Downhole pitching excitation reaming tool

Abstract

The invention discloses an underground pitching excitation reaming tool which comprises a reamer short section and a ball containing short section connected to the upper portion of the reamer short section. The ball containing short section comprises a shell, a limiting barrel, a ball claw, an excitation ball, a spring seat and a first elastic piece. The spring seat is positioned below the ball claw, and the bottom of the ball claw is sectioned; the limiting cylinder comprises a small-diameter part and a large-diameter part which are distributed up and down, and a plurality of overflowing grooves for communicating the interiors of the small-diameter part and the large-diameter part; the inner diameter of the small-diameter part is smaller than the outer diameter of the ball claw in the natural state, and the inner diameter of the large-diameter part is larger than or equal to the outer diameter of the ball claw in the natural state. The reaming tool is used for solving the problem that in the prior art, due to the influence of an existing channel in a drill column, a reaming tool excited by pitching cannot be installed close to a drill bit, and the purposes that the reaming tool excited by pitching can also be installed close to the drill bit, the length of the section, where reaming cannot be conducted, of the well bottom is reduced, and the tripping frequency is reduced are achieved.

Description

Technical Field

[0001] The invention relates to the field of drilling and completion operations, and in particular to a downhole ball-dropping excitation eye-reaming tool. Background Art

[0002] In the field of drilling and completion operations of oil and gas development projects, the existing technology commonly used in reaming tools is to release the shear pins by dropping a ball from the drilling table to hold the pressure and stimulate the extension of the blade of the hydraulic reaming tool. This technology has the advantages of reliable structure, stable operation, and obvious excitation signal. However, the ball dropping structure in the existing technology is affected by the existing channels in the drill string, such as screw drill tools, rotary steerable drill tools, MWD, LWD and other logging instruments, trays in the drill tools, internal blowout preventers, etc. The excitation ball cannot pass through these tools, resulting in the reaming tool being unable to be installed below these tools or instruments in the bottom hole assembly (BHA) for use; for example, it cannot be used in a drill tool assembly such as "drill bit-reamer-screw-drill pipe"; which in turn results in the reaming tool being limited in use and unable to be installed near the drill bit for work, resulting in a long well section at the bottom of the well that cannot complete the reaming operation, which is not conducive to the smooth placement of subsequent casing / screen or completion string.

[0003] In order to reduce the length of the section at the bottom of the well that cannot be expanded in the prior art, it is generally necessary to circulate the well until the wellbore is stable and unobstructed after the drilling operation is completed, and then pull out the drill to replace a special bottom drill assembly without power (without screw drill bits or rotary steerable drill bits) and logging while drilling instruments. This will inevitably lead to a large number of trips and drills, which has an adverse effect on saving construction time and ensuring underground safety. Summary of the invention

[0004] The present invention provides a downhole ball-dropping reaming tool to solve the problem in the prior art that the ball-dropping reaming tool cannot be installed close to the drill bit due to the influence of existing channels in the drill string, so that the ball-dropping reaming tool can also be installed close to the drill bit, thereby reducing the length of the bottom hole section that cannot be reamed and reducing the number of drilling trips.

[0005] The present invention is achieved through the following technical solutions:

[0006] A downhole ball-dropping reaming tool comprises a reamer sub and a ball-receiving sub connected above the reamer sub; the ball-receiving sub comprises a housing, a stopper fixedly connected to the inside of the housing, a ball claw slidably fitted in the stopper along the axial direction, an activating ball placed in the ball claw, a spring seat slidably fitted in the housing along the axial direction, and a first elastic member abutting against the bottom of the spring seat;

[0007] The spring seat is located below the ball claw, the bottom of the ball claw is divided into flaps, and an upper bypass hole and a lower bypass hole are provided on the side of the ball claw;

[0008] The limiting cylinder includes a small diameter portion and a large diameter portion distributed in the upper and lower parts, and a plurality of flow grooves for connecting the small diameter portion and the large diameter portion; the inner diameter of the small diameter portion is smaller than the outer diameter of the ball claw in the natural state, and the inner diameter of the large diameter portion is greater than or equal to the outer diameter of the ball claw in the natural state;

[0009] When the bottom of the ball claw is located in the small diameter portion, the inner diameter of the bottom of the ball claw is smaller than the diameter of the excitation ball, and the two ends of the flow groove are connected to the upper bypass hole and the lower bypass hole respectively;

[0010] When the bottom of the ball claw is located in the large diameter portion, the inner diameter of the bottom of the ball claw is greater than the diameter of the excitation ball.

[0011] In view of the problem in the prior art that the ball-dropping activated reaming tool cannot be installed close to the drill bit due to the influence of the existing channels in the drill string, the present invention proposes a downhole ball-dropping activated reaming tool, wherein the reamer short section can be implemented by the ball-dropping activated reamer short section in the prior art. The present application realizes the downhole ball-dropping function by means of a ball-containing short section, and a limiting cylinder is provided in the outer shell of the ball-containing short section, and a ball claw is slidably fitted in the limiting cylinder, and the stimulating ball is placed in the ball claw in advance. In addition, considering that the present application belongs to a drilling reaming tool, it is necessary to ensure the normal flow of the drilling and completion fluid in the tubing string, and therefore, upper bypass holes and lower bypass holes distributed in the upper and lower directions are provided on the side of the ball claw, and a flow channel is provided in the limiting cylinder.

[0012] In the normal state without turning on the pump, the elastic force of the first elastic member pushes the spring seat upward, so that the top of the spring seat abuts against the bottom of the ball claw. At this time, the bottom of the ball claw is located in the small diameter part of the limit tube, and the petal-type ball claw cannot be opened. The excitation ball is confined in the ball claw and cannot be released downward. At this time, the drilling and completion fluid enters the upper bypass hole, the flow groove, and the lower bypass hole in turn to achieve normal downward flow.

[0013] During normal pumping for drilling or circulation, the displacement of the mud pump is lower than the set displacement (i.e., the lowest displacement at which the excitation ball can be released). The ball claw drives the excitation ball to compress the spring seat and move downward a certain distance together. The spring seat appropriately compresses the first elastic member. However, the ball claw still does not reach the large diameter portion of the limit tube. Limited by the inner hole of the small diameter portion of the limit tube, the petal-type ball claw still cannot open and the excitation ball still cannot be released.

[0014] When it is necessary to throw a ball to stimulate the short section of the reamer below, the mud pump is controlled from the drilling platform to provide a short-term large displacement that exceeds the aforementioned set displacement. Under the action of the short-term large displacement, the ball claw drives the excitation ball to continue to push the spring seat downward, and the spring seat compresses the first elastic member to a shorter state, so that the ball claw moves downward with a greater stroke until the bottom of the ball claw reaches the large diameter part. At this time, the petal structure at the bottom of the ball claw gets rid of the size limitation of the small diameter part, the bottom of the ball claw naturally opens outward, and the excitation ball is automatically released, thereby completing the downhole ball throwing function.

[0015] It can be seen that when the present application is used in practice, it is only necessary to preset the warning force of the first elastic member in advance, so that the above-mentioned set displacement required for ball throwing stimulation is significantly higher than the displacement during normal operation. The present application abandons the idea of ​​prior art that the ball needs to be thrown at the wellhead, and adopts the operation method of automatic ball throwing underground. The entire ball throwing process is not affected by the existing channels in the drill string such as screw drill tools, rotary guide drill tools, MWD, LWD, and internal blowout preventers, thereby solving the problem that the ball-throwing reaming tool in the prior art cannot be installed close to the drill bit, and realizes the installation of the ball-throwing reaming tool in a position close to the drill bit, thereby reducing the length of the bottom hole section that cannot be reamed, and can realize the reaming of the bottom hole area while drilling, reduce the number of drilling trips, improve engineering efficiency, and ensure underground safety.

[0016] It should be noted that the petal structure at the bottom of the ball claw in the present application has an outer diameter that is at least larger than the inner diameter of the small diameter portion in a natural state, thereby ensuring that the bottom of the ball claw is always in a state of being compressed inward when located in the small diameter portion, and can automatically open when the bottom of the ball claw enters the large diameter portion.

[0017] Those skilled in the art should understand that the terms "up" and "down" in the present application refer to the direction toward the bottom of the well after the reaming tool enters the well, and the direction toward the wellhead is considered up.

[0018] Furthermore, the small diameter portion includes a plurality of ridges evenly distributed along the circumferential direction of the inner wall of the limiting cylinder, and a flow groove is formed between two adjacent ridges; a transition portion with a gradually decreasing thickness is provided at the bottom of the ridges.

[0019] In this solution, when installing the ball claw, each petal at the bottom is directly opposite to at least one convex ridge, and the ball claw located therein is squeezed by the reduced diameter of the convex ridge. In addition, the transition portion can form an inclined surface structure to facilitate the smooth opening and resetting of the ball claw, which is beneficial to reduce the risk of blocking and ensure the stability of the pitching operation.

[0020] Furthermore, the shell includes an upper shell body and a lower shell body of a ball-containing short joint connected to each other; the ball claw is slidingly fitted in the upper shell body of the ball-containing short joint, and a step surface is arranged in the lower shell body of the ball-containing short joint, and the bottom end of the first elastic member abuts against the step surface.

[0021] In this solution, the shell of the ball-receiving short joint is set as a two-stage structure, which can be convenient for opening the ball-receiving short joint to install the excitation ball and initialize the ball claw before the tool enters the well. The step surface in the lower shell can prevent the first elastic member from extending downward, thereby ensuring that the spring seat and the ball claw are stably provided with an upward thrust.

[0022] Furthermore, the reamer short section includes an reamer housing, blades connected to the reamer housing, a ball seat located inside the reamer housing and axially slidably connected, and a driving mechanism for driving the blades to open; the ball seat matches the excitation ball.

[0023] Those skilled in the art should understand that after the excitation ball self-contained short section is dropped, it moves downward to the ball seat under the action of gravity and drilling fluid, the excitation ball blocks the ball seat and moves downward with the ball seat, and the internal pressure of the tool is used to start the drive mechanism and realize the opening of the blade.

[0024] Furthermore, an upper end cover and a lower end cover are fixedly connected inside the reamer housing;

[0025] The driving mechanism includes a spindle axially connected to the inside of the reamer housing, a rack portion located on the spindle, and a gear portion located on the blade, wherein the gear portion is meshed with the rack portion; the driving mechanism also includes a second elastic member acting between the spindle and the reamer housing, and the second elastic member is used to apply an axial upward thrust to the spindle.

[0026] In this solution, the upper end cover is used to provide a limit for the spindle at the upper end. When the excitation ball blocks the ball seat and moves downward with the ball seat, due to the pressure drop of the drilling fluid inside the tool, the pressure difference between the upper and lower ends of the spindle is used to drive the spindle to compress the second elastic member and move downward, and then the gear part on the blade is driven to rotate through the rack part on the spindle, so that the blade rotates synchronously and the blade abutting against the surface of the reamer shell is turned outward to open the blade. In addition, as long as the pump is kept on, there is always a pressure difference between the upper and lower ends of the spindle, so that the blade can be kept in an open state; until the pump is stopped, the pressure difference between the upper and lower ends of the spindle disappears, and the spindle moves upward under the action of the second elastic member and resets to abut against the upper end cover. In this process, the blade is retracted by the gear rack structure.

[0027] The gear part in this solution can be a complete gear structure or an incomplete gear structure, and it only needs to cooperate with the rack part to enable the blade to be opened and retracted. It can be seen that the reamer pup provided in this solution can retract the blade after stopping the pump, and the blade can be forcibly retracted when drilling upward, which significantly reduces the difficulty of drilling and the number of drilling trips, and is more conducive to ensuring the safety of drilling and completion projects.

[0028] Furthermore, a shear pin is connected between the ball seat and the lower end cover, and the ball seat has an axial downward stroke; it also includes a guide seat fixedly connected to the inside of the reamer housing, and the guide seat is used to limit the axial downward movement of the ball seat; when the ball seat moves to the bottom end of the stroke, the ball seat and the guide seat are axially abutted.

[0029] After the excitation ball reaches the ball seat, it blocks the fluid channel inside the ball seat, and the pressure inside the tool begins to build up until the shear pin is cut off. The ball seat and the excitation ball move downward together until the ball seat abuts against the guide seat, and the fluid channel is re-established.

[0030] Furthermore, a ball seat bypass hole is provided on the side of the ball seat, and an expanded diameter portion is provided inside the guide seat; when the ball seat moves to the bottom end of the stroke, the ball seat bypass hole is connected to the expanded diameter portion.

[0031] In this solution, the ball seat moves to the bottom of the stroke and abuts against the guide seat. At this time, the bypass hole of the ball seat is connected to the expanded diameter part. The drilling and completion fluid can enter the expanded diameter part through the bypass hole of the ball seat and flow downward through the guide seat to re-establish the fluid channel.

[0032] Furthermore, a diversion hole is provided on the side of the lower end cover, a diversion channel is provided on the side of the reamer shell, and a nozzle is installed in the diversion channel; the spray direction of the nozzle is toward the area after the blade is opened.

[0033] In the prior art, when the blade of the reamer is working, it can only be cleaned and cooled by the drilling and completion fluid returning from the annulus. However, the flow state of the drilling fluid returning from the annulus is relatively stable and there are already a lot of rock cuttings dispersed therein, so the flushing effect is limited and it is easy to cause mud packing on the blade. In this application, since the blade has the ability to be retracted, once mud packing occurs, it will seriously interfere with the retraction function of the blade. In order to overcome this problem, this solution opens a diversion hole on the side of the lower end cover, opens a diversion channel on the side of the reamer shell, and installs a nozzle. When the mandrel is in the initial state, the diversion hole is blocked by the mandrel; when the mandrel moves downward to the end of the stroke, the diversion hole is opened, and part of the drilling and completion fluid enters the diversion hole and is ejected outward through the nozzle of the diversion channel, and the ejected drilling and completion fluid flushes and cools the blade; because the ejected drilling and completion fluid is still in a state of not being contaminated by the formation, it has better dispersion and dissolution ability for the cuttings attached to the blade, which is beneficial to reduce the risk of mud packing on the blade; and the ejected drilling and completion fluid and the drilling and completion fluid that normally returns to the annulus mix with each other at the blade to form a complex turbulence, which can further improve the heat dissipation and cleaning effect of the blade, and is more conducive to ensuring the stable recovery of the blade of the present application. In addition, a significant pressure drop will be formed at the diversion hole inside the tool, making the pressure difference between the upper and lower ends of the mandrel larger, which is more conducive to ensuring that the mandrel can stably compress the second elastomer and ensure the stability of the open state of the blade.

[0034] Furthermore, the diversion hole and the diversion channel are both located below the blade; the diversion channel is gradually inclined upward from the inside to the outside along the radial direction; and the nozzle is detachably connected in the diversion channel.

[0035] In this solution, by limiting the position and direction of the diversion channel, the fluid ejected from the nozzle also has an initial upward motion state in the annulus, which is conducive to flushing the blades and can be quickly mixed with the drilling and completion fluid returning in the annulus to avoid unnecessary energy loss, so that more kinetic energy of the fluid acts on the blades. The nozzle in this solution can be replaced according to specific working conditions, which is more conducive to flexible adaptation to the pressure drop required by the mandrel.

[0036] Furthermore, it also includes a pressure drop matching short section connected below the reamer short section, and a throttle nozzle is detachably connected to the pressure drop matching short section.

[0037] In the prior art, when using a drilling reaming tool, it is necessary to match and calculate the nozzle of the reaming tool with the nozzle of the drill bit according to the displacement and density of the drilling fluid, so that the throttling pressure drop reaches the pressure drop at which the blade of the reaming tool can be normally extended; in order to meet the required pressure drop, it is often necessary to replace the drill bit nozzle (usually it is necessary to replace a small nozzle or block part of the nozzle). Since the drill bit nozzle standards used by various companies are not unified (the nozzle threads are different), and some drill bits even use dead nozzles that cannot be replaced, it is very difficult to match the pressure drop on site, and even the matching requirements cannot be met.

[0038] In order to overcome the above defects, this solution also connects a pressure drop matching short section below the reamer short section, and sets a throttle nozzle in the pressure drop matching short section to replace the traditional method of replacing the drill nozzle, thereby achieving a throttling effect equivalent to replacing the drill nozzle, thereby avoiding the problem that the drill nozzle is difficult to replace or even cannot be replaced. In addition, the use of the throttle nozzle in this solution can ensure the stability of the pressure difference between the upper and lower ends of the mandrel, thereby ensuring the stable movement of the mandrel.

[0039] The specific model and type of the throttle in this solution can be selected by calculating the pressure drop matching based on the displacement of normal drilling or reaming operations before the tool is put into the well, and the throttle can be flexibly replaced according to different working conditions to match different pressure drop requirements.

[0040] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0041] 1. The present invention discloses a downhole ball-dropping irrigating tool, which abandons the operation idea of ​​dropping balls at the wellhead in the prior art and adopts an automatic downhole ball-dropping operation mode. The entire ball-dropping process is not affected by existing channels in the drill string such as screw drill tools, rotary guide drill tools, MWD, LWD, and internal blowout preventer valves, thereby solving the problem that the ball-dropping irrigating tool in the prior art cannot be installed close to the drill bit, and realizes the installation of the ball-dropping irrigating tool close to the drill bit, thereby reducing the length of the section at the bottom of the well that cannot be irrigated, and can realize the irrigating of the bottom area of ​​the well while drilling, reduce the number of tripping and drilling, improve engineering efficiency, and ensure downhole safety.

[0042] 2. The present invention provides a downhole ball-dropping reaming tool, and the reamer short section provided can recycle the blades after stopping the pump, thereby reducing the difficulty of drilling and the number of drilling and drilling times, and is more conducive to ensuring the safety of drilling and completion projects.

[0043] 3. The downhole ball-dropping reaming tool of the present invention is beneficial to reducing the risk of blade mud packing, can improve the heat dissipation and cleaning effect of the blade, and is more conducive to ensuring the stable recovery of the blade.

[0044] 4. The present invention provides a downhole ball-dropping reaming tool, which replaces the traditional method of replacing the drill bit nozzle by setting a throttling nozzle in a pressure drop matching short section, thereby achieving a throttling effect equivalent to replacing the drill bit nozzle, thereby overcoming the problem that the drill bit nozzle is difficult to replace or even cannot be replaced. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0046] Figure 1 It is a schematic diagram of the initial state of a specific embodiment of the present invention;

[0047] Figure 2 It is a quarter-section axonometric view of the limiting cylinder in a specific embodiment of the present invention;

[0048] Figure 3 for Figure 1 A partial enlarged view of the middle A;

[0049] Figure 4 It is a schematic diagram of the pitching process in the ball-containing short section in a specific embodiment of the present invention;

[0050] Figure 5 for Figure 1 A partial enlarged view of point B in the middle;

[0051] Figure 6 for Figure 1 A partial enlarged view of point C in the middle;

[0052] Figure 7 It is a schematic diagram of the eye expansion state after being activated in a specific embodiment of the present invention;

[0053] Figure 8 for Figure 7 A partial enlarged view of point D in the middle;

[0054] Fig. 9 This is a schematic diagram of a specific embodiment of the present invention after the pump is stopped by pitching.

[0055] Marks and corresponding parts names in the attached drawings:

[0056] 111-upper shell of ball-containing short joint, 112-ball claw, 1121-upper bypass hole, 1122-lower bypass hole, 113-excitation ball, 114-limiting cylinder, 1141-transition part, 1142-large diameter part, 1143-small diameter part, 115-spring seat, 116-first elastic member, 117-lower shell of ball-containing short joint, 118-reamer shell, 119-upper end cover, 120-spindle sealing ring, 121-second elastic member, 122-spindle, 1231-rack part, 1232-gear part, 124-pin shaft, 125 -blade, 126-lower end cover sealing ring I, 127-lower end cover sealing ring II, 128-nozzle, 129-ball seat diverter hole sealing ring, 130-lower end cover sealing ring III, 131-lower end cover, 132-ball seat, 133-shear pin, 134-setting screw, 135-guide seat, 1351-expanded diameter part, 136-guide seat sealing ring, 137-hole retaining ring, 138-throttle nozzle sealing ring, 139-throttle nozzle, 140-pressure drop matching short section, 311-flow groove, 312-diverter hole, 313-ball seat bypass hole. DETAILED DESCRIPTION

[0057] In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the examples and the accompanying drawings. The schematic embodiments of the present invention and the description thereof are only used to explain the present invention and are not intended to limit the present invention. In the description of the present application, it should be understood that the orientation or positional relationship indicated by terms such as "front", "rear", "left", "right", "up", "down", "vertical", "horizontal", "high", "low", "inside", "outside", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the scope of protection of the present application.

[0058] Embodiment 1:

[0059] like Figures 1 to 4A downhole ball-dropping reaming tool shown includes a reamer short section and a ball-receiving short section connected above the reamer short section; the ball-receiving short section includes an outer shell, a limiting cylinder 114 fixedly connected to the inside of the outer shell, a ball claw 112 axially slidingly fitted in the limiting cylinder 114, an activating ball 113 placed in the ball claw 112, a spring seat 115 axially slidingly fitted in the outer shell, and a first elastic member 116 abutting against the bottom of the spring seat 115; the first elastic member 116 is preferably a spring.

[0060] The spring seat 115 is located below the ball claw 112. The bottom of the ball claw 112 is divided into petals. An upper bypass hole 1121 and a lower bypass hole 1122 are formed on the side of the ball claw 112.

[0061] The limiting cylinder 114 includes a small diameter portion 1143 and a large diameter portion 1142 which are distributed in the upper and lower parts, and a plurality of flow grooves 311 for connecting the small diameter portion 1143 and the large diameter portion 1142; the inner diameter of the small diameter portion 1143 is smaller than the outer diameter of the ball claw 112 in the natural state, and the inner diameter of the large diameter portion 1142 is greater than or equal to the outer diameter of the ball claw 112 in the natural state;

[0062] When the bottom of the ball claw 112 is located in the small diameter portion 1143, the inner diameter of the bottom of the ball claw 112 is smaller than the diameter of the excitation ball 113, and the two ends of the flow groove 311 are connected to the upper bypass hole 1121 and the lower bypass hole 1122 respectively;

[0063] When the bottom of the ball claw 112 is located in the large diameter portion 1142 , the inner diameter of the bottom of the ball claw 112 is greater than the diameter of the excitation ball 113 .

[0064] The structure of the limiting cylinder 114 in this embodiment is as follows Figure 2 As shown, the small diameter portion 1143 includes a plurality of ridges uniformly distributed along the circumference of the inner wall of the limiting cylinder 114, and a flow groove 311 is formed between two adjacent ridges; a transition portion 1141 with a gradually decreasing thickness is provided at the bottom of the ridges.

[0065] like Figure 3 and Figure 4 As shown, the shell includes an upper shell 111 and a lower shell 117 of a ball-containing short joint connected at the upper and lower ends; the ball claw 112 is slidably fitted in the upper shell 111 of the ball-containing short joint, and a step surface is arranged in the lower shell 117 of the ball-containing short joint, and the bottom end of the first elastic member 116 abuts against the step surface.

[0066] Those skilled in the art should understand that Figure 3 and Figure 4 The directions of the arrows in the figure represent the flow directions of the drilling and completion fluid in the tool.

[0067] Embodiment 2:

[0068] A downhole ball-casting reaming tool. Based on Example 1, this example improves and optimizes the reamer sub. Figures 1 to 9 As shown, the reamer short section includes an reamer housing 118, a blade 125 connected to the reamer housing 118, a ball seat 132 located inside the reamer housing 118 and axially slidably connected, and a driving mechanism for driving the blade 125 to open; the ball seat 132 matches the excitation ball 113.

[0069] The reamer housing 118 is fixedly connected with an upper end cover 119 and a lower end cover 131;

[0070] The driving mechanism includes a spindle 122 axially slidably connected to the inside of the reamer housing 118, a rack portion 1231 located on the spindle 122, and a gear portion 1232 located on the blade 125, wherein the gear portion 1232 is meshed with the rack portion 1231; the driving mechanism also includes a second elastic member 121 acting between the spindle 122 and the reamer housing 118, wherein the second elastic member 121 is used to apply an axial upward thrust to the spindle 122; the second elastic member 121 is preferably a spring.

[0071] A shear pin 133 is connected between the ball seat 132 and the lower end cover 131. In the initial state, the ball seat 132 has an axially downward stroke; it also includes a guide seat 135 fixedly connected to the inside of the reamer housing 118, and the guide seat 135 is used to limit the axial downward movement of the ball seat 132; when the ball seat 132 moves to the bottom of the stroke, the ball seat 132 and the guide seat 135 are axially abutted, and the ball seat can no longer move downward.

[0072] A ball seat bypass hole 313 is provided on the side of the ball seat 132 , and an enlarged diameter portion 1351 is provided inside the guide seat 135 ; when the ball seat 132 moves to the bottom of the stroke, the ball seat bypass hole 313 is communicated with the enlarged diameter portion 1351 .

[0073] A diversion hole 312 is provided on the side of the lower end cover 131, and a diversion channel is provided on the side of the reamer housing 118. A nozzle 128 is installed in the diversion channel; the spraying direction of the nozzle 128 is toward the area after the blade 125 is opened.

[0074] The diversion hole 312 and the diversion channel are both located below the blade 125; the diversion channel is gradually inclined upward from the inside to the outside along the radial direction; and the nozzle 128 is detachably connected in the diversion channel.

[0075] It also includes a pressure drop matching short section 140 connected below the reamer short section, and a throttle nozzle 139 is detachably connected to the pressure drop matching short section 140 .

[0076] In this embodiment, a notch for installing the blade 125 is formed on the surface of the reamer housing 118. The blade 125 is hinged in the notch via a pin 124. The radially inward side of the notch is closed via a spindle 122 to prevent fluid leakage.

[0077] In this embodiment, a groove for mounting the second elastic member 121 is formed on the inner wall of the reamer housing 118 , and the top end of the spindle 122 has a step surface matching the groove, and the second elastic member 121 abuts against the step surface.

[0078] In a more preferred embodiment, in a cross section perpendicular to the axial direction of the tool, the surface area of ​​the upper end of the mandrel is larger than the surface area of ​​the lower end of the mandrel. This arrangement can make the pressure difference between the upper and lower ends of the mandrel 122 larger, which is more conducive to the automatic downward movement of the mandrel after the pressure drop occurs.

[0079] In a more preferred embodiment, the mandrel 122 and the reamer housing 118 are sealed by a mandrel sealing ring 120; the lower end cover 131 above the diverter channel and the reamer housing 118 are sealed by a lower end cover sealing ring I 126; the lower end cover 131 below the diverter channel and the reamer housing 118 are sealed by a lower end cover sealing ring III 130; the lower end cover 131 and the mandrel 122 are sealed by a lower end cover sealing ring II 127; the ball seat 132 at the upper and lower ends of the diverter hole 312 and the lower end cover 131 are sealed by a ball seat diverter hole sealing ring 129; the ball seat 132 and the guide seat 135 are sealed by a guide seat sealing ring 136; the throttle nozzle 139 and the pressure drop matching short section 140 are sealed by a throttle nozzle sealing ring 138.

[0080] In a more preferred embodiment, the bottom end of the throttle nozzle 139 abuts against a dedicated step surface inside the pressure drop matching short section 140 , and the top end of the throttle nozzle 139 is installed on the hole inside the pressure drop matching short section 140 and is limited by a retaining ring 137 .

[0081] Embodiment 3:

[0082] A method for stimulating a hole reaming tool by dropping a ball downhole, for stimulating Figures 1 to 9 The reaming tool shown includes:

[0083] In the initial state, the tool structure is as follows Figure 1 , Figure 3 , Figure 5 and Figure 6As shown: under the action of the first elastic member 116, the top of the spring seat 115 abuts against the bottom of the ball claw 112, and the top of the ball claw 112 abuts against the step surface corresponding to the inner wall of the upper shell 111 of the ball-containing short joint, the bottom of the ball claw 112 is located in the small diameter portion 1143, and the excitation ball 113 is located in the ball claw 112, and the drilling and completion fluid enters the flow groove 311 and the lower bypass hole 1122 from the upper bypass hole 1121 in sequence, and then continues to flow downward; under the action of the second elastic member 121, the mandrel 122 is located at the top of the stroke, and the blade 125 is in a retracted state; the ball seat 132 and the lower end cover 131 are kept in a connected state by the shear pin 133, and the diversion hole 312 is blocked by the ball seat 132 at this time.

[0084] When the pump is turned on for normal drilling, reaming or circulation operations, the mud pump displacement is lower than the set displacement, which is the minimum displacement at which the excitation ball can be released; at this time, the ball claw 112 drives the excitation ball 113 to compress the spring seat 115, and the spring seat 115 appropriately compresses the first elastic member 116, and the ball claw 112 moves downward for a certain stroke, but is limited by the small diameter portion 1143 of the limit tube 114, so the ball claw 112 cannot expand and the excitation ball 113 cannot be released. At this time, the central channel inside the ball-containing short section is still blocked by the excitation ball 113, and the fluid still needs to enter the flow slot 311 and the lower bypass hole 1122 from the upper bypass hole 1121 in turn, and then continue to flow downward.

[0085] When the ball is needed to excite, the mud pump is controlled to give an instantaneous large displacement exceeding the above-mentioned set displacement. After exceeding the set displacement, the ball claw 112 can drive the excitation ball 113 to compress the spring seat 115, and the spring seat 115 continues to compress the first elastic member 116, and the ball claw 112 moves downward with a larger stroke until the bottom of the ball claw 112 moves into the large diameter portion 1142 of the limit cylinder 114. The ball claw 112 automatically opens in this area, and the excitation ball 113 is released. Figure 4 As shown, the downhole ball throwing function is completed.

[0086] The excitation ball 113 continues to move downward until it falls on the ball seat 132. The central channel inside the ball seat 132 is blocked by the excitation ball 113. The pressure inside the tool increases rapidly, cutting off the shear pin 133. The ball seat 132 moves downward until it is limited by the guide seat 135. The diversion hole 312 of the lower end cover is opened. At this time, the state is as follows: Figure 7 and Figure 8As shown in the figure: a part of the fluid enters the nozzle 128 through the diverter hole 312 and is ejected from the nozzle 128, and the other part of the fluid 403 enters the enlarged diameter portion 1351 through the ball seat bypass hole 313, and then continues to flow downward. After the diverter hole 312 is opened, under the action of the pressure difference, the mandrel 122 moves axially downward, compresses the second elastic member 121, and drives the gear portion 1232 to rotate through the linear motion of the rack portion 1231, converting the downward axial motion of the mandrel 122 into the rotational motion of the blade 125 around the pin 124. Finally, the blade 125 is fully extended and limited by the corresponding step on the outer surface of the reamer housing 118, completing the excitation action of the reaming tool. At this time, the mud pump displacement can be reduced to the normal working displacement, and normal reaming operation can be performed.

[0087] When the reaming operation is completed, or the blade wing 125 needs to be retracted: the pump is stopped, the pressure difference at both ends of the spindle 122 disappears, the second elastic member 121 is reset, the spindle 122 is driven to move upward, the linear motion of the rack portion 1231 drives the gear portion 1232 to rotate, and the upward axial motion of the spindle 122 is converted into the rotational motion of the blade wing 125 around the pin 124, and finally the blade wing 125 is completely retracted. At this time, the state is as follows Fig. 9 shown.

[0088] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0089] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In addition, the term "connected" used in this article can be directly connected or indirectly connected via other components without special explanation.

Claims

1. A downhole ball-dropping reaming tool, comprising a reamer sub, characterized in that: It also includes a ball-containing short section connected above the reamer short section; the ball-containing short section includes a housing, a limiting cylinder (114) fixedly connected to the inside of the housing, a ball claw (112) axially slidingly fitted in the limiting cylinder (114), an excitation ball (113) placed in the ball claw (112), a spring seat (115) axially slidingly fitted in the housing, and a first elastic member (116) abutting against the bottom of the spring seat (115); The spring seat (115) is located below the ball claw (112), the bottom of the ball claw (112) is divided into petals, and an upper bypass hole (1121) and a lower bypass hole (1122) are provided on the side of the ball claw (112); The limiting cylinder (114) comprises a small diameter portion (1143) and a large diameter portion (1142) which are distributed in the upper and lower parts, and a plurality of flow grooves (311) for connecting the small diameter portion (1143) and the large diameter portion (1142); the inner diameter of the small diameter portion (1143) is smaller than the outer diameter of the ball claw (112) in a natural state, and the inner diameter of the large diameter portion (1142) is greater than or equal to the outer diameter of the ball claw (112) in a natural state; When the bottom of the ball claw (112) is located in the small diameter portion (1143), the inner diameter of the bottom of the ball claw (112) is smaller than the diameter of the excitation ball (113), and the two ends of the flow groove (311) are respectively connected to the upper bypass hole (1121) and the lower bypass hole (1122); When the bottom of the ball claw (112) is located in the large diameter portion (1142), the inner diameter of the bottom of the ball claw (112) is greater than the diameter of the excitation ball (113).

2. A downhole ball-dropping reaming tool according to claim 1, characterized in that: The small diameter portion (1143) comprises a plurality of ridges evenly distributed along the circumference of the inner wall of the limiting cylinder (114), and a flow groove (311) is formed between two adjacent ridges; a transition portion (1141) with a gradually decreasing thickness is provided at the bottom of the ridges.

3. A downhole ball-dropping reaming tool according to claim 1, characterized in that: The shell comprises an upper shell (111) of a ball-receiving short joint and a lower shell (117) of a ball-receiving short joint which are connected at the upper and lower ends; the ball claw (112) is slidably fitted in the upper shell (111) of the ball-receiving short joint, and a step surface is arranged in the lower shell (117) of the ball-receiving short joint, and the bottom end of the first elastic member (116) abuts against the step surface.

4. A downhole ball-dropping reaming tool according to claim 1, characterized in that: The reamer sub comprises an reamer housing (118), a blade (125) connected to the reamer housing (118), a ball seat (132) located inside the reamer housing (118) and connected in an axial sliding manner, and a driving mechanism for driving the blade (125) to open; the ball seat (132) matches the excitation ball (113).

5. A downhole ball-dropping reaming tool according to claim 4, characterized in that: An upper end cover (119) and a lower end cover (131) are fixedly connected inside the reamer housing (118); The driving mechanism comprises a spindle (122) slidably connected to the inside of the reamer housing (118) along the axial direction, a rack portion (1231) located on the spindle (122), and a gear portion (1232) located on the blade (125), wherein the gear portion (1232) meshes with the rack portion (1231); the driving mechanism also comprises a second elastic member (121) acting between the spindle (122) and the reamer housing (118), wherein the second elastic member (121) is used to apply an axial upward thrust to the spindle (122).

6. A downhole ball-dropping reaming tool according to claim 5, characterized in that: A shear pin (133) is connected between the ball seat (132) and the lower end cover (131), and the ball seat (132) has an axially downward stroke; the ball seat (132) also includes a flow guide seat (135) fixedly connected to the inside of the reamer housing (118), and the flow guide seat (135) is used to limit the axial downward movement of the ball seat (132); when the ball seat (132) moves to the bottom of the stroke, the ball seat (132) and the flow guide seat (135) are axially abutted.

7. A downhole ball-dropping reaming tool according to claim 6, characterized in that: A ball seat bypass hole (313) is provided on the side of the ball seat (132), and an expanded diameter portion (1351) is provided inside the flow guide seat (135); when the ball seat (132) moves to the bottom end of the stroke, the ball seat bypass hole (313) is connected to the expanded diameter portion (1351).

8. A downhole ball-dropping reaming tool according to claim 5, characterized in that: A flow diversion hole (312) is provided on the side of the lower end cover (131), and a flow diversion channel is provided on the side of the reamer housing (118). A nozzle (128) is installed in the flow diversion channel; the spraying direction of the nozzle (128) is toward the area after the blade (125) is opened.

9. A downhole ball-dropping reaming tool according to claim 8, characterized in that: The diversion hole (312) and the diversion channel are both located below the blade (125); the diversion channel gradually tilts upward from the inside to the outside along the radial direction; and the nozzle (128) is detachably connected in the diversion channel.

10. A downhole ball-dropping reaming tool according to claim 5, characterized in that: It also includes a pressure drop matching short section (140) connected below the reamer short section, and a throttle nozzle (139) is detachably connected to the pressure drop matching short section (140).

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