US20030127251A1 - Flexible hose with thrusters for horizontal well drilling - Google Patents

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.

Description

• This application is a continuation-in-part of U.S. patent application Ser. No. 09/825,329 filed Apr. 3, 2001, which claims the benefit of U.S. Provisional Patent Application Serial No. 60/195,076 filed Apr. 6, 2000.[0001]
FIELD OF THE INVENTION
• The invention relates to horizontal well drilling and more particularly to a flexible hose assembly for horizontal well drilling.[0002]
BACKGROUND OF THE INVENTION
• In the process of drilling for hydrocarbons such as oil and natural gas, vertical or substantially vertical wells have been used most often in the past. Those wells will produce for a given amount of time, then begin to dry up. At that point, it is advantageous to drill out horizontally or laterally at an angle from the vertical well in order to try and increase production of, for example, crude oil.[0003]
• There have been several attempts to find an economically viable and reliable system for drilling into the untapped pay zones adjacent an existing vertical well. Horizontal drilling has been proposed as an alternative and has been described in U.S. Pat. Nos. 5,853,056, 5,413,184, 5,934,390, 5,553,680, 5,165,491, 5,458,209, 5,210,533, 5,194,859, 5,439,066, 5,148,877, 5,987,385, 5,899,958, 5,892,460, 5,528,566, 4,947,944, 4,646,831, 4,786,874, 5,410,303, 5,318,121, 4,007,797, 5,687,806, 4,640,362, 5,394,951, 1,904,819, 2,521,976 and Re. 35,386, the contents of all of which are incorporated herein by reference.[0004]
• U.S. Pat. No. 5,413,184 describes a method of horizontal drilling that utilizes a flexible hose and a high pressure nozzle blaster to bore into the earth's strata at significant depths, such as 4000 feet. The nozzle blaster uses high pressure water to clear a path through the strata. The nozzle blaster is advanced through the strata by applying weight to the hose, i.e., slacking off the tension in the vertical portion of the hose. Essentially, the weight of the 4000 feet of hose above the nozzle blaster is used to apply drilling force to the nozzle blaster, thus forcing it along the horizontal path. While this method is effective at significant depths due to the large amount of weight available, it is less effective at shallower depths. At shallow depths, there simply is not enough weight available to supply sufficient force to advance the nozzle blaster through the strata.[0005]
• In addition, drilling substantial lateral or horizontal distances from the vertical well can be very difficult or time consuming or otherwise inhibited due to the accumulation of the loose cuttings from drilling in the lateral bore hole.[0006]
• Thus, there is a need for an apparatus that will effectively advance a drilling tool such as a nozzle blaster horizontally or laterally at an angle relative to an existing vertical or substantially vertical well, through the earth's strata for horizontal or lateral drilling at shallow depths. Preferably, such an improved apparatus will also effectively reduce or prevent the accumulation of cuttings within a lateral bore.[0007]
SUMMARY OF THE INVENTION
• A flexible hose assembly for horizontal well drilling is provided. The assembly includes a flexible hose. The flexible hose assembly has a proximal end and a distal end, wherein the proximal end is located rearward of the distal end. The flexible hose has a plurality of thruster ports disposed therein with at least one of the thruster ports being disposed rearward of the distal end of the flexible hose assembly. Each of the thruster ports is adapted to direct a jet of pressurized fluid in a direction such that a centerline drawn through the jet forms an acute discharge angle with the longitudinal axis of the flexible hose rearward from the location of the thruster port. At least one of the thruster ports is an adjustable thruster port.[0008]
• A method of horizontal well drilling is also provided which includes the following steps: a) providing a flexible hose assembly including a flexible hose that has a proximal end and a distal end, wherein the proximal end is located rearward of the distal end, the flexible hose having a plurality of thruster ports disposed therein with at least one of the thruster ports being disposed rearward of the distal end of the flexible hose, each of the thruster ports being adapted to direct a jet of pressurized fluid in a direction such that a centerline drawn through the jet forms an acute discharge angle with the longitudinal axis of the flexible hose rearward from the location of the thruster port, at least one of the thruster ports being an adjustable thruster port; b) lowering the flexible hose assembly to a desired depth in a vertical well, and redirecting the flexible hose assembly along a direction at an angle to the longitudinal axis of the vertical well; c) forcing at least 2,000 psi fluid through the flexible hose and the thruster ports in the flexible hose; and d) drilling a horizontal bore into the earth's strata adjacent the vertical well.[0009]
• A flexible hose assembly for horizontal well drilling is also provided. The assembly includes a flexible hose. The flexible hose assembly has a proximal end and a distal end, wherein the proximal end is located rearward of the distal end. The flexible hose has a plurality of thruster ports disposed therein with at least one of the thruster ports being disposed rearward of the distal end of the flexible hose assembly. Each of the thruster ports is adapted to direct a jet of pressurized fluid in a direction such that a centerline drawn through the jet forms an acute discharge angle with the longitudinal axis of the flexible hose rearward from the location of the thruster port. Each of the thruster ports has an opening with a cross-sectional area selected from the group consisting of closed polygons, closed curvilinear shapes, and shapes having at least one linear edge.[0010]
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a side view of a thruster coupling according to a first preferred embodiment of the invention.[0011]
• FIG. 2 is a cross-sectional view of the thruster coupling taken along line[0012]2-2 in FIG. 1.
• FIG. 3 is a longitudinal cross-sectional view of the thruster coupling taken along line[0013]3-3 in FIG. 2.
• FIG. 4 is a perspective view of a flexible hose having thruster couplings according to the present invention.[0014]
• FIG. 5A is a perspective view of a nozzle blaster for use with the present invention.[0015]
• FIG. 5B is an alternate perspective view of a nozzle blaster for use with the present invention.[0016]
• FIG. 6 is a perspective view of a flexible hose having thruster ports provided directly in the sidewall according to an embodiment of the invention.[0017]
• FIG. 7 is a side view of a thruster coupling having adjustable thruster ports according to a second preferred embodiment of the invention.[0018]
• FIG. 8 is a cross-sectional view of the thruster coupling taken along line[0019]8-8 in FIG. 7.
• FIG. 9 is a close-up view of an adjustable thruster port indicated at[0020]broken circle9 in FIG. 7.
• FIG. 10 is an alternative preferred embodiment of a thruster coupling having adjustable thruster ports.[0021]
• FIG. 11 is a further alternative preferred embodiment of a thruster coupling having adjustable thruster ports.[0022]
• FIG. 12 is a perspective view of a flexible hose having thruster couplings according to the embodiment illustrated in FIG. 11.[0023]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION
• In the description that follows, when a preferred range such as 5 to 25 (or 5-25) is given, this means preferably at least 5, and separately and independently, preferably not more than 25. As used herein, the following terms having the following meanings: “gal/min” means gallons per minute and “psi” means pounds per square inch.[0024]
• As used herein, the term vertical well refers to a well bore in the earth having an opening at the earth's surface. A vertical well can be substantially vertical relative to the earth's surface, or it can be drilled at an angle, e.g. an acute angle, relative to the earth's surface instead of straight down. Also as used herein, when a horizontal well bore or a horizontal well or direction is mentioned, the word “horizontal” indicates a well bore or direction that is at an angle relative to the vertical well from which the horizontal bore is drilled or depends. For example, as used herein when a horizontal bore is drilled from a vertical well bore, it is not necessary or required that either the vertical well bore be truly vertical, or that the horizontal bore drilled therefrom be truly horizontal. All that is required is that the vertical well bore have an opening at the earth's surface and that the horizontal bore be drilled out from the vertical well at an angle relative to the vertical well. Commonly, the vertical well is truly or substantially vertical, and the horizontal bore drilled therefrom is truly or substantially horizontal; however this is not required or necessary in the present invention.[0025]
• The invention can be used with respect to oil wells, natural gas wells, water wells, solution mining wells, and other wells. The invention includes a flexible hose assembly comprising a flexible hose with thrusters and a nozzle blaster for horizontal well drilling. The hose assembly is fed down into the bore of an existing vertical well to a specified depth, at which point it is redirected along a horizontal direction that can be substantially perpendicular to the vertical well. Preferably, the hose assembly is fed into the well by a coil tubing injector as known in the art. Redirection of the hose assembly is preferably accomplished via an elbow or shoe in upset tubing as is known in the art, less preferably via some other known means.[0026]
• The hose assembly includes a flexible hose having a proximal end and a distal end, such that proximal end is located rearward of the distal end. Preferably, the flexible hose is supplied with a plurality of thruster couplings disposed along the length of the hose. Each coupling contains one or more thrusters or thruster ports, each thruster port comprising a hole or opening through the coupling wall to allow the passage of water or other pressurized fluid or liquid therethrough. In one preferred embodiment, the thruster ports are oriented in a substantially rearward direction about the circumference of the thruster coupling such that high pressure water or other fluid exits the holes at a substantially rearward angle and enters the horizontal bore in a direction effective to impinge upon the walls of the bore, thus thrusting the hose (and thereby the nozzle blaster) forward through the bore.[0027]
• In a further preferred embodiment, the thruster ports are adjustable, meaning that they have variable opening area or diameter, variable discharge angle or both. In this embodiment, the opening diameter or the angle of discharge of the adjustable thrusters can be varied to deliver a variable degree of thrust to the hose assembly (and nozzle blaster) depending on how much force is required or desired to effectively drill through the strata ahead of the nozzle blaster (e.g. sandstone requires comparatively less thrust or drilling force relative to granite or igneous rock). In addition, varying the angle of discharge can aid in steering the flexible hose assembly as it drills a horizontal bore, and in clearing the horizontal bore of drill cuttings and other debris.[0028]
• With reference to FIG. 4, there is shown generally a[0029]flexible hose assembly10 according to the invention, which preferably comprises anozzle blaster24 and aflexible hose11.Flexible hose11 has and comprises a plurality offlexible hose sections22, a pair ofpressure fittings23 attached to the ends of eachhose section22, and a plurality ofthruster couplings12, each of which joins a pair ofadjacent pressure fittings23.Hose assembly10 comprises anozzle blaster24 at its distal end and is connected to a source (not shown) of high pressure fluid, preferably an aqueous liquid, preferably water, less preferably some other liquid, at its proximal end.Couplings12 are spaced at least, or not more than, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90 or 100 feet apart from each other inhose11. The total hose length is preferably at least or not more than 100 or 200 or 400 or 600 or 700 or 800 or 900 or 1000 or 1200 or 1400 or 1600 or 1800 or 2000 feet.Hose sections22 are preferably flexible hydraulic hose known in the art, comprising a steel braided rubber-Teflon (polytetrafluoroethylene) mesh, preferably rated to withstand at least 5,000, preferably at least 10,000, preferably at least 15,000, psi water pressure. High pressure water is preferably supplied at at least 2,000, 5,000, 10,000, 15,000, or 18,000 psi, or at 5,000 to 10,000 to 15,000 psi. When used to drill horizontally from a vertical well, the hose extends about or at least or not more than 7, 10, 50, 100, 200, 250, 300, 350, 400, 500, 1000, or 2000 feet horizontally from the original vertical well. In one embodiment the hose extends about 440 feet horizontally from the original vertical well.
• As illustrated in FIG. 1, in a first preferred[0030]embodiment thruster coupling12 comprises a coupling or fitting, preferably made from metal, preferably steel, most preferably stainless steel, less preferably aluminum. Less preferably,coupling12 is a fitting made from plastic, thermoset, or polymeric material, able to withstand 5,000 to 10,000 to 15,000 psi of water pressure. Still less preferably,coupling12 is a fitting made from ceramic material. It is important to note that when a drilling fluid other than water is used, the material of construction of thecouplings12 must be selected for compatibility with the drilling fluid and yet still withstand the desired fluid pressure.Coupling12 has two threadedend sections16 and amiddle section14. Preferably,end sections16 andmiddle section14 are formed integrally as a single solid part or fitting. Threadedsections16 are female-threaded to receive male-threadedpressure fittings23 which are attached to, preferably crimped within the ends of, hose sections22 (FIG. 4). Alternatively, thefittings23 can be attached to the ends of thehose sections22 via any conventional or suitable means capable of withstanding the fluid pressure. In the illustrated embodiment, each fitting23 has a threaded portion and a crimping portion which can be a unitary or integral piece, or a plurality of pieces joined together as known in the art. Alternatively, the threaded connections may be reversed; i.e. with male-threadedend sections16 adapted to mate with female-threaded pressure fittings attached tohose sections22. Less preferably,end sections16 are adapted to mate with pressure fittings attached to the end ofhose sections22 by any known connecting means capable of providing a substantially water-tight connection at high pressure, e.g. 5,000-15,000 psi.Middle section14 contains a plurality of holes orthruster ports18 which pass through the thickness ofwall15 ofcoupling12 to permit water to jet out. Though thethruster ports18 are shown having an opening with a circular cross-section, the thruster port openings can be provided having any desired cross section; e.g. polygonal, curvilinear or any other shape having at least one linear edge, such as a semi-circle.Coupling12 preferably is short enough to allowhose11 to traverse any bends or elbows in the upset tubing and any shoes or adapters used therewith. Therefore, coupling12 is formed as short as possible, preferably having a length of less than about 3, 2, or 1.5 inches, more preferably about 1 inch or less than 1 inch. Hose11 (and therefore couplings12 and hose sections22) preferably has an outer diameter of about 0.25 to about 1.25 inches, more preferably about 0.375 to about 0.5 inches, and an inner diameter preferably of about 0.125 inches.Couplings12 have a wall thickness of preferably about 0.025-0.25, more preferably about 0.04-0.1, inches.
• Optionally,[0031]hose11 is provided withcouplings12 formed integrally therewith, or withthruster ports18 disposed directly in the sidewall of a contiguous, unitary, non-sectioned hose at spaced intervals along its length (see FIG. 6). A hose so comprised obviates the need of threaded connections or other connecting means as described above.
• In the embodiments shown in FIGS. 1 and 7,[0032]thruster ports18 havehole axes20 which form a discharge angle β with the longitudinal axis of thecoupling12. The discharge angle β is preferably 5° to 95°, more preferably 10° to 90°, more preferably 10° to 80°, more preferably 15° to 70°, more preferably 20° to 60°, more preferably 25° to 55°, more preferably 30° to 50°, more preferably 40° to 50°, more preferably 40° to 45°, more preferably about 45°. Thethruster ports18 are also oriented such that a water jet passing through them exits thecoupling12 in a substantially rearward direction; i.e. in a direction such that a centerline drawn through the exiting water jet forms an acute angle (discharge angle β) with the longitudinal axis of the flexible hose rearward from the location of the thruster port, toward the proximal end of the hose assembly. In this manner, high-pressure water jets30 emerging fromthruster ports18 impart drilling force or thrust to the nozzle blaster, thus forcing the nozzle blaster forward into the earth strata (see FIG. 4). As illustrated in FIG. 2, a plurality ofthruster ports18 are disposed inwall15 around the circumference ofcoupling12. There are 2 to 6 or 8 ports, more preferably 3 to 5 ports, more preferably 3 to 4 ports.Thruster ports18 are spaced uniformly about the circumference ofcoupling12, thus forming an angle α between them. Angle α will depend on the number ofthruster ports18, and thus preferably will be from 45° or 60° to 180°, more preferably 72° to 120°, more preferably 90° to 120°.Thruster ports18 are preferably about 0.010 to 0.017 inches, more preferably 0.012 to 0.016 inches, more preferably 0.014 to 0.015 inches in diameter.
• As best seen in FIGS. 1 and 2,[0033]thruster ports18 are formed in thewall15 ofcoupling12, extending in a substantially rearward direction toward the proximal end of thehose assembly10, connectinginner opening17 at the inner surface ofwall15 withouter opening19 at the outer surface ofwall15. The number ofcouplings12, as well as the number and size ofthruster ports18 depends on the desired water pressure and water flow rate. If a water source of only moderate delivery pressure is available, e.g. 5,000-7,000 psi, then relativelyfewer couplings12 andthruster ports18, as well as possibly smallerdiameter thruster ports18 should be used. However, if higher pressure water is supplied, e.g. 10,000-15,000 psi, thenmore couplings12 andthruster ports18 can be utilized. The number ofcouplings12 andthruster ports18, the diameter ofthruster ports18, and the initial water pressure and flow rate are all adjusted to achieve water flow rates throughnozzle blaster24 of 1-10, more preferably 1.5-8, more preferably 2-6, more preferably 2.2-3.5, more preferably 2.5-3, gal/min.
• In the first preferred embodiment illustrated in FIG. 1, the[0034]thruster ports18 are provided as unobstructed openings or holes through the side wall of thethruster coupling12. Theports18 are provided or drilled at an angle so that the exiting pressurized fluid jets in a rearward direction as explained above.
• In the second preferred embodiment illustrated in FIG. 7, the[0035]thruster couplings12 andthruster ports18 are similarly provided as described above shown in FIG. 1, except that the thruster port orports18 include ashutter31. Theshutter31 is preferably an iris as shown in FIG. 7, and shown close-up in FIG. 9. Theshutter31 is actuated by a servo controller32 (pictured schematically in the figures) which is controlled by an operator at the surface via wireline, radio signal or any other suitable or conventional means. Theservo controller32 is preferably provided in the sidewall of thecoupling12 as shown in FIG. 8, or is mounted on the inner wall surface of thecoupling12. Theservo controller32 has a small motor to control or actuate theshutter31 to thereby regulate the diameter or area of theopening34 for thethruster port18. A fullyopen shutter31 results in the maximum possible thrust from the associatedthruster port18 because the maximum area is available for the expulsion of high pressure fluid. An operator can narrow theopening34 by closing theshutter31 to regulate the amount of thrust imparted to the hose assembly by the associatedthruster port18. The smaller diameter theopening34, the less thrust provided by thethruster port18. Although an iris is shown, it will be understood that other mechanisms can be provided for theshutter31 which are conventional or which would be recognized by a person of ordinary skill in the art; e.g. sliding shutter, flap, etc. Theservo controller32 is preferably a conventional servo controller having a servo motor that is controlled in a conventional manner. Servo controllers are generally known or conventional in the art.
• In addition to providing thrust to the hose (and nozzle blaster[0036]24),thruster ports18 equipped withshutters31 can be used to guide or steer thehose assembly10 as it drills a horizontal bore. It will be understood by a person of ordinary skill in the art that during use, thehose assembly10 is very rigid, i.e. it is biased in a straight or linear configuration due to the internal fluid pressure (e.g. 5,000 or 10,000 or 15,000 psi). This is because the internal fluid pressure seeks to expand thehose assembly10 from within, thereby forcing the assembly to remain stiff and straight without bending. By regulating the relative thrust provided bydifferent thruster ports18 at spaced circumferential locations about the hose assembly at a particular axial position along its length, theassembly10 can be steered at that axial location.
• For example, referring to FIG. 8, if thruster port[0037]18aprovides greater thrust than either of ports18bor18c, then thehose assembly10 will be driven in a lateral direction (relative to the hose's longitudinal axis) substantially opposite the position of the thruster port18aas a result of the excess thrust (i.e. direction indicated by arrow B in FIG. 8). The lateral thrust is countered by and must be balanced against the assembly's10 straight and rigid bias (described above) to provide the desired lateral positioning or steering effect. The assembly's straight and rigid bias makes control of theassembly10 via the thrusters easier to achieve because the assembly is constantly trying to right or straighten itself. Therefore, the thrusters'port openings34 can be finely regulated to control the amount of thrust acting against the straightening bias to provide very precise lateral positioning and steering capability for thehose assembly10.
• Likewise, a corresponding lateral thrust can be imparted by either of thruster ports[0038]18band/or18cin the appropriate direction. It will be understood that the relative thrust of all the thrusters located at the same axial position along the length of the hose assembly10 (i.e. all the thrusters in a single thruster coupling12) can be simultaneously regulated in concert to guide the lateral position of thehose assembly10 at that location. By similarly coordinating the relative thrust of all the groups ofthruster ports18 disposed at discrete axial positions along the length of thehose assembly10, an operator can guide or steer theassembly10 as it drills horizontally from the vertical well to thereby provide a specific desired configuration for thehose assembly10 along its entire length as it drills. This way, a horizontal bore having a desired nonlinear shape or overall configuration can be drilled; the horizontal bore need not be straight. Alternatively, if a straight or linear horizontal bore is desired, the hose assembly10 (particularly at or near its distal end where thenozzle blaster24 is located) can be steered to ensure a straight path despite the presence of obstructions or other forces that could divert the blaster's24 path.
• It will be understood that when complex shape or drilling pathway configurations are desired, it would be very difficult for a human operator to properly control and regulate the relative thrust for all of the[0039]thruster ports18 along the hose assembly's length. Therefore, it is desirable and preferred to have theadjustable thruster ports18 controlled by a computer40 that has been programmed with the desired drilling configuration. Means and methods for programming a computer to control a plurality of servo controllers (for regulating shutters31) are conventional, and are well understood by persons of ordinary skill in the art.
• Preferably, the[0040]flexible hose11 is provided with a plurality ofposition indicating sensors35 along its length.Position indicating sensors35 are shown schematically in FIG. 4 attached to thethruster couplings12 andnozzle blaster24. Alternatively, theposition indicating sensors35 can be provided in the coupling walls, or in the hose wall along its length. Theposition indicating sensors35 can emit a radio signal or can be monitored by wireline from the surface to determine the location and configuration of the flexible hose. Theadjustable thruster ports18 can be controlled as described above based on position and configuration information received from theseposition indicating sensors35. Preferably, the computer receives information from theposition indicating sensors35 and regulates the adjustable thrusters based on that information to achieve the desired steering and position control of thehose assembly10 as it drills a horizontal bore.
• FIG. 10 shows an alternative preferred embodiment of the[0041]adjustable thruster ports18. In this embodiment, theadjustable thruster ports18 compriseflap shutters31aadjacent to, and adapted to seal off, theouter openings19 of theports18. In this embodiment, theflap shutters31aare servo controlled similarly as described above, and can be opened or closed to variable degrees as desired to provide a desired amount of thrust. One advantage of this embodiment is that in addition to regulating the flowrate of thejets30, theflap shutters31aalso can be used to regulate the discharge angle β. This embodiment is less preferred because theflap shutters31aare liable to catch on the horizontal bore wall or on some obstruction therein. Further, the flap shutters can inhibit the passage of rearwardly traveling cuttings to exit the horizontal bore as described below.
• FIG. 11 shows yet another alternative preferred embodiment of the invention, where the[0042]thruster ports18 are provided in servo-controlledpivot arms38. In this embodiment, the discharge angle β between the centerline drawn through the exitingwater jet30 and the longitudinal axis of the flexible hose can be regulated. The smaller angle β, the larger axial thrust force vector for a given fluid pressure and discharge rate; conversely, the larger angle β, the smaller axial thrust force vector for the same fluid pressure and discharge rate. Thus, the degree of forward thrust for thehose assembly10 can be controlled for a given fluid pressure and discharge rate by regulating the discharge angle of thewater jets30. This is achieved by controlling thepivot arms38 to provide the desired discharge angle β. Preferably, thepivot arms38 are adjustable to provide a discharge angle in the range of 10° to 90°, 10° to 80°, 15° to 70°, 20° to 60°, 25° to 50°, 30° to 50°, or 40° to 50° in a rearward direction toward the proximal end of thehose assembly10.
• In addition to providing thrust, the[0043]thruster ports18 also provide another important function.Thruster ports18 keep the bore clear behindnozzle blaster24 as the rearwardly jetting high pressure fluid (water) washes the drill cuttings out of the horizontal bore so that the cuttings do not accumulate in the horizontal bore. The high pressure water or aqueous liquid forced through thethruster ports18 also cleans and reams the bore by clearing away any sand and dirt that has gathered behind the advancingnozzle blaster24, as well as smoothing the wall of the freshly drilled bore.
• This is an important feature because, left to accumulate, the cuttings and other debris can present a significant obstacle to horizontal drilling, effectively sealing of already-drilled portions of the horizontal bore around the advancing[0044]hose assembly10. This can make removal of thehose assembly10 difficult once drilling is completed. In a worst case, the remaining debris can cause the horizontal bore to reseal once thehose assembly10 has been withdrawn. By forcing these cuttings rearward to exit the lateral bore, the rearwardly directedwater jets30 ensure the horizontal bore remains substantially open and clear after drilling is completed and thehose assembly10 is removed. By providing thethruster ports18 along substantially the entire length of thehose assembly10, drill cuttings can be driven out of the horizontal bore from great distances into the horizontal bore, preferably at least 50, 100, 200, 250, 300, 350, 400, 500, 1000, or more, feet.
• [0045]Nozzle blaster24 is of any type known in the art, for example, the type shown in FIGS.5A-5B.Nozzle blaster24 comprises a plurality ofholes50 disposed about afront portion46awhich preferably has a substantially domed shape.Holes50 are positioned to form angle θ with the longitudinal axis ofnozzle blaster24. Angle θ is 10°-30°, more preferably 15°-25°, more preferably about 20°.Nozzle blaster24 also comprises a plurality ofholes46b, which are oriented in a reverse or rearward direction on arear portion60 ofnozzle blaster24, the direction and diameter ofholes46bbeing similar to that ofthruster ports18 disposed aroundcouplings12.Holes46bserve a similar function asthruster ports18 to impart forward drilling force tonozzle blaster24 and to wash drill cuttings rearward to exit the horizontal bore. Optionally,front portion46ais rotatably coupled torear portion60, withholes50 oriented at an angle such that exiting high-pressure water imparts rotational momentum tofront portion46a, thus causingfront portion46ato rotate while drilling.Rear portion60 is either fixed with respect tohose11 unable to rotate, or is rotatably coupled tohose11 thus allowingrear portion60 to rotate independently ofhose11 andfront portion46a. In this embodiment, holes46bare oriented at an angle effective to impart rotational momentum torear portion60 upon exit of high-pressure water, thus causingrear portion60 to rotate while drilling.Holes50 and46bcan be oriented such that front and rear portions (46aand60 respectively) rotate in the same or opposite directions during drilling.
• [0046]Thruster ports18 and46bare oriented in a reverse or rearward direction, relative to forward direction A (FIGS. 1 and 4), toward the proximal end of the hose assembly to thrust the nozzle blaster forward to drill the bore. High pressure water is propelled throughthruster ports18 forming highpressure water jets30 which impinge on the walls of the bore at such an angle as to impart drilling force to thenozzle blaster24. Thus, the present invention has great utility at shallow depths where the length (and thereby the weight) of flexible hose in the vertical well is generally insufficient to supply adequate drilling force to thenozzle blaster24 to propel it forward while drilling. As such, the present invention is effectively used to drill horizontal bores at depths of at least, or not more than, 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, or 2000 feet. However, the invented hose assembly can also be advantageously used to drill horizontal bores at greater depths, e.g. 5,000, 8,000, 10,000, or 15,000 feet or greater.
• Although the hereinabove described embodiments of the invention constitute the preferred embodiments, it should be understood that modifications can be made thereto without departing from the scope of the invention as set forth in the appended claims.[0047]

Claims (34)

What is claimed is:

1. A flexible hose assembly for horizontal well drilling comprising a flexible hose, said flexible hose assembly having a proximal end and a distal end, said proximal end being located rearward of said distal end, said flexible hose having a plurality of thruster ports disposed therein with at least one of said thruster ports being disposed rearward of said distal end of said flexible hose assembly, at least one of said thruster ports being adapted to direct a jet of pressurized fluid in a direction such that a centerline drawn through said jet forms an acute discharge angle with the longitudinal axis of said flexible hose rearward from the location of said thruster port, at least one of said thruster ports being an adjustable thruster port.

2. A flexible hose assembly according toclaim 1, said flexible hose further comprising a plurality of flexible hose sections and at least one thruster coupling, said thruster coupling being joined to adjacent flexible hose sections, said adjustable thruster port being disposed in said thruster coupling.

3. A flexible hose assembly according toclaim 2, further comprising a plurality of said thruster couplings, each thruster coupling having at least one adjustable thruster port.

4. A flexible hose assembly according toclaim 1, said hose comprising flexible hydraulic hose rated to withstand at least 5,000 psi.

5. A flexible hose assembly according toclaim 3, said thruster couplings being spaced at least 10 feet apart from each other in said hose.

6. A flexible hose assembly according toclaim 3, each of said thruster couplings comprising two threaded end sections and a middle section, each of said end sections adapted to mate with a pressure fitting attached to a section of said flexible hose.

7. A flexible hose assembly according toclaim 1, said adjustable thruster port having a variable opening area, said jet being discharged from said thruster port through said opening.

8. A flexible hose assembly according toclaim 1, said adjustable thruster port having a variable discharge angle.

9. A flexible hose assembly according toclaim 7, said adjustable thruster port comprising a shutter for regulating the area of said opening of said thruster port.

10. A flexible hose assembly according toclaim 9, said shutter being an iris.

11. A flexible hose assembly according toclaim 9, further comprising a servo controller for actuating said shutter to thereby regulate said opening area of said adjustable thruster port.

12. A flexible hose assembly according toclaim 11, said servo controller being controlled via wireline or radio signal.

13. A flexible hose assembly according toclaim 2, said thruster coupling comprising 2-8 thruster ports evenly spaced around the circumference of said thruster coupling.

14. A flexible hose assembly according toclaim 8, said adjustable thruster port comprising a servo-controlled pivot arm, said pivot arm being adjustable to regulate said discharge angle.

15. A flexible hose assembly according toclaim 14, said pivot arm being adjustable to provide said discharge angle in the range of 10° to 90° in a rearward direction toward said proximal end of said hose assembly.

16. A flexible hose assembly according toclaim 1, said flexible hose being 400-2000 feet in length.

17. A flexible hose assembly according toclaim 1, further comprising a nozzle blaster joined to said flexible hose at said distal end of said hose assembly, at least one of said thruster ports being disposed in said flexible hose rearward of the point where said flexible hose joins said nozzle blaster.

18. A method of horizontal well drilling comprising the following steps:

a) providing a flexible hose assembly comprising a flexible hose having a proximal end and a distal end, said proximal end being located rearward of said distal end, said flexible hose having a plurality of thruster ports disposed therein with at least one of said thruster ports being disposed rearward of said distal end of said flexible hose, at least one of said thruster ports adapted to direct a jet of pressurized fluid in a direction such that a centerline drawn through said jet forms an acute discharge angle with the longitudinal axis of said flexible hose rearward from the location of said thruster port, at least one of said thruster ports being an adjustable thruster port;

b) lowering said flexible hose assembly to a desired depth in a vertical well, and redirecting said flexible hose assembly along a direction at an angle to the longitudinal axis of said vertical well;

c) forcing at least 2,000 psi fluid through said flexible hose and said thruster ports in said flexible hose; and

d) drilling a horizontal bore into the earth's strata adjacent said vertical well.

19. A method according toclaim 18, said adjustable thruster port having a variable opening area, said jet being discharged from said thruster port through said opening.

20. A method according toclaim 18, said adjustable thruster port having a variable discharge angle.

21. A method according toclaim 19, said adjustable thruster port comprising a shutter for regulating the area of said opening of said thruster port.

22. A method according toclaim 21, said shutter being an iris.

23. A method according toclaim 21, further comprising a servo controller for actuating said shutter to thereby regulate said opening area of said adjustable thruster port.

24. A method according toclaim 23, said servo controller being controlled via wireline or radio signal.

25. A method according toclaim 20, said adjustable thruster port comprising a servo-controlled pivot arm, said pivot arm being adjustable to regulate said discharge angle.

26. A method according toclaim 25, said pivot arm being adjustable to provide said discharge angle in the range of 10° to 90° in a rearward direction toward said proximal end of said hose assembly.

27. A method according toclaim 18, further comprising the step of drilling a horizontal bore from a vertical well at a depth of 50-2000 feet.

28. A method according toclaim 18, further comprising the step of withdrawing said hose assembly from said horizontal bore, and during said withdrawing step forcing fluid through said thruster ports to clean and ream said horizontal bore.

29. A method according toclaim 18, said flexible hose assembly further comprising a nozzle blaster attached to said flexible hose at said distal end thereof, at least one of said thruster ports being disposed in said flexible hose rearward of the point where said flexible hose joins said nozzle blaster.

30. A flexible hose assembly according toclaim 1, said fluid being aqueous liquid.

31. A method according toclaim 18, said fluid being aqueous liquid.

32. A flexible hose assembly according toclaim 1, further comprising at least one position indicating sensor.

33. A flexible hose assembly according toclaim 32, comprising a plurality of said position indicating sensors provided along the length of said flexible hose assembly.

34. A flexible hose assembly for horizontal well drilling comprising a flexible hose, said flexible hose assembly having a proximal end and a distal end, said proximal end being located rearward of said distal end, said flexible hose having a plurality of thruster ports disposed therein with at least one of said thruster ports being disposed rearward of said distal end of said flexible hose assembly, at least one of said thruster ports being adapted to direct a jet of pressurized fluid in a direction such that a centerline drawn through said jet forms an acute discharge angle with the longitudinal axis of said flexible hose rearward from the location of said thruster port, each of said thruster ports having an opening with a cross-sectional area selected from the group consisting of closed polygons, closed curvilinear shapes, and shapes having at least one linear edge.

Images