A drilling-free graded cementing device and its use method

Abstract

The present invention belongs to the technical field of graded collars, and relates to a drill-free graded cementing device and a method for using the same. It comprises: a main body, the main body is provided with a plurality of fixed grouting holes distributed circumferentially, a sleeve is spline-connected inside the main body, the sleeve is provided with dynamic grouting holes equal in number to the fixed grouting holes, a closed-hole ring is provided inside the sleeve and is slidably connected to an open-hole ring, a limiting assembly for maintaining stability is provided on the sleeve; the limiting assembly comprises: a plurality of circumferentially distributed limiting elastic members. The present invention limits the sleeve by limiting elastic members, and utilizes the open-hole ring to squeeze the limiting elastic members, so that the limiting elastic members remain stable during the grouting operation. In this way, the purpose of maintaining the stability of the grouting holes can be achieved without using pins with high shear strength, thereby avoiding the occurrence of overpressure when switching the grouting hole state, thereby reducing the risk of damage to the wellbore structure and channeling of formation fluids.

Description

Technical Field

[0001] The invention relates to the technical field of graded collars, and in particular to a drill-free graded cementing device and a use method thereof. Background Art

[0002] As a key cementing tool in oil and gas drilling projects, graded collars are mainly used to solve the technical difficulties of cementing operations in long well sections: when the bearing capacity of the formation is insufficient or there is a leakage layer, the traditional cementing process is prone to cause cement slurry leakage or formation rupture; graded cementing technology achieves precise control of annular space pressure through segmented grouting, among which the graded collar is the core control device, which adopts a pressure-holding ball activation mechanism to control the opening and closing of the corresponding grouting channel through pressure-holding balls of different diameters. Modern products are mainly divided into two categories: conventional graded collars that require later drilling to remove internal components and drill-free graded collars made of soluble materials.

[0003] The existing drill-free grading collar usually adopts a pressure-holding ball control scheme, which requires a multi-stage reducing structure to be set inside the grading collar, and the axial displacement of the sleeve is triggered by the pressure-holding ball to switch the grouting channel state; during the grouting process, in order to maintain the open state of the grouting channel, shear pins are generally used to mechanically lock the sleeve. During the grouting operation, pressure fluctuations caused by wellbore blockage, tool sticking or abnormal formation pressure will generate dynamic shear loads on the pins through hydraulic transmission, and the pins may be mistakenly sheared, causing abnormal closure of the grouting channel; to reduce the probability of false triggering, high-strength alloy pins are usually used and their structural dimensions are optimized so that the nominal shear strength of the pins is significantly higher than the conventional grouting pressure fluctuation value. However, in the subsequent pressurization process of shearing the pins, this scheme is prone to local deformation of the casing due to overpressure, inducing formation fracturing leakage or generating microcracks. These situations will endanger the structural integrity of the wellbore and increase the risk of formation fluid crossflow. In severe cases, it may lead to cementing failure or even well control accidents. Summary of the Invention

[0004] The present invention provides a drill-free plug-type staged cementing device and a method for using the device, which overcomes the shortcomings of the existing method of increasing the shear strength of the pins, which easily leads to local deformation of the casing, induces formation fracturing and leakage, or generates microcracks.

[0005] The technical solution is: a drilling-free plug-type graded cementing device, comprising:

[0006] A main body, wherein the main body is provided with a plurality of fixed grouting holes distributed in a circumferential direction, a sliding sleeve is spline-connected in the main body, the sliding sleeve is provided with dynamic grouting holes equal in number to the fixed grouting holes, a closed-hole ring is provided in the sliding sleeve and is slidably connected to an open-hole ring, the sliding sleeve is slidably connected to a locking pin slidably connected to the main body, and a limiting assembly is provided on the sliding sleeve for maintaining its stability;

[0007] The limiting assembly includes: a plurality of limiting springs distributed circumferentially, the position of the sliding sleeve near the opening ring is provided with lower slot bodies equal to the number of the limiting springs, the limiting springs are fixed in the adjacent lower slot bodies, the inner side of the main body is provided with limiting grooves equal to the number of the limiting springs, the limiting springs are located above the adjacent limiting grooves, and the limiting springs are provided with an extrusion slope in contact with the opening ring and a support slope for fitting with the lower side surface of the adjacent limiting groove.

[0008] Furthermore, the angle between the extrusion slope and the horizontal plane is always greater than the angle between the support slope and the horizontal plane, so that the outward extrusion force on the limiting elastic member is greater than the inward extrusion force on the limiting elastic member.

[0009] Furthermore, a sliding slope is provided on a side of the limiting elastic member away from the central axis of the main body, and the sliding slope is used to fit with the main body and the adjacent limiting groove.

[0010] Furthermore, it also includes:

[0011] A locking assembly is provided in the main body and is used to lock the sliding sleeve after grouting is completed. The locking assembly includes:

[0012] Locking spring, accommodating groove and inclined groove, and the number of the above three is equal to that of the limiting spring, the position of the sliding sleeve near the closed-hole ring is provided with upper groove bodies with a number equal to that of the locking spring, the locking spring is fixedly connected to the adjacent upper groove body, the main body is provided with fixing grooves with a number equal to that of the locking spring, the fixing grooves are used to limit the locking spring, the locking spring is provided with a force-applying inclined surface in contact with the closed-hole ring, the closed-hole ring is slidably connected to the sliding sleeve, the accommodating groove and the inclined groove are both provided on the inner side of the main body and are connected to each other, and the limiting spring is located above the adjacent accommodating groove.

[0013] Furthermore, the sum of the depth of the fixing groove and the depth of the upper groove body is greater than the maximum width of the locking spring in the radial direction of the sliding sleeve cross section, so that the locking spring can completely lose contact with the closed-hole ring, and the sum of the depth of the inclined groove and the depth of the lower groove body is greater than the maximum width of the limiting spring in the radial direction of the sliding sleeve cross section, so that the limiting spring can completely lose contact with the open-hole ring.

[0014] Furthermore, the central angle corresponding to the projection of the inclined groove on the cross section of the main body is greater than the central angle corresponding to the projection of the fixed grouting hole on the cross section of the main body.

[0015] Furthermore, the locking spring is provided with a lateral displacement inclined surface, and the main body is provided with locking grooves equal in number to the inclined grooves, the locking grooves are connected to the adjacent inclined grooves, and the fixed groove is located above the adjacent locking grooves, and the central angle corresponding to the lateral displacement inclined surface on the circle formed by the cross section of the main body is equal to the central angle corresponding to the locking groove on the circle formed by the cross section of the main body.

[0016] Furthermore, all of the fixed grouting holes and all of the inclined grooves are staggeredly distributed circumferentially within the main body.

[0017] Furthermore, in the direction from the outside to the inside, the height of the locking groove gradually decreases, and the height of the lower part of the limiting elastic member gradually decreases.

[0018] A method for using a drill-free plug-type graded cementing device, based on the above-mentioned drill-free plug-type graded cementing device, specifically includes the following steps:

[0019] Step 1: Put the first pressure-holding ball into the casing, make it stuck on the opening ring to achieve sealing, and inject cement slurry into the casing;

[0020] Step 2: The pressure in the casing increases and pushes the sliding sleeve downward to cut the lock pin. At the same time, the limiting groove limits the limiting spring, the dynamic grouting hole corresponds to the fixed grouting hole, and the cement slurry in the casing is filled into the wellbore;

[0021] Step 3: After the grouting is completed, the second pressure-holding ball is put into the casing so that the pressure-holding ball is stuck on the closed-hole ring to achieve sealing;

[0022] Step 4: Increase the pressure in the casing to drive the pressure-holding ball and the closing ring downward, and the sliding sleeve drives the limiting elastic member downward, so that the limiting elastic member enters the receiving groove and slides along the inclined groove, and at the same time, the dynamic grouting hole is misaligned with the fixed grouting hole;

[0023] Step 5: The locking spring corresponds to the fixing groove and enters it. During this process, the locking spring drives the sliding sleeve and the limiting spring to move, so that the limiting spring enters the locking groove;

[0024] Step 6: The limiting spring and the locking spring release the support for the closed-hole ring and the open-hole ring, causing the closed-hole ring and the open-hole ring to fall to the bottom of the casing. Finally, the closed-hole ring and the open-hole ring are recovered using tools.

[0025] The beneficial effect of adopting the above technical solution is that: the present invention limits the sliding sleeve through the limiting spring piece, and uses the opening ring to squeeze the limiting spring piece, so that the limiting spring piece remains stable during the grouting operation. In this way, the purpose of maintaining the stability of the grouting hole can be achieved without using pins with high shear strength, avoiding the occurrence of overpressure when switching the grouting hole state, thereby reducing the risk of damage to the wellbore structure and channeling of formation fluid.

[0026] The sliding slope is fitted with the main body, which improves the stability of the limiting spring during sliding. At the same time, it can disperse part of the extrusion force exerted by the opening ring on the limiting spring to the main body, thereby improving the structural strength of the limiting spring.

[0027] The inclined groove is used to guide the rotation of the sliding sleeve, so that the dynamic grouting holes and the fixed grouting holes are circumferentially staggered. This maintains the sealing state of the grouting holes after cementing is completed, and at the same time reduces the probability of the grouting holes being reconnected due to collision between the downhole tool and the sliding sleeve.

[0028] The locking groove is used to limit the axial position of the limiting spring, thereby reducing the probability of the sliding sleeve moving axially due to the collision during the movement of the downhole tool, and further reducing the probability of the grouting hole being opened by mistake; the locking groove is used to limit the limiting spring, thereby reducing the probability of the limiting spring being forcibly dislodged from the locking groove, and further enhancing the stability of the sliding sleeve. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0030] Figure 2 It is a three-dimensional structural cross-sectional view of the main body and the sliding sleeve of the present invention;

[0031] Figure 3 Schematic diagram of the three-dimensional structure of the opening ring and the limiting elastic member of the present invention;

[0032] Figure 4 Schematic diagram of the three-dimensional structure of the limiting elastic member and the locking elastic member of the present invention;

[0033] Figure 5 This is a schematic diagram of the three-dimensional structure when the fixed grouting hole and the dynamic grouting hole are connected;

[0034] Figure 6 The present invention is attached Figure 5 Enlarged view of point A in the middle;

[0035] Figure 7 Schematic diagram of the three-dimensional structure of the limiting elastic member of the present invention;

[0036] Figure 8 It is a schematic diagram of the three-dimensional structure of the present invention during the misalignment process of the fixed grouting hole and the dynamic grouting hole;

[0037] Figure 9 The present invention is attached Figure 8 Enlarged view of point B in the middle;

[0038] Figure 10 Schematic diagram of the three-dimensional structure of the limiting groove and the fixing groove of the present invention;

[0039] Figure 11 Schematic diagram of the positional relationship between the fixing groove and the locking groove of the present invention;

[0040] Figure 12 It is a schematic diagram of the three-dimensional structure of the locking spring of the present invention.

[0041] Markings in the accompanying drawings: 1-main body, 101-fixed grouting hole, 2-sliding sleeve, 201-dynamic grouting hole, 202-lower trough body, 203-upper trough body, 3-closed hole ring, 4-open hole ring, 5-limiting spring, 501-limiting groove, 502-extrusion slope, 503-support slope, 504-sliding slope, 6-locking pin, 7-locking spring, 701-fixed groove, 702-force slope, 703-side displacement slope, 801-accommodating groove, 802-inclined groove, 803-locking groove. DETAILED DESCRIPTION

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work. Example 1

[0043] This embodiment provides a drill-free plug-free staged cementing device, which is used to reduce the pressure required for triggering the closure of the staged collar.

[0044] refer to Figures 1-4 A drilling-free plug-type graded cementing device comprises: a main body 1, the main body 1 is provided with three circumferentially distributed fixed grouting holes 101, (reference Figure 4 ) The upper middle part of the main body 1 is provided with three circumferentially distributed ridges, and the outer peripheral side of the sliding sleeve 2 is provided with three circumferentially distributed spline grooves. The sliding sleeve 2 and the main body 1 are spline-connected through the spline grooves and ridges. (Refer to Figure 2 ) A step surface is provided at the lower part of the inner side of the main body 1, and the above-mentioned step surface is used to limit the lower limit position of the sliding sleeve 2. The sliding sleeve 2 is provided with three dynamic grouting holes 201. Initially, the dynamic grouting holes 201 are located above the adjacent fixed grouting holes 101, that is, the two are staggered; a closed-hole ring 3 is provided in the sliding sleeve 2 and is slidably connected to an open-hole ring 4. The inner diameter of the closed-hole ring 3 is larger than the inner diameter of the open-hole ring 4. The sliding sleeve 2 is slidably connected to a locking pin 6 that is slidably connected to the main body 1, and a limiting component is provided on the sliding sleeve 2 to keep it stable.

[0045] refer to Figure 3-Figure 8The limiting assembly includes: three circumferentially distributed limiting springs 5, three circumferentially distributed lower slots 202 are provided at the lower part of the sliding sleeve 2, the height of the lower slots 202 is greater than the height of the limiting springs 5, the upper side of the limiting springs 5 ​​is fixed to the adjacent lower slots 202, the limiting springs 5 ​​are composed of an elastic rod and an extrusion head, the elastic rod of the limiting spring 5 is in a bent force storage state, and in a free state, (refer to Figure 8 ) The elastic rod of the limiting spring 5 is in a vertical state; initially, the limiting spring 5 limits the hole ring 4, so that the hole ring 4 cannot move downward relative to the sliding sleeve 2; three limiting grooves 501 are provided on the inner side of the main body 1, and the limiting spring 5 is located above the adjacent limiting grooves 501. The extrusion head of the limiting spring 5 is provided with an extrusion slope 502 in contact with the hole ring 4, and the extrusion slope 502 is inclined downward from the outside to the inside. The extrusion head of the limiting spring 5 is provided with a supporting slope 503 for fitting with the lower side of the adjacent limiting groove 501, and the supporting slope 503 is inclined downward from the outside to the inside. The angle between the extrusion slope 502 and the horizontal plane (during the entire swing process of the extrusion head of the limiting spring 5) is 0. During the entire swing process, the above-mentioned angle changes in the range of 20°-30°) is always greater than the angle between the supporting slope 503 and the horizontal plane (during the entire swing process of the extrusion head of the limiting spring 5, the above-mentioned angle changes in the range of 5°-15°). When the limiting spring 5 enters the limiting groove 501 and the supporting slope 503 is in contact with the lower side of the limiting groove 501, the component of the outward extrusion force exerted on the extrusion head of the limiting spring 5 by the opening ring 4 is greater than the component of the force of the limiting spring 5 sliding inward along the supporting slope 503; the vertical distance between the supporting slope 503 and the lower side of the adjacent limiting groove 501 is equal to the vertical distance between the center point of the dynamic grouting hole 201 and the center point of the adjacent fixed grouting hole 101.

[0046] It should be noted that the height herein refers to the height of the component itself, rather than the height of the component relative to the horizontal plane; in this embodiment, the closed-hole ring 3 and the sliding sleeve 2 can be regarded as being fixedly connected.

[0047] The above setting can achieve the purpose of limiting the sliding sleeve 2 by using the limiting elastic member 5 and squeezing the limiting elastic member 5 by using the opening ring 4, so that the limiting elastic member 5 remains stable during the grouting operation. In this way, the purpose of maintaining the stability of the grouting hole can be achieved without using pins with high shear strength, avoiding the occurrence of overpressure when switching the grouting hole state, thereby reducing the risk of damage to the wellbore structure and crossflow of formation fluid.

[0048] refer to Figure 5-Figure 7 A sliding slope 504 is provided on the outer side of the extrusion head of the limiting spring 5, and the sliding slope 504 is used to fit with the main body 1 and the adjacent limiting groove 501.

[0049] The above setting can achieve the purpose of utilizing the sliding slope 504 to fit with the main body 1, thereby improving the stability of the limiting spring 5 during the sliding process, and at the same time can disperse part of the extrusion force applied by the opening ring 4 to the limiting spring 5 to the main body 1, thereby improving the structural strength of the limiting spring 5.

[0050] The cementing process after adopting the above settings is as follows: during the cementing process, the number of graded collars required is determined according to the wellbore depth and the pressure bearing capacity of the formation (this article takes two-stage grouting, two-stage cementing construction, and the need for one graded collar as an example), the specifications of the graded collar are selected according to the inner diameter of the casing, and the main body 1 is connected to the corresponding position of the casing through threads, and then the casing is lowered into the wellbore, and the drilling fluid is circulated in the wellbore to start the first-stage cementing construction.

[0051] First-level cementing construction:

[0052] Inject pre-pad fluid into the casing to remove drilling fluid residue and isolate the drilling fluid from cement slurry;

[0053] Inject a fixed amount of cement slurry and drilling fluid in sequence, so that all the fixed amount of cement slurry flows out from the bottom of the casing and fills the lower half of the wellbore (the wellbore is divided into upper and lower sections based on the main body 1);

[0054] Wait for the cement to initially set and confirm the quality of the first-level cementing;

[0055] A pressure-holding ball (the pressure-holding ball used in this article is made of soluble material) with a diameter smaller than the inner diameter of the closed-hole ring 3 and larger than the inner diameter of the open-hole ring 4 is thrown into the casing, so that the pressure-holding ball is stuck on the open-hole ring 4 to achieve sealing. The pressure-holding ball and the open-hole ring 4 are used to separate the entire casing into two sections, upper and lower sections.

[0056] Secondary cementing construction:

[0057] Inject prepad fluid;

[0058] The cam 504 is pressed against the inner wall of the casing 100, and the cam 506 is pressed against the inner wall of the casing 100. The cam 507 is pressed against the outer wall of the casing 100, and the cam 508 is pressed against the outer wall of the casing 100.

[0059] All the cement in the casing flows out of the casing through the dynamic grouting holes 201 and the adjacent fixed grouting holes 101 and fills the lower half of the wellbore.

[0060] Wait for the cement to initially set and confirm the quality of the secondary cementing;

[0061] While waiting for the initial setting of cement, the pressure-holding ball dissolves, and a pressure-holding ball with a diameter smaller than the inner diameter of the casing and larger than the inner diameter of the obturator ring 3 is put into the casing, so that the pressure-holding ball is stuck on the obturator ring 3 to achieve sealing;

[0062] Increasing the pressure in the sleeve drives the pressure-holding ball and the obturator ring 3 downward, the obturator ring 3 drives the sliding sleeve 2 downward, and the sliding sleeve 2 drives the limiting spring 5 downward, causing the supporting inclined surface 503 to slide along the lower side surface of the limiting groove 501, and causing the extrusion head of the limiting spring 5 to move inward, and then the extrusion head of the limiting spring 5 disengages from the limiting groove 501, and the limiting groove 501 releases the limit on the limiting spring 5; in the process of the limiting spring 5 moving out of the limiting groove 501, the limiting spring 5 squeezes the opening ring 4 upward through the extrusion inclined surface 502, until the limiting spring 5 moves out of the limiting groove 501, and the limiting spring 5 is reset relative to the opening ring 4.

[0063] After the limiting spring 5 moves out of the limiting groove 501, the closed-hole ring 3 continues to drive the sleeve 2 to move downward until the sleeve 2 contacts the step surface inside the main body 1, and the sleeve 2 stops moving. At this time, the dynamic grouting hole 201 is located below the adjacent fixed grouting hole 101 and is staggered, and the cementing operation is completed. Example 2

[0064] This embodiment provides a drill-free plug-free staged cementing device, which provides a function of locking the grouting hole based on the first embodiment.

[0065] refer to Figure 4 、 Figure 5 and Figures 8-12, also includes: a locking component, which is arranged in the main body 1, and the locking component is used to lock the sliding sleeve 2 after the grouting is completed. The locking component includes: three circumferentially distributed locking springs 7, three circumferentially distributed receiving grooves 801 and three circumferentially distributed inclined grooves 802. The upper part of the sliding sleeve 2 is provided with three upper groove bodies 203. The upper side of the locking spring 7 is fixedly connected to the adjacent upper groove bodies 203. The locking spring 7 consists of an elastic rod and a locking head. Three fixing grooves 701 are provided in the middle part of the main body 1. The fixing groove 701 and the adjacent locking spring 7 are not on the same vertical line. The locking spring 7 is provided with a force-applying inclined surface 702 that contacts the lower side of the obturator ring 3. The force-applying inclined surface 70 2 is tilted downward from the outside to the inside, and the closed-hole ring 3 is slidably connected to the sliding sleeve 2. Initially, the locking spring 7 limits the closed-hole ring 3 so that the closed-hole ring 3 cannot move downward relative to the sliding sleeve 2. The accommodating groove 801 and the inclined groove 802 are both arranged on the inner side of the main body 1, and the accommodating groove 801 is connected to the upper part of the inclined groove 802. The extrusion head of the limiting spring 5 is located above the adjacent accommodating groove 801; the length of the contact between the ridge on the main body 1 and the sliding sleeve 2 is less than the minimum distance between the limiting spring 5 and the accommodating groove 801 at the initial time; the central angle corresponding to the projection of the inclined groove 802 on the cross section of the main body 1 is greater than the central angle corresponding to the projection of the fixed grouting hole 101 on the cross section of the main body 1.

[0066] It should be noted that, in this embodiment, the fixing groove 701 is located above the lower end of the inclined groove 802 .

[0067] The above arrangement can achieve the goal of using the inclined groove 802 to guide the rotation of the sleeve 2, so that the dynamic grouting hole 201 and the fixed grouting hole 101 are circumferentially staggered, thereby maintaining the sealing state of the grouting hole after the cementing is completed, and at the same time reducing the probability of the downhole tool colliding with the sleeve 2 and causing the grouting hole to be reconnected.

[0068] After adopting the above-mentioned setting, the locking operation of the sleeve 2 is as follows: after the grouting operation is completed, the closed-hole ring 3 drives the sleeve 2 to move downward through the locking spring 7, and the sleeve 2 drives the limiting spring 5 to move downward. When the extrusion head of the limiting spring 5 corresponds to the accommodating groove 801, the extrusion head of the limiting spring 5 enters the accommodating groove 801 under the elastic action of its elastic rod.

[0069] When the locking head of the locking spring 7 is in the fixed groove 701, the locking head of the locking spring 7 enters the fixed groove 701 under the elastic action of its elastic rod and the force of the closing ring 3 on it toward the outside. At this time, the fixed groove 701 limits the locking spring 7, so that the locking spring 7 and the sliding sleeve 2 cannot rotate circumferentially, thereby locking the sliding sleeve 2 and maintaining the sealing state of the grouting hole. Example 3

[0070] This embodiment provides a drill-free plug-free staged cementing device, which provides a function of eliminating the diameter change point inside the staged collar on the basis of the second embodiment.

[0071] refer to Figures 8-12 The sum of the depth of the fixing groove 701 and the depth of the upper groove body 203 (i.e., the thickness of the sliding sleeve 2) is greater than the maximum width of the extrusion head of the locking spring 7 in the radial direction of the cross section of the sliding sleeve 2, so that the locking spring 7 can completely lose contact with the closed-hole ring 3, and the sum of the depth of the inclined groove 802 (the depth of the accommodating groove 801 is equal to the depth of the inclined groove 802) and the depth of the lower groove body 202 (i.e., the thickness of the sliding sleeve 2) is greater than the maximum width of the limiting spring 5 in the radial direction of the cross section of the sliding sleeve 2, so that the limiting spring 5 can completely lose contact with the open-hole ring 4.

[0072] The above arrangement can achieve that, after the cementing is completed, the limiting elastic member 5 and the locking elastic member 7 are fully retracted, thereby releasing the limiting of the closed-hole ring 3 and the open-hole ring 4, so that the closed-hole ring 3 and the open-hole ring 4 can be separated from the sliding sleeve 2, thereby eliminating the reducing structure inside the grading collar, reducing the influence of the grading collar on the inner diameter of the casing, and reducing the probability of the downhole tool getting stuck in the reducing section.

[0073] After the limiting spring 5 enters the accommodating groove 801, the extrusion inclined surface 502 loses contact with the opening ring 4, and the opening ring 4 slides downward under the action of its own weight, and detaches from the sliding sleeve 2 and the main body 1, and finally falls to the bottom of the sleeve; after the locking spring 7 enters the fixing groove 701, the force-applying inclined surface 702 loses contact with the closed-hole ring 3. At this time, the closed-hole ring 3 gradually moves downward under the action of its own weight and finally falls to the bottom of the sleeve. Then the operator uses tools to retract the closed-hole ring 3 and the opening ring 4. Example 4

[0074] This embodiment provides a drill-free plug-free staged cementing device, which provides a function of enhancing the locking stability of the grouting hole on the basis of the third embodiment.

[0075] refer to Figure 11 and Figure 12 The locking spring 7 is provided with a lateral inclined surface 703, and three locking grooves 803 are provided in the main body 1. The locking groove 803 is connected to the lower end of the adjacent inclined groove 802. The locking groove 803 is a rectangular groove, and the fixed groove 701 is located above the adjacent locking groove 803. The central angle corresponding to the lateral inclined surface 703 on the circle formed by the cross section of the main body 1 is equal to the central angle corresponding to the locking groove 803 on the circle formed by the cross section of the main body 1, so that the limiting spring 5 can eventually slide into the locking groove 803.

[0076] The above arrangement can achieve axial limiting of the limiting spring 5 by the locking groove 803, thereby reducing the probability of the sliding sleeve 2 moving axially due to collision during movement of the downhole tool, and further reducing the probability of the grouting hole being opened by mistake.

[0077] refer to Figure 10 The three fixed grouting holes 101 and the three inclined grooves 802 are staggeredly distributed in the circumferential direction inside the main body 1.

[0078] The above arrangement can achieve, by utilizing the misalignment between the fixed grouting hole 101 and the inclined groove 802, that the dynamic grouting hole 201 maintains a dual misalignment state in the circumferential and axial directions with the fixed grouting hole 101 after the grouting is completed, and even during subsequent use, when the sleeve 2 is impacted by the downhole tool and moves axially, the dynamic grouting hole 201 and the fixed grouting hole 101 can still maintain a circumferential misalignment state, thereby enhancing the reliability of the grouting hole sealing.

[0079] refer to Figure 11 In the direction from the outside to the inside, the height of the locking groove 803 gradually decreases, and the height of the lower part of the limiting elastic member 5 gradually decreases.

[0080] The above arrangement can achieve the goal of limiting the position of the limiting elastic member 5 by utilizing the locking groove 803 , thereby reducing the probability of the limiting elastic member 5 being forcibly released from the locking groove 803 and further enhancing the stability of the sliding sleeve 2 .

[0081] When the locking cam 703 is in the closed position, the locking cam 703 is in the closed position, and the locking cam 703 is in the open position, so that the locking cam 703 is in the open position. Example 5

[0082] This embodiment provides a method for using a drill-free plug-free staged cementing device.

[0083] refer to Figures 1-12 A method for using a drill-free plug-type graded cementing device is based on the above-mentioned drill-free plug-type graded cementing device. The specific steps are as follows:

[0084] Step 1: Put the first pressure-holding ball into the casing, make it stuck on the opening ring 4 to achieve sealing, and inject cement slurry into the casing;

[0085] Step 2: The pressure in the casing increases and pushes the sliding sleeve 2 downward to cut the lock pin 6. At the same time, the limiting groove 501 limits the limiting spring 5. The dynamic grouting hole 201 corresponds to the fixed grouting hole 101, and the cement slurry in the casing is filled into the wellbore.

[0086] Step 3: After the grouting is completed, a second pressure-holding ball is put into the casing so that the pressure-holding ball is stuck on the closed-hole ring 3 to achieve sealing;

[0087] Step 4: Increase the pressure in the casing, drive the pressure-holding ball and the obturator ring 3 downward, and the sliding sleeve 2 drives the limiting elastic member 5 downward, so that the limiting elastic member 5 enters the receiving groove 801 and slides along the inclined groove 802, and at the same time, the dynamic grouting hole 201 is misaligned with the fixed grouting hole 101;

[0088] Step 5: The locking spring 7 corresponds to the fixing groove 701 and enters it. During this process, the locking spring 7 drives the sliding sleeve 2 and the limiting spring 5 to move, so that the limiting spring 5 enters the locking groove 803;

[0089] Step 6: The limiting elastic member 5 and the locking elastic member 7 release the support for the obturator ring 3 and the open hole ring 4, so that the obturator ring 3 and the open hole ring 4 fall to the bottom of the casing, and finally use a tool to recover the obturator ring 3 and the open hole ring 4.

[0090] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some of the technical features thereof can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A drill-free plug-type graded cementing device, characterized in that: include: A main body (1), the main body (1) being provided with a plurality of fixed grouting holes (101) distributed in a circumferential direction, a sleeve (2) being spline-connected inside the main body (1), the sleeve (2) being provided with movable grouting holes (201) equal in number to the fixed grouting holes (101), a closed-hole ring (3) being provided inside the sleeve (2) and being slidably connected to an open-hole ring (4), the sleeve (2) being slidably connected to a locking pin (6) slidably connected to the main body (1), and a position limiting assembly for maintaining stability being provided on the sleeve (2); The limiting assembly comprises: a plurality of limiting springs (5) distributed circumferentially, the sliding sleeve (2) is provided with a lower slot body (202) equal to the number of the limiting springs (5) at a position close to the opening ring (4), the limiting springs (5) are fixed in the adjacent lower slot body (202), the inner side of the main body (1) is provided with a limiting groove (501) equal to the number of the limiting springs (5), the limiting springs (5) are located above the adjacent limiting grooves (501), and the limiting springs (5) are provided with an extrusion inclined surface (502) in contact with the opening ring (4) and a supporting inclined surface (503) for fitting with the lower side surface of the adjacent limiting groove (501); The angle between the extrusion slope (502) and the horizontal plane is always greater than the angle between the support slope (503) and the horizontal plane, so that the outward extrusion force on the limiting elastic member (5) is greater than the inward extrusion force on the limiting elastic member (5); A sliding slope (504) is provided on one side of the limiting spring (5) away from the central axis of the main body (1), and the sliding slope (504) is used to fit with the main body (1) and the adjacent limiting groove (501).

2. The drilling-free plug-in graded cementing device according to claim 1 is characterized in that: include: A locking assembly is provided in the main body (1), and is used to lock the sliding sleeve (2) after grouting is completed. The locking assembly comprises: A locking spring (7), an accommodating groove (801) and an inclined groove (802), and the number of the above three is equal to that of the limiting spring (5); the position of the sliding sleeve (2) close to the closed hole ring (3) is provided with an upper groove body (203) equal to the number of the locking spring (7); the locking spring (7) is fixed in the adjacent upper groove body (203); the main body (1) is provided with a fixing groove (701) equal to the number of the locking spring (7); the fixing groove (701) is used to limit the locking spring (7); the locking spring (7) is provided with a force-applying inclined surface (702) in contact with the closed hole ring (3); the closed hole ring (3) is slidably connected to the sliding sleeve (2); the accommodating groove (801) and the inclined groove (802) are both provided on the inner side of the main body (1) and are connected to each other; the limiting spring (5) is located above the adjacent accommodating groove (801).

3. The drilling-free plug-type graded cementing device according to claim 2 is characterized in that: The sum of the depth of the fixing groove (701) and the depth of the upper groove body (203) is greater than the maximum width of the locking spring (7) in the radial direction of the cross section of the sliding sleeve (2), so that the locking spring (7) can completely lose contact with the closed hole ring (3); the sum of the depth of the inclined groove (802) and the depth of the lower groove body (202) is greater than the maximum width of the limiting spring (5) in the radial direction of the cross section of the sliding sleeve (2), so that the limiting spring (5) can completely lose contact with the open hole ring (4).

4. The drilling-free plug-in graded cementing device according to claim 3 is characterized in that: The central angle corresponding to the projection of the inclined groove (802) on the cross section of the main body (1) is greater than the central angle corresponding to the projection of the fixed grouting hole (101) on the cross section of the main body (1).

5. The drilling-free plug-in graded cementing device according to claim 4 is characterized in that: The locking spring (7) is provided with a lateral inclined surface (703), and the main body (1) is provided with locking grooves (803) equal in number to the inclined grooves (802), the locking grooves (803) are communicated with adjacent inclined grooves (802), the fixed groove (701) is located above the adjacent locking groove (803), and the central angle of the circle formed by the cross section of the main body (1) corresponding to the lateral inclined surface (703) is equal to the central angle of the circle formed by the cross section of the main body (1) corresponding to the locking grooves (803).

6. The drilling-free plug-in graded cementing device according to claim 5 is characterized in that: All of the fixed grouting holes (101) and all of the inclined grooves (802) are distributed circumferentially and staggered within the main body (1).

7. A drilling-free plug-in graded cementing device according to claim 6, characterized in that In the direction from the outside to the inside, the height of the locking groove (803) gradually decreases, and the height of the lower part of the limiting elastic member (5) gradually decreases.

8. A method for using a drill-free plug-type graded cementing device, according to claim 7, characterized in that: The specific steps are as follows: Step 1: insert the first pressure-holding ball into the casing, so that the pressure-holding ball is stuck on the opening ring (4) to achieve sealing, and inject cement slurry into the casing; Step 2: The pressure in the casing increases and pushes the sliding sleeve (2) downward to cut the locking pin (6). At the same time, the limiting groove (501) limits the limiting spring (5), and the dynamic grouting hole (201) corresponds to the fixed grouting hole (101). The cement slurry in the casing is filled into the wellbore; Step 3: After the grouting is completed, a second pressure-holding ball is put into the casing so that the pressure-holding ball is stuck on the closed-hole ring (3) to achieve sealing; Step 4: increasing the pressure in the casing, driving the pressure-holding ball and the closing ring (3) downward, and the sliding sleeve (2) driving the limiting elastic member (5) downward, so that the limiting elastic member (5) enters the receiving groove (801) and slides along the inclined groove (802), and at the same time, the movable grouting hole (201) and the fixed grouting hole (101) are dislocated; Step 5: The locking spring (7) corresponds to the fixing groove (701) and enters into it. During this process, the locking spring (7) drives the sliding sleeve (2) and the limiting spring (5) to move, so that the limiting spring (5) enters the locking groove (803); Step 6: The limiting spring (5) and the locking spring (7) release the support for the closed-hole ring (3) and the open-hole ring (4), so that the closed-hole ring (3) and the open-hole ring (4) fall to the bottom of the casing, and finally the closed-hole ring (3) and the open-hole ring (4) are recovered using a tool.

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