Method and system for reducing friction in radial and jet working operations

Abstract

A method for reducing friction in radial drilling applications is disclosed. The method involves coating the interior of the deflector shoe (52) with at least one lubricant (70). Lubrication of the deflector shoe (52) may be accomplished by applying a dry lubricant to the interior of the deflector shoe, allowing the dry lubricant to harden, and applying a wet lubricant on the hardened dry lubricant. The inner surface (80) of the deflector shoe (52) may be roughened prior to application of the lubricant. The method may also include coating the hose (54) and / or the spray nozzle (64) through the coated interior of the deflector shoe (52). The method may also include coating a component of the milling cutter, and passing the component of the milling cutter through the coated interior of the deflector shoe. An apparatus for reducing friction in radial drilling applications is also disclosed.

Description

Technical Field

[0001] The present invention relates to operating downhole oil and gas well equipment from the surface. More particularly, the present invention relates to deflector shoes for use in downhole operations. Even more particularly, the present invention relates to reducing friction in deflector shoes. Background Art

[0002] In hydrocarbon drilling operations of the type where the drill string is redirected to laterally penetrate the side of the wellbore, a downhole device known as a "deflector shoe" is often used that is attached to the lower end of the work string or production tubing to "deflect" the casing milling and drill string laterally. When more than one lateral borehole is to be drilled from the wellbore, the deflector device is also often reoriented by manipulating the work string or production tubing (hereinafter generally referred to as "tubing" or "production tubing") from the surface, for example, by rotating and / or raising and lowering the tubing to operate a deflector rotating device. These methods require expensive, slow and / or difficult to move machinery on the surface to raise and lower the entire production tubing.

[0003] One such indexing deflector arrangement is shown and described in Applicant's US Patent No. 7,669,672.

[0004] 1 schematically illustrates such a prior art deflector assembly, which generally includes a retractable tubing anchor 22, a deflector shoe 20, a deflector tool 18, and a pipe segment or connector or landing profile 17 for connecting the deflector shoe to the production tubing 14. Milling tools and drilling tools (e.g., injection nozzles 16a) are lowered via the coiled tubing string 16 into operative engagement with the deflector shoe 20. The tubing 14 may also be connected directly to the deflector shoe 20.

[0005] The details of such a deflector assembly are known to those skilled in the art and are not necessary for understanding the present invention. However, for context, the tubing anchor 22 is a device that houses a slide that is biased outward to contact and "dig into" the sidewall of the wellbore casing 12. The tubing anchor 22 is operated mechanically by rotating the production tubing 14 from the surface or hydraulically by fluid pressure. The deflector shoe 20 is a tubular member having a curved channel or passage 20a milled through the tubular member from its upper end, the channel entering the upper end of the deflector shoe 20 in an orientation parallel to the long axis of the deflector shoe and exiting from a side of the deflector shoe that is perpendicular to the long axis. The shoe 20 is connected to the indexer 18 and the tubing anchor 22 at its lower end and to the production tubing 14 at its upper end. The shifting tool 18 is connected to the deflector shoe 20 to reorient the deflector shoe 20 in the wellbore 10 in response to a combination of up and down reciprocating motion and rotation of the production tubing 14, and thereby to change the radial direction along which the casing milling and drilling drilling apparatus (such as 16a) is reoriented by the deflector shoe 20 to engage the wellbore casing 12 and the surrounding formation 11.

[0006] The applicant has developed a downhole tubing displacement tool and method, as shown in U.S. Patent No. 8,813,856, which overcomes the problems of the prior art associated with the reorientation of the deflector device, thereby reducing the time, expense and difficulty associated with the reorientation. This is achieved by utilizing hydraulic pressure and a tool that rotates the diverter shoe via an indexer.

[0007] Various patents related to radial drilling and jet drilling applications have been issued in the past, including many patents owned by the present applicant. For example, U.S. Patent No. 9,145,738, issued on September 29, 2015, describes a method and apparatus for forming a borehole. In particular, the patent discloses a jet nozzle for forming a borehole or for cleaning other tubular formations, the jet nozzle having a vibration inducing mechanism that maximizes the penetration rate and expands the borehole diameter. The vibration inducing mechanism can be an internal turbine in response to the flow of pressurized jet fluid through the nozzle. The nozzle has a forward opening that defines an axial vortex spray pattern for the forward-pointing jet portion of the fluid leaving the nozzle. The nozzle can also have a tip adapted to penetrate the formation. The vibration also reduces friction between the fluid supply hose and the borehole ejected by the nozzle through the formation. A system for forming a borehole with a jet nozzle and a method for forming a borehole are also disclosed.

[0008] U.S. Patent No. 8,590,637, issued on November 26, 2013, describes an apparatus and method for controlling the feed rate of a high-pressure hose in a jet drilling operation. Specifically, the patent discloses a jet hose that is delivered downhole and retracted at the end of a tubing string (coiled tubing) for jetting lateral drilling from the main wellbore. The apparatus allows the operator to sense the speed at which the jet hose and nozzle penetrate the formation and adjust the feed rate of the coiled tubing string accordingly, thereby optimizing the direction and length of the lateral drilling relative to the main wellbore.

[0009] The first step in the two-step process of radial jet drilling is a casing milling process that utilizes a system as described above and in Figure 1 or a modification thereof. This process is critical to ensuring that the nozzles of the jet drilling system can exit the casing to begin cutting the formation.

[0010] The second step in the radial jet drilling process is the water jet cutting or jetting process. In this step, the hose and jet nozzle assembly passes through the deflector shoe and changes its direction to horizontal before exiting the casing and cutting through the formation material.

[0011] In Figure 2, it can be seen how an injection nozzle 22 connected to a flexible hose 24 extends through the deflector shoe 20. As the injection nozzle 22 is pushed through the interior of the deflector shoe 20, it necessarily comes into contact with the wall of the deflector shoe 20. As shown in Figure 2, the flexible hose is connected to a plurality of nipples 28 and ultimately to a coiled tubing string 26 that enters the casing 12.

[0012] Figure 3 shows a prior art example of a jar nozzle subassembly of the type that may be used in radial jet drilling operations. As can be seen in Figure 3, the jar nozzle subassembly 30 includes a flexible hose 24 connected to a hose crimp 32, a turbine jet nipple 34, a rotor jet nipple 36, and finally the jet nozzle 22. Many different types of jet nozzles and assemblies may be used in radial jet drilling operations, which result in different amounts of friction between the respective assemblies and the inner wall of the deflector shoe.

[0013] Ultimately, friction between components moved by the deflector shoes results in reduced useful life of such components and increased power requirements for the motors and pumps utilized in these operations.

[0014] It is therefore an object of the present invention to provide a method of reducing friction in radial drilling and jet drilling applications.

[0015] It is another object of the present invention to provide a method of reducing power requirements in radial jet drilling and jet drilling applications.

[0016] It is another object of the present invention to provide a method of extending the useful life of components used in radial drilling and jet drilling applications.

[0017] It is another object of the present invention to provide a method of reducing the cost and time associated with radial drilling and jet drilling applications.

[0018] It is yet another object of the present invention to provide a relatively simple and inexpensive method for reducing friction in radial drilling and jet drilling applications.

[0019] Finally, it is an object of the present invention to provide a method for reducing friction in radial drilling and jet drilling applications that can be applied in the field.

[0020] These and other objects and advantages of the present invention will become apparent from a reading of the accompanying description and the appended claims. Summary of the invention

[0021] The present invention is a method for reducing friction in radial drilling applications, the method comprising coating the interior of a deflector shoe with at least one lubricant. In an embodiment, the method comprises applying a wet lubricant to the wellbore and to the interior of the deflector shoe, wherein the wet lubricant is a liquid mixed with a friction reducer. The coating step may also include: applying a dry lubricant on the interior of the deflector shoe; hardening the applied dry lubricant; and applying a wet lubricant on the hardened dry lubricant.

[0022] In an embodiment, the method further comprises the steps of: coating a hose and / or a spray nozzle with at least one lubricant; and passing the hose and / or the spray nozzle through the coated interior of the deflector shoe.

[0023] In an embodiment, the coating step comprises coating the contact surface between the deflector shoe and the hose and / or spray nozzle.

[0024] In an embodiment, the method further comprises the steps of: coating a component of the milling cutter with at least one lubricant; and passing the coated component of the milling cutter through the coated interior of the deflector shoe.

[0025] In one embodiment, the lubricant is selected from the group consisting of tire shine, fluoropolymer coating, tungsten disulfide coating, Never Seez ® , polytetrafluoroethylene, molybdenum disulfide, graphite, silicone and epoxy resin.

[0026] In one embodiment, the method further comprises the step of roughening the interior of the deflector shoe prior to the coating step. The roughening may be accomplished by sanding the interior of the deflector shoe or by dimpling the surface in another manner.

[0027] The present invention is also a method for reducing friction in a radial drilling application, the method comprising: roughening the interior of a deflector shoe; coating the interior of the deflector shoe with at least one lubricant; passing a hose through the coated interior of the deflector shoe; and applying a wet lubricant to the deflector shoe during the passing step.

[0028] In an embodiment, the at least one lubricant applied to the deflector shoe comprises a hardened dry lubricant, wherein a layer of wet lubricant is on the hardened dry lubricant.

[0029] In one embodiment, the method further comprises the step of coating the exterior of the hose with at least one lubricant prior to the passing step.

[0030] In an embodiment, the method further comprises the steps of: coating a spray nozzle with at least one lubricant; and passing the spray nozzle through the coated interior of the deflector shoe.

[0031] In an embodiment, the method further comprises the steps of: coating a component of the milling cutter with at least one lubricant; and passing the component of the milling cutter through the coated interior of the deflector shoe.

[0032] The at least one lubricant may be selected from the group consisting of tire shine, fluoropolymer coating, tungsten disulfide coating, polytetrafluoroethylene, molybdenum disulfide, graphite, silicone, epoxy, and Never Seez ® .

[0033] In one embodiment, the step of applying a wet lubricant is continuous during the drilling process, wherein the wet lubricant is a liquid mixed with a friction reducer.

[0034] The present invention is also an apparatus for reducing friction in radial drilling applications. The apparatus comprises: a deflector shoe having an inner surface; and at least one lubricant applied to the inner surface of the deflector shoe. In one embodiment, the inner surface of the deflector shoe is roughened prior to applying the at least one lubricant. In one embodiment, the at least one lubricant is a wet lubricant. In another embodiment, the at least one lubricant is a dry lubricant. In a preferred embodiment, the at least one lubricant is a hardened dry lubricant, wherein the wet lubricant layer is on the hardened dry lubricant. The at least one lubricant may be selected from the group consisting of: tire shine, fluoropolymer coating, tungsten disulfide coating, polytetrafluoroethylene, molybdenum disulfide, graphite, silicone, epoxy, and NeverSeez ® .

[0035] The foregoing section is intended to specifically describe the preferred embodiment of the present invention. It should be understood that this preferred embodiment can be modified within the scope of the present claims. Therefore, this section should not be interpreted as limiting the broad scope of the present invention in any way. The present invention should only be limited by the following claims and their legal equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] FIG. 1 is a schematic diagram showing a prior art indexing deflector assembly having a deflector shoe.

[0037] 2 is a schematic diagram showing the jet drilling process of a jet nozzle passing through a deflector shoe.

[0038] FIG. 3 is an example of a prior art jar nozzle subassembly as used in radial jet drilling operations.

[0039] Figure 4 The method and system of the present invention are shown.

[0040] Figure 5 Graph 1 is shown, where test results show that as the internal pressure of the hose increases, the force required to pull the hose through the boot also increases.

[0041] Figure 6 Graph 2 is shown, in which test results illustrate how the required force varies depending on different coatings of the hose.

[0042] Figure 7 Figure 3 shows the test results of a hose coated with Never Seez ® is provided.

[0043] Fig. 8A and Figure 8B The interface between the surface of the hose and the surface of the deflector shoe is shown at a microscopic level.

[0044] Figure 8C The interface between the surface of the hose and the surface of the deflector shoe is shown when the surface of the hose and the surface of the deflector shoe have been lubricated and the surface of the deflector shoe has been roughened. DETAILED DESCRIPTION

[0045] refer to Figure 4 , a diagram showing the system and method of the present invention. A deflector shoe 52 is associated with a casing 62 of a wellbore. The deflector shoe 52 has an interior through which a flexible hose 54 moves. The flexible hose 54 has an injection nozzle 64 at its end. Figure 4 Also shown is a work tubing 53 having a coiled tubing 56 therein. This is connected to a flexible hose 54 via a connector 58. Figure 4 Also shown is a centralizer 60 which is used to position the deflector shoe within the casing 62.

[0046] The interior of the deflector shoe 52 is provided with a lubricant coating 70. Figure 4 As seen in FIG. 5 , a lubricant coating 70 is disposed on the inner surface of the deflector shoe 52, and importantly, on the contact surfaces between the flexible hose 54, the spray nozzle 64 and the interior of the deflector shoe 52. The lubricant coating 70 may include a wet lubricant or a dry lubricant, or a combination of both.

[0047] In the case of a wet lubricant, the lubricant coating 70 can be manually applied by workers on site or on site. In the case of a dry lubricant, the lubricant coating is preferably sprayed or otherwise manually applied to the interior of the deflector shoe 52.

[0048] As used herein, the term "wet lubricant" may be any lubricant that remains in a wet, liquid, or non-hardened state. For example, wet lubricants include less viscous lubricants such as water and relatively more viscous liquids such as those having a grease or paste consistency. A wet lubricant may also be a combination of wet lubricants, such as water or other liquids with a friction reducer introduced into the water. The friction reducer may be a polyacrylamide-based polymer.

[0049] The term "dry lubricant" includes those lubricants that harden, either by heat treatment or by the nature of the lubricant. In the hardened state, these dry lubricants result in a surface having a lower coefficient of friction than the bare metal of the deflector shoe or other equipment. The dry lubricant may be applied to the equipment and heat treated or otherwise allowed to harden prior to introduction into the wellbore, resulting in the lubricant remaining on the equipment during operations.

[0050] In the present invention, the flexible hose 54 and the spray portion 64 may also be coated with the same or additional lubricant coating to further reduce friction between the components. It is also within the concept of the present invention that the components of the milling cutter may be coated with lubricant before passing through the lubricated deflector shoe 52.

[0051] In a preferred embodiment of the present invention, both the wellbore (casing 62) and the drilling equipment (i.e., the flexible hose 54, the jet 64, and the milling cutter) are lubricated. A wet lubricant is applied to the borehole from the ground. The wet lubricant applied to the borehole is preferably a liquid (e.g., brine or water) containing a powder and is applied continuously during the drilling operation. The wet lubricant may also include a friction reducer added to a liquid treatment fluid that is continuously pumped into the wellbore.

[0052] In one embodiment, a dry lubricant is applied to the drilling equipment and deflector shoe, ensuring complete coverage of the surface. Epoxy based and spray applied lubricants can be applied. Once the dry lubricant hardens, a wet lubricant (such as a grease type lubricant) is preferably applied over the hardened dry lubricant. It has been found that this additional application of lubricant results in the lubricant remaining on the equipment longer.

[0053] A variety of different commercially available lubricants can be utilized in the systems and methods of the present invention, including tire shine, fluoropolymer coatings, tungsten disulfide coatings, polytetrafluoroethylene, molybdenum disulfide, graphite, silicone, epoxy, and NeverSeez ® Commercially available lubricants may also be modified by adding substances to increase lubricity.

[0054] Tire shiners are a family of products that use special polymer technology to create a shine on the tire surface. This polymer compound is formulated to not only make tires look good (due to the shine), but also protect them from harmful UV rays, dirt, and other contaminants picked up on the road surface. Typically, tire shiners are silicone-based lubricants.

[0055] Never-Seez ® The product line (provided by BOSTIK) covers a range of anti-seize compounds to meet a wide range of anti-seize, anti-wear and lubrication applications. Special greases are entrained with specific particles (mainly metals) to protect parts even in high temperature, high pressure and corrosive environments, allowing parts to work longer with less wear. Not all compounds are suitable for every application. Known Never-Seez ® The lubricant contains graphite, copper flakes, aluminum powder and zinc oxide.

[0056] Experiments by the present inventors have found that treating the contact surface between the hose and the deflector boot with a lubricant helps to significantly reduce the force required to pull the hose through the deflector boot. This in turn reduces the required propulsion force required to pull the hose from the nozzle and the required flow rate of the nozzle itself. It has been found that the maximum force required to pull a 5600 psi pressurized hose through the deflector boot is reduced by 65%, from 25 lbft for a dry hose to 10 lbft for a hose coated with tire shine or oil through a hose coated with Never Seez. ® of the boot's 8 lbft.

[0057] The inventors conducted experiments utilizing a combination of wet lubricants and are described in detail below. First, a pull-through boot test was performed. Specifically, this tests the force required to pull a pressurized hose through a boot with different surface conditions. The test was performed by varying the amount of pressure under different surface conditions to analyze how much force is required to pull the hose through the deflector boot. The hose was placed between two steel deflector boots. The hose was pulled out at a continuous rate and the maximum force required was recorded. The test was performed under various hose conditions: (1) dry hose, (2) hose wetted with water, (3) dry hose passing through a boot coated with a commercially available lubricant, and (4) oily hose passing through a boot coated with a commercially available lubricant. A commercially available hose was used. In this test, the commercially available lubricant was Never Seez ® .

[0058] The results of the test are shown in Figure 1 (see Figure 5 ). Graph 1 shows that as the internal pressure of the hose increases, the force required to pull the hose through the boot also increases. The maximum hose pressure applied was 5600 psi. However, by lubricating the surface of the hose, from a dry hose to an oily hose and a boot coated with a commercially available lubricant, the required pulling force was reduced by about 50%.

[0059] By reducing friction on the hose, more force can be effectively transferred. Additional experiments were conducted with different coatings. Figure 6 ) shows three additional conditions, namely, (5) the hose coated with tire shine passes through the deflector boot, (6) the hose coated with tire shine / oil passes through the deflector boot, and (7) the hose coated with tire shine / oil passes through the Never Seez ® It was found that for condition (7), i.e., the hose coated with tire shine / oil passed through the boot coated with Never Seez ® boot, the maximum force required to pull a 5600 psi hose through the deflector boot is down from 8.4 lbft at the tire.

[0060] Use Never Seez ® Coating the hose also results in a difference in the average force required to pull the hose through the deflector shoe, as shown in Figure 3 (see Figure 7 ).

[0061] The experiments detailed above were conducted using a wet lubricant that can be applied manually. Additional experiments have shown that dry lubricants may also adhere to the interior of the deflector shoe over time, thereby maintaining reduced friction. These dry lubricants can be sprayed or otherwise applied manually and allowed to dry and / or heat treat, and can also be used for longer periods of time. In terms of the difference in pull force, the inventors expect similar or better results to be obtained with dry lubricants.

[0062] The present invention may also include the step of roughening the surface of the deflector shoe 52 , or in the case of an apparatus or system, providing a roughened deflector shoe 62 . Fig. 8A The interface between the metal surface 80 of the deflector shoe 62 and the irregular surface 82 of the rubber hose is shown at a microscopic level. Figure 8B The interface is shown when the hose is tensioned and pressurized. Figure 8B In FIG. 8 , it can be seen how the flattened hose surface 82 bears against the metal surface 80, which can create a vacuum between the surfaces and cause higher drag. A vacuum is created between the contact points between the hose and the metal surface 80. The increased contact area between the surfaces can also result in higher drag.

[0063] As a solution to this problem, in the present invention, the initially smooth and shiny metal surface of the deflector shoe can be roughened and coated with lubricant prior to installation. Roughening can be accomplished in a variety of ways, including sanding with various grades of sandpaper. The roughened surface 80 can be created by dimpling the surface in another way.

[0064] The resulting roughened surface 80 is Figure 8C 80. As can be seen, the role of the roughened surface 80 is to create a channel for releasing air or fluid and thus relieving the vacuum. It has been found that this reduces the drag on the hose. Wet lubricants and / or dry lubricants applied to the rigid hose reduce deformation, while wet lubricants applied to the wellbore further reduce hose deformation and friction between surfaces. The roughened surface 80 also results in enhanced application and retention of the lubricant.

[0065] The method and system of the present invention allow for a significant reduction in friction between drilling components and deflector shoes. This in turn increases the useful life of components associated with these operations. Additionally, the reduced friction allows for a reduction in the power requirements of equipment used to run tools in drilling operations, thereby helping to reduce costs associated with these operations.

[0066] The foregoing disclosure and description of the present invention are illustrative and explanatory thereof. Various changes may be made to the details of the structures shown within the scope of the present invention without departing from the true spirit of the invention.

Claims

1. A method for reducing friction in a radial drilling application, the method comprising: The interior of the deflector shoe is coated with at least one lubricant.

2. The method according to claim 1, further comprising the steps of: A wet lubricant is applied to the wellbore and the interior of the deflector shoe, the wet lubricant comprising a liquid mixed with a friction reducer.

3. The method according to claim 1, wherein the coating step comprises: applying a dry lubricant on an interior of the deflector shoe; hardening the applied dry lubricant; as well as Apply wet lubricant over hardened dry lubricant.

4. The method according to claim 1, further comprising: coating the hose with at least one lubricant; as well as The hose is passed through the coated interior of the deflector shoe.

5. The method according to claim 1, further comprising: coating the spray nozzle with at least one lubricant; as well as Pass the spray nozzle through the coated interior of the deflector shoe.

6. The method according to claim 1, further comprising: coating components of the milling cutter with at least one lubricant; as well as Passing the component of the milling cutter through the coated interior of the deflector shoe.

7. The method of claim 1, wherein the at least one lubricant is selected from the group consisting of tire shine, fluoropolymer coatings, tungsten disulfide coatings, polytetrafluoroethylene, molybdenum disulfide, graphite, silicone, epoxy, and Never Seez ® .

8. The method according to claim 1, further comprising the steps of: The interior of the deflector shoe is roughened prior to the coating step.

9. The method of claim 8, the roughening step comprising sanding the interior of the deflector shoe.

10. A method for reducing friction in a radial drilling application, the method comprising: roughening the interior of the deflector boot; coating an interior of the deflector shoe with at least one lubricant; passing a hose through the coated interior of the deflector shoe; as well as A wet lubricant is applied to the deflector shoe during the threading step.

11. The method of claim 10, wherein the at least one lubricant applied to the deflector shoe comprises a hardened dry lubricant, wherein the wet lubricant layer is on the hardened dry lubricant.

12. The method according to claim 10, further comprising the steps of: The exterior of the hose is coated with at least one lubricant prior to the threading step.

13. The method according to claim 10, further comprising the steps of: coating the spray nozzle with at least one lubricant; and Pass the spray nozzle through the coated interior of the deflector shoe.

14. The method according to claim 10, further comprising the steps of: coating components of the milling cutter with at least one lubricant; and Passing the component of the milling cutter through the coated interior of the deflector shoe.

15. The method of claim 10, wherein the at least one lubricant is selected from the group consisting of tire shine, fluoropolymer coatings, tungsten disulfide coatings, polytetrafluoroethylene, molybdenum disulfide, graphite, silicone, epoxy, and Never Seez ® .

16. The method of claim 10, wherein the step of applying a wet lubricant is continuous during the drilling process, wherein the wet lubricant is a liquid mixed with a friction reducer.

17. An apparatus for reducing friction in radial drilling applications, the apparatus comprising: a deflector shoe having an inner surface; At least one lubricant applied to an inner surface of the deflector shoe.

18. The apparatus of claim 17, wherein an inner surface of the deflector shoe is roughened prior to applying the lubricant.

19. The apparatus of claim 17, the at least one lubricant comprising a hardened dry lubricant, wherein the wet lubricant layer is on the hardened dry lubricant.

20. The apparatus of claim 17, wherein the at least one lubricant is selected from the group consisting of tire shine, fluoropolymer coatings, tungsten disulfide coatings, polytetrafluoroethylene, molybdenum disulfide, graphite, silicone, epoxy, and Never Seez ® .

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