A device for reducing friction in small-hole coiled tubing drilling and a method for using the same

Abstract

The present invention discloses a device for reducing frictional resistance in small-bore continuous tubing drilling and a method for using the device, and belongs to the technical field of petroleum drilling. The device includes a hydraulic oscillator and a free-limiting spiral ball straightener; the hydraulic oscillator is arranged at the lower part of the hand-dropping tool; the free-limiting spiral ball straightener is arranged at intervals in the inclined well section, including a straightener body and a free-limiting fixing device coaxially arranged at both ends of the straightener body, the axial ends of the straightener body are inner cone structures, and the connecting end of the free-limiting fixing device is an outer cone structure, and the two are plug-fitted, and the straightener body and the free-limiting fixing device are both provided with a center hole for accommodating the continuous tubing to pass through. The present invention utilizes a hydraulic oscillator and a free-limiting spiral ball straightener to solve the problems of difficulty in carrying sand, large frictional resistance, and severe blocking in continuous tubing drilling operations.

Description

Technical Field

[0001] The invention relates to the field of petroleum drilling, and in particular to a device for reducing friction in small-hole continuous pipe drilling and a use method thereof. Background Art

[0002] With the continuous development of oil fields, the number of extended-reach wells, low-yield and low-efficiency wells in oil fields, long-stopped wells, and casing-damaged wells has increased year by year, which has put forward a great challenge to the development and sustained stable production of oil fields. Large-scale old wells are in urgent need of production increase and recovery management. The use of old well sidetracking technology to redevelop oil reservoirs has outstanding advantages such as extending the service life of old wells, restoring and improving the development well network, and improving the recovery rate. It is an effective means to realize the utilization of remaining reserves. At the same time, with the requirements of safety and environmental protection, the wellbore is also transitioning from 8-1 / 2" wellbore to 6" or even smaller wellbore.

[0003] Conventional drilling tools are connected by drill rod units one by one. The length of each drill rod unit is about 9.5m. There are couplings between the drill rod units, and the installation and fixation of the stabilizer is relatively easy. Unlike conventional drill rods, the coiled tubing is a continuous pipe column without couplings and cannot use the general stabilizer structure. Small wells use coiled tubing for drilling operations. The coiled tubing can only slide forward and cannot rotate. There is no suitable stabilizer, which causes problems such as difficulty in carrying sand, high friction, and serious obstruction. Only by replacing the coiled tubing with 2-7 / 8" drill rods or 3-1 / 2" drill rods can the lower drilling work be completed.

[0004] At present, the drilling technology of 2-7 / 8" drill pipe or 3-1 / 2" drill pipe used in the side drilling of 5-1 / 2" casing old wells is relatively mature, and the side drilling technology of the coiled tubing old wells with windows is in the research and test stage. The use of coiled tubing to drill cement plugs in the 5-1 / 2" casing of the large-displacement directional well has not been applied due to the large friction resistance. Therefore, a device for reducing friction resistance in small-hole coiled tubing drilling is urgently needed to solve the problem of large friction resistance and serious blocking. Summary of the invention

[0005] The present invention aims to solve the problems of difficulty in carrying sand, large friction and serious blocking in the prior art of coiled tubing drilling operations, and proposes a device for reducing friction in small-bore coiled tubing drilling and a method for using the device. The device and the method can reduce blocking in the process of small-bore coiled tubing drilling, thereby achieving the purpose of safe and smooth operation.

[0006] In order to achieve the above-mentioned object of the invention, the technical solution of the present invention is as follows:

[0007] A device for reducing friction resistance in small-bore coiled tubing drilling, characterized in that it includes a hydraulic oscillator and a free-limiting spiral ball centralizer; the hydraulic oscillator is arranged at the lower part of the hand-dropping tool, and is used to make the drill tool vibrate to prevent the front-end tool from sticking; the free-limiting spiral ball centralizer is arranged at intervals in the inclined well section, and includes a centralizer body and free-limiting fixing devices coaxially arranged at both ends of the centralizer body, the axial ends of the centralizer body are inner cone structures, and the connecting end of the free-limiting fixing device is an outer cone structure, and the two are matched by plugging, and the centralizer body and the free-limiting fixing device are both provided with a center hole for accommodating the passage of the coiled tubing.

[0008] Furthermore, the centralizer body is provided with a spiral flow channel and a centralizer wing, and the spiral flow channel and the centralizer wing are evenly distributed on the outer surface of the centralizer body.

[0009] Furthermore, a rigid ball groove is provided on the wing of the centralizer, and rigid balls are installed in the rigid ball groove. The number of rigid balls in each rigid ball groove is 4.

[0010] Furthermore, the rigid ball groove is a half-open structure, and a cross cover plate is fixedly provided at the open end of the rigid ball groove, and a long groove for limiting the exposure of the rigid ball portion is provided on the cross cover plate.

[0011] Furthermore, the free limiting fixing device adopts a half-type structure, including two semi-circular arc blocks that can be spliced ​​into a complete column, and the joint of the two semi-circular arc blocks is fixed with hexagonal bolts.

[0012] Furthermore, the continuous tube and the center hole on the free-limiting spiral ball centralizer are interference fit.

[0013] Furthermore, the inner cone structure and the outer cone structure are both at an angle of 60 degrees.

[0014] Furthermore, the overall length of the free-limiting spiral ball centralizer is 110 mm, the inner diameter of the centralizer body is 74 mm, and the outer diameter is 110 mm.

[0015] Furthermore, the spiral flow channel is 22 mm wide, 10 mm deep, and has an axial angle of 30° with the centralizer body; the centralizer wing is 30 mm wide, 10 mm high, and has an axial angle of 30° with the centralizer body.

[0016] The present invention also provides a method for using a device for reducing friction in slim-hole coiled tubing drilling, comprising the following steps:

[0017] Step 1: Determine the drilling tool assembly, including drill bit, single-bend screw, non-magnetic pressure-bearing drill pipe, directional tool, hand-drop tool, and hydraulic oscillator;

[0018] Step 2: Connect the drill bit, single-bend screw, non-magnetic pressure-bearing drill pipe, directional tool, and hand-drop tool in sequence according to the drilling tool assembly, and start entering the wellbore;

[0019] Step 3: Connect the hydraulic vibrator and enter the wellbore;

[0020] Step 4: Connect the upper and lower non-rotating joints and connectors, and seat the elevators;

[0021] Step 5: insert a certain number of centralizer bodies into the coiled tubing as required;

[0022] Step 6: Connect the connector to the coiled tubing, open the elevator, place the elevator between the connector and the centralizer body, and start drilling;

[0023] Step 7: Lift up the bottom centralizer body, fix the free limit fixture on the coiled tubing, so that the lower end of the centralizer body sits in the free limit fixture; then install and fix the free limit fixture on the upper end of the centralizer body, so that it sits on the upper end of the centralizer body, and fix it with screws;

[0024] Step 8: Continue drilling and install the free-limit rigid ball centralizer as required;

[0025] Step 9: Drill down to the bottom, start the pump, and perform drilling operations as required;

[0026] Step 10: After the operation is completed, pull the drill out. When you see the free-limit rigid ball centralizer, first remove the fixed free-limit fixture on the upper end of the centralizer body, and then remove the fixed free-limit fixture on the lower end of the centralizer body; continue to pull the drill out and remove the free-limit fixture on the free-limit rigid ball centralizer until the coiled tubing is pulled out. Remove the coiled tubing and continue to pull the drill out to pull out the lower tool string.

[0027] In summary, the present invention has the following advantages:

[0028] 1. The present invention uses mechanical tools to reduce resistance, and installs a hydraulic oscillator at the bottom of the hand-release tool. The hydraulic oscillator is used to vibrate the drill bit to prevent the tool with a larger front end from getting stuck. A free-limiting spiral ball straightener is placed every 150 meters or so in the inclined well section to increase the rigidity of the continuous pipe and the drilling pressure transmission capacity. The spiral flow channel on the straightener is used to change the flow state of the drilling fluid, so as to suspend and carry the cuttings and reduce the accumulation of cuttings. The straightening effect of the straightener wing is used to prevent the continuous pipe from sticking to the well wall and reduce the adsorption force of the mud cake. The rigid balls on the straightener wing are rotated to reduce the sliding resistance. The present invention solves the problems of difficulty in carrying sand, high friction and serious blocking during continuous pipe drilling operations, and can achieve the purpose of safe, efficient and smooth operation.

[0029] 2. The present invention provides technical support for the research and field test of the technology and process matching of slim-bore coiled tubing old well side drilling and slim-bore coiled tubing drilling. It is expected that with the safe, fast and smooth implementation of coiled tubing drilling, coiled tubing drilling will play an important role in the side drilling of old wells in oil fields and slim-bore coiled tubing drilling. With the increase in the number of slim-bore coiled tubing drilling, the application effect of the present invention will be apparent.

[0030] 3. The free-limiting spiral ball centralizer in the present invention is provided with free-limiting fixing devices at the two ends of the centralizer body. The free-limiting fixing devices are interference-fitted with the inner cone structure on the centralizer body through the outer cone structure. During the process of drilling, the free-limiting fixing devices are squeezed tighter and tighter with the centralizer body, thereby holding the coiled tubing and preventing the centralizer from moving up and down, so that the present invention can be smoothly implemented. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic diagram of an embodiment of the present invention;

[0032] Figure 2 It is a structural schematic diagram of the free-limiting spiral ball centralizer in the present invention;

[0033] Figure 3 It is a structural schematic diagram of the centralizer body in the present invention;

[0034] Figure 4 It is a structural schematic diagram of the centralizer wing in the present invention;

[0035] Figure 5 It is a side view of the free limiting fixing device in the present invention;

[0036] Figure 6 It is a schematic diagram of the connection of the semicircular arc blocks in the present invention;

[0037] In the figure,

[0038] 1. Continuous pipe, 2. Hydraulic oscillator, 3. Free-limit spiral ball centralizer, 4. Wellbore, 5. Centralizer body, 6. Free-limit fixing device, 7. Spiral flow channel, 8. Centralizer wing, 9. Cross cover plate, 10. Rigid ball groove, 11. Rigid ball, 12. Fixing screw, 13. Center hole, 15. Inner cone structure, 16. Outer cone structure, 17. Semicircular arc block. DETAILED DESCRIPTION

[0039] The present invention is further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

[0040] Example 1

[0041] The present invention provides a device for reducing frictional resistance in small-bore continuous pipe drilling. The idea of ​​the present invention is to use mechanical tools to reduce resistance. A hydraulic oscillator 2 is installed at the bottom of the hand-release tool. The hydraulic oscillator 2 is used to shake the drill bit to prevent the tool with a larger front end from sticking. A free-limiting spiral ball straightener 3 is placed every 150 meters or so in the inclined well section to increase the rigidity and drilling pressure transmission capacity of the continuous pipe 1. The spiral flow channel 7 on the straightener is used to change the flow state of the drilling fluid, so as to suspend and carry the cuttings and reduce the accumulation of cuttings. The straightening effect of the straightener wing 8 is used to prevent the continuous pipe 1 from sticking to the well wall and reduce the adsorption force of the mud cake. The rigid balls 11 on the straightener wing 8 are rotated to reduce the sliding resistance.

[0042] like Figure 1 As shown, the device of the present invention includes a hydraulic oscillator 2 and a free-limiting spiral ball centralizer 3. The hydraulic oscillator 2 is arranged at the lower part of the hand-release tool to make the drill tool vibrate so as to prevent the front-end tool from sticking; the free-limiting spiral ball centralizer 3 is arranged at intervals in the inclined well section. As the core tool for drag reduction, considering the free limiting property, the safety of the downhole tool, and the small size, the free-limiting spiral rigid ball centralizer 11 includes a centralizer body 5 and a free-limiting fixing device 6. The free-limiting fixing device 6 is arranged at both ends of the axial direction of the centralizer body 5, and plays a limiting role on the centralizer body 5 when drilling up and drilling down.

[0043] like Figure 2 and Figure 3 As shown, the centralizer body 5 is a sleeve structure, and a spiral flow channel 7 and a centralizer wing 8 are arranged on its circumferential surface. The spiral flow channel 7 and the centralizer wing 8 are evenly distributed on the outer surface of the centralizer body 5. A rigid ball groove 10 is opened on the centralizer wing 8, and a rigid ball 11 is installed in the rigid ball groove 10. The number of rigid balls 11 in each rigid ball groove 10 is 4.

[0044] like Figure 4 As shown, the rigid ball groove 10 is a half-open structure, and a cross cover plate 9 is fixedly provided at the open end of the rigid ball groove 10. The cross cover plate 9 is provided with a long groove for limiting the partial exposure of the rigid ball 11.

[0045] Preferably, the overall length of the free-limiting spiral rigid ball 11 centralizer is 110 mm, the spiral flow channel 7 is 22 mm wide, 10 mm deep, and the axial angle with the centralizer body 5 is 30°; the centralizer wing 8 is 30 mm wide, 10 mm high, and the axial angle with the centralizer body 5 is 30°. The rigid ball 11 has a diameter of 12 mm.

[0046] The two axial ends of the centralizer body 5 are inner cone structures 15, and the connecting end of the free limit fixture 6 is an outer cone structure 16. The two are plugged together, and the centralizer body 5 and the free limit fixture 6 are both provided with a center hole 13 for accommodating the continuous pipe 1. In order to reduce the axial pressure, prevent the free limit type spiral rigid ball 11 centralizer from moving up and down during drilling, increase the radial pressure, ensure that the inner side of the free limit fixture 6 is close to the outer wall of the continuous pipe 1, and prevent the free limit fixture 6 from falling off, the inner cone structure 15 and the outer cone structure 16 are both designed at a 60-degree angle.

[0047] like Figure 5 The diagram shows the structure of the free limit fixing device 6. In order to facilitate installation, the free limit fixing device 6 adopts a split-half structure, including two semicircular arc blocks 17 that can be spliced ​​into a complete column, and the splicing of the two semicircular arc blocks is fixed with hexagonal bolts. Figure 6 As shown, in order to facilitate fixation, the joint of the two semicircular arc blocks is designed to be L-shaped.

[0048] The free-limiting spiral rigid ball 11 centralizer is installed on the coiled tubing 1 and can rotate but cannot move up and down. The principle of the free-limiting fixture 6 preventing the centralizer body 5 from moving up and down is as follows: the upper and lower ends of the centralizer body 5 are designed as inner cones, and the limit block is designed as outer cones, and the two are interference fit. When the coiled tubing 1 string moves downward during drilling, the centralizer body 5 squeezes the free-limiting fixture 6 upward, the more it squeezes, the tighter it is, and the free-limiting fixture 6 is buckled on the coiled tubing 1 to prevent movement; when drilling, the centralizer body 5 squeezes the free-limiting fixture 6 downward, also squeezing more and more tightly to prevent movement.

[0049] Example 2

[0050] Based on the device for reducing friction in slim-hole coiled tubing drilling described in Example 1, this embodiment further discloses a method for using the device for reducing friction in slim-hole coiled tubing drilling. The following are specific application steps:

[0051] Step 1: Determine the drilling tool assembly: including drill bit (Φ118mm), single-bend screw (Φ102mm), non-magnetic pressure-bearing drill pipe (measurement while drilling tool), directional tool, hand-drop tool, hydraulic oscillator 2 (Φ95-100mm), upper and lower non-rotating joints, connectors, coiled pipe 1 (2-3 / 8″), and add a free-limiting spiral rigid ball 11 centralizer every 150m in the inclined well section;

[0052] Step 2: Connect the drill bit, single-bend screw, non-magnetic pressure-bearing drill pipe, directional tool, and hand-drop tool in sequence according to the drilling tool assembly, and start entering the wellbore 4;

[0053] Step 3, connect the hydraulic vibrator 2 and enter the wellbore 4;

[0054] Step 4: Connect the upper and lower non-rotating joints and connectors, and seat the elevators;

[0055] Step 5: insert a certain number of centralizer bodies 5 into the coiled tubing 1 as required;

[0056] Step 6: Connect the connector to the coiled tubing 1, open the elevator, place the elevator between the connector and the centralizer body 5, and start drilling;

[0057] Step 7: Lift up the bottom centralizer body 5, fix the free limit fixture 6 on the coiled tubing 1, so that the lower end of the centralizer body 5 sits in the free limit fixture 6; then install and fix the free limit fixture 6 on the upper end of the centralizer body 5, so that it sits on the upper end of the centralizer body 5, and fix it with screws;

[0058] Step 8: Continue drilling and continue to install the free-limiting rigid ball centralizer 3 as required;

[0059] Step 9: Drill down to the bottom, start the pump, and perform drilling operations as required;

[0060] Step 10: After the operation is completed, the drill is pulled out. After seeing the free-limiting rigid ball centralizer 3, first remove the fixed free-limiting fixture 6 on the upper end of the centralizer body 5, and then remove the fixed free-limiting fixture 6 on the lower end of the centralizer body 5; continue to pull out the drill and remove the free-limiting fixture 6 on the free-limiting rigid ball centralizer 3 until the coiled tubing 1 is pulled out, remove the coiled tubing 1, continue to pull out the drill, and pull out the lower tool string.

[0061] Although the specific implementation of the present invention is described in detail in conjunction with the drawings, it should not be understood as limiting the scope of protection of this patent. Within the scope described in the claims, various modifications and variations that can be made by those skilled in the art without creative work still fall within the scope of protection of this patent.

[0062] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A device for reducing friction in slim hole coiled tubing drilling, characterized in that: The invention comprises a hydraulic oscillator (2) and a free-positioning spiral ball centralizer (3); the hydraulic oscillator (2) is arranged at the bottom of the hand-release tool to vibrate the drill tool so as to prevent the front-end tool from sticking; the free-positioning spiral ball centralizer (3) is arranged at intervals in the inclined well section, and comprises a centralizer body (5) and free-positioning fixing devices (6) coaxially arranged at both ends of the centralizer body (5); the axial ends of the centralizer body (5) are inner cone structures (15), and the connecting end of the free-positioning fixing device (6) is an outer cone structure (16); the two are plug-fitted, and the centralizer body (5) and the free-positioning fixing device (6) are both provided with a center hole (13) for accommodating the continuous pipe (1) to pass through; The centralizer body (5) is provided with a spiral flow channel (7) and a centralizer wing (8), and the spiral flow channel (7) and the centralizer wing (8) are evenly spaced on the outer surface of the centralizer body (5); the centralizer wing (8) is provided with a rigid ball groove (10), and a rigid ball (11) is installed in the rigid ball groove (10), and the number of rigid balls (11) in each rigid ball groove (10) is 4; the rigid ball groove (10) is a half-open structure, and a cross cover plate (9) is fixedly provided at the open end of the rigid ball groove (10), and the cross cover plate (9) is provided with a long groove for limiting the partial exposure of the rigid ball (11); the free limit fixing device (6) adopts a half-split structure, comprising two semi-circular arc blocks (17) that can be spliced ​​into a complete column, and the splicing position of the two semi-circular arc blocks is fixed by a hexagonal bolt.

2. The device for reducing friction in slim hole coiled tubing drilling according to claim 1, characterized in that: The continuous tube (1) and the center hole (13) on the free-limiting spiral ball centralizer (3) are in interference fit.

3. The device for reducing friction in slim hole coiled tubing drilling according to claim 1, characterized in that: The inner cone structure (15) and the outer cone structure (16) are both at an angle of 60 degrees.

4. The device for reducing friction in slim hole coiled tubing drilling according to claim 1, characterized in that: The overall length of the free-limiting spiral ball centralizer (3) is 110 mm, and the inner diameter of the centralizer body (5) is 74 mm and the outer diameter is 110 mm.

5. The device according to claim 1, characterized in that The spiral flow channel (7) is 22 mm wide and 10 mm deep, and its axial angle with the centralizer body (5) is 30°; the centralizer wing (8) is 30 mm wide and 10 mm high, and its axial angle with the centralizer body (5) is 30°.

6. A method for using a device for reducing friction in slim hole coiled tubing drilling according to any one of claims 1 to 5, characterized in that: The steps include: Step 1, determine the drilling tool assembly, including a drill bit, a single-bend screw, a non-magnetic pressure-bearing drill pipe, a directional tool, a hand-release tool, and a hydraulic oscillator (2); Step 2: Connect the drill bit, single-bend screw, non-magnetic pressure-bearing drill pipe, directional tool, and hand-drop tool in sequence according to the drilling tool assembly, and start entering the wellbore (4); Step 3: Connect the hydraulic oscillator (2) and enter the wellbore (4); Step 4: Connect the upper and lower non-rotating joints and connectors, and seat the elevators; Step 5: insert a certain number of centralizer bodies (5) into the coiled tubing (1) as required; Step 6: Connect the connector to the coiled tubing (1), open the elevator, place the elevator between the connector and the centralizer body (5), and start drilling; Step 7: Lift up the lowermost centralizer body (5), fix the free limit fixture (6) on the coiled tube (1), so that the lower end of the centralizer body (5) sits in the free limit fixture (6); then install and fix the free limit fixture (6) on the upper end of the centralizer body (5), so that it sits on the upper end of the centralizer body (5), and fix it with screws; Step 8: Continue drilling and install the free-limiting rigid ball centralizer (3) as required; Step 9: Drill down to the bottom, start the pump, and perform drilling operations as required; Step 10: After the operation is completed, the drill is pulled out. When the free-limit rigid ball centralizer (3) is seen, the fixed free-limit fixture (6) at the upper end of the centralizer body (5) is first removed, and then the fixed free-limit fixture (6) at the lower end of the centralizer body (5) is removed; the drill is continued to be pulled out and the free-limit fixture (6) on the free-limit rigid ball centralizer (3) is removed until the coiled tubing (1) is pulled out. The coiled tubing (1) is removed and the drill is continued to be pulled out to pull out the lower tool string.

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