Abstract: A large diameter bore—in the range of 30 inches or more—is made through a geologic formation, such as the active surf zone and into the maritime zone. The drill head is provided with a mud powered motor (typically of the Moyno variety) which drives a hydraulic pump connected to a plurality of closed loop hydraulic circuits remotely controlled through electrical connection along the large diameter bore. One hydraulic circuit powers the rotating drill head; a second hydraulic circuit powers a mud and tailings evacuation pump; and a third hydraulic circuit articulates the drill head to provide direction. Mud exhausted from the mud motor is exhausted to the cutting head of the drill and evacuated along with dislodged cuttings through a pump in the drill head. The pump is individually controlled to pump at a rate, which assures a slight negative pressure in the required annulus about the drilled conduit, thus assuring that any leakage is from the surrounding soil into the annulus.

Abstract: The present invention involves a method and apparatus for monitoring conditions downhole and/or manipulating downhole tools by placing electrical wire on a casing string while drilling with casing. Wire is inserted into a groove within the casing string while drilling with the casing string into a formation. The wire connects downhole equipment to surface equipment. Multiple casing strings may be drilled into the formation while wire is simultaneously inserted into a groove therein.

Abstract: The present invention generally relates to a method and apparatus for drilling with a top drive system. In one aspect, the present invention provides for a top drive system having a top drive, top drive adapter, and a tubular positioning apparatus. In one aspect, the top drive adapter is pivotably connected to the top drive for pivoting the top drive adapter toward the casing string with respect to the top drive. In another aspect, the system includes a telescopic link system connected to a lower portion of the top drive adapter to move the casing string into engagement with the top drive adapter. In another aspect, the top drive adapter includes a housing operatively connected to the top drive and a plurality of retaining members disposed in the housing for gripping the tubular. In another aspect, the tubular positioning apparatus includes a gripping member for engaging a tubular and a conveying member for positioning the gripping member. A spinner may be provided to rotate the tubular.

Abstract: Apparatus and methods for drilling with casing. In an embodiment, methods and apparatus for deflecting casing using a diverter apparatus are disclosed. In another embodiment, the apparatus comprises a motor operating system disposed in a motor system housing, a shaft operatively connected to the motor operating system, the shaft having a passageway, and a divert assembly disposed to direct fluid flow selectively to the motor operating system and the passageway in the shaft. In another aspect, methods and apparatus for directionally drilling a casing into the formation are disclosed. Methods and apparatus for measuring the trajectory of a wellbore while directionally drilling a casing into the formation are also described.

Abstract: A method and apparatus for a drilling with casing includes therewith a drill shoe configured for later drilling through thereof in situ, with cutters retainable thereon in response to the forces encountered during borehole drilling, yet moveable from the envelope through which the later drill shoe will pass when cutting through the in situ drill shoe. The drill shoe includes one or more profiles thereon, into which blades carrying the formation drilling cutters are disposed. The profiles include at least one projection thereon, which is received within a mating slot in the blades. The blades also may be configured to have opposed sections which are configured with respect to one another to have an included angle of less than ninety degrees.

Abstract: The present invention relates methods and apparatus for lining a wellbore. In one aspect, a drilling assembly having an earth removal member and a wellbore lining conduit is manipulated to advance into the earth. The drilling assembly includes a first fluid flow path and a second fluid flow path. Fluid is flowed through the first fluid flow path, and at least a portion of which may return through the second fluid flow path. In one embodiment, the drilling assembly is provided with a third fluid flow path. After drilling has been completed, wellbore lining conduit may be cemented in the wellbore.

Abstract: A well drilling system includes a platform mounted on the ground, a tubular sleeve mounted movably on the platform, a drilling device inserted into the sleeve, and a circulation device. The drilling device includes a support seat connected detachably to a lower end of the sleeve, a drilling head mounted rotatably on the support seat, and at least one powered actuator connected to the support seat and the drilling head to actuate the drilling head to rotate relative to the support seat. The circulation device includes a pipe, and is mounted inside the sleeve for removing soil out of the sleeve.

Abstract: A tube (1) in a borehole (2) in the ground (3) is displaced. The tube is simultaneously displaced along and about its axis, such that it is axially introduced into or retracted from the borehole. According to the invention, displacing the composed tube about its axis comprises an oscillating movement. The invention further relates to a device for displacing a tube in a borehole.

Abstract: An apparatus and method for completing an interval of a wellbore while drilling comprises a drill string (52) having a drill bit (30) mounted on the lower end thereof. A completion assembly (50) is positioned around a section of the drill string (52) such that when the wellbore (32) is extended by rotating the drill bit (30) and advancing the drill string (52), the completion assembly (50) does not rotate. The advancement of the drill string (52) and rotation of the drill bit (30) is ceased when the completion assembly (50) has reached the desired interval of the wellbore (32). Thereafter, the drill string (52) is disconnected from the drill bit (30) for retrieval to the surface leaving the completion assembly (50) and the drill bit (30) downhole.

Abstract: There is disclosed a method of forming a tubing lined borehole, the method comprising the steps of forming a borehole; enlarging part of the borehole by increasing the diameter thereof; and locating bore-lining tubing in the borehole with at least part of the tubing located in the enlarged part of the borehole, and a corresponding a tubing lined borehole.

Abstract: The steel drill string attached to a drilling bit during typical rotary drilling operations used to drill oil and gas wells is used for a second purpose as the casing that is cemented in place during typical oil and gas well completions. Methods of operation are described that provide for the efficient installation a cemented steel cased well wherein the drill string and the drill bit are cemented into place during one single drilling pass down into the earth. The normal mud passages or watercourses present in the rotary drill bit are used for the second independent purpose of passing cement into the annulus between the casing and the well while cementing the drill string into place during one single pass into the earth. A one-way cement valve is installed near the drill bit of the drill string that allows the cement to set up efficiently under ambiently hydrostatic conditions while the drill string and drill bit are cemented into place during one single drilling pass into the earth.

Abstract: The steel drill string attached to a drilling bit during typical rotary drilling operations used to drill oil and gas wells is used for a second purpose as the casing that is cemented in place during typical oil and gas well completions. Methods of operation are described that provide for the efficient installation of a cemented steel cased well wherein the drill string and the drill bit are cemented into place during one single drilling pass down into the earth. Methods of operation are described wherein at least one geophysical parameter is measured with a geophysical parameter sensing member located within the drill string. A one-way cement valve is installed near the drill bit of the drill string that allows the cement to set up efficiently under ambient hydrostatic conditions while the drill string and drill bit are cemented into place during one single drilling pass into the earth.

Abstract: The steel drill string attached to a drilling bit during typical rotary drilling operations used to drill oil and gas wells is used for a second purpose as the casing that is cemented in place during typical oil and gas well completions. Methods of operation are described that provide for the efficient installation of a cemented steel cased well wherein the drill string and the drill bit are cemented into place during one single drilling pass down into the earth. Methods are provided to selectively cause a drilling trajectory to change during drilling with casing. A one-way cement valve is installed near the drill bit of the drill string that allows the cement to set up efficiently under ambient hydrostatic conditions while the drill string and drill bit are cemented into place during one single drilling pass into the earth.

Abstract: A borehole may be drilled utilizing the bottom hole assembly 10, 50 with a downhole motor 14, which may offset at a selected bend angle. The motor housing is preferably run slick, and a gauge section 36 secured to the pilot bit 18 has a uniform diameter bearing surface along an axial length of at least 60% of the pilot bit diameter. The bit or reamer 16 has a bit face defining the cutting diameter of the drilled hole. The axial spacing between the bend and the bit face is controlled to less than fifteen times the bit diameter. The downhole motor, pilot bit and-bit may be retrieved from the well while leaving the casing string in the well.

Abstract: The steel drill string attached to a drilling bit during typical rotary drilling operations used to drill oil and gas wells is used for a second purpose as the casing that is cemented in place during typical oil and gas well completions. Methods of operation are described that provide for the efficient installation a cemented steel cased well wherein the drill string and the drill bit are cemented into place during one single drilling pass down into the earth. The normal mud passages or watercourses present in the rotary drill bit are used for the second independent purpose of passing cement into the annulus between the casing and the well while cementing the drill string into place during one single pass into the earth. A one-way cement valve is installed near the drill bit of the drill string that allows the cement to set up efficiently under ambiently hydrostatic conditions while the drill string and drill bit are cemented into place during one single drilling pass into the earth.

Abstract: The steel drill string attached to a drilling bit during typical rotary drilling operations used to drill oil and gas wells is used for a second purpose as the casing that is cemented in place during typical oil and gas well completions. Methods of operation are described that provide for the efficient installation of a cemented steel cased well wherein the drill string and the drill bit are cemented into place during one single drilling pass down into the earth. A stabilizer is attached to the drill string that is used to centralize the drill string in the well during cementing operations. A one-way cement valve is installed near the drill bit of the drill string that allows the cement to set up efficiently under ambient hydrostatic conditions while the drill string and drill bit are cemented into place during one single drilling pass into the earth.

Abstract: A system for controlling sand has an expandable screen and an inner string to isolate the sand screen allowing for drilling fluids to be circulated to the bottom of the drilling assembly, before returning up the annulus in normal fashion. Both ends of the expandable screen are mounted on an inner string by means of a swivel and seals, the former allowing for drill string rotation and the latter ensuring that drilling fluids do not circulate to the inside of the screen. The inner string is integral with the internals of the bottomhole drilling assembly, allowing for retrieval thereof, including a pilot bit. Upon retrieval an isolation valve will close and seal thus providing sand control integrity in the well. Release from the sand screen will be by pumping a ball down the string and engaging this in a catcher to slim the sliding sleeve open, giving hydraulic access to the liner hanger and engaging slips in the previous casing.

Abstract: The invention relates to a method for drilling, being carried out by a drilling apparatus, having a drilling device (1) unit (3), in the drilling head (I) of which there hole and second drilling means (5) for reaming of the center hole for the casing part (2) as well as flushing flow arrangement (6) for flushing of waste, being generated. At least during the drilling situation, the first drilling means (4) are coupled by a power transmitting and, in order to enable removal of the same from the hole, removable arrangement, such as a bayonet coupling or like, with the second drilling means (5).

Abstract: A directional casing drilling system including a casing string for rotation of a drill bit, a shaft coupled to the casing string, and a sleeve having pads that are hydraulically extensible. The sleeve may be positioned about a portion of the shaft. The invention may also include a tube connecting the sleeve to the drill collar, the tube adapted to conduct drilling fluid, and a valve system adapted to operatively conduct at least a portion of the drilling fluid to the pads whereby the pads move between an extended position and a retracted position.

Abstract: A method and apparatus is provided for drilling and lining a wellbore in one downhole trip. The method comprises mounting a drill bit on a drill string including a section of expandable tubing and providing a tubing expander in the string, then rotating the drill bit and advancing the drill string through a bore, then passing the expander through the expandable tubing to expand the tubing, wherein the expandable tubing is deformed by compressive plastic deformation of the tubing with a localised reduction in wall thickness, resulting in a subsequent increase in tubing diameter, and then retrieving the drill bit from the bore through the expanded tubing.

Abstract: The invention relates to a method and a device for the drilling, in particular the percussive or percussive rotary drilling of a hole (7) in earth or rock and for securing an anchorage in said hole. According to the invention, a bore hole (7) is created by a drill bit (1) mounted on a drill pipe (5) and a sliding sleeve (4) that surrounds the drill pipe (5) at a distance is simultaneously introduced. The invention is characterised in that a sliding sleeve (4) configured with a longitudinal slit (8) is introduced at least partially and rests substantially against the bore hole (7) during the drilling, whereby a reliable anchorage can be achieved with a simple construction by means of the sliding sleeve (4) with a longitudinal slit.

Abstract: A device for drilling holes, including a drill bit with a drilling or breaking surface, a drill rod for introducing a rotary or percussive force and for introducing a rinsing or cooling fluid into the drill bit and a sheath pipe which defines a hollow space between the drill rod and the inside of the sheath pipe and which is supported on the drill rod or which can be connected to the drill bit. In a drilling position, the sheath pipe is situated at a distance from the rear side of the drill bit facing away from the breaking surface and the drill bit can be introduced into a rinsing position for the hollow space between the sheath pipe and the drill rod with its rear side resting on the front end of the sheath pipe facing towards the drill bit or can be connected to the front end of the sheath pipe.

Abstract: A method to deliver an expandable casing string to an uncased borehole coaxially upon a composite coiled tubing drilling string is presented. Once the drilling operation is completed, the casing string is expanded by supplying pressure between the coaxially positioned strings to expand the casing string to the borehole. Preferably, the outer diameter of the casing string contains an adhesive agent designed to be activated by the expansion of the casing string against the borehole wall. Alternatively, the mechanical structure of the casing string itself may be configured to prevent the casing string from collapsing once it has been expanded. Once expanded, the casing string is left behind to isolate the well formation from drilling and production fluids that may subsequently flow therethrough.

Abstract: There is provided drilling apparatus (10) comprising a hammer casing (11), a free piston motor piston guide and porting sleeve (12), a drive sub (13), a drill bit (15) splined by shank (16) to the drive sub (13). Below the splined portion (17) the drive sub is relieved at (23) to form an annular air space for motor exhaust air from the splines (16) and (17). The drive sub (13) retains a gauge sleeve (24) via an annular flange (25) between the hammer casing (11) at (26) and a shoulder (27) on the drive sub (13). Below the shoulder (27) the outer diameter of the drive sub (13) is provided with eight grooves that form conduits (30) with the lower portion (31) of the gauge sleeve (24) extending parallel to the drill axis in communication with the space (23) via ports (32). The lower portion (31) extends down the side of the drive sub (13) and terminates with it at (34) adjacent the shoulder (33) at the transition from the bit shank (16) and the bit head (35).

Abstract: A method and apparatus for installing casing with a top drive drilling rig. A first step involves securing a first body to a rotating top head of the top drive drilling unit. A second step involves securing a second body to a length of casing. A third step involves detachably coupling the first body and the second body so that the second body rotates with the first body. This method allows for rapid connection to the top head of the top drive. The process can be further accelerated by using several of the second bodies. While one of the second bodies is being used, another can be secured to the next length of casing in readiness for installation.

Abstract: A method and associated equipment are disclosed which allow drilling at least a portion of a well and subsequently cementing casing in a single trip. The method is particularly suited for deep-water offshore operations where the drill string can be run through a section of casing leaving a bit and an under-reamer extending out below. The casing is equipped with ports through which cement can be pumped as well as an external casing packer to prevent the uncured cement in the annulus from U-tubing. Several casing sections can be run in during drilling and cemented succession using the one trip method.

Abstract: A large diameter bore—in the range of 30 inches or more—is made through a geologic formation, such as the active surf zone and into the maritime zone. The drill head is provided with a mud powered motor (typically of the Moyno variety) which drives a hydraulic pump connected to a plurality of closed loop hydraulic circuits remotely controlled through electrical connection along the large diameter bore. One hydraulic circuit powers the rotating drill head; a second hydraulic circuit powers a mud and tailings evacuation pump; and a third hydraulic circuit articulates the drill head to provide direction. Mud exhausted from the mud motor is exhausted to the cutting head of the drill and evacuated along with dislodged cuttings through a pump in the drill head. The pump is individually controlled to pump at a rate, which assures a slight negative pressure in the required annulus about the drilled conduit, thus assuring that any leakage is from the surrounding soil into the annulus.

Abstract: A method of lining and drilling a bore (10) comprises the steps: mounting a first section of bore-lining tubing (20) on the lower end portion of a drill string (18); running the drill string and tubing into a bore having an unlined section and an existing tubing lined section; locating the first tubing section (20) in the unlined section: uncoupling the first tubing section (20) from the drill string (18); and drilling the bore beyond the first tubing section.

Abstract: A clamp system for allowing a pile driving/pulling system to be attached to a caisson to be driven into or extracted from the earth. The clamp system comprises a structural member, first and second clamp systems, first and second locking systems, and a clamp displacement system. The clamp displacement assembly is operatively connected between the structural member and the first and second clamp assembly. When the first and second clamp systems are disengaged from the pile and the first and second locking systems are disengaged from the structural member, the clamp displacement system may be operated to obtain a desired clamp distance between the first and second clamp assemblies.

Abstract: A wellbore casing is formed simultaneously with the drilling out of the wellbore.

Abstract: A drilling apparatus includes a platform for positioning at a drilling site) a mast pivotally mounted on the platform) a rod clamp on one end of the mast for clamping a drill rod) a drill head slidably mounted on the mast for driving the drill rod during a drilling operation, a main ram connected to said mast and said drill head for moving the drill head longitudinally of the mast) a casing clamp on the rod clamp for clamping the mast to a top end of a casing carrying the rod) whereby the mast is anchored to the ground during drilling) and a drill head slidable on the mast for driving the drill rod during drilling.

Abstract: A method of drilling and lining a bore in an earth formation comprises providing a tubular outer elongate member and an inner elongate member located within the outer member. At least one of the members is spoolable. A drill bit is mounted to one of the members and a bore is drilled by advancing the drill bit through the earth formation and advancing the members through the bore.

Abstract: A method and apparatus is provided for drilling and lining a wellbore in one downhole trip. The method comprises mounting a drill bit on a drill string including a section of expandable tubing and providing a tubing expander in the string, then rotating the drill bit and advancing the drill string through a bore, then passing the expander through the expandable tubing to expand the tubing, wherein the expandable tubing is deformed by compressive plastic deformation of the tubing with a localised reduction in wall thickness, resulting in a subsequent increase in tubing diameter, and then retrieving the drill bit from the bore through the expanded tubing.

Abstract: A downhole well drilling apparatus includes an above-ground mast and an axially elongated generally cylindrical pneumatic hammer drill supported by the mast and mounted in an axially vertical above-ground position. An installation and removal adapter mounted on the lower end of the pneumatic hammer drill couples the hammer drill to a pipe string and maintains a movable part of the hammer drill in an operative condition at all times thereby enabling the hammer drill to operate while rotational torque and upward directed force are simultaneously applied to the operating hammer drill by the apparatus during removal of a casing from a downhole position. Hammer operation is controlled by a manually operable air supply valve.

Abstract: An apparatus and method for forming a wellbore casing. A mandrel is used to position a tubular member within a wellbore. The mandrel is then driven into the bottom of the wellbore. The tubular member is then radially expanded by the mandrel.

Abstract: The drilling system includes a work string supporting a bottom hole assembly. The work string including lengths of pipe having a non-metallic portion. The work string preferably includes a composite coiled tubing having a fluid impermeable liner, multiple load carrying layers, and a wear layer. Multiple electrical conductors and data transmission conductors may be embedded in the load carrying layers for carrying current or transmitting data between the bottom hole assembly and the surface. The bottom hole assembly includes a bit, a gamma ray and inclinometer instrument package, a steerable assembly, an electronics section, a transmission, and a power section for rotating the bit. It may or may not include a propulsion system. The drilling system may be a gravity based drilling system that does include a propulsion system. Various motive means may be provided such as gravity, to apply weight on the bit.

Abstract: A method and apparatus is provided for drilling and lining a wellbore in one downhole trip. The method comprises mounting a drill bit on a drill string including a section of expandable tubing and providing a tubing expander in the string, then rotating the drill bit and advancing the drill string through a bore, then passing the expander through the expandable tubing to expand the tubing, wherein the expandable tubing is deformed by compressive plastic deformation of the tubing with a localised reduction in wall thickness, resulting in a subsequent increase in tubing diameter, and then retrieving the drill bit from the bore through the expanded tubing.

Abstract: An apparatus for providing a mooring anchorage, and a method of drilling and installing a pile in ground comprising the steps of: providing a pile, providing a drill bit at an end of the pile rotatable relative to the pile, engaging the ground with the drill bit, and rotating the drill bit relative to the ground and the pile generating a hole into which the pile is received.

Abstract: The present invention provides apparatus and method for drilling a wellbore wherein a pilot wellbore section is drilled with a bit which section is enlarged by a trailing underreamer to the desired size. One or more steering sections between the underreamer and the drill bit are utilized for maintaining and changing the drilling direction. Each steering section includes a plurality of independently adjustable force application devices on a non-rotating sleeve. If an expandable liner is used, then an expansion device disposed above the underreamer expands the liner during retrieval of the drilling assembly to the surface.

Abstract: Apparatus and a method are described for drilling with casing in a borehole in a typically unconsolidated formation, wherein the method involves isolating the annulus between the casing and the borehole section from fluid circulation and creating a hydrostatic pressure in the annulus which is adapted to balance any over-pressurized water in the formation.

Abstract: A drive mechanism for a subterranean boring machine includes a drive motor, primary and secondary drive wheels, a drive sprocket and an idler sprocket attached to the primary and secondary drive wheels, respectively, and a chain operatively extending between the drive sprocket and the idler sprocket. The drive mechanism is movably mounted on the sled of a subterranean boring machine that rolls along a track, the drive mechanism being biased against the track by a set of springs to cause the primary and secondary drive wheels to frictionally engage the track. The drive motor selectively and rotatably drives the primary drive wheel which, in turn, drives the secondary drive wheel. The drive mechanism translates the sled along the track under conditions when the sled is not driving a pipe into a subterranean location. The drive mechanism is configured to be largely self-contained to permit existing sleds to be retrofitted with the drive mechanism.

Abstract: A downhole well drilling apparatus includes an above-ground mast and an axially elongated generally cylindrical pneumatic hammer drill supported by the mast and mounted in an axially vertical above-ground position. An installation and removal adapter mounted on the lower end of the pneumatic hammer drill couples the hammer drill to a pipe string and maintains a movable part of the hammer drill in an operative condition at all times thereby enabling the hammer drill to operate while rotational torque and upward directed force are simultaneously applied to the operating hammer drill by the apparatus during removal of a casing from a downhole position. Hammer operation is controlled by a manually operable air supply valve.

Abstract: A method of drilling and installing a pile in ground comprising the steps of providing a pile, providing a drill bit at an end of the pile rotatable relative to the pile; engaging the ground with the drill bit, and rotating the drill bit relative to the ground and the pile generating a hole into which the pile is received.

Abstract: A wall is built in the ground by pulling a wall building device having cross-sectional dimensions which are substantially equal to the dimensions of at least a part of the cross-section of the wall through the ground, at least a part of the wall being formed by injecting a hardenable material behind the wall building device. A tunnel is made by first making a tunnel wall, leaving the ground inside the tunnel wall substantially intact, followed by excavating the ground inside the tunnel wall.

Abstract: An apparatus for placing auger type anchors into the earth includes a machine frame that supports an elongated housing. The housing has upper and lower end portions. An anchor holder is positioned at the lower end of a tubular member rotatably mounted in the housing for holding an anchor and rotating it during placement. A plurality of drive wheels carried by the frame transport the housing between upper and lower positions. The wheels are loaded with adjustable compression springs so that extensive pressure can be applied from the drive wheels to the housing for gripping and driving the housing during insertion. A gear train interconnects the driving wheels so that all of the driving wheels rotate at the same rotational speed.

Abstract: A method of creating a wellbore in an underground formation comprising drilling a borehole in the underground formation using a drilling tubular, capable of being expanded, to which a downhole motor driving a drill bit has been connected, and, after drilling to the desired casing setting depth, expanding the drilling tubular into place to line the borehole by applying a radial load to the drilling tubular and removing said load from the drilling tubular.

Abstract: An apparatus for drilling boreholes into the earth includes a mobile carrier with a frame that supports an elongated housing. The housing has upper and lower end portions. An drill pipe section holder is positioned at the lower end of a tubular member rotatably mounted in the housing for holding a drill pipe section and rotating it during placement. A plurality of drive wheels carried by the frame transport the housing between upper and lower positions. The wheels are loaded with adjustable compression springs so that extensive pressure can be applied from the drive wheels to the housing for gripping and driving the housing during insertion. A gear train interconnects the driving wheels so that all of the driving wheels rotate at the same rotational speed. Water is supplied to the housing via a bore that communicates with openings and a bore of the tubular member. The tubular member bore conveys the water to multiple sections of drill pipe (i.e.

Abstract: The present invention provides a method and apparatus for mechanically interconnecting a lateral wellbore liner to a main, or parent, wellbore casing. The present invention further provides a method of wellbore construction for the construction of multiple wellbores which are interconnected downhole to form a manifold of pipelines in a reservoirs of interest. Provision is made for flow controls, sensors, data transmission, power generation, and other operations positioned in the lateral wellbores during the drilling, completion and production phases of such wellbores.

Abstract: A drilling liner having a core bit at its bottom end is carried along with a pilot bit on an inner bottom hole assembly driven by a downhole mud motor. In one embodiment, the motor is powered by mud carried by an inner string. Alternatively, the inner string may be omitted and the flow of mud through the liner powers the motor: this requires a locking tool for locking the motor assembly to the outer assembly. Once an abnormally (high or low) pressured zone has been traversed, the liner is set as a casing, the inner assembly is pulled out, and drilling may be resumed using a conventional tool. Directional drilling is accomplished by having an MWD device for providing directional information and having directional devices on the inner and outer assembly. These include retractable steering pads. Expandable bits, under-reamers and jetting nozzles may also be used in the drilling process.

Abstract: A system for drilling a horizontal bore through frangible material includes a barrel mechanism containing a automatically reciprocating piston mechanism for automatically delivering hammering blows to a bit for chipping away the frangible material, a fluid distributor for directing fluid to and exhausting pressurized fluid from the piston mechanism without exposing the wall of the bore being created to fluid pressure greater than ambient atmospheric pressure, a spline/flute arrangement for causing the bit to rotate with the barrel mechanism, a motor and swivel mounted on a driven platform mounted on a supporting frame for urging the bit against the frangible material and for supplying the pressurized fluid, a pushing mechanism for non-rotatingly and simultaneously installing casing joints as various components of the system is rotatingly drilling the bore, an augering arrangement for, in conjunction with the casing joints, removing the drilling debris, and drill/auger stem sections for extending the drilling