either using a bent sub for supporting the drilling motor or by using a drilling motor with a bent housing or a combination of the two. A bypass tool is connected to the bent sub or motor housing, an orienting sub and mule shoe keying sub are connected to the bypass tool, and a surveying tool is connected in the drill string above the orienting sub and mule shoe sub. The bypass tool is in fluid connection with the motor and has a telescopic housing and a valve for circulating fluid into the bore hole to flush cuttings and debris therefrom. The surveying tool determines and controls the direction of drilling.

Abstract: A flexible tunneling apparatus has an articulated thrust rod made up of a plurality of substantially identical tubular elements having complementary end surfaces, the elements being disposed in end-to-end relation and strung on a cable which is tensioned to effectively integrate the elements to form the rod. The rod is inserted into a tubular guide member which extends axially through and along the sidewall of a shaft. At one end the tubular guide member defines a rounded 90 degree turn causing flexure of the rod and diverting it to a path perpendicular to the axis of the shaft. Repetitive thrusting and retraction of the rod create a tunnel extending radially with respect to the axis of the shaft.

Abstract: A pressure-medium driven ram boring machine for boring in the earth, having an impact tip acted on by a percussion piston reciprocating in the machine housing, wherein the impact tip is arranged to be radially adjustable in the housing whereby controlled directional changes of the machine can be effected.

Abstract: A drill string deflection tool is arranged to function as a segment of drill string. An upper and a lower portion telescope together to form a mid-section with limited telescoping movement and limited angular deflection of the axes of the opposite ends. Axial load compresses the tool and a cam and fulcrum arrangement deflects the tool when it is axially compressed. The tool extends axially when pulled in tension and the axis becomes straight. Drilling fluid pressure acts on rams in the tool to lock it in whatever state exists when pressure is applied. The locking mechanism acts upon the drilling fluid channel to cause a pressure drop, detectable at the surface, that indicates the state of the tool downhole.

Abstract: A directional drill bit utilizing pressurized fluid as a means for eroding earth in a forward path of the bit and being used to drill at least a portion of an arcuate path, comprises an elongate hollow body having two sections joined one to the other by a flexible joint, a box end connection, a jet nozzle, an articulation device comprising a spring and a stop, the articulation device being responsive to changes in fluid pressure by permitting a forward portion of the bit bearing the nozzle structure to change angular position with respect to an aft portion of the bit, by the forward portion moving from a first position relative to the aft portion to a second position relative to the aft portion.

Abstract: A device for transmitting a thrust from one of a pair of adjacent pipes so as to propel the other comprises a pair of annular members adapted to be slidable relatively to each other along their spherical surfaces.

Abstract: A downhole adjustable bent sub is provided for use in a drilling process in which a drill bit is subjected to a drilling force. The bent sub has a tubular housing and a tubular mandrel. The tubular housing has a bend along its length to define an upper part and a lower part, the respective longitudinal axes of which intersect at an angle. The tubular mandrel also has a bend along its length to define a first part and a second part, the respective longitudinal axis of which intersect at an angle. The first part of the mandrel slidably engages the interior of the lower part of the tubular housing. a longitudinal stop prevents the mandrel from being slid out of the housing. Longitudinal biasing means urge the mandrel toward the longitudinal stop to a first position. A rotational stop prevents relative rotation between the mandrel and the housing when the mandrel is in the first position.

Abstract: A near bit offset stabilizer for use with a bent sub or bent motor housing is presented wherein a mechanism is provided to correctly orient and lock the stabilizer in a desired position in alignment with the bend angle in the bent sub or bent motor housing. This alignment and locking mechanism comprises a ring nut having a series of radial slots on its lower end; and the provision of a series of corresponding radial slots on the upper end of the stabilizer. The corresponding slots permit mutual interlocking between the ring nut and stabilizer for locking the stabilizer in any one of a plurality of radial positions. A scribe line or other indicia on the stabilizer permits visual alignment with the bend in the bent sub or bent motor housing in the drill string above. Finally, a second nut locks the stabilizer in the selected radial position.

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 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: 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: The invention provides apparatus for making a tunnel. A flexible tube connects to a head consisting of a body and a nose mounted for movement thereon. The nose has an abutment face adjustable in position relative to said body, and carries a nozzle. The nose may be a bevelled cylinder which may be rotatable relatively to the body by a steering mechanism or be conical and be tiltable by jacks operable from above the ground.

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: There is disclosed an adjustable bent sub for use in directional drilling in earth formations which is adapted to be placed between the power unit and bearing assembly components of a downhole motor and which can be angularly adjusted without requiring disassembly of the downhole motor unit.

Abstract: An adjustable bent sub for use in directional drilling in earth formations comprises a first body member having a first body portion defining a first primary axis and a second body portion defining a first secondary axis disposed at a first offset angle with respect to the first primary axis, a second body member having a first body portion defining a second primary axis and a second body portion defining a second secondary axis disposed at a second offset angle with respect to the first primary axis, the second body member being adapted to be secured to the first body member such that the first secondary axis and the second primary axis are coaxial and define a common axis and the second body member is rotatable about the common axis. A device is provided for non-rotatably coupling the second body member to the first body member in predetermined angular relation about the common axis so as to provide a predetermined angular relationship between the first primary axis and the second secondary axis.

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.