A wellbore string inner wall cleaning tool and method

Abstract

The present application relates to the technical field of oil and gas development, and is specifically directed to a wellbore pipe string inner wall cleaning tool and method for the workover operation of daily oil wells, natural gas wells, water injection wells and other production wells, wherein the wellbore pipe string inner wall cleaning tool comprises a cylinder, a first piston, a second piston and a blocking piece. The first channel is arranged axially in the cylinder, and a through hole is formed on the outer periphery of the cylinder; the first piston and the second piston are movably arranged at the two ends of the first channel along the axial direction of the cylinder body, and the outer walls of the first piston and the second piston are in close contact with the inner wall of the first channel; the second channel is formed axially in the second piston, the water outlet end of the second channel is arranged towards the first piston and communicates with the first channel; and the blocking piece is movably arranged at the water inlet end of the second channel. The tool can realize the pressurized operation when the pipe string is lowered and lifted, and provides the most basic process preparation for the existing workover operation technology, and realizes the wellbore cleaning.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of oil and gas development, and particularly relates to a wellbore string inner wall cleaning tool and method. BACKGROUND

[0002] In the process of oil and gas exploitation, a single connected oil pipe is mostly used as a production string to form a continuous channel for oil and gas exploitation. In the process of lifting crude oil in daily oil wells, as the pressure field and temperature field change, long-chain hydrocarbons will gradually solidify, form a mixture with sand and water scaling, and be adsorbed on the inner wall of the oil pipe, thereby affecting the efficiency of crude oil exploitation. In the process of lifting natural gas in natural gas wells, as the produced water in the gas reservoir changes with the pressure field, temperature field and liquid carrying speed, it will also cause the inner wall of the oil pipe to gradually scale, thereby affecting the flow area and causing subsequent measures to be blocked, affecting the gas recovery efficiency. At the same time, as a common way to maintain stable production of oilfields, the produced water of the oilfield is generally injected into the target layer at the bottom of the well through the oil pipe under high pressure. The scaling tendency of the produced water when injected will further cause the flow area of the oil pipe to become smaller, thereby reducing the reliability of the surface equipment and facilities. Therefore, the above three kinds of oil and gas production wells all need to be cleaned regularly.

[0003] The existing oil pipe inner wall can be cleaned by water injection, especially by re-injection of the produced water of the oil and gas field, which can save water resources while fully supplementing the formation energy to ensure the continuous exploitation of oil and gas. However, the produced water of the oil and gas field is easily scaled on the inner wall of the oil pipe due to the influence of water type and salinity, thereby increasing the water injection pressure when the produced water of the oil and gas field is re-injected, and the increase of the water injection pressure may cause damage to the parts of the water injection equipment, thereby increasing the intermittent cost of production and the maintenance cost of the equipment, and causing great safety risks. For example, the patent document with the publication number CN209025650U discloses an oil-water well downhole pipe string flushing device, which is a wellhead at the oil-water well operation site of the petroleum industry, and flushes the crude oil attached to the surface of the oil-water well downhole pipe string, protects the environment, and improves the operation efficiency. The downhole pipe string flushing device comprises a mud umbrella and a leak-proof pipe, the mud umbrella is fixed below the liquid inlet hole of the leak-proof pipe; the leak-proof pipe and the flushing pipe are connected through a flange and connecting bolts, the washing port is arranged on the pipe body of the flushing pipe, the liquid storage bag is arranged outside the washing port, the outer wall of the liquid storage bag is provided with a liquid inlet, and the liquid outlet is arranged on the pipe body of the flushing pipe below the liquid storage bag. SUMMARY

[0004] In view of the above problems, for the workover operation of daily oil wells, natural gas wells, water injection wells and other production wells, the present application provides a wellbore string inner wall cleaning tool, which comprises:

[0005] a cylinder body, a first channel being arranged axially in the cylinder body, and a through hole being arranged on the outer periphery of the cylinder body;

[0006] a first piston, the first piston being arranged axially movably in one end of the first channel of the cylinder body tube, and the outer wall of the first piston being fitted with the inner wall of the first channel;

[0007] a second piston, the second piston being arranged axially movably in the other end of the first channel of the cylinder body, and the outer wall of the second piston being fitted with the inner wall of the first channel;

[0008] a second channel being arranged axially in the second piston, the water outlet end of the second channel being arranged towards the first piston and being communicated with the first channel;

[0009] a blocking member, the blocking member being arranged movably in the water inlet end of the second channel.

[0010] In some embodiments, a tube is arranged coaxially on the inner wall of the cylinder body, so that the inner wall of the tube encloses the first channel;

[0011] a through slot being arranged on the outer periphery of the tube, when the through hole coincides with the through slot, the through hole is communicated with the first channel.

[0012] In some embodiments, two thrust bearings are arranged coaxially on the inner wall of the cylinder body, and the tube is located between the two thrust bearings;

[0013] one of the thrust bearings is arranged rotatably on the outer periphery of the first piston, and the other thrust bearing is arranged rotatably on the outer periphery of the second piston.

[0014] In some embodiments, a first outer boss is arranged on the outer wall of the first piston, and a second outer boss is arranged on the outer wall of the second piston;

[0015] a third inner boss is arranged on the inner wall of the cylinder body, when the first piston moves axially away from the second piston to a first preset position, the third inner boss is clamped with the first outer boss;

[0016] a fourth inner boss is arranged on the inner wall of the tube, when the second piston moves axially away from the first piston to a second preset position, the fourth inner boss is clamped with the second outer boss.

[0017] In some embodiments, the first piston and the cylinder body are connected by a first shear pin;

[0018] The second piston is connected with the barrel through a second shear pin;

[0019] When the pressure of the first piston in the axial direction of the barrel reaches a first pressure value, the first shear pin is broken;

[0020] When the pressure of the second piston in the axial direction of the barrel reaches a second pressure value, the second shear pin is broken.

[0021] In some embodiments, the through holes are provided in multiple groups, each group of through holes comprising a plurality of through holes;

[0022] The multiple groups of through holes are uniformly arranged in the circumferential direction of the barrel, and the multiple through holes in each group of through holes are uniformly arranged in the axial direction of the barrel;

[0023] The through grooves are provided in multiple groups, each group of through grooves comprising a plurality of through grooves;

[0024] The multiple groups of through grooves are uniformly arranged in the axial direction of the barrel, and the multiple through grooves in each group of through grooves are uniformly arranged in the circumferential direction of the barrel.

[0025] In some embodiments, the multiple groups of through holes are arranged in axial misalignment with respect to the barrel.

[0026] In some embodiments, a plurality of isolation rings are arranged around the outer wall of the barrel;

[0027] An isolation zone is formed between two adjacent isolation rings;

[0028] The multiple isolation zones correspond one-to-one to the multiple groups of through grooves.

[0029] In some embodiments, the angle between the center line of the through hole and the axis of the barrel ranges from 40 degrees to 50 degrees;

[0030] The angle between the end connection line of the through groove and the axis of the barrel ranges from 40 degrees to 50 degrees.

[0031] A method for cleaning the inner wall of a wellbore string based on the same concept, using the wellbore string inner wall cleaning tool as described in any of the above embodiments, comprising the following steps:

[0032] Lowering the wellbore string inner wall cleaning tool into the wellbore to the position to be cleaned;

[0033] The cleaning liquid is continuously conveyed, and the cleaning liquid is sprayed out of the through hole to clean the inner wall of the wellbore;

[0034] The cleaning liquid is continuously conveyed, and the cleaning liquid is sprayed out of the through hole to clean the inner wall of the wellbore;

[0035] After the cleaning is completed, the blocking member is lowered to be arranged at the water inlet end of the second channel, and the cleaning liquid is continuously conveyed to press the second piston and move the second piston along the axial direction of the barrel, until the second piston is coincided with the through hole to block the through hole.

[0036] Compared with the prior art, the wellbore string inner wall cleaning tool has at least the following advantages: through the arrangement of the first piston, the first piston can be pressed and moved along the axial direction of the barrel after the cleaning liquid reaches the first channel, so that the starting pressure during cleaning is maintained within a safe range through the movement of the first piston to reduce the pressure of the parts and the safety of the operating personnel and equipment at the wellhead. After the cleaning is completed, the through hole can be blocked by the movement of the second piston, so that the cleaning is stopped, and the movement of the second piston can be buffered again to further reduce the pressure of the parts and the safety of the operating personnel and equipment at the wellhead, so as to achieve the purpose of safely pulling out the string. At the same time, the wellbore string inner wall cleaning tool can be adapted to all operating strings of the existing workover operation, realizes the pressure operation during the "lowering" and "pulling out" of the string, and is widely applied to production wells such as oil wells, natural gas wells and water injection wells, and can provide the most basic process preparation for the existing workover operation technology to realize the wellbore cleaning.

[0037] The wellbore string inner wall cleaning method has the same beneficial effects as the wellbore string inner wall cleaning tool, and thus, the details are not described herein.

[0038] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application. The objects and other advantages of the present application can be achieved and obtained by means of the structures pointed out in the description and the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without any creative effort.

[0040] Figure 1 A schematic view of a wellbore string inner wall cleaning tool in an embodiment of the present application is shown;

[0041] Figure 2 A schematic view of a cylinder in an embodiment of the present application is shown;

[0042] Figure 3 A partially expanded schematic view of a cylinder in an embodiment of the present application is shown;

[0043] Figure 4 A schematic view of a first piston in an embodiment of the present application is shown;

[0044] Figure 5 A schematic view of a second piston in an embodiment of the present application is shown;

[0045] Figure 6 A schematic view of a pipe body in an embodiment of the present application is shown;

[0046] Figure 7 A partially expanded schematic view of a pipe body in an embodiment of the present application is shown;

[0047] Figure 8 A flow chart of a wellbore string inner wall cleaning method in an embodiment of the present application is shown.

[0048] In the figure, 100, cylinder; 110, through hole; 120, third inner boss; 130, first shear pin; 140, second shear pin; 150, thrust bearing; 200, first piston; 210, first outer boss; 300, second piston; 310, second outer boss; 320, fixed block; 400, plugging element; 500, pipe body; 510, through slot; 520, isolation ring; 530, fourth inner boss. DETAILED DESCRIPTION

[0049] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0050] Reference Figure 1 and Figure 2The embodiment of the present application provides a wellbore string inner wall cleaning tool, which comprises a cylinder body 100, a first piston 200, a second piston 300 and a blocking piece 400. The first channel is arranged in the cylinder body 100 in the axial direction, and the through hole 110 is arranged on the outer periphery of the cylinder body 100. The first piston 200 is movably arranged in one end of the first channel in the axial direction of the cylinder body 100, and the outer wall of the first piston 200 is attached to the inner wall of the first channel. The second piston 300 is movably arranged in the other end of the first channel in the axial direction of the cylinder body 100, and the outer wall of the second piston 300 is attached to the inner wall of the first channel. The second channel is arranged in the second piston 300 in the axial direction of the cylinder body 100, and the water outlet end of the second channel is arranged towards the first piston 200 and communicates with the first channel. The blocking piece 400 is movably arranged at the water inlet end of the second channel.

[0051] Specifically, the cylinder body 100 is a main cylinder body, the first piston 200 is movably arranged in one end of the first channel in the axial direction of the cylinder body 100, and the outer wall of the first piston 200 is attached to the inner wall of the first channel, so that when the outer wall of the first piston 200 coincides with the through hole 110 of the cylinder body 100, the through hole 110 can be blocked by the outer wall of the first piston 200. When the cleaning liquid is delivered, the cleaning liquid can pass through the second channel of the second piston 300 and reach the first channel of the cylinder body 100 through the water outlet end of the second channel to press the first piston 200 and move the first piston 200 in the axial direction of the cylinder body 100 until the first piston 200 is dislocated from the through hole 110 of the cylinder body 100, so that the cleaning liquid in the first channel can be sprayed out of the through hole 110 to clean the inner wall of the wellbore. The movement of the first piston 200 can also provide buffering, so that the starting pressure during cleaning is maintained within a safe range to reduce the pressure on the parts. After cleaning is completed, the blocking piece 400 is arranged at the water inlet end of the second channel and is moved along with the continuous delivery of the cleaning liquid to press the second piston 300 and move the second piston 300 in the axial direction of the cylinder body 100 until the outer wall of the second piston 300 coincides with the through hole 110, so that the through hole 110 is re-blocked by the outer wall of the second piston 300 to facilitate the removal of the whole string. The movement of the second piston 300 can also provide buffering to further reduce the pressure on the parts and achieve the purpose of safely pulling out the string.

[0052] In some specific embodiments of the present application, referring to Figure 1 and Figure 6 , the pipe body 500 is coaxially arranged on the inner wall of the cylinder body 100, so that the inner wall of the pipe body 500 encloses the first channel. The through slot 510 is arranged on the outer periphery of the pipe body 500, and the through hole 110 communicates with the first channel when the through hole 110 coincides with the through slot 510.

[0053] Specifically, the pipe body 500 is coaxially arranged in the barrel 100 and located between the inner wall of the barrel 100 and the outer wall of the first piston 200 and the outer wall of the second piston 300. The outer periphery of the pipe body 500 is provided with a through slot 510, and when the through hole 110 coincides with the through slot 510, the through hole 110 is in communication with the first channel. The relative position relationship and the degree of mutual coincidence between the through slot 510 and the through hole 110 can be adjusted by rotating the through slot 510 through the pipe body 500, so that the injection angle range of the cleaning liquid can be increased through the cooperation of the through slot 510 and the through hole 110.

[0054] Further, the circumferential outer wall of the pipe body 500 is completely nested on the inner wall of the barrel 100, so that the first channel enclosed by the inner wall of the pipe body 500 can be in communication with the channel in the barrel 100.

[0055] When the cleaning is not started, one end of the first piston 200 is arranged in the pipe body 500 from one end of the pipe body 500, and the other end of the first piston 200 is arranged out of the corresponding end of the barrel 100, wherein the outer wall of the one end of the first piston 200 arranged in the pipe body 500 coincides with the through slot 510 of the pipe body 500. One end of the second piston 300 is arranged in the pipe body 500 from one end of the pipe body 500, and the other end of the second piston 300 extends to the corresponding end of the barrel 100. When the cleaning liquid starts to be transported into the second channel of the second piston 300, the cleaning liquid passes through the second channel and reaches the pipe body 500 through the water outlet end of the second channel to press the first piston 200, and when the pressure in the pipe body 500 reaches the first pressure value, the hydraulic pressure drives the first piston 200 to move along the axial direction of the barrel 100 away from the second piston 300, until the outer wall of the one end of the first piston 200 arranged in the pipe body 500 is dislocated from the through slot 510 of the pipe body 500, so as to remove the blockage of the through slot 510, and at the same time, the hydraulic pressure also drives the pipe body 500 to rotate relative to the barrel 100 in the circumferential direction, so that the through slot 510 coincides with the through hole 110 of the barrel 100, and then the cleaning liquid in the pipe body 500 can be sprayed out through the through slot 510 and the through hole 110 in turn, so as to realize the cleaning of the inner wall of the wellbore. When the inner wall of the wellbore is cleaned, the blocking member 400 is arranged at the water inlet end of the second channel, and when the pressure at the water inlet end of the second channel reaches the second pressure value, the hydraulic pressure drives the second piston 300 to move along the axial direction of the barrel 100 to approach the first piston 200, until the outer wall of the one end of the second piston 300 arranged in the pipe body 500 coincides with the through slot 510 of the pipe body 500, so as to stop the injection of the cleaning liquid.

[0056] Further, the outer wall of the one end of the first piston 200 located outside the barrel 100 is provided with a thread, which is convenient for connecting with other pipe string equipment.

[0057] Further, the outer wall of the end of the second piston 300 away from the first piston 200 is sleeved with a fixed block 320, the fixed block 320 is a bowl-shaped structure, so that the bowl-shaped structure of the fixed block 320 is formed around the water inlet end of the second channel to form a slope surface arranged around the water inlet end of the second channel. The blocking piece 400 is a sphere, when the blocking piece 400 is lowered, the blocking piece 400 can be covered on the water inlet end of the second channel along the slope surface, so as to realize the blocking of the water inlet end of the second channel.

[0058] Further, the outer wall of the fixed frame is threadedly connected with the inner wall of the barrel 100.

[0059] In some embodiments of the present application, referring to Figure 1 , the inner wall of the barrel 100 is coaxially rotatably provided with two thrust bearings 150, and the pipe body 500 is located between the two thrust bearings 150. One of the thrust bearings 150 is rotatably sleeved on the outer periphery of the first piston 200, and the other thrust bearing 150 is rotatably sleeved on the outer periphery of the second piston 300.

[0060] Specifically, the pipe body 500 is located between the two thrust bearings 150, and the two ends of the pipe body 500 are connected with the two thrust bearings 150 respectively, so that the pipe body 500 can be rotatably arranged in the barrel 100 through the two thrust bearings 150. One of the thrust bearings 150 is rotatably sleeved on the outer periphery of the first piston 200, and the other thrust bearing 150 is rotatably sleeved on the outer periphery of the second piston 300, so as to avoid affecting the movement of the first piston 200 and the second piston 300.

[0061] In some embodiments of the present application, referring to Figure 1 , the outer wall of the first piston 200 is provided with a first outer boss 210, and the outer wall of the second piston 300 is provided with a second outer boss 310. The inner wall of the barrel 100 is provided with a third inner boss 120, when the first piston 200 moves away from the second piston 300 along the axial direction of the barrel 100 to the first preset position, the third inner boss 120 is clamped with the first outer boss 210. The inner wall of the pipe body 500 is provided with a fourth inner boss 530, when the second piston 300 moves away from the first piston 200 along the axial direction of the barrel 100 to the second preset position, the fourth inner boss 530 is clamped with the second outer boss 310.

[0062] Specifically, referring to Figure 4 , the outer wall of the end of the first piston 200 penetrating into the pipe body 500 is circumferentially provided with a first outer boss 210, and the outer wall of the first outer boss 210 is attached to the inner wall of the pipe body 500, so that the first outer boss 210 is moved to block and unblock the through slot 510 of the pipe body 500. Referring to Figure 2, the inner wall of the one end of the cylinder body 100, in which the first piston 200 is arranged, is provided with a third inner boss 120, and the first outer boss 210 and the third inner boss 120 coincide with each other in the axial direction of the cylinder body 100, after the cleaning liquid is delivered, when the first piston 200 moves in the axial direction of the cylinder body 100 away from the second piston 300 and moves to a first preset position, the third inner boss 120 abuts against the first outer boss 210, thereby realizing the clamping of the first piston 200 and the cylinder body 100, so as to avoid the first piston 200 from being taken out of the cylinder body 100. Referring to Figure 5 , the outer wall of the one end of the pipe body 500, in which the second piston 300 is arranged, is provided with a second outer boss 310, and the outer wall of the second outer boss 310 is attached to the inner wall of the pipe body 500, so that the pipe body 500 can also be blocked and unblocked through the movement of the second outer boss 310. Referring to Figure 6 , the inner wall of the one end of the pipe body 500, in which the first piston 200 is arranged, is provided with a fourth inner boss 530, and the fourth inner boss 530 is located on the side of the second outer boss 310 away from the first piston 200, and the second outer boss 310 and the fourth inner boss 530 coincide with each other in the axial direction of the cylinder body 100, when the second piston 300 moves in the axial direction of the cylinder body 100 away from the second piston 300 and moves to a second preset position, the fourth inner boss 530 abuts against the second outer boss 310, thereby realizing the clamping of the second piston 300 and the pipe body 500, so as to avoid the second piston 300 from being taken out of the pipe body 500.

[0063] Further, the outer wall of the first outer boss 210 is provided with an annular groove, and a sealing ring is embedded in the annular groove, so as to ensure the sealing effect.

[0064] Further, the first piston 200, the second piston 300, the cylinder body 100 and the pipe body 500 are all made of 35CrMo in a quenched and tempered state, and the final heat treatment state is 200HB to 250HB.

[0065] Further, one of the two thrust bearings 150 is located on the side of the third inner boss 120 close to the first outer boss 210, so that the first piston 200 can abut against the third inner boss 120 through the thrust bearing 150. The other thrust bearing 150 is located on the one end of the pipe body 500 away from the third inner boss 120, and the side of the thrust bearing 150 away from the pipe body 500 is provided with a limiting nail on the inner wall of the cylinder body 100, so that the two thrust bearings 150 and the pipe body 500 can be limited between the limiting nail and the third inner boss 120, so as to avoid the pipe body 500 from moving in the axial direction of the cylinder body 100.

[0066] Further, the two thrust bearings 150 are both of the 51305 type.

[0067] In some embodiments of the present application, referring to Figure 1 The first piston 200 is connected with the barrel 100 through the first shear pin 130. The second piston 300 is connected with the barrel 100 through the second shear pin 140. When the pressure of the first piston 200 in the axial direction of the barrel 100 reaches the first pressure value, the first shear pin 130 is broken. When the pressure of the second piston 300 in the axial direction of the barrel 100 reaches the second pressure value, the second shear pin 140 is broken.

[0068] Specifically, before the cleaning is started, the first shear pin 130 is screwed between the third inner boss 120 and the outer wall of the first piston 200, thereby fixedly connecting the first piston 200 and the barrel 100. When the pressure of the first piston 200 reaches the first pressure value, the first shear pin 130 is broken, thereby driving the first piston 200 to move. Before the cleaning is started, the second shear pin 140 is screwed between the end of the barrel 100 away from the first piston 200 and the outer wall of the fixed block 320, thereby fixedly connecting the second piston 300 and the barrel 100. When the pressure of the second piston 300 reaches the second pressure value, the second shear pin 140 is broken, thereby driving the second piston 300 to move. The first shear pin 130 and the second shear pin 140 are arranged to maintain the pressure within a safe range.

[0069] Further, the first shear pin 130 and the second shear pin 140 are each provided with at least two, and are arranged symmetrically about the axial direction of the barrel 100.

[0070] Further, the first shear pin 130 and the second shear pin 140 are made of brass.

[0071] In some embodiments of the present application, referring to Figure 3 and Figure 7 The through holes 110 are provided with multiple groups, and each group of through holes 110 contains multiple through holes 110. The multiple groups of through holes 110 are uniformly arranged along the circumferential direction of the barrel 100, and the multiple through holes 110 in each group of through holes 110 are uniformly arranged along the axial direction of the barrel 100. The through grooves 510 are provided with multiple groups, and each group of through grooves 510 contains multiple through grooves 510. The multiple groups of through grooves 510 are uniformly arranged along the axial direction of the barrel 100, and the multiple through grooves 510 in each group of through grooves 510 are uniformly arranged along the circumferential direction of the barrel 100.

[0072] Specifically, the plurality of groups of through holes 110 are uniformly arranged along the circumferential direction of the cylinder body 100, and the plurality of through holes 110 in each group of through holes 110 are uniformly arranged along the axial direction of the cylinder body 100. The plurality of groups of through grooves 510 are uniformly arranged along the axial direction of the cylinder body 100, and the plurality of through grooves 510 in each group of through grooves 510 are uniformly arranged along the circumferential direction of the cylinder body 100. The range of the spray angle of the cleaning liquid can be further expanded to ensure the cleaning effect of the inner wall of the wellbore.

[0073] In some embodiments of the present application, with reference to Figure 3 , the plurality of groups of through holes 110 are arranged in a staggered manner along the axial direction of the cylinder body 100.

[0074] Specifically, the plurality of through holes 110 in each group of through holes 110 are arranged one by one, and there is a phase difference of 20 degrees between the two corresponding through holes 110 in the adjacent two groups of through holes 110, so that the plurality of through holes 110 in the plurality of groups of through holes 110 are arranged in a staggered manner. The range of the spray angle of the cleaning liquid can be further expanded to ensure the cleaning effect of the inner wall of the wellbore.

[0075] In some embodiments of the present application, with reference to Figure 6 , a plurality of isolation rings 520 are arranged on the outer wall of the pipe body 500. An isolation band is formed between the adjacent two isolation rings 520. The plurality of isolation bands correspond one by one to the plurality of groups of through grooves 510.

[0076] Specifically, the isolation ring 520 is arranged on the outer wall of the pipe body 500 in a surrounding manner, so that the outer wall of the pipe body 500 can abut against the inner wall of the cylinder body 100 through the isolation ring 520. The isolation ring 520 is provided in a plurality of forms, and the plurality of isolation rings 520 are uniformly arranged along the axial direction of the cylinder body 100. An isolation band is formed between each adjacent two isolation rings 520, and a plurality of isolation bands are formed through the plurality of isolation rings 520. The plurality of isolation bands correspond one by one to the plurality of groups of through grooves 510, so that the plurality of through grooves 510 in each group of through grooves 510 are located in the isolation band enclosed by the corresponding two isolation rings 520, so as to ensure the sealing between the cylinder body 100 and the pipe body 500, and the cleaning liquid passing through the through groove 510 can be accurately sprayed out through the through hole 110.

[0077] In some embodiments of the present application, with reference to Figure 2 and Figure 3 , the included angle between the center line of the through hole 110 and the axis of the cylinder body 100 ranges from 40 degrees to 50 degrees. With reference to Figure 6 and Figure 7 , the included angle between the connecting line between the two ends of the through groove 510 and the axis of the cylinder body 100 ranges from 40 degrees to 50 degrees.

[0078] Specifically, the included angle between the center line of the through hole 110 and the axis of the barrel 100 ranges from 45 degrees, and the included angle between the connecting line between the two ends of the through groove 510 and the axis of the barrel 100 ranges from 45 degrees, which can further expand the spraying angle range of the cleaning liquid to ensure the cleaning effect of the inner wall of the wellbore.

[0079] In some embodiments of the present application, the length of the first piston 200 is 300 mm, and the diameter is 30 mm. The length of the first outer boss 210 is 60.76 mm, and the outer diameter is 40 mm. The diameter of the sealing ring is 36.3*1.78 mm. The thread size of the first shear pin 130 is M5*0.8 mm, and the length is 20 mm. The thread size of the second shear pin 140 is M5*1 mm, and the length is 7.75 mm. The length of the barrel 100 is 410 mm. The length of the third inner boss 120 is 40 mm. The wall thickness of the barrel 100 at the position where the third inner boss 120 is not arranged is 6.02 mm. The diameter of the through hole 110 is 10 mm. The length of the tube body 500 is 232.06 mm, and the inner diameter is 40 mm. The length of the fourth inner boss 530 is 33 mm, and the inner diameter is 25 mm. The outer diameter of the isolation ring 520 is 51.96 mm. Three isolation rings 520 are arranged, and the distance between the three isolation rings 520 away from the one end of the fourth inner boss 530 of the tube body 500 is 60.44 mm, and the distance between the adjacent two isolation rings 520 is 30.38 mm. The length of the through groove 510 is 21.47 mm, and the diameter is 5 mm. The length of the second piston 300 is 201 mm, and the inner diameter is 15 mm. The outer diameter of the second outer boss 310 is 40 mm, and the length is 60 mm. The length of the limiting pin is 10 mm. The length of the fixed block 320 is 18.87 mm, and the angle of the inclined surface is 123.41 degrees.

[0080] With reference to Figure 8 The present application also provides a wellbore string inner wall cleaning method, which uses the wellbore string inner wall cleaning tool as described in any one of the above embodiments, and comprises the following steps: lowering the wellbore string inner wall cleaning tool into the wellbore to the position to be cleaned; conveying the cleaning liquid into the second passage of the second piston 300, and the cleaning liquid passes through the second passage and reaches the first passage of the barrel 100 through the water outlet end of the second passage, the first piston 200 is pressed and pushed to move along the axial direction of the barrel 100 until the first piston 200 is misaligned with the through hole 110 of the barrel 100, so that the through hole 110 is communicated with the first passage; continuously conveying the cleaning liquid to spray the cleaning liquid out of the through hole 110 to clean the inner wall of the wellbore; after the cleaning is completed, lowering the plugging member 400 to plug the water inlet end of the second passage, and continuing to convey the cleaning liquid to press and push the second piston 300 to move along the axial direction of the barrel 100 until the second piston 300 is coincided with the through hole 110 to plug the through hole 110.

[0081] Through the setting of the first piston 200, after the cleaning liquid reaches the first channel, the first piston 200 can be pressed and pushed to move along the axial direction of the barrel 100, so that the starting pressure during cleaning is maintained within a safe range through the movement of the first piston 200, so as to reduce the pressure of the parts. When the cleaning is completed, the through hole 110 can be blocked by the movement of the second piston 300, so as to stop the continuous cleaning, and the movement of the second piston 300 can be used for buffering again, so as to further reduce the pressure of the parts, so as to achieve the purpose of safe tripping.

[0082] Since the wellbore string inner wall cleaning method adopts the wellbore string inner wall cleaning tool described in any one of the foregoing embodiments, it has the same beneficial effects as the wellbore string inner wall cleaning tool described above, and thus will not be described here again.

[0083] Although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A wellbore string inner wall cleaning tool characterized by, The utility model relates to a kind of piston pump, including: Cylinder (100), first channel is provided in the axial direction in the cylinder (100), and through hole (110) is opened on the outer periphery of the cylinder (100); First piston (200), first piston (200) is movably arranged in one end of the first channel along the axial direction of the cylinder (100) pipe body (500), and the outer wall of first piston (200) is attached to the inner wall of the first channel; Second piston (300), second piston (300) is movably arranged in the other end of the first channel along the axial direction of the cylinder (100), and the outer wall of second piston (300) is attached to the inner wall of the first channel; Second channel is opened in the axial direction of the cylinder (100) in the second piston (300), and the water outlet end of the second channel is arranged towards the first piston (200) and is communicated with the first channel; Blocking piece (400), blocking piece (400) is movably arranged in the water inlet end of the second channel; The inner wall of the cylinder (100) is coaxially rotatably provided with a pipe body (500), so that the inner wall of the pipe body (500) is enclosed to form the first channel; The outer periphery of the pipe body (500) is provided with a through slot (510), and when the through hole (110) coincides with the through slot (510), the through hole (110) is communicated with the first channel; Two thrust bearings (150) are coaxially rotatably arranged on the inner wall of the cylinder (100), and the pipe body (500) is located between the two thrust bearings (150); One of the thrust bearings (150) is rotatably arranged on the outer periphery of the first piston (200), and the other thrust bearing (150) is rotatably arranged on the outer periphery of the second piston (300); The first piston (200) and the cylinder (100) are connected by a first shear pin (130); The second piston (300) and the cylinder (100) are connected by a second shear pin (140); When the pressure of the first piston (200) in the axial direction of the cylinder (100) reaches the first pressure value, the first shear pin (130) breaks; When the pressure of the second piston (300) in the axial direction of the cylinder (100) reaches the second pressure value, the second shear pin (140) breaks.

2. The wellbore string inner wall washing tool of claim 1, wherein, The outer wall of the first piston (200) is provided with a first outer boss (210), and the outer wall of the second piston (300) is provided with a second outer boss (310); The inner wall of the cylinder (100) is provided with a third inner boss (120), and when the first piston (200) is away from the second piston (300) to a first predetermined position along the axial direction of the cylinder (100), the third inner boss (120) is connected with the first outer boss (210). The inner wall of the pipe body (500) is provided with a fourth inner boss (530), and the fourth inner boss (530) is clamped with the second outer boss (310) when the second piston (300) is axially away from the first piston (200) to the second preset position of the barrel (100).

3. The wellbore string inner wall washing tool of claim 1, wherein, The through holes (110) are provided in multiple groups, and each group of the through holes (110) comprises a plurality of the through holes (110); The multiple groups of the through holes (110) are uniformly arranged along the circumferential direction of the barrel (100), and the multiple through holes (110) in each group of the through holes (110) are uniformly arranged along the axial direction of the barrel (100); The through grooves (510) are provided in multiple groups, and each group of the through grooves (510) comprises a plurality of the through grooves (510); The multiple groups of the through grooves (510) are uniformly arranged along the axial direction of the barrel (100), and the multiple through grooves (510) in each group of the through grooves (510) are uniformly arranged along the circumferential direction of the barrel (100).

4. The wellbore string inner wall washing tool of claim 3, wherein, The multiple groups of the through holes (110) are arranged in a staggered manner along the axial direction of the barrel (100).

5. The wellbore string inner wall washing tool of claim 3, wherein, The outer wall of the pipe body (500) is circumferentially provided with a plurality of isolation rings (520); An isolation zone is formed between adjacent two isolation rings (520); The multiple isolation zones correspond to the multiple groups of the through grooves (510) one by one.

6. The wellbore string inner wall washing tool of claim 1, wherein, The included angle between the center line of the through hole (110) and the axis of the barrel (100) ranges from 40 degrees to 50 degrees; The included angle between the end connection line of the through groove (510) and the axis of the barrel (100) ranges from 40 degrees to 50 degrees.

7. A method of cleaning the inside of a wellbore string, using a wellbore string inside cleaning tool according to any one of claims 1 to 6, characterized in that, The method comprises the following steps: Lowering the wellbore pipe string inner wall cleaning tool into the wellbore to the position to be cleaned; Pumping cleaning fluid into the second channel of the second piston (300), and the cleaning fluid passes through the second channel and reaches the first channel in the barrel (100) through the water outlet end of the second channel, thereby pressing the first piston (200) and pushing the first piston (200) to move along the axial direction of the barrel (100) until the first piston (200) is misaligned with the through hole (110) of the barrel (100), so that the through hole (110) is communicated with the first channel; Continuously pumping the cleaning fluid to spray the cleaning fluid out of the through hole (110) to clean the inner wall of the wellbore; After the cleaning is completed, the plugging member (400) is lowered to be plugged at the water inlet end of the second channel, and the cleaning fluid is continuously pumped to press the second piston (300) and push the second piston (300) to move along the axial direction of the barrel (100) until the second piston (300) is aligned with the through hole (110) to plug the through hole (110).

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