Abstract: A self-tightening safety tubular clamp for suspending a casing string or other tubular member within a well. In one embodiment, a base has an opening for receiving the casing string. A first gripping member and an opposing second gripping member are each adapted to frictionally engage the casing string. First and second pivot arms include parallel linkages for supporting the gripping members. Each parallel linkage is pivotally secured to the base at one pivot pair, and pivotally secured to one of the gripping members at an upper pivot pair. Frictional contact with the gripping members allows the weight of the casing string to move the pivot arms downward. As the pivot arms move downward, the gripping members move downward and inward into engagement with the casing string. The parallel linkages ensure that gripping surfaces of the gripping members remains vertical, in alignment.

Abstract: A system and method for excavating a subterranean formation, according to which a suspension of liquid and a plurality of impactors are passed between a drill string to a body member for discharge from the body member to remove at least a portion of the formation. The flow of the suspension between the drill string and the body member is controlled in order to present the impactors from settling near the bottom of the formation.

Abstract: An earth boring bit includes a bit body including plurality of PDC cutter elements and a fluid plenum connecting a fluid inlet to at least one fluid orifice. Furthermore, a ledge formed between a bottom of the fluid plenum and the at least one fluid orifice includes a relief region formed therein located across a flow change angle. Additionally, a method to improve a polycrystalline diamond compact drill bit body design includes determining flow change angles from a fluid plenum into a fluid orifice and modeling a relief region on a ledge to optimize fluid into the fluid orifice.

Abstract: A Tool for excavating an object, the tool having a jetting system arranged to impinge the object to be excavated with a jetted stream of a drilling fluid mixed with abrasive particles, the jetting system being provided with at least a mixing chamber with a drilling fluid inlet, a second inlet for abrasive particles, and an outlet nozzle for releasing the drilling fluid mixed with the abrasive particles; a recirculation system arranged to recirculate at least some of the abrasive particles, from a return stream of the fluid mixed with the abrasive particles downstream impingement of the jet with the object back to the jetting system, whereby the abrasive particles have a magnetic material, which recirculation system has a separator magnet for separating the abrasive particles from the return stream and for transporting the particles to the second inlet; and, a piece of magnetic material that is provided in or in the vicinity of the mixing chamber such as to draw a part of the magnetic field generated by the s

Abstract: The drill string is fitted for drilling activity in the formation expected, including a jet nozzle equipped drill head, and a near bit kick sub. The drill string is deflected to change the progressing well bore to a preferred direction. After the change in well bore direction is accomplished by jetting, the kick sub is straightened and drilling proceeds along the new well bore center line. Ideally, the kick sub responds to direction from the surface and produces a change in drilling fluid pressure at the surface to indicate which mode, straight or deflected, is being carried out down hole.

Abstract: An improved water nozzle (100, 200) for use in a horizontal drill string (14) to prevent clogging of the string when water flow is stopped so a new section of drill rod (12) can be added to the string. The nozzle includes a tapered passage (116, 216) in which a ball (20) is installed. The resulting ball valve allows water injected into the one end of the rod string to flow through the nozzle during drilling. However, when water flow stops for attachment of a new section of rod to the string, the valve blocks the flow path back through the nozzle so sand, gravel, and other particles are not sucked into the string causing it to clog and necessitating that the string be withdrawn from the hole and disassembled so the nozzle can be cleaned out and unclogged.

Abstract: Methods for forming a portion of a wellbore are provided. The well is drilled from a first selected depth to a second selected depth to form a bore through a surrounding earth formation. A fluid heating apparatus is disposed within the bore on a working string. Fluid is then heated by moving the fluid through the fluid heating apparatus in the wellbore. The process of circulating fluid adjacent the earth formation serves to also heat the surrounding formation so as to increase the fracture gradient. The fluid heating process may be conducted during a drilling procedure. Alternatively, the fluid heating process may be conducted in connection with a liner hanging and cementing process. A fluid flow restrictor is provided along a run-in assembly that serves to warm the fluids as they are circulated. The warm fluids provide convective heat to the surrounding earth formation, thereby reducing the formation's fracture gradient.

Abstract: A drill bit for drilling a well bore using solid material impactors comprising a nozzle and a cavity for accelerating the velocity of the solid material impactors and directing flow of the solid material impactors through the nozzle. The drill bit may also comprise a junk slot for return flow of the drilling fluid and solid material impactors.

Abstract: An apparatus and method for forming a support pier having a single or multiple compacted aggregate lifts in a soil matrix, wherein the apparatus includes a vertical, hollow tube with a bulbous leading end or head element that is forced into the soil matrix. The hollow tube includes a mechanism for releasing aggregate from the lower head element of the tube as the tube is lifted incrementally. The same hollow tube is then utilized to compact the released aggregate. The process may be repeated to form a series of compacted lifts comprising a pier.

Abstract: Rotary jetting tool including a rotor with axially-opposed pressure-balanced mechanical face seals. Vented upper mechanical face seal enables the rotor to be operated with the relativity low starting torque achievable using reaction forces from offset jets energized with a pressurized fluid. When rotor is displaced axially due to set-down conditions, a pressure chamber exerts a pressure imbalance on the rotor, forcing the rotor to return to a normal operating position. Alternate structure to achieve low starting torque includes a volume disposed adjacent to a lower mechanical face seal, the volume being coupled in fluid communication with the pressurized fluid. Mechanical face seal surfaces are fabricated from ultra-hard materials, such as tungsten carbide, silicon carbide, and diamond. A gage ring designed to ensure the jets remove all of the material from the gage of the protective housing before the tool can advance can be incorporated.

Abstract: A hole digger for digging a hole in ground. The hole digger includes a handle end for manually turning the hole digger. The hole digger includes a support section extending from the handle end. The hole digger includes a digging end extending from the support section.

Abstract: The invention relates to pumping engineering, mainly to well pumping devices for extracting oil from wells. The inventive method consists in assembling from the bottom upward an input cone provided with a shank, a packer and a jet pump and in running said assembly with the aid of a tubing string into a well. Afterwards, a receiver transformer of physical fields is also run into said well, background measurements of temperature and other physical fields are carried out, a formation is drained and the work of the individual interlayer of a productive strata is evaluated. An ultrasonic action is performed on the productive strata. The hydrodynamic action being performed on the productive strata during said operation, the entire formation is exposed to the combined action of ultrasonic oscillations and a hydrodynamic effect. Afterwards, the unit for ultrasonic effect is pulled out from the well to the surface.

Abstract: An orbital tool apparatus and method of using the apparatus for boring, drilling, reaming, and cutting having a tool housing, a tool collar located within the housing, the tool housing having the ability to couple to a conduit structure, fluid orbiting jets within the tool collar, and a tool funnel located below the tool collar and within a lower portion of the tool housing. The orbital tool creating a bore in a surface, when fluid flowing into the orbital tool via a conduit is directed out of the orbital tool towards the structure, a portion of the fluid flowing within the orbital tool being diverted through the fluid orbiting jets causing the diverted fluid to impinge against the tool funnel, causing the tool funnel to oscillate creating a sweeping flow towards the surface.

Abstract: The present invention is directed to a nozzle capable of producing a high impact waterjet when supplied with a source of ulta-high pressure liquid. The nozzle is constructed and arranged to infuse fluid into a high velocity stream of liquid passing through the nozzle to create a bubble rich waterjet. When the waterjet strikes against a surface the bubbles implode, amplifying the impact of the water against the surface.

Abstract: According to one embodiment of the invention, a flow conditioning system for fluid jetting tools includes a housing having a plurality of jet nozzle openings and a fluid straightener disposed within the housing. The fluid straightener is defined by one or more vanes, and the vanes form a plurality of flow channels within the housing. Each flow channel is associated with at least one jet nozzle opening.

Abstract: A fluid drilling head has a plurality of nozzles (3, 4, 5, 6) in a rotatable nozzle assembly (2) to provide high pressure cutting jets (7). The head is provided with a gauging ring (10) having an annular clearance (11) to the rotatable nozzle assembly (2) to provide for the passage of rock particles eroded by the cutting action of the jets (7) while regulating the progress of the drilling head in the borehole and controlling drill stalling. A stepped rotatable nozzle assembly having a smaller diameter portion (8) and a larger diameter portion (9) to extend the cutting zone of a reaming jet closer to the outer diameter of the gauging ring (10) is also described and claimed.

Abstract: The present invention relates to a roller cone drill bit that has improved flow characteristics. The roller cone drill bit includes forming at least one relief region inside a bit body of the roller cone drill bit on a ledge formed between a fluid plenum and at least one of the fluid orifices. A method of locating the at least one relief region is also disclosed.

Abstract: The invention relates to jet device used for extracting oil from wells. The inventive method consists in the following: a pump, a connecting and disconnecting unit, a valve unit, a packer and a shank are mounted on a tubing string before actuating the inventive device. A perforator is run into the well on a mounting seat in the pass channel of the pump, the packer being released. Differential pressure being produced, the perforator is blasted against the productive stratum which is then drained. The perforator being replaced by the transmitter and receiver-transducer of physical fields, the stratum is studied while the pump operates. Said transmitter and receiver-transducer being pulled from the well, a valve chamber and a blocking insert separating the cavity of the tubing string from environment are thrown into the well. The well starts to work in a natural flow regime.

Abstract: A jet cutting device having a cutter head provided with a nozzle for ejecting a stream of fluid against a body so as to create a selected cut in said body. The cutter head is provided with a deflector having a deflection surface arranged to deflect the stream of fluid ejected by the nozzle into a selected direction in accordance with the position of said cut to be created.

Abstract: Apparatus connected to the downhole end of a tubing string for cleaning and flushing wells has a threaded connection to the string and at least one primary jet to direct circulating gases toward the downhole end of the well, together with a plurality of secondary jets which are arranged around the exterior of the tubular member and directed upwardly at an acute angle with respect to the longitudinal axis of the tubular member and skewed radially at an acute angle with respect to the surface of the tubular member the skew angle being opposed to the thread angle so as to tend to tighten the threaded connection and the upwardly directed gas volume being approximately one and one-half to four times that which is directed toward the downhole end of the well.

Abstract: A hole forming tool is disclosed utilizing compressed gas discharged into a shaped shroud resulting in minimal disturbance to the surrounding ground.

Abstract: The present invention provides a head for injecting a fluid under pressure for breaking up the ground from a borehole and mounted at the end of a string of rods. The body of the drilling head has a bottom wall for mounting a mechanical drilling tool having a feed pipe, at least one injection nozzle, and duct-forming means for connecting the feed pipe with liquid at the inlet of said nozzle, the duct-forming means presenting a mean line having a radius of curvature that varies continuously, the right section of said duct-forming means decreasing regularly over at least half its length from its first end towards its second end. The injection head further comprises at least one pipe for feeding said mechanical tool, said pipe being connected at a first end to said duct-forming means and at a second end to a chamber disposed at the bottom end of said injection head and fitted with a controllable shutter member interposed between said chamber and the pipe for feeding said mechanical tool.

Abstract: A computer-implemented method and system for designing transportation routes, wherein design criteria to be met in respect of at least one of said transportation routes are supplied and route profile data are obtained showing land heights at sampled points along each of said at least one transportation route. Per-unit cost estimates in respect of land-cut and land-fill operations are supplied, and a height profile is computed of the at least one transportation route which meets the design criteria and for which the land-cut and land-fill operations are adjusted to give a minimum cost.

Abstract: The invention relates to pumping engineering, mainly to downhole jet production units. The inventive downhole jet unit comprises a packer, a pipe column and a jet pump. An active nozzle is embodied in the body of the jet pump, and a pass channel provided with a mounting face for a sealing assembly with an axial channel is embodied therein. Said unit is also provided with an irradiator and a receiver transformer of physical fields which are mounted on a cable. The output of the jet pump is connected to a space around the pipe column. The input of a channel for feeding the pumped out medium of the jet pump is connected to the internal space of the pipe column below the sealing assembly. The input of a channel supplying a working medium to the active nozzle is connected to the internal space of the pipe column above the sealing assembly. The invention makes it possible to optimise dimensions of various elements of the unit, thereby increasing the operating reliability of the downhole jet unit.

Abstract: A drilling apparatus for earth boring operations is of the type having cutter blades mounted on a support body at the lower end of a drill string and includes a novel arrangement of fluid bore sections for delivering fluid under pressure into fluid discharge passages in each of the blades and a bifurcated pivotal mounting portion on the body which enables the bore sections to supply fluid to the cutter blades through a ball joint on the pivotal axis. Modified forms of invention are specifically designed for cutter blades which are intended to perform reaming operations but include the fluid delivery system as well as an extended delivery system for delivering fluid under pressure to other tools in the drill string.

Abstract: A method for facilitating horizontal drilling by positioning in a well casing a shoe defining a passageway extending from an upper opening in the shoe through the shoe to a side opening in the shoe. A rod is connected, through at least one block and pin assembly operative as a universal joint, to a casing mill end, and inserted into the well casing and through the passageway in the shoe until the casing mill end substantially abuts the well casing. The rod and casing mill end are then rotated until the casing mill end substantially forms a perforation in the well casing. The rod and casing mill end are then withdrawn from the well casing, and a nozzle attached to the end of a flexible hose is extended through the passageway to the perforation. Fluid is then ejected from the nozzle and impinges and erodes subterranean formation material.

Abstract: A self-advancing drilling system comprising a drilling apparatus, the drilling apparatus having at least one leading fluid cutting nozzle, an advancing device on the drilling apparatus to provide forward movement to the drilling apparatus, the drilling system further comprising a drill string formed from recoverable flexible hose and a steering device having at least one jet nozzle.

Abstract: A portable apparatus for exploration and sampling of placers which is capable of being disassembled for transport into areas not accessible to traditional sampling methods. The sampling unit operates on a principle of power augering and water jetting a sampling pipe to bedrock while concurrently recovering ¾? minus materials, including particles and nuggets of valuable minerals and gemstones, through a concentric center pipe, such recovery powered by a ring jet venturi and supplemented by a sample hole plug to increase the water pressure in the sampling hole.

Abstract: Systems and methods relating to subterranean drilling while maintaining containment of any contaminants released during the drilling. A thrust block installed over a zone of interest provides an overflow space for retaining any contaminants and excess sealant returns. Negative air pressure may be maintained in the overflow space by a ventilation system. Access ports in the thrust block seal the overflow space from the surrounding environment with a membrane seal. A flexible sack seal in the access port may be connected to a drill shroud prior to drilling, providing containment during drilling after the drill bit penetrates the membrane seal. The drill shroud may be adapted to any industry standard drilling rig and includes a connection conduit for connecting to the flexible sack seal and a flexible enclosure surrounding the drill shaft and of a length to accommodate full extension thereof.

Abstract: The invention relates to fluidics, in particular to jet devices for lifting various liquids, essentially for lifting petrol out of wells and for well examination. The inventive jet device comprises a packer and a flow column provided with a bearing assembly. Bypass openings are embodied in said bearing assembly and a jet pump is arranged inside the body thereof. A channel for running a medium mixture off the jet pump into an annular space connected to the bypass openings, a channel for supplying fluid pumped-out from the well to the jet pump and a channel for supplying ejecting medium to a nozzle of the jet pump are embodied inside the body. In addition, a pressure-sealing unit is arranged in the channel for supplying the pumped-out fluid in such a way that it is superposed with respect to the jet pump. A bypass channel is embodied in the pressure-sealing unit in such a way that it enables a logging cable to be passed through said channel and the channel for supplying the pumped-out liquid.

Abstract: A rolling cone rock bit having one or more nozzle retention bodies attached by a single orientation mounting is disclosed, as is the associated method for its manufacture. The upper end of the nozzle retention body has a fluid inlet in communication with the internal fluid plenum of the drill bit, and the lower end of the nozzle retention body includes a fluid outlet that defines an exit flow angle. The fluid outlet is located between two rolling cones, but is positioned closer to one of the cones than the other. Further, the exit flow angle is preferably within 3 degrees of parallel to the drill bit longitudinal axis and, even more preferably, is parallel with the drill bit longitudinal axis.

Abstract: A jet cutting device comprising a cutter head provided with at least one nozzle for ejecting a stream of fluid against a body so as to create a selected cut in said body, is discloded. For each nozzle, the cutter head is provided with a deflector having a deflection surface arranged to deflect the stream of fluid ejected by the nozzle into a selected direction in accordance with the position of said cut to be created.

Abstract: A rock drilling rig has a carrier (1) provided with a service platform (7) which is arranged on a boom (6). The carrier (1) is provided with a four link mechanism (8) which is swingable in a plane perpendicular to the longitudinal direction (2) of the carrier. The boom (6) is swingably arranged on one link (9) of the four link mechanism (8) and arranged at a distance from the carrier (1).

Abstract: A jet nozzle is provided for drilling holes through the earth, such as drainholes around a well. The nozzle may include orifices for discharging fluid to drive the nozzle forward and includes a disk or other device having orifices to produce a swirling motion to fluid in the body of the nozzle. Swirling fluid is discharged from a front orifice and an extension is placed forward of the front orifice to confine the swirling fluid in a radial direction.

Abstract: The invention provides a head for injecting a liquid under pressure from a borehole to break up the soil, said head being mounted at the end of a drill string including a liquid feed for feeding a liquid under pressure. The head comprises a body and an outside wall, the body having at least one injection nozzle mounted therein, the nozzle having an inlet diameter equal to d and presenting an axis (x-x′), the body also having a tube. The tube presents a mean line having a first end connected to the bottom end of the liquid feed and having a second end connected to the nozzle tangentially to the axis (x-x′). The mean line is defined by at least one curved portion presenting a radius of curvature that varies continuously. The right section of the tube decreases regularly over at least half of its length from its first end to its second end.

Abstract: A jet nozzle is provided for drilling holes through the earth, such as drainholes around a well. The nozzle may include orifices for discharging fluid to drive the nozzle forward and includes a disk or other device having orifices to produce a swirling motion to fluid in the body of the nozzle. Swirling fluid is discharged from a front orifice and an extension is placed forward of the front orifice to confine the swirling fluid in a radial direction.

Abstract: An improved method and apparatus for sawing or drilling concrete or like material comprises use of a fluid flow device for transmitting a stream of water from a pressurized water supply to the cutting elements of a masonry saw or core drill and for injecting a speed-enhancing compound into the stream of water, with the compound being injected under the influence of a venturi-induced suction force created by the stream of water as it flows through the device. Preferably the device includes means for varying the rate at which the speed-enhancing compound is sucked into the water stream.

Abstract: Methods and materials for chemically enhanced drilling of oil/gas wells are disclosed. The use of drilling fluids containing chemicals that dissolve formation constituents results in the creation of boreholes. Fluids containing acids such as hydrochloric acid, formic acid, acetic acid, or combinations thereof have been found to be especially useful in chemical drilling of formations containing basic minerals such as calcium carbonate. The use of acid has the further advantage of simultaneously stimulating the borehole.

Abstract: A drill bit nozzle (1) providing a through bore for the passage of drilling fluid through a drill bit. The nozzle (1) is made of a material or materials which can be drilled through by standard well bore drilling equipment. The material(s) are selected to provide a surface (5) to the through bore which has a relatively high resistance to erosion to withstand the abrasive and corrosive impact of jetted drilling fluid. Embodiments are described using a hard chrome/copper combination and a single rubber material.

Abstract: The present invention generally provides apparatus and methods for reducing the pressure of a circulating fluid in a wellbore. In one aspect of the invention an ECD (equivalent circulation density) reduction tool provides a means for drilling extended reach deep (ERD) wells with heavyweight drilling fluids by minimizing the effect of friction head on bottomhole pressure so that circulating density of the fluid is close to its actual density. With an ECD reduction tool located in the upper section of the well, the friction head is substantially reduced, which substantially reduces chances of fracturing a formation (see also FIG. 2 later on).

Abstract: This invention aims to provide a gas-hydrate extracting device and method whereby a high-performance jet fluid is injected from a nozzle at the tip of an extraction pipe inserted into a gas-hydrate stratum, and whereby said jet fluid breaks said stratum so as to form a gas-hydrate mixed fluid that is transferred to surface of the earth, and whereby the void resulting from the removal of said gas hydrate is filled with the components of said high-performance jet fluid and a void-refilling fluid.

Abstract: A flexible hose assembly for horizontal well drilling is provided. The flexible hose assembly has a number of spaced thruster couplings along its length to impart drilling force to a nozzle blaster at an end of the flexible hose. The thruster couplings have rearwardly oriented thruster ports which impart a forward drilling force upon exit of high pressure water through the thruster ports. At least one of the thruster ports is an adjustable thruster port having variable opening area, variable discharge angle or both. The opening area and discharge angle can be adjusted or controlled to regulate the amount of thrust imparted to the flexible hose and the nozzle blaster, as well as to clear the bore of debris and prevent its accumulation behind the nozzle blaster. A method of horizontal well drilling using the above-described flexible hose is also provided. The method is particularly useful at shallow depths, such as 50-2000 feet.

Abstract: A method and system is disclosed for extending the depth of a subterranean borehole that uses heated aqueous fluid to dissolve rock of the subterranean formation. The heated aqueous fluid comprises water and hydroxides of Group I elements of The Periodic Table of Elements and mixtures thereof. The drilling system comprises means for delivering aqueous fluid and heating the aqueous fluid prior to contacting rock of a subsurface formation.

Abstract: Drill rod holder (10) mounted on a support (6) for clamping action towards a drill rod (40), which rod holder (10) is suitable for use in surface and underground drilling equipment, comprising a first jaw (34) arranged to co-operate with a second jaw (36) in clamping action towards the drill rod (40) from opposite sides; a piston-cylinder arrangement (22) in which a piston rod (28) in one end is attached to a first side of the piston (26) and in the other end is arranged to co-operate with the second jaw (36); a medium supply inlet (48) in the cylinder (2) through which a medium pressure is arranged to force the piston from its first side to pull the piston rod (28) into the cylinder (2) and thereby releases the clamping force on the jaws (34, 36) so that the jaws can be separated, wherein the cylinder (2) on the second side of the piston (26) is pre-filled with pressurised gas (46) acting as a gas spring exerting a pushing force on the piston (26) and thereby on the second jaw (36) via the piston rod (28) an

Abstract: A method and system for drilling or cutting a subterranean well or formation 52 using a drilling rig 5, a drill string 55, a plurality of solid material impactors 100, a drilling fluid and a drill bit 60 is disclosed. This invention may have particular utility in drilling wells for the petroleum industry and for cutting formation in the mining and tunnel boring industries. In a preferred embodiment, a plurality of solid material impactors are introduced into the drilling fluid and pumped through the drill string and drill bit to impact the formation ahead of the bit. At the point of impact, a substantial portion by weight of the impactors may have sufficient energy to structurally alter, excavate, and/or fracture the impacted formation. The majority by weight of the plurality of solid material impactors may have a mean diameter of at least 0.100 inches, and may structurally alter the formation to a depth of at least twice the mean diameter of the particles comprising the impacted formation.

Abstract: A drill bit having one or more nozzle retention bodies attached by a single orientation mounting is disclosed, as is the associated method for its manufacture. The upper end of the nozzle retention body has a fluid inlet in communication with the internal fluid plenum of the drill bit, and the lower end of the nozzle retention body includes a fluid outlet that defines an exit flow angle. The exit flow angle is angularly disposed from the longitudinal axis of the drill bit. The nozzle retention body may advantageously be chamfered or the like to provide a reduced cross-sectional area at the lower end of the nozzle retention body. The outer surface of the nozzle retention body (and attached hardened elements) may extend substantially to gage, or may fall short of that diameter.

Abstract: A method of fracturing a downhole formation according to which a plurality of jet nozzles are located in a spaced relation to the wall of the formation to form an annulus between the nozzles and the formation. A non-acid containing stimulation fluid is pumped at a predetermined pressure through the nozzles, into the annulus, and against the wall of the formation, and a gas is introduced into the annulus so that the stimulation fluid mixes with the gas to generate foam before the mixture is jetted towards the formation to form fractures in the formation. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that 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 under 37CFR 1.72.

Abstract: A “wet” pick box 1 comprises a body member 2, adapted in use to be welded to a rotary cutting head, whilst an aperture 5 is provided in the body member. Bores 15, 16 in the body member define an internal water course 6 connectable, at an inlet end 7, to a source of pressurised water, an aperture 8 in the body member is adapted to house a water discharge nozzle and is connected to an outlet end 9 of the watercourse 6. A tapped hole 10 intersects the bores 15 and 16 and a member 11A or 11B is insertable into, and removable from, the hole 10. A rotary mineral cutting head can be provided to which a plurality of such pick boxes are welded.

Abstract: A drilling assembly for drilling a borehole into an earth formation is disclosed having a drill string extending into the borehole and a jetting device arranged at a lower part of the drill string, the jetting device is provided with a mixing chamber having a first inlet in fluid communication with a drilling fluid supply conduit, a second inlet for abrasive particles and an outlet which is in fluid communication with a jetting nozzle arranged to jet a stream of abrasive particles and drilling fluid against at least one of the borehole bottom and the borehole wall. The jetting device is further provided with an abrasive particles recirculation system for separating the abrasive particles from the drilling fluid at a selected location where the stream flows from the at least one of the borehole bottom and the borehole wall towards the upper end of the borehole and for supplying the separated abrasive particles to the second inlet.

Abstract: Method for installing a duct in the ground, whereby a longitudinal organ is already present in the ground near the route along which the duct is to be installed, whereby the existing longitudinal element is used as a guide for the duct to be installed and the duct is pushed into the ground with the aid of a fluid under pressure fed through the duct, whereby the duct to be installed is coupled to the existing longitudinal element by means of at least one divisible coupling piece and whereby the coupling element is advanced along the existing longitudinal element. The invention also provides a coupling piece for guiding the duct along the longitudinal element.