Abstract: A trench wall apparatus includes a base frame held at its top end by a holding means held by at least one soil excavation means, which is positioned at a bottom end of the base frame. When soil is excavated while forming the trench, the trench wall apparatus is held by a clamping means that includes at least two clamping elements on opposite sides extended laterally by at least one actuating cylinder, whereby at least one part of the trench wall apparatus is clamped in the trench, and a pressing means applies a pressing force on the at least one soil excavation means. The clamping elements and clamping cylinder are positioned on an intermediate frame displaceably mounted along the base frame. The intermediate frame is clamped and fixed to the ground by the clamping means. The base frame having the soil excavation means is pressed downward by the pressing means.

Abstract: A method for estimating a steady state response of a drill string in a borehole includes calculating a first displacement of the drill string in a frequency domain for a first excitation force frequency and a number of multiples of this frequency using an equation of motion of the drill string. The equation of motion has a static force component, an excitation force component, and a non-linear force component with respect to at least one of a deflection and a derivative of the deflection of the drill string. The method further includes: transforming the first displacement from the frequency domain into a time domain; calculating a non-linear force in the time domain; calculating a frequency domain coefficient derived from the calculated non-linear force in the time domain; and calculating a second displacement of the drill string in the frequency domain using the equation of motion and the frequency domain coefficient.

Abstract: A gripper assembly for anchoring a tool within a downhole passage and for possibly assisting movement of the tool within the passage. The gripper assembly includes an elongated mandrel and flexible toes that can be radially displaced to grip onto the surface of the passage. The toes are displaced by the interaction of a driver slidable on the mandrel and a driver interaction element on the toes. In one embodiment, the toes are displaced by the interaction of rollers and ramps that are longitudinally movable with respect to one another. In another embodiment, the toes are displaced by the interaction of toggles that rotate with respect to the toes.

Abstract: A piston tractor system can include at least two piston assemblies which sealingly engage a wellbore, and a pump which transfers fluid between an annulus isolated between the piston assemblies, and another annulus. A method of operating a piston tractor system can include sealingly engaging at least two piston assemblies with a wellbore, grippingly engaging one piston assembly with the wellbore, and then pumping a fluid from an annulus formed between the piston assemblies, while the other piston assembly is secured to a tubular string, thereby biasing the tubular string to displace through the first piston assembly. A method of advancing a tubular string through a wellbore can include sealingly engaging piston assemblies with the wellbore, each of the piston assemblies including a gripping device which selectively grips the wellbore, and one piston assembly including another gripping device which selectively grips the tubular string.

Abstract: A tractor configured for grip locking during advancement to avoid slippage, particularly in open-hole wells. The tractor is equipped with a grip lock mechanism for independently locking an anchor grip in a radially outward direction. This locking occurs sequentially in advance of the power stroke of a reciprocating drive piston associated with the anchor. Thus, radial outward expansion and gripping are ensured at the time pulling of a load in an axial downhole direction is pursued. Such grip locking may be employed throughout tractoring or intermittently, depending upon well characteristics such as formation hardness and well diameter.

Abstract: The method and apparatus involves the positioning of an arm of a wellbore tool, such that the tool moves bidirectionally in a wellbore. Techniques also include predicting and acting in advance on the mechanism of an oilfield tool inside a wellbore, enhancing bidirectional movement and operation of the tool inside a wellbore environment typically for logging the well. Such regulation or control between different sensing parts may control placement of the sensors with respect to the wellbore wall.

Abstract: A gripper for use in a downhole tool is provided. The gripper can include an actuator, an engagement assembly, and an expandable assembly. The engagement assembly can comprise a leaf-spring like elongate continuous beam. The expandable assembly can comprise a linkage including a plurality of links. The linkage can be coupled to the actuator such that the actuator expands the expandable assembly which in turn expands the engagement assembly. In operation, during one stage of expansion radial forces are transmitted to the engagement assembly through both interaction of a rolling mechanism on the engagement assembly with the expandable assembly and pressure of the linkage assembly directly on an inner surface of the engagement assembly.

Abstract: An anchor tool for anchoring a downhole tool within a casing, a well, or any other downhole, hollow space. The tool has a longitudinal tool body with a center axis extending through the tool body in the center of the body, a first recess, a second recess, a third recess, and a fourth recess in the tool body; and a first anchor, a second anchor, a third anchor, and a fourth anchor. The first anchor is provided in the first recess, and so forth, and the anchors are outwards movable in the recesses for anchoring the tool. Each anchor provided in the recesses extends through the tool body transverse to and across the center axis and the anchors and the corresponding recesses are situated in the tool body for providing a symmetrical anchoring of the anchor tool.

Abstract: A gripper assembly for anchoring a tool within a downhole passage and for possibly assisting movement of the tool within the passage. The gripper assembly includes an elongated mandrel and flexible toes that can be radially displaced to grip onto the surface of the passage. The toes are displaced by the interaction of a driver slidable on the mandrel and a driver interaction element on the toes. In one embodiment, the toes are displaced by the interaction of rollers and ramps that are longitudinally movable with respect to one another. In another embodiment, the toes are displaced by the interaction of toggles that rotate with respect to the toes.

Abstract: A gripper mechanism for downhole tool is disclosed that includes a linkage mechanism and a flexible toe disposed over the linkage mechanism. In operation, an axial force generated by a power section of the gripper expands the linkage mechanism, which applies a radial expansion force to the flexible toe. For certain expansion diameters, the expansion force can be primarily transmitted to the toe from a roller-ramp interface expanding the linkage. For other expansion diameters, the expansion force can be primarily transmitted to the toe by expansion of the linkage in a three-bar linkage configuration. For other expansion diameters, the expansion force can be primarily transmitted to the toe by expansion of the linkage in a four-bar linkage configuration. Thus, the gripper can provide a desired expansion force over a large range of expansion diameters.

Abstract: An accumulator membrane unit (2) for inclusion into an accumulator chamber (6) in an accumulator (1) for storing hydraulic energy under pressure. The accumulator membrane unit includes membrane elements (3) that are sealingly joined at their peripheries and limit an inside membrane volume (V) which varies in dependence of a pressure at an outside of the accumulator membrane unit. The invention also concerns an accumulator, a method and a rock drilling machine.

Abstract: An expandable gripper assembly may be configured for anchoring a tool in a passage. The expandable gripper assembly includes first, second, and third pivotally connected links that are coupled to a tool. The third link is adapted to engage an inner wall in the passage. An actuation mechanism causes the third link to move radially outward from the tool for engagement with the inner wall. The actuation mechanism may comprise a roller mechanism that pushes on an inner surface of the first link for causing the first link to pivot outward away from the body. As the first and second links pivot outward, the third link moves in a radial direction for engagement with an inner wall.

Abstract: A gripper for use in a downhole tool is provided. The gripper can include an actuator, an engagement assembly, and an expandable assembly. The engagement assembly can comprise a leaf-spring like elongate continuous beam. The expandable assembly can comprise a linkage including a plurality of links. The linkage can be coupled to the actuator such that the actuator expands the expandable assembly which in turn expands the engagement assembly. In operation, during one stage of expansion radial forces are transmitted to the engagement assembly through both interaction of a rolling mechanism on the engagement assembly with the expandable assembly and pressure of the linkage assembly directly on an inner surface of the engagement assembly.

Abstract: A method of constructing a borehole drilled with a drilling apparatus (16), the method comprises: connecting a flexible tubular liner sleeve (22) around the outside of the drilling apparatus and connecting the sleeve around an upper opening of the borehole so as to pass into the borehole; progressively extending the sleeve into the borehole as drilling progresses while maintaining connection to the drilling apparatus and borehole opening; at a predetermined point in the drilling, expanding the sleeve so as to contact the borehole wall; and setting the sleeve so as to be fixed to the borehole wall after expansion. Apparatus for use in such a method comprises: a flexible, expandable sleeve (22); a first connector for connecting the sleeve around the outside of a drilling assembly; and a second connector for connecting the sleeve around the opening of the borehole; wherein the sleeve is arranged to extend through the borehole between the connectors as drilling progresses.

Abstract: In a method for producing a cased horizontal string bore extending from a well shaft, a starter drill pipe is driven into the rock mass surrounding the well shaft. A hydraulically driven drill motor is arranged in the starter drill pipe and rotates a drilling tool protruding from the leading end of the starter drill pipe. The drill motor is fixed against rotation and axial displacement by a clamping device. When the final depth of the string bore is reached, the drilling tool is retracted into the starter drill pipe by axial movement of the clamping device and a free space is formed at the drift face of the string bore. The free space is filled and sealed by injection of a quick-setting, expanding filling compound. Afterwards, the clamping device, the drill motor and the drilling tool are removed from the drill pipes.

Abstract: A hydraulically powered tractor adapted for advancement through a borehole including an elongate body, aft and forward gripper assemblies, and a valve control assembly housed within the elongate body. The aft and forward gripper assemblies are adapted for selective engagement with the inner surface of the borehole. The valve control assembly includes a gripper control valve for directing pressurized fluid to the aft and forward gripper assemblies. The valve control assembly also includes a propulsion control valve for directing fluid to an aft or forward power chamber for advancing the body relative to the actuated gripper assembly. Aft and forward mechanically actuated valves may be provided for controlling the position of the gripper control valve by detecting and signaling when the body has completed an advancement stroke relative to an actuated gripper assembly.

Abstract: A gripper mechanism for downhole tool is disclosed that includes a linkage mechanism and a flexible toe disposed over the linkage mechanism. In operation, an axial force generated by a power section of the gripper expands the linkage mechanism, which applies a radial expansion force to the flexible toe. For certain expansion diameters, the expansion force can be primarily transmitted to the toe from a roller-ramp interface expanding the linkage. For other expansion diameters, the expansion force can be primarily transmitted to the toe by expansion of the linkage in a three-bar linkage configuration. For other expansion diameters, the expansion force can be primarily transmitted to the toe by expansion of the linkage in a four-bar linkage configuration. Thus, the gripper can provide a desired expansion force over a large range of expansion diameters.

Abstract: An apparatus for running a liner into a wellbore may include an inner string, a device coupled to the inner string that is operable to engage the interior of the liner and facilitates running of the liner into the wellbore, and a control mechanism operable to control fluid communication between the interior of the liner and the wellbore. A method of running a liner into a wellbore may include the steps of positioning an inner string into the liner, wherein the inner string includes a device operable to engage the interior of the liner, engaging the interior of the liner, and supplying a fluid pressure to move the liner relative to the inner string to advance the liner into the wellbore.

Abstract: A gripper for use in a downhole tool is provided. The gripper can include an actuator, a toe assembly, and an expandable assembly. The toe assembly can be a leaf-spring like elongate continuous beam. The expandable assembly can be a linkage including a plurality of links. The linkage is coupled to the actuator such that the actuator expands the expandable assembly which in turn expands the toe assembly. In operation, during one stage of expansion radial forces are transmitted to the toe through both interaction of a rolling mechanism on the toe with the expandable assembly and pressure of the linkage assembly directly on an inner surface of the toe.

Abstract: An expandable gripper assembly may be configured for anchoring a tool in a passage. The expandable gripper assembly includes first, second, and third pivotally connected links that are coupled to a tool. The third link is adapted to engage an inner wall in the passage. An actuation mechanism causes the third link to move radially outward from the tool for engagement with the inner wall. The actuation mechanism may comprise a roller mechanism that pushes on an inner surface of the first link for causing the first link to pivot outward away from the body. As the first and second links pivot outward, the third link moves in a radial direction for engagement with an inner wall.

Abstract: A gripper assembly for anchoring a tool within a downhole passage and for possibly assisting movement of the tool within the passage. The gripper assembly includes an elongated mandrel and flexible toes that can be radially displaced to grip onto the surface of the passage. The toes are displaced by the interaction of a driver slidable on the mandrel and a driver interaction element on the toes. In one embodiment, the toes are displaced by the interaction of rollers and ramps that are longitudinally movable with respect to one another. In another embodiment, the toes are displaced by the interaction of toggles that rotate with respect to the toes.

Abstract: A percussion device (1) with a reciprocating percussion piston (3), includes a first chamber (5) that can be pressurized for forward driving of the percussion piston (3) and a second chamber (8) that can be periodically pressurized for back-driving of the percussion piston (3). The percussion device includes at least one driving piston (7) arranged for actuating the back-driving of the percussion piston (3) wherein a portion of said driving piston (7) is arranged to enter into the second chamber (8) for pressure actuating on a driving surface of the driving piston by pressure medium being present in this chamber in the direction of back-driving, wherein the driving piston (7) includes means for back-driving co-operation with the percussion piston (3), and wherein the driving piston (7) is free for axial movement with respect to the percussion piston (3), opposite the direction of back-driving. The invention also concerns a method and a rock drilling machine.

Abstract: A hydraulically powered tractor adapted for advancement through a borehole including an elongate body, aft and forward gripper assemblies, and a valve control assembly housed within the elongate body. The aft and forward gripper assemblies are adapted for selective engagement with the inner surface of the borehole. The valve control assembly includes a gripper control valve for directing pressurized fluid to the aft and forward gripper assemblies. The valve control assembly also includes a propulsion control valve for directing fluid to an aft or forward power chamber for advancing the body relative to the actuated gripper assembly. Aft and forward mechanically actuated valves may be provided for controlling the position of the gripper control valve by detecting and signaling when the body has completed an advancement stroke relative to an actuated gripper assembly.

Abstract: An expandable gripper assembly may be configured for anchoring a tool in a passage. The expandable gripper assembly includes first, second, and third pivotally connected links that are coupled to a tool. The third link is adapted to engage an inner wall in the passage. An actuation mechanism causes the third link to move radially outward from the tool for engagement with the inner wall. The actuation mechanism may comprise a roller mechanism that pushes on an inner surface of the first link for causing the first link to pivot outward away from the body. As the first and second links pivot outward, the third link moves in a radial direction for engagement with an inner wall.

Abstract: A wireline drill train is used to drill an elongated, small diameter, lateral branch borehole from near the base of a main well. The drill train, includes a drill module, a first self-propelled thrust module coupled to the drill module, and a second self-propelled thrust module pivotally coupled to the first self-propelled thrust module. Each thrust module includes at least two extendible thrusters. Each extendible thruster includes a six-bar mechanism and a traction tread. The drill train further includes a first articulated linkage linking the first self-propelled thrust module to the drill module, and a second articulated linkage linking the second thrust module to the first thrust module. The second articulated linkage includes a thrust-transmission bar and three retractable stiffener bars.

Abstract: In a method for producing a cased string bore (5) extending from a well shaft (1) in the horizontal direction for the installation of a filter string, a starter drill pipe (13) and subsequently further drill pipes are driven into the rock mass (6) surrounding the well shaft through an opening (4) in the wall (2) of the well shaft (1) using a drive means (11) arranged in the well shaft. Arranged in the starter drill pipe (13) is a hydraulically driven drill motor (18) which drives in rotation a drilling tool (19) protruding from the leading end of the starter drill pipe (13) and is supported in the starter drill pipe (13) by means of a clamping device (21, 22) so as to be fixed against rotation and axial displacement, a partition sealing the starter drill pipe (13) being formed by means of the clamping device (21, 22).

Abstract: An expandable gripper assembly may be configured for anchoring a tool in a passage. The expandable gripper assembly includes first, second, and third pivotally connected links that are coupled to a tool. The third link is adapted to engage an inner wall in the passage. An actuation mechanism causes the third link to move radially outward from the tool for engagement with the inner wall. The actuation mechanism may comprise a roller mechanism that pushes on an inner surface of the first link for causing the first link to pivot outward away from the body. As the first and second links pivot outward, the third link moves in a radial direction for engagement with an inner wall.

Abstract: A down-the-hole hammer includes a casing and a piston movable in the casing between a lowermost operating position and an uppermost operating position. A recess is provided between the piston and the casing so that the piston and the casing define an intermediate chamber between a top end of the piston and a bottom end of the piston. A passageway is provided between a source of pressurized fluid and the intermediate chamber such that, at all positions of the piston between the lowermost and the uppermost operating positions, the source of pressurized fluid is in flow communication with the intermediate chamber through the passageway. An opening in the piston at least partially defines the passageway.

Abstract: A large scale hydraulically driven downhole reciprocating tractor to display substantially continuous advancement. The tractor may be configured to pull coiled tubing downhole in a continuous manner so as to substantially avoid static frictional resistance to the pulling. As a result, the tractor and coiled tubing may achieve up to about twice the depth into the well otherwise attainable. Additionally, the tractor may include a fail safe mechanism whereby a plurality of pilot operated valves are employed to ensure that immobilization of at least one anchor of the tractor is present at all times during downhole advancement to thereby avoid the undesired effects of coiled tubing spring-back.

Abstract: A hydraulically powered tractor adapted for advancement through a borehole including an elongate body, aft and forward gripper assemblies, and a valve control assembly housed within the elongate body. The aft and forward gripper assemblies are adapted for selective engagement with the inner surface of the borehole. The valve control assembly includes a gripper control valve for directing pressurized fluid to the aft and forward gripper assemblies. The valve control assembly also includes a propulsion control valve for directing fluid to an aft or forward power chamber for advancing the body relative to the actuated gripper assembly. Aft and forward mechanically actuated valves may be provided for controlling the position of the gripper control valve by detecting and signaling when the body has completed an advancement stroke relative to an actuated gripper assembly.

Abstract: In a drilling apparatus of the type comprising a rotatable drilling shaft and a housing for rotatably supporting a length of the drilling shaft for rotation therein, a rotation restraining device associated with the housing for restraining rotation of the housing. In one embodiment, the rotation restraining device is comprised of at least one roller on the housing, the roller having an axis of rotation substantially perpendicular to a longitudinal axis of the housing and being oriented such that it is capable of rolling about its axis of rotation in response to a force exerted on the roller substantially in the direction of the longitudinal axis of the housing. In a further embodiment, the rotation restraining device is comprised of at least one piston on the housing.

Abstract: An earth boring apparatus for sinking shafts and removing shaft material from the shaft, the apparatus having at least two decks; hydraulic means for allowing movement of the decks relative to one another; releasable anchoring means associated with the decks for engaging walls of the shaft to secure the apparatus in a stationary position; whereby the releasable anchoring means of one of the decks engages the wall while the releasable anchoring means of the other deck is released from the wall to allow motion of the other deck along the shaft, in cooperation with the hydraulic means. The apparatus also includes guide means for forcing a bucket for hoisting shaft material from the shaft along a predetermined path, and an in-stage cut-boom drill.

Abstract: An apparatus for steerable rotary drilling of a borehole having a wall in the earth comprising a mandrel having a central opening there through for the passage of drilling fluids. The mandrel having a lower connection for operatively connecting to a drill bit structure and an upper connection for operatively connecting to a drill string above said apparatus. The mandrel further having an intermediate portion, an outer housing surrounding longitudinal extent of the mandrel intermediate portion, a differential displacement drive within the outer housing, one or more pairs of radially-extensible, opposed side-force exerting elements controlled by the differential displacement drive to provide for side force exertion against the borehole wall.

Abstract: A gripper assembly for anchoring a tool within a downhole passage and for possibly assisting movement of the tool within the passage. The gripper assembly includes an elongated mandrel and flexible toes that can be radially displaced to grip onto the surface of the passage. The toes are displaced by the interaction of a driver slidable on the mandrel and a driver interaction element on the toes. In one embodiment, the toes are displaced by the interaction of rollers and ramps that are longitudinally movable with respect to one another. In another embodiment, the toes are displaced by the interaction of toggles that rotate with respect to the toes.

Abstract: A method and apparatus for propelling a tool having a body within a passage. The tool includes a gripper including at least a gripper portion which can assume a first position that engages an inner surface of the passage and limits relative movement of the gripper portion relative to the inner surface. The gripper portion can also assume a second position that permits substantially free relative movement between the gripper portion and the inner surface of the passage. The tool includes a propulsion assembly for selectively continuously moving the body of the tool with respect to the gripper portion while the gripper portion is in the first position. This allows the tool to move different types of equipment within the passage. For example, the tool advantageously may be used in drilling processes to provide continuous force to a drill bit. This enables the drilling of extended horizontal boreholes.

Abstract: A downhole tool is provided that includes a grip assembly for contacting a well formation. The grip assembly includes a gripper body; and a centralizer that is attached to and radially expandable with respect to the gripper body and that has a geometry which is lockable by a locking device. The grip assembly also includes a force amplifier in force transmitting relation with the centralizer, wherein the force amplifier transfers a force in a first direction to a much larger force in a second direction when the centralizer is locked by the locking device.

Abstract: A gripper assembly for anchoring a tool within a downhole passage and for possibly assisting movement of the tool within the passage. The gripper assembly includes an elongated mandrel and flexible toes that can be radially displaced to grip onto the surface of the passage. The toes are displaced by the interaction of a driver slidable on the mandrel and a driver interaction element on the toes. In one embodiment, the toes are displaced by the interaction of rollers and ramps that are longitudinally movable with respect to one another. In another embodiment, the toes are displaced by the interaction of toggles that rotate with respect to the toes.

Abstract: A method and apparatus for propelling a tool having a body within a passage. The tool includes a gripper including at least a gripper portion which can assume a first position that engages an inner surface of the passage and limits relative movement of the gripper portion relative to the inner surface. The gripper portion can also assume a second position that permits substantially free relative movement between the gripper portion and the inner surface of the passage. The tool includes a propulsion assembly for selectively continuously moving the body of the tool with respect to the gripper portion while the gripper portion is in the first position. This allows the tool to move different types of equipment within the passage. For example, the tool advantageously may be used in drilling processes to provide continuous force to a drill bit. This enables the drilling of extended horizontal boreholes.

Abstract: Apparatus, system and methods useful for controlling the traction of a downhole tractor in a borehole include the capability of repeatedly adjusting the normal force applied to at least one component that causes movement of the tractor in the borehole.

Abstract: A device for anchoring a drill string in a borehole an anchoring member connected to the drill string, the anchoring member being movable between a retracted position in which the anchoring member is retracted from the borehole wall, and, an extended position in which the anchoring member is extended against the borehole wall so as to anchor the drill string to the borehole wall, and an activating member operable to move the anchoring member from the extended position to the retracted position by the action of pressure of drilling fluid present in the borehole.

Abstract: A downhole drilling tractor for moving within a borehole comprises a tractor body, two packerfeet, two aft propulsion cylinders, and two forward propulsion cylinders. The body comprises aft and forward shafts and a central control assembly. The packerfeet and propulsion cylinders are slidably engaged with the tractor body. Drilling fluid can be delivered to the packerfeet to cause the packerfeet to grip onto the borehole wall. Drilling fluid can be delivered to the propulsion cylinders to selectively provide downhole or uphole hydraulic thrust to the tractor body. The tractor receives drilling fluid from a drill string extending to the surface. A system of spool valves in the control assembly controls the distribution of drilling fluid to the packerfeet and cylinders. The valve positions are controlled by motors. A programmable electronic logic component on the tractor receives control signals from the surface and feedback signals from various sensors on the tool.

Abstract: A method and apparatus for propelling a tool having a body within a passage. The tool includes a gripper including at least a gripper portion which can assume a first position that engages an inner surface of the passage and limits relative movement of the gripper portion relative to the inner surface. The gripper portion can also assume a second position that permits substantially free relative movement between the gripper portion and the inner surface of the passage. The tool includes a propulsion assembly for selectively continuously moving the body of the tool with respect to the gripper portion while the gripper portion is in the first position. This allows the tool to move different types of equipment within the passage. Preferred uses for the tool include drilling, well completion, logging, retrieval, pipeline service, and communication line activities.

Abstract: A gripper assembly for anchoring a tractor within a downhole passage and for assisting movement of the tractor within the passage. The gripper assembly includes an elongated mandrel and flexible toes that can be radially displaced to grip onto the surface of the passage. The toes are displaced by the interaction of a driver slidable on the mandrel and a driver interaction element on the toes. In one embodiment, the toes are displaced by the interaction of rollers and ramps that are longitudinally movable with respect to one another. In another embodiment, the toes are displaced by the interaction of toggles that rotate with respect to the toes.

Abstract: A disclosure is provided describing a filling and circulating tool and method of use. The filling and circulating tool comprises a tubular housing having a first fluid passage and a longitudinal axis, a movable seal coupled to an exterior of the housing, the seal adapted to substantially block a flow of fluid through the first fluid passage when the seal is in a closed position and to allow the flow of fluid when the seal is in an open position, and an actuating device coupled to the movable seal such that in response to insertion into the casing, the actuating device causes the movable seal to move from the closed position to the open position.

Abstract: A method and apparatus for advancing a rotating motorized downhole tool for operations in oil/gas wells. The apparatus is adapted for drilling and milling away of casing sections in the wells, as preparation for plugging the same. The apparatus includes a rotating tool and a driving motor indirectly suspended on coiled tubing. The apparatus also includes a carriage connected to the motor adapted to absorb torques that occur during use. The carriage is connected to the coiled tubing via a swivel coupling such that a tensile force on the coiled tubing provides an advancing force for the tool and motor.

Abstract: The invention relates to equipment for drilling a vertical borehole in hard ground, the equipment comprising: casing put successively into place in the borehole; a drilling machine having a rotary cutting head and presenting a structural frame; torque and thrust transmission means having a first end secured to the structural frame of the drilling machine; and securing means for securing the second end of the torque and thrust transmission means in translation and in rotation to said casing.

Abstract: A traction apparatus (1) for propulsion along a bore comprises first and second traction members (6) having outwardly extending legs (14). A propulsion system for operating the traction members (6) comprises a turbine-driven shaft (7) which drives the traction members (6) by way of bearing members (15). In a first phase, one of the legs of the first traction member is moved in one direction whilst in contact with the traction surface to impart the propulsion force at the same time as one of the legs of the second traction member is moved in opposite direction whilst out of contact. In a second phase one of the legs of the second traction member is moved in said one direction whilst in contact with the traction surface to impart the propulsion force at the same time as one of the legs of the first traction member is moved in opposite direction whilst out of contact.

Abstract: Subsea controlled milling apparatus and methods. In a described embodiment, a method of controlling displacement of a cutting device conveyed on a tubular string in a subterranean well includes the steps of: interconnecting an apparatus in the tubular string, the apparatus including an axial advancement device and an anchoring device; actuating the anchoring device to anchor the apparatus in the well; applying a pressure differential to the advancement device, thereby displacing the cutting device relative to the apparatus; and operating the cutting device to cut a structure in the well.

Abstract: A six-bar linkage mechanism for conforming to the configuration of a tractored surface having a central link defined by a tool body and a saddle link spaced from the central link and movable for conforming with the tractored surface. A pair of front links each having pivotal connection with respective ends of the saddle link and having linearly movable pivotal connection with the central link to permit angular and spacing changes of the saddle link relative to the central link. A pair of centralizer links are located between the front links and have pivotal connections with the saddle link and pivotal connections with the central link. One of the pivotal connections is linearly movable on the central link. For tractor tools, when the tractored surface is a wellbore or well pipe, a plurality of six-bar linkages radiate from a tool body for surface conforming traction with the tractored surface.

Abstract: An apparatus for drilling trenches in the ground comprising a main frame having two vertical main faces, a drilling assembly comprising a support disposed at the bottom of said frame, means for causing said drilling assembly to move in vertical translation relative to said main frame by applying a predetermined force to said drilling assembly relative to said main frame, and anchoring means mounted on said main faces for anchoring the main frame to the walls of said trench. The anchoring means comprise a plurality of deformable elements secured to said main faces of the top frame, means for injecting a fluid under pressure into said inflatable elements thereby applying a force between said main frame and the walls of the trench, and means enabling said fluid under pressure to escape from said inflatable elements whereby no force is transmitted between said main frame and the walls of the trench.