Abstract: A continuous geomechanically stable trajectory in a subterranean formation is found by calculating at least one reachable stable position relative to a starting position based on geological data indicative of characteristics of the subterranean formation, and iteratively utilizing the calculated reachable stable position as a new starting position. The calculation may be constrained by a boundary including selected distance and direction relative to the starting position, and selected rate of angle change. Within the constraints of the boundary, the possible new trajectories considered may be discretized. The result of the calculations is a three dimensional tree which defines a stability volume. Pruning of at least some branches of the tree may be employed so that not all stable positions have the preselected number of branches, thereby helping to elongate the tree. Either or both of the tree and stability volume are used to select at least one trajectory.

Abstract: A drilling system includes a steerable bottomhole assembly (BHA) having a steering unit and a control unit that provide dynamic control of drill bit orientation or tilt. Exemplary steering units can adjust bit orientation at a rate that approaches or exceeds the rotational speed of the drill string or drill bit, can include a dynamically adjustable articulated joint having a plurality of elements that deform in response to an excitation signal, can include adjustable independently rotatable rings for selectively tilting the bit, and/or can include a plurality of selectively extensible force pads. The force pads are actuated by a shape change material that deforms in response to an excitation signal. A method of directional drilling includes continuously cycling the position of the steering unit based upon the rotational speed of the drill string and/or drill bit and with reference to an external reference point.

Abstract: A borehole network including first and second end surface locations and at least one intermediate surface location interconnected by a subterranean path, and a method for connecting a subterranean path between a first borehole including a directional section and a second borehole including a directional section. A directional drilling component is drilled in at least one of the directional sections to obtain a required proximity between the first and second boreholes. An intersecting component is drilled, utilizing magnetic ranging techniques, from one directional section to provide a borehole intersection between the first and second boreholes, thereby connecting the subterranean path.

Abstract: Methods for installing tubulars into a highly deviated wellbore may include a) drilling the well to the planned total depth of the interval, b) placing a first fluid into the wellbore below a prescribed measured depth in the high-angle portion of the wellbore, c) placing a second fluid into the wellbore above the prescribed measured depth, d) plugging the distal port ion of the tubular with a lower plug and an upper plug, e) as the tubular is run into the wellbore, placing a lightweight fluid into the plugged section of tubular and a heavy fluid above the plugged section of tubular, and f) running the tubular into the wellbore to the planned total depth. The first fluid has a density that causes the portion of the tubular that extends into the first fluid to become substantially neutrally buoyant, and the second fluid has a density less than the first fluid.

Abstract: This invention relates to drilling a sidetrack wellbore out of the side of an existing wellbore utilizing a drillable billet having a path formed in the billet to lead a bi-centered drillbit to kick-out from the wellbore and form a sidetrack wellbore. The bi-centered bit is arranged for the lands of the pilot section to follow the path of the billet while the wings of the ream out a portion of the billet and also ream out the earth to form the full dimension sidetrack wellbore. The bi-centered bit is used to drill the sidetrack wellbore to the target zone so that the entire drilling process extends from the existing wellbore to the target zone without a mandatory withdrawal of the drillstring from the wellbore. Tripping time is therefore less and drill time and rig time would inherently be less resulting in lower costs and increased profitability.

Abstract: A cutting device for downhole operations includes a first cutting structure, and a second cutting structure, wherein at least the second cutting structure is selectively presentable for operation. A method of performing a downhole cutting operation comprises running into a well bore a cutting device including a plurality of cutting structures, performing a first cutting operation with a first cutting structure of the cutting device, moving the first cutting structure to selectively present a second cutting structure of the cutting device, and performing a second cutting operation with at least the second cutting structure. The method may further include aligning movable cutting structures of the cutting device to allow the second cutting structure to be selectively presented.

Abstract: A method of extending an earthen bore comprises the steps of rotating a drill bit at the end of a tubular while vibrating the tubular. The method results in reduced friction to tubular advance through the bore and results in stabilized drill bit loading and longer usable drill bit life. A method of conditioning a cement slurry in an annulus between a casing and a bore to improve a resulting cement liner comprises the steps of coupling a vibration generator to the casing, running the casing into the bore, displacing the cement slurry into the annulus and using the vibration generator to vibrate the casing. A vibration generator may comprise a mass, having a mass center, coupled to a frame, a motor and a power source to spin the mass about an axis offset from the mass center.

Abstract: Steerable drilling systems for facilitating drilling according to a prescribed, three-dimensional trajectory are described. Steering may be achieved using passive actuators which require little or no power. For example, damping elements which couple a drill bit to a drill collar can be used to tilt the drill bit with respect to the drill collar. Alternatively, rotary cutting elements disposed on the drill bit may be used to control the force between the drill bit and the formation at different axial locations. The passive elements used to control the tilt or rotation of the rotary cutting elements are actuated in a certain pattern, e.g., geostationary, in order to achieve a desired deviation of the well bore while drilling ahead. One way to achieve this is through the use of field-sensitive materials, e.g. magnetorheological (MR) fluids, that change viscosity in response to an applied magnetic field.

Abstract: A steering tool is movable by a drill string to form an underground bore along an intended path. A sensing arrangement of the steering tool detects its pitch and yaw orientations at a series of spaced apart positions along the bore, each position is characterized by a measured extension of the drill string. The steering tool further includes a receiver. At least one marker is positioned proximate to the intended path, for transmitting a rotating dipole field to expose a portion of the intended path to the field for reception by the receiver. The detected pitch orientation, the detected yaw orientation and the measured extension of the drill string are used in conjunction with magnetic information from the receiver to locate the steering tool. The steering tool may automatically use the magnetic information when it is available. A customized overall position determination accuracy can be provided along the intended path.

Abstract: A drilling assembly is disclosed that in one embodiment includes a bi-directional wireless data transfer device between a rotating and a non-rotating member of the drilling assembly. Power may be supplied to the rotating member via any suitable method, including an inductive device and direct electrical connections.

Abstract: A system for steering the direction of a borehole advanced by cutting action of a rotary drill bit by periodically varying the rotation speed of the drill bit. The steering system comprises a motor disposed in a bent housing subsection and operationally connected to a drill string and to the drill bit. The rotation speed of the drill bit is periodically varied by periodic varying the rotation speed of the motor or by periodic varying the rotation speed of the drill string. Periodic bit speed rotation results in preferential cutting of material from a predetermined arc of the borehole wall which, in turn, resulting in borehole deviation. Both the drill string and the drill motor are rotated simultaneously during straight and deviated borehole drilling.

Abstract: A preferred embodiment of a system for rotating and guiding a drill bit in an underground bore includes a drilling motor and a drive shaft coupled to drilling motor so that drill bit can be rotated by the drilling motor. The system further includes a guidance module having an actuating arm movable between an extended position wherein the actuating arm can contact a surface of the bore and thereby exert a force on the housing of the guidance module, and a retracted position.

Abstract: A cutting device for downhole operations comprises a first cutting structure, and a second cutting structure, wherein at least the second cutting structure is selectively presentable for operation. A method of performing a downhole cutting operation comprises running into a well bore a cutting device comprising a plurality of cutting structures, performing a first cutting operation with a first cutting structure of the cutting device, selectively presenting a second cutting structure of the cutting device, and performing a second cutting operation with at least the second cutting structure. The method may further comprise aligning the cutting device to allow the second cutting structure to be selectively presented.

Abstract: 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.

Abstract: A system and method for performing an adaptive drilling operation is provided. The method involves obtaining data prior to drilling, constructing a base model with a base model unit from data obtained prior to drilling, constructing an overburden posterior model with an overburden model unit using the base model and data obtained from overburden drilling, constructing a reservoir posterior model with a reservoir model unit using the overburden posterior model and the data obtained from reservoir drilling and updating drilling operation based on the models.

Abstract: In one embodiment, a method for drilling a wellbore includes injecting drilling fluid through a drill string disposed in the wellbore and rotating a drill bit disposed on a bottom of the drill string. The drilling fluid includes a liquid and a gas. The drilling fluid is injected at the surface. The drilling fluid exits the drill bit and carries cuttings from the drill bit. The drilling fluid and cuttings (returns) flow to the surface via an annulus formed between the drill string and the wellbore. The liquid is injected at a rate so that a liquid velocity of the returns in the annulus is sufficient to transport the cuttings. The method further includes drilling through at least a portion of a non-productive formation.

Abstract: A method and apparatus for forming a window in the wall of a tubular wellbore. In one embodiment described herein, a down hole apparatus for forming a window in the wall of a wellbore utilizing a plurality of tubing string sections and a thick tailpipe positioned at the down hole end of a tubing section.

Abstract: A system and method of interfacing a drilling machine with one of a number of different walk-over guidance systems involves receiving an ID signal from a particular walk-over guidance system selected for use with the drilling machine. A protocol library associated with the particular walk-over guidance system is accessed in response to the ID signal. The protocol library is used to effect communication between the particular walk-over guidance system and a control system of the drilling machine during cooperative use of the particular walk-over guidance system and drilling machine. Using the protocol library involves converting, as prescribed by the protocol library, locator signals received from the particular walk-over guidance system from a locator protocol to a common protocol used by the control system of the drilling machine. Locator and drilling machine data of various types can be presented to a drilling machine operator via an on-board display.

Abstract: The invention provides ball piston steering devices and methods for use of ball piston devices. One aspect of the invention provides a ball piston steering device including: a sleeve in fluid communication with a fluid source and a ball received within the sleeve. The ball is movable within the sleeve from a recessed position and an extended position.

Abstract: A bottomhole assembly (BHA) coupled to a drill string includes one or more controllers, and a hole enlargement device that selectively enlarges the diameter of the wellbore formed by the drill bit. The hole enlargement device includes an actuation unit that may move extendable cutting elements o the hole enlargement device between a radially extended position and a radially retracted position. The actuation unit may be responsive to a signal that is transmitted from a downhole and/or a surface location. The hole enlargement device may also include one or more position sensors that transmit a position signal indicative of a radial position of the cutting elements. In an illustrative operating mode, one or more operating parameters of the hole enlargement device may be adjusted based on one or more measured parameters. This adjustment may be done in a closed-loop or automated fashion and/or by human personnel.

Abstract: In one aspect of the present invention, a drill bit has a jack element that is substantially coaxial with an axis of rotation of the drill bit and the jack element has an asymmetrical distal end that extends beyond a working face of the drill bit. A turbine is located within a bore formed in the drill bit and a flow valve is actuated by the turbine. The flow valve is adapted to route a drilling fluid in the bore into a porting mechanism adapted to extend the jack element farther beyond the working surface of the drill bit. The turbine is also adapted to rotate the jack element at variable speeds.

Abstract: A wellbore servicing apparatus, comprising a first mandrel movable longitudinally along a central axis and rotatable about the central axis, an orienting member configured to selectively interfere with movement of the first mandrel along the central axis, and a second mandrel connected to the first mandrel and configured to rotate about the central axis when the first mandrel rotates about the central axis. A method of orienting a wellbore servicing tool, comprising connecting an orienting tool to the wellbore servicing tool, identifying a predetermined direction, increasing a pressure within the orienting tool, rotating a portion of the orienting tool in response to the increase in pressure within the orienting tool, and rotating the wellbore servicing tool in response to the rotating of the portion of the orienting tool.

Abstract: The invention relates to a bit for drilling wells comprising:—a front face,—a plurality of radial blades (2) provided with cutting elements (3), the blades being distributed around the front face,—a space (4) for forming a core (10), the space being situated at the centre of the front face,—a cavity (5) for evacuating the core towards the periphery of the bit, the cavity being situated between two adjacent blades. The invention also relates to a method for drilling wells using the bit. The invention makes it possible to rapidly drill wells of great depth in all types of rocks without the risk of clogging.

Abstract: The present invention relates to systems and methods for controlling downhole motors. One aspect of the invention provides a valve-controlled downhole motor including: a downhole motor and a spool valve. The downhole motor includes a sealed chamber having a first port and a second port, a stator received within the sealed chamber, and a rotor received within the stator. The spool valve includes a barrel and a spool received within the barrel. The barrel includes an inlet port, an exhaust port, a first feed port, a second feed port, a first return port, and a second return port. The inlet port is located in proximity to the first feed port and second port. The exhaust port is located in proximity to the first return port and the second return port. The spool includes a first gland and a second gland.

Abstract: A method of forming a wellbore includes providing a drilling assembly comprising one or more lengths of casing and an axially retracting assembly having a first tubular; a second tubular at least partially disposed in the first tubular and axially fixed thereto; and a support member disposed in the second tubular and movable from a first axial position to a second axial position relative to the second tubular, wherein, in the first axial position, the support member maintains the second tubular axially fixed to the first tubular, and in the second axial position, allows the second tubular to move relative to the first tubular; and an earth removal member disposed below the axially retracting assembly. The method also includes rotating the earth removal member to form the wellbore; moving the support member to the second axial position; and reducing a length of the axially retracting assembly.

Abstract: An insert for an earth boring drill bit, such as a PDC rock bit or a roller cone rock bit, is provided. The insert includes a base integrally joined to a top section, the top section having a first flank that curves in a substantially helical manner about a longitudinal axis of the insert to join a crest.

Abstract: Aspects of this invention include methods for surveying a subterranean borehole. In one exemplary aspect, a change in borehole azimuth between first and second longitudinally spaced gravity measurement sensors may be determined directly from gravity measurements made by the sensors and a measured angular position between the sensors. The gravity measurement sensors are typically disposed to rotate freely with respect to one another about a longitudinal axis of the borehole. Gravity MWD measurements in accordance with the present invention may be advantageously made without imposing any relative rotational constraints on first and second gravity sensor sets. The present invention also advantageously provides for downhole processing of the change in azimuth between the first and second gravity sensor sets. As such, Gravity MWD measurements in accordance with this invention may be advantageously utilized in closed-loop steering control methods.

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: One embodiment includes an apparatus comprising a steerable well bore drilling tool having a main tool body. The steerable well bore drilling tool includes an inertial measurement unit to output a measurement used to determine an azimuthal deviation and inclination of the steerable well bore drilling tool during a drilling operation.

Abstract: A method and apparatus for constructing large vertical boreholes and underground cut-off walls is disclosed. A drill rig assembly with double rotary heads drives a small diameter drill string and a much larger diameter drill string which is concentric with the smaller drill string and has a donut shaped drill bit configuration at the lower end thereof. Preferably, a steerable mud motor/drill is provided on one end of the small drill string and is guided to make as vertical a borehole as possible. In a preferred embodiment, the small inner drill is advanced to the full depth using the steerable mud motor/drill to achieve a high degree of verticality and a slight smaller casing is installed and used as a verticality guide for the much larger diameter outer drill string. In a further embodiment, the inner drill string is advanced a predetermined distance, then the outer string is advanced using the inner string as a verticality guide, these steps being repeated in alternating fashion to the final depth.

Abstract: A drilling apparatus includes an upper drill string, a lower drill string including a rotary drilling motor, an orientable rotatable connection between the drill strings, a reactive torque control device associated with the orientable rotatable connection, an orientation sensing device for providing a sensed actual orientation of the lower drill string, and a feedback control system configured to actuate the control device in response to the sensed actual orientation to achieve a target orientation of the lower drill string. A drilling method includes actuating the control device to prevent relative rotation of the drill strings, providing a sensed actual orientation of the lower drill string, comparing the sensed actual orientation with a target orientation of the lower drill string, actuating the control device to allow the lower drill string to rotate to provide the target orientation, and actuating the control device to prevent relative rotation of the drill strings.

Abstract: A wellsite system includes a drill string suspended within a borehole, anti-whirl drill bits for use in the system, and methods of drilling a curved borehole in a subsurface formation. The drill bit can have an interior cavity in fluid communication with the drill string and a first gauge pad located on the exterior of the drill bit. The first gauge pad includes a first orifice in fluid communication with the interior cavity, where the first orifice is arranged at an angle relative to cutters fixed to the drill bit. The drill bit is configured such that a fluid continuously flows from the first orifice.

Abstract: A method of removing cuttings includes the steps of disposing a pipe string in a high-angle wellbore, circulating mud through the wellbore and creating a viscous coupling layer of mud spiraling about a section of the pipe string. Wherein the wellbore may be deviated from vertical thirty degrees or greater. The viscous coupling layer desirably extends outwardly beyond the outside diameter of the tooljoint upsets in the section of the pipe string. A pipe joint for creating a viscous coupling layer of drilling fluid spiraling about the pipe to remove cuttings from high angle wells includes an elongated tubular having an outer surface extending between opposing tooljoints, tooljoint upsets and projections provided on substantially the entire outer surface.

Abstract: A method of optimizing drill bit design and an optimized drill bit for drilling a well into an earth formation comprising a bit body; a number of blades spaced around the bit body, each blade having a curved outer edge and a forward face; a first row of cutter pockets recessed into the face along the outer edge of each blade; a second group of cutter pockets recessed into the face of each blade offset from the first row; and a plurality of cutting elements, each cutting element being brazed into a different one of the cutter pockets.

Abstract: A method of downlinking to a downhole tool located in a borehole is provided. The downhole tool detects transitions in the flow velocity of fluid circulating in the borehole at the downhole tool. To provide for the detection of the transitions fluid is pumped into the drillstring so that it circulates in the borehole at the downhole tool and the pumping rate of fluid into the drillstring is either increased to a rate which overshoots a steady state pumping rate needed to produce a transition or is decreased to a rate which undershoots a steady state pumping rate needed to produce a transition.

Abstract: The present application is directed to an apparatus for forming one or more holes in a wellbore casing, the apparatus comprising a deflector assembly and a drive assembly to drive said deflector assembly, wherein the deflector assembly may be optionally assembled at a surface of the wellbore prior to casing hole formation, and to methods employing the apparatus.

Abstract: A method of completing a lateral channel in a coal seam using a flexible hose with a waterjet that may be directed down a well casing and into a guide shoe. The guide shoe defines a window configured to open into the coal seam and allow the waterjet to engage the coal seam in a substantially horizontal direction. High pressure fluid is then pumped into the waterjet to make a lateral channel therein, and the flexible hose is rigid enough to allow an operator to manually-move the flexible hose.

Abstract: An embodiment according to the disclosure provides a drill bit that includes a pad on a face section thereof, which pad extends from the bottom section upon application of a force thereon and retracts upon the removal of the force to control fluctuations of the drill bit during drilling of a wellbore.

Abstract: Preferred methods and systems generate a control input based on a periodically-varying characteristic associated with the rotation of a drill string. The periodically varying characteristic can be correlated with the magnetic tool face and gravity tool face of a rotating component of the drill string, so that the control input can be used to initiate a response in the rotating component as a function of gravity tool face.

Abstract: A top drive system for wellbore operations, the top drive system including motor apparatus, a main shaft driven by the motor apparatus, and sensing apparatus for sensing bending of the main shaft; and, in certain aspects, the system providing information regarding the extent of main shaft bending and/or for warning an operator of an undesirable amount of main shaft bending. This abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure and is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims, 37 C.F.R. 1.72(b).

Abstract: A system of components and a method is provided for radial and level drilling and completion with an ultra-short radius which includes a deflecting drill tool assembly and a level drill tool assembly. The deflecting drill tool has a deflecting rotary assembly, flexible drill pipe, directional follow-up tube, tail tube for deflecting drill tool, and drill pipe nipple joints. The level tool has a level rotary assembly, the flexible drill pipe, quick couplings, the directional follow-up tube, a tail tube for level drill tool, the drill pipe nipple joint, an adjusting nipple joint, a recessed left hand thread bushing, and convex left hand thread coupling. A triangle backing block is installed on outside of a casing of the deflecting rotary assembly. Splines matched with each other are provided at the level rotary assembly and the flexible drill pipe. The tail tube for level drill tool has a recessed left hand thread bushing and convex left hand thread coupling.

Abstract: Exhaust pressure from at least one actuator (34,36) which can tilt joint 6 of a bottom hole assembly 4 can be utilized to determine the direction 26 tiltable joint 6 is pointing (e.g., orientation, angular displacement, and/or inclination and azimuth). In one embodiment, a known exhaust pressure can be correlated to a known orientation and/or angular displacement, and the measured exhaust pressure can be compared to the known exhaust pressure to determine the orientation and/or angular displacement. In another embodiment, the flow rate of fluid exhausted from an actuator (34,36) can be derived from the exhaust pressure. The exhaust flow rate can then be used to calculate the state of actuation, which can allow determination of the angular displacement of the tiltable joint 6. Orientation and/or angular displacement with respect to the bottom hole assembly 4 can be resolved into an inclination and azimuth with respect to a formation 14.

Abstract: A procedure for the installation of horizontal drains for uptake of seawater of the type of those that use horizontal directional drilling (HDD) with widening by means of reamers and use of drilling muds for consolidation of the drilled galleries, and subsequent installation of drains, characterized in that the horizontal directional drilling (HDD), of single or multiple holes, is carried out from behind the coastline and directed towards the sea, crossing predetermined submerged productive strata; in the boreholes drilled, tubular drains are introduced, with grooves or holes only in stretches that correspond to predicted productive areas, remaining closed in the other sections; the space between the hole and the drain is sealed in the non-productive parts.

Abstract: Provided are drill stem assemblies with ultra-low friction coatings for subterraneous drilling operations. In one form, the coated drill stem assemblies for subterraneous rotary drilling operations include a body assembly with an exposed outer surface including a drill string coupled to a bottom hole assembly or a coiled tubing coupled to a bottom hole assembly and an ultra-low friction coating on at least a portion of the exposed outer surface of the body assembly, wherein the coefficient of friction of the ultra-low friction coating is less than or equal to 0.15. The coated drill stem assemblies disclosed herein provide for reduced friction, vibration (stick-slip and torsional), abrasion and wear during straight hole or directional drilling to allow for improved rates of penetration and enable ultra-extended reach drilling with existing top drives.

Abstract: The present invention involves methods and apparatus for permanent downhole deployment of optical sensors. Specifically, optical sensors may be permanently deployed within a wellbore using a casing string. In one aspect, one or more optical sensors are disposed on, in, or within the casing string. The optical sensors may be attached to an outer surface of the casing string or to an inner surface of the casing string, as well as embedded within a wall of the casing string. The optical sensors are capable of measuring wellbore parameters during wellbore operations, including completion, production, and intervention operations.

Abstract: A device for drilling controlled directional wells comprises a central hollow element and three hollow tubular elements connected thereto out-of-line with respect to each other. The first hollow tubular element connected by a thread to the spindle and the central hollow element, are each provided with a contact segmental section, thereby forming a pair of contact segmental sections. The sections are disposed on the opposite sides with respect to the meridian plane of the spindle in the bending plane of the drill string and at a distance L between the nearest edges of the contact segmental sections along the central axis of the first element. L?D, where D is the spindle outer diameter. The contact segmental section of the first element is deviated from the meridian plane of the spindle in the bending plane of the drilling string in an opposite direction with respect to the reaction torque of a drilling bit.

Abstract: A housing including longitudinally extending tubular members interconnected to allow controlled relative bending thereof, during a drilling operation, a rotary drive transmitting torsion bar extending generally longitudinally within the housing to controllably bend in response to relative bending of said members, a rotary drill bit operatively connected to said torsion bar to be rotated as the bar rotates, a rotary drive operatively connected to the torsion bar to rotate the bar, means for controlling relative bending of the said members during torsion bar rotation and as a function of such rotation.

Abstract: A drilling system, comprising: a non-rotating conveyance system; a tool connected to the non-rotating conveyance system and including anchors by which the tool can be anchored in position when located in a borehole; a drill bit connected to the tool; a motor for rotating the drill bit; and a directional control system interposed between the tool and the drill bit; wherein, in use, with the drilling system located in a borehole, the directional control system can be operates so as to displace the drill bit away from the axis of the borehole.

Abstract: The present invention provides a directional drilling apparatus and method for use in drilling bore holes. The apparatus comprises a plurality of movably mounted cutting elements, wherein the cutting elements are movable between radially retracted and extended cutting positions. A rotary valve is provided for synchronizing the movement of the cutting elements between their respective extended and retracted positions. Control of the directional drilling system is affected by synchronized movement of the cutting elements from an inner to an outer radial position in accordance with the angular position of the drill bit. Means are provided for directing high pressure cutting fluid to the region between the cutting elements and the rotatable body to prevent the accumulation of debris that could prevent movement of the cutting elements. The cutting elements enlarge the bore hole formed by the drill bit, so that the cutting elements continuously engage the wall of the bore hole.

Abstract: Method for drilling horizontal or deviated fresh water wells through such volcanics as occur in Hawaii, including hard lavas and fragmented interbeds that are prone to caving. The method provides effective means to drill into basal aquifers directly underlain by salt water, or into compartmented or confined aquifers or perched aquifers. The method uses deviated drilling and may use formation grouting, casing or drill-stem drilling, percussion or rotary drilling and all combinations thereof.