Bridge plug anchoring and load bearing test device and test method

Abstract

The application discloses a bridge plug anchoring and bearing test device and a test method, wherein the bridge plug anchoring and bearing test device comprises a pressure control device and a casing segment; the pressure control device is provided with a piston rod; an annular conical body and an anchoring block assembly are arranged in the casing segment; the anchoring block assembly comprises a plurality of anchoring blocks; a releasing core shaft is connected to the bottom of the piston rod; a releasing joint is connected to the lower end of the releasing core shaft; after the releasing core shaft is pulled by the piston rod and the internal thread of the releasing joint is sheared, the anchoring blocks are initially set in the casing segment. The application can simulate the setting and initial anchoring of the bridge plug under different releasing forces and the biting of the anchoring teeth into the casing under different loads to realize the working process of stable anchoring; the anchoring effect and the maximum bearing capacity of the anchoring blocks under different structural parameter conditions and the effective bearing time under the immersion of a solution at a certain temperature are tested and verified, so as to provide guidance for the stress analysis and structural design of the bridge plug anchoring blocks.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of soluble bridge plug for well completion fracturing in the oil industry, and particularly relates to a bridge plug anchoring and bearing test device and a test method. BACKGROUND

[0002] With the development of the oilfield into the middle and high water cut stage, the development layer gradually develops to thin and poor layers. In order to increase the oil recovery and improve the oilfield production efficiency, separate layer injection is one of the effective means for the development of special oil layers. The annulus is usually sealed by a packer, or the target layer is isolated, so that the high, medium and low permeability layers can play the role of water injection, and the interlayer contradiction can be adjusted. The soluble bridge plug is a new type of separate layer and separate section reconstruction tool for shale gas fracturing. After fracturing, the bridge plug body can be completely dissolved by relying on the wellbore temperature and a certain degree of mineralized liquid environment, to ensure the full borehole production, and has the advantages of low comprehensive cost, short production time, reduced operation risk and realized secondary reconstruction.

[0003] The soluble bridge plug is continuously expanded under the action of the releasing force of the anchor block, and then bites the inner wall of the casing. After the bridge plug is released, the elastic body is locked and the bridge plug is anchored. Therefore, the anchor block assembly, as the key part of the bridge plug, plays a decisive role in the setting, bearing and anchoring performance of the bridge plug, and the anchoring effect directly affects the reliability of the fracturing operation. That is, it is necessary to ensure that the bridge plug meets the process requirements of "stable setting and reliable sealing". Due to the low hardness and strength of the soluble metal material, the setting and bearing capacity of the soluble bridge plug are limited to a certain extent, and the structure design of the anchor block is also required to be higher. Therefore, in the design process of the soluble bridge plug, in order to further improve the bearing capacity and anchoring stability of the anchor block, the anchor block under different structure parameter conditions should be tested and verified for anchoring effect and bearing capacity in combination with loading experiments, so as to guide the structure design, ensure that the strength and anchoring stability of the anchor block meet the actual working condition requirements, avoid the waste of time, economic cost and other aspects caused by direct whole machine experiment verification, and even directly affect the sealing effect of the bridge plug, leading to the failure of the wellbore plugging and separate fracturing construction. SUMMARY

[0004] The present application aims to provide a bridge plug anchoring and bearing test device and a test method, which can effectively simulate the setting and initial anchoring of the bridge plug under the action of different releasing forces, and the bite of the anchor teeth into the casing under different loads to realize stable anchoring, test and verify the anchoring effect, maximum bearing capacity and effective bearing time of the anchor block under different structure parameter conditions, and provide guidance for the stress analysis and structure design of the bridge plug anchor block.

[0005] The above-mentioned purpose of the present application can be realized by using the following technical scheme:

[0006] The present invention provides a bridge plug anchoring and load-bearing test device, comprising a pressure control device and a casing joint; the pressure control device has a piston rod located above the casing joint and can apply an axial load through the piston rod; an annular cone and an anchor block assembly are provided in the casing joint, the top of the casing joint is provided with a limiting portion, and the top of the annular cone is axially limited, and the lower outer wall of the annular cone is formed with an outer cone surface; the anchor block assembly includes a plurality of anchor blocks that can move radially and can be anchored on the pipe wall of the casing joint, and the upper part of the anchor block has a the upper inclined surface; before the anchor block is initially anchored in the pipe wall of the casing section, the bottom of the piston rod is detachably connected to a release core shaft, and the release core shaft is axially movable and penetrates the annular cone and the anchor block assembly, and the bottom end of the release core shaft is connected to a release joint, and the bottom of the anchor block can be supported on the release joint; the release joint can be disengaged from the release core shaft when the axial load applied by the piston rod reaches a certain value; after the anchor block is initially anchored in the pipe wall of the casing section, the bottom end of the piston rod is detachably connected to a pressure plate, and the pressure plate can abut against the top of the annular cone.

[0007] In a preferred embodiment of the present invention, the release joint is an annular structure and is threadedly connected to the bottom outer side of the release core shaft.

[0008] In a preferred embodiment of the present invention, a tapered surface with an outer diameter tapering upward is formed on the top of the release joint, and the bottom surface of each anchor block is a downward inclined surface matching the tapered surface, and the anchor block is supported on the tapered surface.

[0009] In a preferred embodiment of the present invention, the anchor block assembly further comprises an upper hoop and a lower hoop sleeved on the periphery of each anchor block, and each anchor block can move radially outward after the upper hoop and the lower hoop are broken in sequence.

[0010] In a preferred embodiment of the present invention, a limit base is provided on the bottom of the sleeve section, the limit base is an annular structure and is fixedly connected to the sleeve in an energy-saving and detachable manner; a supporting convex ring is protruded inwardly on the inner wall of the bottom end of the limit base, and the bottom of the sleeve section can rest on the supporting convex ring; a clamping mechanism is provided on the outer side of the limit base for clamping the limit base on the test platform.

[0011] In a preferred embodiment of the present invention, a sealing base is provided at the bottom of the casing section. The sealing base is a cylindrical structure with an open upper end and is sealed and fixed to the casing in an energy-saving and detachable manner. The bottom of the casing section can rest against the bottom surface of the sealing base to form a sealed cavity with a bottom seal in the casing section. A clamping mechanism is provided on the outer side of the sealing base for clamping the sealing base on the test platform.

[0012] In a preferred embodiment of the present invention, the bridge plug anchoring and bearing test device also includes an induction heating device; a simulated solution is poured into the sealed cavity, and the induction heating device includes an electromagnetic heating controller, a temperature measuring module, an induction coil and a temperature sensor; the induction coil is wound around the outside of the casing section, and both ends of the induction coil are connected to the electromagnetic heating controller, the temperature sensor is provided on the outer wall of the casing section, and the temperature measuring module is connected to the temperature sensor and the electromagnetic heating controller.

[0013] In a preferred embodiment of the present invention, a spacer is further provided in the sleeve section, and a limiting convex ring is provided on the upper end of the spacer to protrude outward. The annular cone is sleeved on the outside of the spacer and rests on the limiting convex ring, and the limiting portion can limit the axial position of the limiting convex ring.

[0014] In a preferred embodiment of the present invention, an annular positioning gland is detachably mounted on the upper end of the sleeve section, and a stop ring is protruding inwardly from the inner wall of the upper end of the positioning gland, which constitutes a limiting portion.

[0015] In a preferred embodiment of the present invention, the pressure control device includes a control operating device, a hydraulic source device and a hydraulic cylinder having a piston rod. The hydraulic source device is connected to the rod chamber of the hydraulic cylinder through a first hydraulic oil pipe and is connected to the rodless chamber of the hydraulic cylinder through a second hydraulic oil pipe. The control operating device is connected to the hydraulic source device and is used to control the inlet and outlet circulation and pressure of the hydraulic oil in the hydraulic source device, and can record the breaking force of the upper hoop ring and the breaking force of the lower hoop ring when the upper hoop ring and the lower hoop ring are broken in sequence, record the shear force when the release joint is disengaged from the release core shaft, and record the numerical relationship curve between the axial load applied by the piston rod and time, and between the axial load and the stroke of the piston rod during the anchoring process of the anchor block.

[0016] The present invention also provides a bridge plug anchoring and load-bearing test method, which uses the above-mentioned bridge plug anchoring and load-bearing test device to conduct the test;

[0017] First, simulate the bridge plug setting and initial anchoring process, which includes the following steps:

[0018] Assemble the casing joint, annular cone, anchor block assembly, release mandrel, release joint and piston rod, and fix the casing joint on the test platform;

[0019] The pressure control device provides an upward axial pulling force to the piston rod. The release mandrel pulls the release joint axially, while each anchor block expands and moves radially outward. The axial loading continues until the anchor block fits against the inner wall of the casing joint and locks the position.

[0020] Then, the axial force is further applied until the release joint is disengaged from the release mandrel, at which point the anchor block forms the initial anchoring; the shear force when the release joint is disengaged is recorded by the pressure control device;

[0021] Check the distribution status of the anchor blocks and the initial anchoring status of the anchor teeth on the anchor blocks;

[0022] The working process of the bridge plug under pressure is then simulated, which includes the following steps:

[0023] Remove the throw-away mandrel, connect a pressure plate to the lower end of the piston rod, and place the casing joint again and fix it on the test platform;

[0024] The pressure control device provides downward axial pressure to the piston rod, which is transmitted through the pressure plate and ultimately acts on the annular cone and the anchor block. At this time, the anchor teeth of the anchor block gradually bite into the inner wall of the casing joint, achieving stable anchoring.

[0025] When the axial pressure increases to a predetermined pressure value, the predetermined pressure value is maintained to continuously load the anchor block;

[0026] When the effective bearing time reaches the predetermined time, the axial pressure is continued to increase to verify the maximum bearing capacity of the anchor block, and the data relationship curve is recorded and saved through the pressure control device;

[0027] After the test is completed, check the final state of the anchor block and anchor teeth.

[0028] In a preferred embodiment of the present invention, during the operation of the simulated bridge plug under pressure, before placing the casing section on the test platform again, the following steps are also included: installing a sealing base at the bottom of the casing section to seal the bottom of the casing section, so that a sealed cavity with a bottom seal is formed in the casing section; after the casing section is fixed on the test platform, before using the pressure control device to provide axial pressure, the following steps are also included: injecting a simulated solution into the sealed cavity, installing an induction coil on the outside of the casing section, and using an electromagnetic heating controller to control the induction coil to induction heat the casing section and heat it to a preset temperature.

[0029] As described above, the test apparatus and test method of the present invention, by simulating the initial anchoring and pressure-bearing state of the anchor block, can effectively simulate the setting and initial anchoring of the bridge plug under different release forces, as well as the anchor teeth biting into the casing under different loads to achieve stable anchoring. This can test and verify the anchoring effect and maximum bearing capacity of the anchor block under different structural parameter conditions. Simultaneously, during the initial anchoring process, an upward axial load is applied by the piston rod, which is then transmitted through the release mandrel and release joint to achieve the setting and initial anchoring of the anchor block. After the initial anchoring is established, the release joint can be disengaged to achieve release. This better simulates the actual release method and actual operating conditions of the bridge plug during downhole setting and initial anchoring, making the test data more realistic and reliable. During the test, parameters such as the actual release force and maximum bearing capacity during release can also be conveniently detected, providing guidance for the force analysis and structural design of the anchor block in the bridge plug, ensuring that the strength and anchoring stability of the anchor block meet the requirements of actual operating conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The following drawings are intended only to illustrate and explain the present invention, and are not intended to limit the scope of the present invention.

[0031] Figure 1 : Schematic diagram of the structural principle of the bridge plug anchoring and load-bearing test device provided by the present invention.

[0032] Figure 2 : Schematic diagram of the working condition simulation bearing test principle of the bridge plug anchoring and bearing test device provided by the present invention.

[0033] Figure 3 : Schematic diagram of the principle of initial anchoring and continuous biting of the casing joint by the anchor block provided by the present invention.

[0034] Figure 4 : Schematic diagram of the relationship between load and stroke values ​​during the loading process of the bridge plug anchoring and load-bearing test device provided by the present invention.

[0035] Description of Figure Numbers:

[0036] 1. Pressure control device; 11. Hydraulic cylinder; 111. Piston rod; 12. Hydraulic source device; 121. First hydraulic oil pipe; 122. Second hydraulic oil pipe; 13. Control operation device;

[0037] 2. Casing joint; 21. Positioning gland; 211. Stop ring; 22. Limiting base; 221. Supporting convex ring; 23. Sealing base; 24. Simulated solution;

[0038] 3. Annular cone; 31. Outer cone; 32. Spacer; 321. Position limiting convex ring;

[0039] 4. Anchor block assembly; 41. Anchor block; 411. Upper inclined surface; 412. Lower inclined surface; 413. Anchor teeth; 42. Upper hoop; 43. Lower hoop;

[0040] 5. Release mandrel; 51. Release joint; 511. Conical surface;

[0041] 6. Press plate;

[0042] 7. Clamping mechanism;

[0043] 8. Test platform;

[0044] 9. Induction heating device; 91. Electromagnetic heating controller; 92. Temperature measurement module; 93. Induction coil; 94. Temperature sensor. DETAILED DESCRIPTION

[0045] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described with reference to the accompanying drawings.

[0046] Implementation Method 1

[0047] like Figures 1 to 4 As shown, the present application provides a bridge plug anchoring and load-bearing test device, comprising a pressure control device 1 and a casing segment 2. The pressure control device 1 has a piston rod 111 located above the casing segment 2 and can apply an axial load through the piston rod 111. An annular cone 3 and an anchor block assembly 4 are provided within the casing segment 2. A limiting portion is provided at the top of the casing segment 2, which can axially limit the top of the annular cone 3. The lower outer wall of the annular cone 3 is formed with an outer conical surface 31. The anchor block assembly 4 includes a plurality of anchor blocks 41 that can move radially and anchor to the pipe wall of the casing segment 2. The upper portion of the anchor block 41 has an upper inclined surface 411 that cooperates with the outer conical surface 31. Before the anchor block 41 is initially anchored to the wall of the casing section 2, the bottom of the piston rod 111 is detachably connected to the release mandrel 5. The release mandrel 5 is axially movable and extends through the annular cone 3 and the anchor block assembly 4. The bottom end of the release mandrel 5 is connected to a release joint 51, and the bottom of the anchor block 41 is supported on the release joint 51. The release joint 51 can be disengaged from the release mandrel 5 when the axial load applied by the piston rod 111 reaches a certain value. After the anchor block 41 is initially anchored to the wall of the casing section 2, the bottom end of the piston rod 111 is detachably connected to the pressure plate 6, which can abut against the top of the annular cone 3.

[0048] During the test, the process of the bridge plug being set and released in the downhole casing to form the initial anchoring is simulated. Figure 1As shown, the release mandrel 5 is connected to the lower end of the piston rod 111, and the release joint 51 is connected to the release mandrel 5. Each anchor block 41 is supported on the release joint 51, and the upper inclined surface 411 of the anchor block 41 cooperates with the outer conical surface 31 of the annular cone 3. After installation, the pressure control device 1 provides an upward axial pulling force to the piston rod 111, which is directly transmitted to the release joint 51 through the release mandrel 5. While the release mandrel 5 pulls the release joint 51 to move axially, the outer conical surface 31 of the annular cone 3 interacts with the upper inclined surface 411 of the anchor block 41, converting the axial force into a radial force that pushes the anchor block 41 to expand outward. Under the action of the radial force, each anchor block 41 will expand and move radially outward; continue axial loading until the anchor block 4 1 is fitted against the inner wall of the casing section 2 to lock the position; further axial force is applied until the release joint 51 is released from the release mandrel 5. At this time, the anchoring teeth 413 on the anchor block 41 have slightly bitten into the inner wall of the casing section 2, establishing the initial anchoring; the shear force at the time of release is recorded by the pressure control device 1, that is, the actual release force of the bridge plug; then the distribution state of the anchor block 41 and the initial anchoring state of the anchoring teeth 413 are checked (the release joint 51 will fall directly to the bottom because it has been released).

[0049] Then, the working process of the anchoring teeth 413 of the anchoring block 41 continuously biting into the casing to achieve stable anchoring is simulated under pressure, such as Figure 2 As shown, after the anchor block 41 is initially anchored, the release mandrel 5 is removed and replaced with a pressure plate 6 connected to the lower end of the piston rod 111. After installation, the pressure control device 1 provides downward axial pressure to the piston rod 111, which is transmitted through the pressure plate 6 and ultimately acts on the annular cone 3 and the anchor block 41; at this time, the anchor teeth 413 of the anchor block 41 gradually bite into the inner wall of the casing section 2, achieving stable anchoring, as shown in FIG. Figure 3 As shown; as the axial load increases, when it increases to a predetermined pressure value, the axial load is maintained to continuously load the anchor block 41 to test whether the anchor block 41 has slippage or whether the slip distance is qualified (the pressure control device 1 is used to detect whether the piston rod 111 has displacement and the stroke size to achieve this). When the effective load time reaches the predetermined time, the axial load is continued to increase to verify the maximum load-bearing capacity of the anchor block 41; that is, the load is continuously applied until the anchor fails, as shown in FIG. Figure 4 As shown, the pressure control device 1 records and saves the data relationship curve, ends the test, and checks the final status of the anchor block 41 and the anchor teeth 413.

[0050] Thus, the test device in the embodiment can effectively simulate the setting and initial anchoring of the bridge plug under different releasing forces, and the work process of the anchoring teeth 413 in the casing under different loads to achieve stable anchoring, test and verify the anchoring effect and maximum bearing capacity of the anchoring block 41 under different structural parameter conditions. Meanwhile, the upward axial load is applied by the piston rod 111 during the initial anchoring process, the upward axial load is transmitted through the releasing mandrel 5 and the releasing sub 51 to achieve the setting and initial anchoring of the anchoring block 41, and the releasing sub 51 can be detached after the initial anchoring is established to achieve releasing. The actual releasing mode and actual working condition of the bridge plug during the setting and initial anchoring in the well are better simulated, and the test data is more real and reliable. The actual releasing force, maximum bearing capacity and other parameters during releasing can be conveniently detected during the test, which provides guidance for the stress analysis and structural design of the anchoring block 41 in the bridge plug, and ensures that the strength and anchoring stability of the anchoring block 41 can meet the actual working condition requirements.

[0051] Further, as shown in Figure 1 the releasing sub 51 is in a ring structure and is threadedly connected to the outer side of the bottom of the releasing mandrel 5. After the anchoring block 41 is attached to the inner wall of the casing section 2, the axial force is further loaded until the inner thread of the releasing sub 51 is instantaneously sheared and broken, and the releasing sub 51 is detached from the releasing mandrel 5.

[0052] The top of the releasing sub 51 is formed with a conical surface 511 which is tapered upward in radial direction, and the bottom surface of each anchoring block 41 is a lower inclined surface 412 which cooperates with the conical surface 511, and the anchoring block 41 is supported on the conical surface 511. The lower inclined surface 412 and the conical surface 511 are cooperated between the anchoring block 41 and the releasing sub 51, compared with the case that the contact surface between them is a plane, the radial force acting on the anchoring block 41 can be larger, and the initial anchoring effect is better.

[0053] The releasing sub 51 is in a ring shape and has an inner thread and a conical surface 511, and the connection thread type between the releasing sub 51 and the releasing mandrel 5 can be selected from rectangular thread, trapezoidal thread or ordinary thread, etc. The length of the thread connection between them directly determines the releasing force of the actual setting of the bridge plug, which is a key parameter and needs to be obtained by thread shear force calculation. The thread connection length between them can be designed according to the size of the releasing force required by the test. Of course, in an alternative embodiment, the releasing sub 51 can also be connected to the releasing mandrel 5 through a shear pin, and when the axial load reaches a certain value, the shear pin is sheared to achieve releasing.

[0054] Further, the anchoring block assembly 4 further includes an upper hoop ring 42 and a lower hoop ring 43 which are sleeved on the outer periphery of each anchoring block 41, and each anchoring block 41 can move radially outward after the upper hoop ring 42 and the lower hoop ring 43 are sequentially broken.

[0055] The upper inner wall of each anchor block 41 has an upper inclined surface 411, which cooperates with the outer cone 31 of the annular cone body 3. The inclination angle of the upper inclined surface 411 is consistent with the cone angle of the outer cone 31. The outer sides of the upper end and lower end of each anchor block 41 are respectively provided with an upper groove and a lower groove for installing the upper hoop 42 and the lower hoop 43. Multiple anchor blocks 41 are evenly distributed along the circumference to form an anchor body. The number of anchor blocks 41 is determined according to needs, usually 6-8 blocks. Multiple anchor blocks 41 are limited into a whole by the upper hoop 42 and the lower hoop 43. When setting the seal, it is necessary to first break the upper hoop 42 and the lower hoop 43 in turn before the anchor body can disintegrate, and each anchor block 41 expands evenly outward. Specifically, while the release mandrel 5 pulls the release joint 51 to move, the outer conical surface 31 of the annular cone 3 interacts with the upper inclined surface 411 of the anchor block 41, and the conical surface 511 of the release joint 51 interacts with the lower inclined surface 412 of the anchor block 41, converting the axial force into a radial force that pushes the anchor block 41. Under the action of the radial force, the upper hoop 42 will be broken first, and then the lower hoop 43 will be broken by continuing to expand. At this time, the breaking force of the upper hoop 42 and the lower hoop 43 can be recorded by the pressure control device 1; then the axial loading is continued, and the anchor block 41 is attached to the inner wall of the casing section 2.

[0056] Reference Figure 1 and Figure 3 The outside of the anchor block 41 is also provided with a number of inclined holes, which are arranged upward and inclined outward from the center of the casing section 2, and the anchor teeth 413 are embedded in the inclined holes. Since the downward axial pressure is provided when simulating the pressure-bearing state, the inclined holes are arranged upward and inclined to ensure that the anchoring is more stable during the pressure-bearing process. The number of inclined holes and anchor teeth 413 is the same, usually 3-5, and can be distributed in various ways such as rectangles, triangles, and diamonds. The parameters such as the diameter, depth, inclination angle of the inclined holes on the specific anchor block 41, and the size of the upper and lower grooves are determined according to the structural design of different anchor blocks 41 and specific test results.

[0057] In one embodiment, a limiting base 22 is sleeved on the bottom of the sleeve section 2. The limiting base 22 is an annular structure and is detachably fixedly connected to the sleeve section 2. A supporting protrusion ring 221 is protruded inwardly on the inner wall of the bottom end of the limiting base 22, and the bottom of the sleeve section 2 can rest on the supporting protrusion ring 221. A clamping mechanism 7 is provided on the outer side of the limiting base 22 for clamping and fixing the limiting base 22 on the test platform 8.

[0058] Typically, the limiting base 22 has internal threads and is threadedly connected to the casing section 2, thereby supporting and protecting the external threads at the lower end of the casing section 2. The clamping mechanism 7 can be a clamp (existing structure) comprising a set of V-shaped clamping jaws spaced evenly at 120°. The clamping jaws are used to clamp the limiting base 22, thereby securing the limiting base 22 and the casing section 2, ensuring stability during the test and preventing unbalanced loading or slippage of the device during the test.

[0059] When performing the setting and initial anchoring tests, the limiting base 22 and the clamping mechanism 7 can be used to conveniently and stably fix the casing section 2 on the test platform 8. After the initial anchoring is established, the clamping clamp is released and the release joint 51 dropped onto the test platform 8 is removed, and the distribution status of the anchor block 41 and the initial anchoring status of the anchor teeth 413 can be checked.

[0060] If a pressure test is to be performed under simulated normal temperature conditions, after the initial anchoring, it is only necessary to remove the release mandrel 5 and replace it with the pressure plate 6, place the limit base 22 on the test platform 8 again and clamp it with a clamp, and then the pressure simulation test can be started.

[0061] In another embodiment, a sealing base 23 is sleeved on the bottom of the casing section 2. The sealing base 23 is a cylindrical structure with an open upper end and is detachably sealed and fixed to the casing section 2. The bottom of the casing section 2 can abut against the bottom surface of the sealing base 23 to form a sealed cavity with a bottom seal in the casing section 2. A clamping mechanism 7 is provided on the outer side of the sealing base 23 for clamping and fixing the sealing base 23 on the test platform 8.

[0062] Typically, the sealing base 23 has internal threads and is threadedly connected to the casing section 2. This seal seals the lower end of the casing section 2 after the sealing ring is installed, creating a sealed chamber for containing a solution simulating downhole conditions. The clamping mechanism 7 can also employ the aforementioned clamping pliers to ensure test stability.

[0063] During the setting and initial anchoring tests, the sealing base 23 and the clamping mechanism 7 can be used to conveniently and stably fix the casing section 2 on the test platform 8. After the initial anchoring is established, the clamping clamp is loosened, the sealing base 23 is removed, and the release joint 51 that has fallen on the sealing base 23 is removed. The distribution status of the anchor block 41 and the initial anchoring status of the anchor teeth 413 can be checked.

[0064] If a pressure test is to be performed under simulated normal temperature conditions, after the initial anchoring, it is only necessary to remove the release core shaft 5 and replace it with the pressure plate 6, reinstall the sealing base 23, place the sealing base 23 on the test platform 8 again and clamp it with a clamp, and then the pressure simulation test can be started.

[0065] If the pressure test under certain solution conditions and certain temperature conditions is simulated, the bridge plug anchoring and load-bearing test device also includes an induction heating device 9. A simulated solution 24 is poured into the sealed cavity. The induction heating device 9 includes an electromagnetic heating controller 91, a temperature measuring module 92, an induction coil 93 and a temperature sensor 94; the induction coil 93 is wound around the outside of the casing section 2, and both ends of the induction coil 93 are connected to the electromagnetic heating controller 91. The temperature sensor 94 is arranged on the outer wall of the casing section 2, and the temperature measuring module 92 is connected to the temperature sensor 94 and the electromagnetic heating controller 91.

[0066] The simulated solution 24 here can be selected according to specific working conditions or relevant industry standards, and can be clean water or KCl liquid with a certain mass fraction. The induction heating device 9 is mainly used to heat the casing section 2 and conduct heat to the simulated solution 24 inside it to simulate the solution, temperature and other parameters in the well, so as to realize the bearing capacity of the anchor block 41 when immersed in a solution at a certain temperature. The induction coil 93 is made of copper core cable and is used to be wound around the outside of the casing section 2. Both ends are connected to the electromagnetic heating controller 91. When the electromagnetic heating controller 91 starts working, the induction coil 93 directly induction heats the casing section 2. The electromagnetic heating controller 91 is used to control and adjust the heating temperature. The temperature measurement module 92 is used to feed back the data detected by the temperature sensor 94 to the electromagnetic heating controller 91. The electromagnetic heating controller 91 adjusts the temperature, working mode and working state according to the temperature actually measured and fed back by the temperature sensor 94 and the temperature measurement module 92, so as to achieve a constant temperature state of the solution or control the temperature fluctuation range during the experiment.

[0067] The specific test operation is as follows: after the initial anchoring, the release core shaft 5 is removed and replaced with the pressure plate 6. After the sealing base 23 is reinstalled and clamped with a clamp, a certain amount of simulated solution 24 needs to be poured from the top of the casing section 2; then the induction coil 93 is wrapped around the outer circumference of the casing section 2, and the induction heating device 9 is started to the working mode to start heating. When the temperature reaches the predetermined temperature, the pressure control device 1 provides a downward axial pressure to the piston rod 111, and the pressure simulation test begins.

[0068] In yet another embodiment, in order to facilitate testing and verifying the maximum load-bearing capacity of the anchor block 41 and the effective load-bearing time in a certain temperature solution environment, the following operation can be performed during the test:

[0069] When performing the setting and initial anchoring tests, the above-mentioned limit base 22 is installed at the bottom of the casing section 2. The limit base 22 and the clamping mechanism 7 are used to stably fix the casing section 2 on the test platform 8. After the initial anchoring is established, the clamping clamp is released and the release joint 51 dropped onto the test platform 8 is removed. The distribution status of the anchor block 41 and the initial anchoring status of the anchor teeth 413 can be checked.

[0070] When the pressure test is performed, after the initial anchoring, if the distribution state of the anchoring block 41 and the initial anchoring state of the anchoring teeth 413 are normal, the release mandrel 5 is removed and replaced by the pressing plate 6, the limiting base 22 is removed and replaced by the sealing base 23, and then clamped by the clamping tongs, the simulated solution 24 is poured, the induction heating device 9 is installed, and the pressure test under the condition of the simulated solution and the simulated temperature can be performed.

[0071] Of course, the test can be performed by using the above-mentioned operation, and the pressure test is simulated under the condition of the normal temperature or the condition of the simulated solution and the simulated temperature, and the actual test needs, and the embodiment is only an example.

[0072] Further, the spacer 32 is arranged in the casing segment 2, the upper end of the spacer 32 is outwardly protruded with the limiting convex ring 321, the annular conical body 3 is arranged outside the spacer 32 and abuts against the limiting convex ring 321, and the limiting part can axially limit the limiting convex ring 321.

[0073] The spacer 32 is a T-shaped cylindrical structure, which is arranged in the inner hole of the annular conical body 3 and used to support the annular conical body 3 and transmit the axial load. The annular conical body 3 is mainly used to simulate that when the bridge plug is anchored and loaded, the axial load is converted into the radial force through the conical surface, the anchoring block 41 is axially slid along the conical surface and radially expanded, and the anchoring block 41 is initially anchored on the inner wall of the casing segment 2. The outer conical surface 31 of the annular conical body 3 can be a whole circle conical surface, or can be a plurality of conical planes uniformly distributed along the circumference and matched with the upper inclined surface 411 of the anchoring block 41. The size of the annular conical body 3 and the angle of the outer conical surface 31 can be designed according to the structure of the anchoring block 41, and the angle between the outer conical surface 31 and the vertical surface is usually 10-20°. The specific size of the spacer 32 is set according to the specific specifications of the annular conical body 3 and the anchoring block 41, so as to be suitable for the test conditions of different size parameters of the anchoring block assembly 4.

[0074] Further, the annular positioning gland 21 is detachably arranged at the upper end of the casing segment 2, the inner wall of the upper end of the annular positioning gland 21 is inwardly protruded with the stop ring 211, and the stop ring 211 constitutes the limiting part.

[0075] The general positioning gland 21 is screwed with the upper end of the casing section 2, and is mainly used for the axial positioning of the spacer 32. The casing section 2 is a circular ring cylinder structure, and is provided with external threads at both ends. The upper end is connected with the positioning gland 21, the lower end external thread is connected with the limiting base 22 or the sealing base 23, and the lower end is provided with a sealing groove for installing a sealing ring. In order to fully simulate the actual working condition, the casing section 2 is processed from the casing cut off by the specified steel grade and specification in the petroleum industry. The lower end of the piston rod 111 is provided with an internal threaded hole, which is convenient for connecting with the release mandrel 5 or the pressing plate 6. The release mandrel 5 is a round rod provided with external threads at both ends. The upper end external thread is directly connected with the piston rod 111, and the lower end external thread is connected with the release sub 51 and transmits the axial load.

[0076] Further, the pressure control device 1 comprises a control operation device 13, a hydraulic source device 12, and a hydraulic cylinder 11 with a piston rod 111. The hydraulic source device 12 is connected with the rod cavity of the hydraulic cylinder 11 through the first hydraulic oil pipe 121, and is connected with the rodless cavity of the hydraulic cylinder 11 through the second hydraulic oil pipe 122. The control operation device 13 is connected with the hydraulic source device 12, and is used for controlling the in-out circulation and pressure of the hydraulic oil in the hydraulic source device 12, and can record the fracture force of the upper collar 42 and the fracture force of the lower collar 43 when the upper collar 42 and the lower collar 43 are broken in turn, record the shearing force when the release sub 51 is separated from the release mandrel 5, and record the numerical relation curve between the axial load and the time and the numerical relation curve between the axial load and the stroke of the piston rod 111 during the anchoring process of the anchoring block 41.

[0077] The hydraulic cylinder 11 is a single-out-rod hydraulic cylinder, which is an execution unit for providing the axial load of the test device. The hydraulic source device 12 is used for storing the hydraulic oil and has a plunger and other power devices, which are used for pumping the hydraulic oil to the rod cavity or the rodless cavity. The pressure control device 1 can further comprise a remote control device, so as to facilitate remote operation. The control operation device 13 controls the working of the hydraulic source device 12, and adjusts the change of the pressure and the in-out circulation of the hydraulic oil, so as to realize the timely adjustment of the axial action direction, speed, stroke and load force of the piston rod 111, and can timely adjust and state lock. The control operation device 13 can also automatically identify and record the numerical relation curve between the axial load and the time, the numerical relation curve between the axial load and the stroke of the piston rod 111 and other parameters.

[0078] Embodiment two

[0079] The application also provides a bridge plug anchoring and bearing test method, which adopts the bridge plug anchoring and bearing test device in the embodiment one to perform the test.

[0080] First, the bridge plug setting and initial anchoring process is simulated, which comprises the following steps:

[0081] Assemble the casing section 2, the annular cone 3, the anchor block assembly 4, the release mandrel 5, the release joint 51, and the piston rod 111, and fix the casing section 2 on the test platform 8;

[0082] The pressure control device 1 provides an upward axial pulling force to the piston rod 111. The release core shaft 5 pulls the release joint 51 to move axially, while each anchor block 41 expands and moves radially outward. The axial loading is continued until the anchor block 41 contacts the inner wall of the casing section 2 and locks the position.

[0083] The axial force is further applied until the release joint 51 is released from the release core shaft 5, at which point the anchor block 41 forms an initial anchor; the shear force when the release joint 51 is released is recorded by the pressure control device 1;

[0084] Check the distribution state of the anchor block 41 and the initial anchoring state of the anchor teeth 413 on the anchor block 41;

[0085] The working process of the bridge plug under pressure is then simulated, which includes the following steps:

[0086] Remove the throw-away mandrel 5, connect the pressing plate 6 to the lower end of the piston rod 111, and place the casing section 2 again and fix it on the test platform 8;

[0087] The pressure control device 1 applies downward axial pressure to the piston rod 111. The axial pressure is transmitted through the pressure plate 6 and ultimately acts on the annular cone 3 and the anchor block 41. At this time, the anchor teeth 413 of the anchor block 41 gradually bite into the inner wall of the casing section 2, achieving stable anchoring.

[0088] When the axial pressure increases to a predetermined pressure value, the predetermined pressure value is maintained to continuously load the anchor block 41;

[0089] When the effective load-bearing time reaches the predetermined time, the axial pressure is continued to be increased to verify the maximum load-bearing capacity of the anchor block 41, and the data relationship curve is recorded and saved by the pressure control device 1;

[0090] After the test is completed, the final state of the anchor block 41 and the anchor teeth 413 is checked.

[0091] Preferably, during the operation of the simulated bridge plug under pressure, before placing the casing section 2 again on the test platform 8, the following steps are also included: installing a sealing base 23 at the bottom of the casing section 2 to seal the bottom of the casing section 2, so that a sealed cavity with a bottom seal is formed in the casing section 2; after the casing section 2 is fixed on the test platform 8 and before the pressure control device 1 is used to provide axial pressure, the following steps are also included: injecting a simulated solution 24 into the sealed cavity, installing an induction coil 93 on the outside of the casing section 2, and using the electromagnetic heating controller 91 to control the induction coil 93 to induction heat the casing section 2 to a preset temperature.

[0092] Specifically, since the working process of the bridge plug being seated, anchored and pressurized in the wellbore is to first release the bridge plug by providing a certain releasing force through the seating tool, and seat it at a designated position in the casing, the anchoring teeth 413 of the anchor block 41 form an initial anchoring in the casing; then, during the fracturing construction process, the pressure in the wellbore continues to increase, and at this time the anchoring teeth 413 further bite into the casing wall, keeping the anchoring state of the bridge plug stable; therefore, the key to the bridge plug lies in its pressure-bearing capacity during the fracturing construction process, that is, under a certain pressure, the bearing capacity and stability of the bridge plug can meet the process requirements.

[0093] The actual design requirements for the downhole sealing force of the bridge plug are in tons, ranging from 12 to 16 tons, which translates to an axial load pressure of approximately 120 to 160 kN. The actual operating conditions for anchoring and bearing pressure in downhole casing require the bridge plug to meet a pressure range of 50 to 70 MPa. The conversion of bottomhole liquid pressure into an axial pressure load utilizes the pressure-to-pressure relationship P = F / S (i.e., pressure is the ratio of the pressure on an object to the area under load). Based on the actual operating conditions for anchoring and bearing pressure in downhole casing, the bridge plug must meet a pressure range of 50 to 70 MPa. Based on the 5.5-inch Q125 steel grade casing commonly used in the oil industry, with an outer diameter of 139.7 mm and an inner diameter of 114.3 mm, it can be calculated that the axial load for the bridge plug's maximum bearing capacity test should meet a pressure range of 512.8 to 717.9 kN.

[0094] During downhole operation, several key factors are crucial: first, ensuring the smooth release of the bridge plug, disengaging from the setting tool, and setting it at the designated location in the casing for initial anchoring. Secondly, and more importantly, ensuring that the bridge plug maintains a certain load-bearing capacity and effective load-bearing duration under specific downhole solution conditions and temperature. Specifically, during fracturing operations, under a certain pressure, the anchoring stability of the bridge plug meets requirements, with the anchor block 41 experiencing no significant slippage or direct anchor failure. The aforementioned test method effectively simulates the process of setting and initial anchoring of the bridge plug, as well as its stable anchoring under pressure. It also simulates the load-bearing conditions of immersion in a solution at a certain temperature, better simulating actual operating conditions.

[0095] The specific working principle and beneficial effects of this test method are the same as those of the test device in embodiment 1, and will not be repeated here.

[0096] In summary, this application provides a bridge plug anchoring and load-bearing test device and method for soluble bridge plugs used in petroleum completion and fracturing. These devices effectively simulate the setting and initial anchoring of a bridge plug under varying release forces, as well as the process of the anchor teeth 413 engaging the casing to achieve stable anchoring under varying loads. They also test and verify the maximum load-bearing capacity and anchoring stability of the anchor block 41 under varying structural parameters, and simulate the effective load-bearing time of the anchor block 41 under conditions of rated load and immersion in a solution at a certain temperature. Furthermore, the device can timely lock the state of the anchor block 41, automatically and accurately obtain multiple parameters such as the release force, hoop breaking force, and maximum load-bearing capacity, and record the numerical relationship between each parameter and travel. Furthermore, by converting the actual downhole bearing pressure into an axial pressure load, the anchor block 41 can be continuously loaded and tested on the surface. This method offers the advantages of automation and parameterization, achieving axial load accuracy of 0.1 N and axial travel accuracy of 0.01 mm. Furthermore, it provides guidance for force analysis and structural optimization design of the anchor block 41, effectively reducing the design cycle and economic costs of the bridge plug.

[0097] The above is only an illustrative embodiment of the present invention and is not intended to limit the scope of the present invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principle of the present invention should fall within the scope of protection of the present invention.

Claims

1. A bridge plug anchoring and bearing test device, characterized in that: Includes pressure control device and casing joint; The pressure control device has a piston rod located above the casing section and can apply an axial load through the piston rod; an annular cone and an anchor block assembly are provided in the casing section, the top of the casing section is provided with a limiting portion, and can axially limit the top of the annular cone, and the lower outer wall of the annular cone is formed with an outer cone surface; the anchor block assembly includes a plurality of anchor blocks that can move radially and be anchored on the pipe wall of the casing section, and the upper part of the anchor block has an upper inclined surface that matches the outer cone surface; the anchor block assembly also includes an upper hoop and a lower hoop mounted on the outer circumference of each anchor block, and each anchor block can move radially outward after the upper hoop and the lower hoop are broken in sequence; Before the anchor block is initially anchored to the pipe wall of the casing joint, the bottom of the piston rod is detachably connected to a release mandrel, and the release mandrel is axially movably arranged in the annular cone and the anchor block assembly. The bottom end of the release mandrel is connected to a release joint, and the bottom of the anchor block can be supported on the release joint; the release joint can be disengaged from the release mandrel when the axial load applied by the piston rod reaches a certain value, and the pressure control device can record the breaking force of the upper hoop and the lower hoop and the release The shear force when the joint is disengaged from the release core shaft; after the anchor block is initially anchored to the pipe wall of the casing joint, the bottom end of the piston rod is detachably connected to a pressure plate, and the pressure plate can abut against the top of the annular cone. The pressure control device can provide downward axial pressure to the piston rod, and the axial pressure is transmitted through the pressure plate and acts on the annular cone and the anchor block. The pressure control device detects whether the piston rod has displacement and the stroke size to test whether the anchor block has slipped or whether the slip distance is qualified.

2. The bridge plug anchoring and load-bearing test device according to claim 1, characterized in that: The release joint is an annular structure and is threadedly connected to the outer side of the bottom of the release core shaft.

3. The bridge plug anchoring and load-bearing test device according to claim 1, characterized in that: A conical surface with an outer diameter gradually contracting upward is formed on the top of the release joint. The bottom surface of each anchor block is a downward inclined surface matching the conical surface, and the anchor block is supported on the conical surface.

4. The bridge plug anchoring and load-bearing test device according to claim 1, characterized in that: A limit base is sleeved on the bottom of the sleeve section, and the limit base is an annular structure and is fixedly connected to the sleeve in an energy-saving and detachable manner; a supporting convex ring is protruded inwardly on the inner wall of the bottom end of the limit base, and the bottom of the sleeve section can rest on the supporting convex ring; a clamping mechanism is provided on the outer side of the limit base for clamping the limit base on the test platform.

5. The bridge plug anchoring and load-bearing test device according to claim 1, characterized in that: A sealing base is sleeved on the bottom of the casing section. The sealing base is a cylindrical structure with an open upper end and is sealed and fixed to the casing in an energy-saving and detachable manner. The bottom of the casing section can abut against the bottom surface of the sealing base to form a sealed cavity with a bottom seal in the casing section; a clamping mechanism is provided on the outer side of the sealing base for clamping the sealing base on the test platform.

6. The bridge plug anchoring and load-bearing test device according to claim 5, characterized in that: The bridge plug anchoring and bearing test device also includes an induction heating device; A simulated solution is poured into the sealed cavity, and the induction heating device includes an electromagnetic heating controller, a temperature measurement module, an induction coil and a temperature sensor; the induction coil is wound around the outside of the casing section, and both ends of the induction coil are connected to the electromagnetic heating controller, the temperature sensor is arranged on the outer wall of the casing section, and the temperature measurement module is connected to both the temperature sensor and the electromagnetic heating controller.

7. The bridge plug anchoring and load-bearing test device according to claim 1, characterized in that: A spacer is also provided in the sleeve section, and a limiting convex ring is protruded outward from the upper end of the spacer. The annular cone is sleeved on the outside of the spacer and abuts against the limiting convex ring. The limiting portion can limit the axial position of the limiting convex ring.

8. The bridge plug anchoring and load-bearing test device according to claim 1, characterized in that: An annular positioning cover is detachably mounted on the upper end of the sleeve section, and a stop ring is protruding inwardly from the inner wall of the upper end of the positioning cover, and the stop ring constitutes the limiting portion.

9. The bridge plug anchoring and load-bearing test device according to claim 1, characterized in that: The pressure control device includes a control operation device, a hydraulic source device and a hydraulic cylinder having the piston rod, wherein the hydraulic source device is connected to the rod chamber of the hydraulic cylinder through a first hydraulic oil pipe and is connected to the rodless chamber of the hydraulic cylinder through a second hydraulic oil pipe; The control and operation device is connected to the hydraulic source device and is used to control the inflow and outflow circulation and pressure of the hydraulic oil in the hydraulic source device, and is capable of recording the breaking force of the upper hoop ring and the breaking force of the lower hoop ring when the upper hoop ring and the lower hoop ring are broken in sequence, recording the shear force when the release joint is disengaged from the release core shaft, and recording the numerical relationship curves between the axial load applied by the piston rod and time, and between the axial load and the stroke of the piston rod during the anchoring process of the anchor block.

10. A bridge plug anchoring and bearing test method, characterized in that: Conducting the test using the bridge plug anchoring and load-bearing test device according to any one of claims 1 to 9; First, simulate the bridge plug setting and initial anchoring process, which includes the following steps: Assemble the sleeve section, the annular cone, the anchor block assembly, the release mandrel, the release joint, and the piston rod, and secure the sleeve section on a test platform; The pressure control device provides an upward axial pulling force to the piston rod, and the release core shaft pulls the release joint to move axially, while each anchor block expands and moves radially outward; the axial loading is continued until the anchor block fits against the inner wall of the casing joint and locks the position; Further axial force is applied until the release joint is released from the release mandrel, at which point the anchor block forms an initial anchor; and the shear force when the release joint is released is recorded by a pressure control device; checking the distribution state of the anchor blocks and the initial anchoring state of the anchor teeth on the anchor blocks; The working process of the bridge plug under pressure is then simulated, which includes the following steps: The release mandrel is removed, and the pressure plate is connected to the lower end of the piston rod, and the sleeve joint is placed and fixed on the test platform again; The pressure control device provides downward axial pressure to the piston rod, and the axial pressure is transmitted through the pressure plate and ultimately acts on the annular cone and the anchor block; at this time, the anchor teeth of the anchor block gradually bite into the inner wall of the casing section to achieve stable anchoring; When the axial pressure increases to a predetermined pressure value, the predetermined pressure value is maintained to continuously load the anchor block; When the effective bearing time reaches a predetermined time, the axial pressure is continuously increased to verify the maximum bearing capacity of the anchor block, and the data relationship curve is recorded and saved by the pressure control device; After the test is finished, the final states of the anchor block and the anchor teeth are checked.

11. The bridge plug anchoring and bearing test method according to claim 10, characterized in that: During the operation of the simulated bridge plug under pressure, before the casing section is placed on the test platform again, the following steps are further included: installing a sealing base at the bottom of the casing section to seal the bottom of the casing section, so that a sealed cavity with a bottom seal is formed in the casing section; After the casing section is fixed on the test platform and before the pressure control device is used to provide axial pressure, the following steps are also included: injecting a simulated solution into the sealing cavity, installing an induction coil on the outside of the casing section, and using an electromagnetic heating controller to control the induction coil to induction heat the casing section to a preset temperature.

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