Cement ring seal failure test device and method

Abstract

The application discloses a cement sheath sealing failure test device and method, and belongs to the technical field of oil and gas field development. The test device comprises a curved wellbore, a wellbore fixing unit, an impact simulation unit, a cement sheath forming unit and a sealing detection unit. The curved wellbore comprises an annular space formed by coaxially arranged inner and outer cylinders, and the two ends of the curved wellbore are closed by a top plate and a bottom plate. The top plate and the bottom plate are provided with through holes. The wellbore fixing unit is used for fixing the curved wellbore. The impact simulation unit is used for simulating impact load. The cement sheath forming unit is used for forming a cement sheath in the annular space. The sealing detection unit is used for being connected with the annular space and sampling when the impact simulation unit simulates impact. The application can effectively solve the technical problem that the high-frequency transient impact damage effect of the downhole drill pipe centralizer passing through the curved well section due to the jam-release effect on the wellbore cement sheath cannot be reproduced in the prior art.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field development, and specifically to a test apparatus and method for cement ring seal failure. Background Technology

[0002] Horizontal well technology, as a core means of modern efficient oil and gas development, holds an irreplaceable strategic position in the development of unconventional oil and gas resources globally. By maximizing reservoir contact through ultra-long horizontal sections (kilometer-level), this technology can significantly improve single-well production and ultimate recovery rate, especially achieving economically feasible development in low-permeability reservoirs such as shale oil and gas and tight sandstone.

[0003] However, the unique three-dimensional curved wellbore trajectory of horizontal wells (high dogleg sections) leads to exceptionally complex tubing passage. During the vulnerable curing period after cementing operations, before the cement sheath reaches its design strength, drill pipe assemblies equipped with centralizers are highly susceptible to jamming and release phenomena when traversing curved sections during subsequent drilling or completion operations due to geometric constraints and friction effects. This triggers high-frequency transient impact loads from the drill pipe centralizer on the wellbore. Numerous field cases demonstrate that such impacts induce micron-level cracks and annular gaps in the cement sheath and casing / formation interface, becoming a key contributing factor to annular pressure, interlayer flow, and wellbore integrity failure in later production stages.

[0004] There is a significant technological gap in the current research on impact damage to cement sheaths in curved sections of horizontal wells. Traditional test devices are mostly used to test the sealing performance of cement sheaths in vertical well sections, and cannot reproduce the high-frequency transient impact damage to the wellbore cement sheath caused by the jamming-release effect when the downhole drill pipe centralizer passes through curved sections. Summary of the Invention

[0005] The purpose of this invention is to provide a cement sheath sealing failure test device and method, which can effectively solve the technical problem in the prior art that the high-frequency transient impact damage to the wellbore cement sheath caused by the jamming-release effect when the downhole drill pipe centralizer passes through a curved well section cannot be reproduced.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] The cement ring seal failure test apparatus includes:

[0008] The curved wellbore comprises an inner and outer cylinder arranged coaxially to form an annular space, and is closed at both ends by a top plate and a bottom plate, with through holes provided on the top plate and the bottom plate.

[0009] A wellbore fixing unit is used to fix a bent wellbore.

[0010] An impact simulation unit, used to simulate impact loads;

[0011] A cement sheath forming unit for forming a cement sheath in an annular space;

[0012] A sealing detection unit connected with the annular space for sampling when the impact simulation unit simulates impact.

[0013] Further, the wellbore fixing unit comprises a spacer for fixing the curved wellbore, the impact simulation unit comprises a drill pipe penetrating through the curved wellbore and a centralizer mounted on the drill pipe, the cement sheath forming unit comprises a grouter communicating with the top plate, and the sealing detection unit comprises a gas injection pipe and a flowmeter communicating with the annular space.

[0014] The drill pipe is connected with a drill pipe guiding unit, and the drill pipe guiding unit comprises at least two spacers arranged at intervals on the drill pipe, and the inner diameter of the spacer is smaller than the diameter of the drill pipe to constrain the radial displacement and allow the axial sliding.

[0015] Further, the spacer is composed of a top-end spacer and a bottom-end spacer for fixing the top end and the bottom end of the wellbore respectively, and the top-end spacer and the bottom-end spacer both adopt a split base and a cover plate which are connected by bolts.

[0016] The centralizer is provided with a spiral wing and a central hole for connecting the drill pipe.

[0017] Further, the top plate and the bottom plate are both provided with at least one interface for connecting the grouter, the flowmeter or the gas injection pipe.

[0018] Further, one end of the drill pipe is provided with a thread, and the drill pipe is connected with the centralizer through the thread.

[0019] Further, one end of the grouter is provided with a thread, and the grouter is connected with the curved wellbore through the thread.

[0020] The cement sheath sealing failure test method is also disclosed, which comprises using the cement sheath sealing failure test device, and the specific steps are as follows:

[0021] Fixing the top end and the bottom end of the curved wellbore;

[0022] Injecting cement slurry into the annular space and curing to form a cement sheath;

[0023] Installing the drill pipe with the centralizer to constrain the radial displacement of the drill pipe;

[0024] Passing the detection gas into the bottom end of the curved wellbore, and connecting a plurality of flowmeters at the top end to detect the flow of the detection gas;

[0025] Applying a pulse impact load to the drill pipe to push the centralizer to move to the inner wall of the wellbore at a first speed and then to the bottom end of the wellbore at a second speed;

[0026] The reverse pulse impact load is applied, the drill pipe is pulled back to the centralizer to be separated from the inner wall of the wellbore at a third speed, and then the centralizer is moved out at a fourth speed;

[0027] The flow meter values during the whole test process are recorded to determine the cement sheath sealing property.

[0028] The first speed is greater than the second speed, and the fourth speed is greater than the third speed.

[0029] Further, the peak value of the pulse impact load ranges from 5 to 20 kN, and the frequency ranges from 5 to 15 kHz.

[0030] The detection gas pressure ranges from 0.5 to 1.5 MPa.

[0031] Further, the axis of the fixed drill pipe coincides with the axis of the top end of the curved wellbore.

[0032] Further, the test method is used to evaluate the impact damage of the drill pipe and the centralizer to the cement sheath of the curved wellbore, and the multiple flow meter values are all zero, which indicates that the cement sheath sealing property is good, and at least one flow meter value is not zero, which indicates that the cement sheath sealing property is damaged.

[0033] Compared with the prior art, the present application has the following beneficial effects:

[0034] The drill pipe centralizer cement sheath sealing failure test device and method disclosed by the present application can realize efficient analysis and accurate evaluation of the cement sheath sealing failure law under the synergistic mechanism of the bending constraint-dynamic impact-cement sheath response-sealing integrity monitoring full elements, and provide a scientific benchmark and preventive solution for the optimization design of the horizontal wellbore integrity. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments, and it should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor.

[0036] Figure 1 It is a whole three-dimensional structure diagram of the present application.

[0037] Figure 2 The curved wellbore profile of the present application.

[0038] Figure 3 The wellbore bottom end limiter structure of the present application.

[0039] Figure 4 The drill pipe structure of the present application.

[0040] Figure 5 The centralizer structure of the present application.

[0041] Figure 6 The drill pipe limiter A structure of the present application.

[0042] Figure 7 The grouting device structure of the present application.

[0043] Figure 8 The gas injection tube structure of the present application.

[0044] Figure 9 The rubber plug structure of the present application.

[0045] Figure 10 The wellbore top end limiter structure of the present application.

[0046] Figure 11 The drill pipe limiter B structure of the present application.

[0047] Reference signs:

[0048] 1 - curved wellbore, 2 - wellbore bottom end limiter, 3 - wellbore top end limiter, 4 - grouting device, 5 - flowmeter, 6 - drill pipe, 7 - centralizer, 8 - drill pipe limiter A, 9 - drill pipe limiter B, 10 - gas injection tube, 11 - outer cylinder, 12 - inner cylinder, 13 - bottom plate, 14 - top plate, 31 - wellbore limiter base A, 32 - wellbore limiter cover A, 21 - wellbore limiter base B, 22 - wellbore limiter cover B, 81 - drill pipe limiter base A, 82 - drill pipe limiter cover A, 91 - drill pipe limiter base B, 92 - drill pipe limiter cover B, 311 - fixed through hole A, 312 - cylinder base limiter through hole A, 321 - cylinder cover limiter through hole A, 211 - fixed through hole B, 212 - cylinder base limiter through hole B, 221 - cylinder cover limiter through hole B, 811 - through hole A, 812 - rod base limiter through hole A, 821 - rod cover limiter through hole A, 911 - through hole B, 912 - rod base limiter through hole B, 921 - rod cover limiter through hole B, 71 - helical wing, 72 - central hole, 131 - bottom plate through hole, 141 - top plate through hole, 41 - grouting port, 42 - rubber plug. DETAILED DESCRIPTION

[0049] In the following, only certain exemplary embodiments are simply described. As those skilled in the art can recognize, the described embodiments can be modified in various different manners without departing from the spirit or scope of the embodiments of the present application. Therefore, the drawings and the description are considered to be exemplary in nature rather than limiting.

[0050] In the description of the embodiments of the present application, it needs to be understood that the terms "length", "vertical", "horizontal", "top", "bottom", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, only for the purpose of facilitating the description of the embodiments of the present application and simplifying the description, and do not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0051] In addition, the terms "first", "second", etc. are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0052] In the embodiments of the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing", etc. should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected, or it can be communicated; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0053] In the embodiments of the present application, unless otherwise explicitly specified and limited, the "upper" or "lower" of the first feature to the second feature can include that the first and second features are in direct contact, or it can include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the "upper", "above" and "on" of the first feature to the second feature include that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The "below", "under" and "under" of the first feature to the second feature include that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0054] The following disclosure provides many different embodiments, or examples, for implementing different structures of the present embodiments. For the purpose of simplifying the present embodiments' disclosure, the components and arrangements of the specific examples are described below. Of course, they are merely examples and are not intended to limit the present embodiments. Moreover, the present embodiments can repeat reference numerals and / or letters in various examples and this repetition is for the purpose of simplicity and clarity, and does not in itself dictate a relationship between the various embodiments and / or configurations discussed.

[0055] The embodiments of the present application will be described in detail below with reference to the drawings.

[0056] The present example discloses a cement sheath failure test device, comprising a curved wellbore 1, a wellbore fixing unit, an impact simulation unit, a drill pipe 6 guide unit, a cement sheath forming unit and a sealing detection unit.

[0057] Among them, the curved wellbore 1 is composed of an annular space formed by the coaxially arranged inner cylinder 12 and outer cylinder 11, and the two ends are closed by the top plate 14 and the bottom plate 13. The top plate 14 and the bottom plate 13 are provided with through holes, specifically the bottom plate through hole 131 and the top plate through hole 141, and are provided with rubber plugs 42 for plugging.

[0058] The wellbore fixing unit includes a limiter for fixing the curved wellbore;

[0059] The impact simulation unit includes a drill pipe 6 penetrating the curved wellbore 1 and a centralizer 7 installed on the drill pipe 6;

[0060] The drill pipe 6 guide unit includes at least two limiters spaced apart on the drill pipe 6, and the inner diameter of the limiter is smaller than the diameter of the drill pipe 6 to constrain the radial displacement and allow axial sliding;

[0061] The cement sheath forming unit includes a grouter 4 in communication with the top plate 14;

[0062] The sealing detection unit includes a gas injection pipe and a flowmeter in communication with the annular space. Further, the gas injection pipe 10 is installed on the bottom plate 13, and the flowmeter 5 is installed on the top plate 14.

[0063] Further, the limiter is composed of a top end limiter and a bottom end limiter for fixing the top end and the bottom end of the wellbore. The top end limiter and the bottom end limiter both adopt a split base and cover plate structure and are fixed by bolts.

[0064] Among them, the centralizer 7 is provided with a spiral wing 71 and a central hole 72 for connecting the drill pipe 6.

[0065] Further, the top plate 14 and the bottom plate 13 are each provided with at least one interface for connecting the grouter 4, the flowmeter 5 or the gas injection pipe 10.

[0066] Further, the drill pipe 6 is provided with a thread at one end, and the drill pipe 6 is connected to the centralizer 7 through the thread.

[0067] Further, the grouting device 4 is provided with a thread at one end, and the grouting device 4 is connected to the curved wellbore 1 through the thread.

[0068] The cement sheath sealing failure test method is also disclosed in the embodiment, which comprises using the cement sheath sealing failure test device, and the specific steps are as follows:

[0069] The top end and the bottom end of the curved wellbore 1 are fixed;

[0070] Cement slurry is injected into the annular space to form a cement sheath;

[0071] The drill pipe 6 with the centralizer 7 is installed to constrain the radial displacement of the drill pipe 6;

[0072] The detection gas is introduced into the bottom end of the curved wellbore 1, and the top end is connected to the flowmeter 5;

[0073] The pulse impact load is applied to the drill pipe 6 to push the centralizer 7 to move to the inner wall of the wellbore at a first speed, and then move to the bottom end of the wellbore at a second speed;

[0074] The reverse pulse impact load is applied to pull back the drill pipe 6 to the centralizer 7 to move away from the inner wall of the wellbore at a third speed, and then move out of the centralizer 7 at a fourth speed;

[0075] The value of the flowmeter during the test is recorded to determine the sealing property of the cement sheath.

[0076] The first speed is greater than the second speed, and the fourth speed is greater than the third speed.

[0077] Further, the peak value of the pulse impact load ranges from 5kN to 20kN, and the frequency ranges from 5kHz to 15kHz.

[0078] The pressure of the detection gas ranges from 0.5MPa to 1.5MPa.

[0079] In order to further understand the present application by those skilled in the art, the present application is further described as follows.

[0080] As shown in Figure 1 - Figure 11 The cement sheath sealing failure test device comprises a curved wellbore 1, a wellbore top end limiter 3, a wellbore bottom end limiter 2, a drill pipe 6, a centralizer 7, a drill pipe limiter A 8, a drill pipe limiter B 9, a grouting device 4, a gas injection pipe 10, a flowmeter 5 and a rubber plug 42.

[0081] As shown in Figure 2As shown, the curved wellbore 1 includes a top plate 14, a bottom plate 13, an inner cylinder 12 and an outer cylinder 11, the annular space formed by the inner cylinder 12 and the outer cylinder 11 is used to pour cement slurry, and the cement slurry is solidified to form a cement ring, the top plate 14 is provided with two center-symmetric top plate through holes 141, and the bottom plate 13 is provided with two center-symmetric bottom plate through holes 131.

[0082] The drill pipe 6 and the centralizer 7 constitute the impact simulation unit.

[0083] The drill pipe stopper A 8 and the drill pipe stopper B 9 constitute the drill pipe 6 guiding unit.

[0084] The wellbore top end stopper 3 is composed of a wellbore stopper cover A 32 and a wellbore stopper base A 31, the wellbore stopper cover A 32 is provided with four cylinder cover limiting through holes A 321, the upper part of the wellbore stopper base A 31 is provided with four cylinder seat limiting through holes A 312, the four cylinder cover limiting through holes A 321 and the four cylinder seat limiting through holes A 312 can be locked by bolts, and the lower part of the wellbore stopper base A 31 is provided with four fixing through holes A 311, which can be connected and fixed with ground fixing facilities by bolts.

[0085] The wellbore bottom end stopper 2 is composed of a wellbore stopper cover B 22 and a wellbore stopper base B 21, the wellbore stopper cover B 22 is provided with four cylinder cover limiting through holes B 221, the upper part of the wellbore stopper base B 21 is provided with four cylinder seat limiting through holes B 212, the four cylinder cover limiting through holes B 221 and the four cylinder seat limiting through holes B 212 can be locked by bolts, and the lower part of the wellbore stopper base B 21 is provided with four fixing through holes B 211, which can be connected and fixed with ground fixing facilities by bolts.

[0086] The drill pipe stopper A 8 includes a drill pipe stopper cover A 82 and a drill pipe stopper base A 81, the drill pipe stopper cover A 82 is provided with four axis-symmetric rod cover limiting through holes A 821, the drill pipe stopper base A 81 is provided with four rod seat limiting through holes A 812, the four rod cover limiting through holes A 821 and the four rod seat limiting through holes A 812 can be locked by bolts, and the lower part of the drill pipe stopper base A 81 is provided with four through holes A 811, which can be connected and fixed with ground fixing facilities by bolts.

[0087] The drill pipe limiter B9 comprises a drill pipe limiting cover B92 and a drill pipe limiting base B91. The drill pipe limiting cover B92 is provided with four axis-symmetric rod cover limiting through holes B921. The drill pipe limiting base B91 is provided with four rod seat limiting through holes B912. The four rod cover limiting through holes B921 and the four rod seat limiting through holes B912 can be locked by bolts. The drill pipe limiting base B91 is provided with four through holes B911 in the lower part. The through holes B911 can be connected and fixed with ground fixing facilities by bolts.

[0088] The drill pipe limiter A8 and the drill pipe limiter B9 are arranged at a certain distance on the drill pipe 6. The diameter of the circular structure on the drill pipe limiter is 1mm smaller than the diameter of the drill pipe 6. The drill pipe limiter A8 and the drill pipe limiter B9 jointly constrain the radial displacement of the drill pipe 6. The drill pipe limiter A8 and the drill pipe limiter B9 can freely slide along the axis of the drill pipe 6.

[0089] The central hole 72 of the centralizer 7 is provided with a thread.

[0090] One end of the drill pipe 6 is provided with a thread. The drill pipe 6 is connected and matched with the centralizer 7 through the thread.

[0091] One end of the grouting device 4 is provided with a thread. The grouting device 4 is connected and matched with the curved wellbore 1 through the thread.

[0092] The cement sheath sealing failure test device comprises the following steps:

[0093] In step S1, the wellbore limiting base A31 is supported at the top end of the curved wellbore 1. The wellbore limiting cover A32 is fastened with the wellbore limiting base A31 by bolts. The wellbore limiting base B21 is supported at the bottom end of the curved wellbore 1. The wellbore limiting cover B22 is fastened with the wellbore limiting base B21 by bolts. The top end and the bottom end of the curved wellbore 1 are fixed.

[0094] In step S2, two grouting devices 4 are connected with two threaded holes on the top plate 14 of the curved wellbore 1. Two threaded holes on the bottom plate 13 of the curved wellbore 1 are sealed by the rubber plugs 42.

[0095] In step S3, the prepared cement slurry is poured into the grouting port 41 of the grouting device 4. The cement slurry flows into the annular space between the inner cylinder 12 and the outer cylinder 11 through the grouting device 4. The cement slurry is stopped after filling the annular space. The grouting device 4 is removed. The threaded holes on the top plate 14 of the wellbore are sealed by the rubber plugs 42.

[0096] In step S4, the cement slurry is left to cure for 7 days to form a cement sheath.

[0097] In step S5, the centralizer 7 is connected and matched with the drill pipe 6 through the thread.

[0098] Step S6, the drill pipe limiting base A81 and the drill pipe limiting base B91 support the drill pipe 6 respectively, and then the drill pipe limiting cover A82 and the drill pipe limiting cover B92 are locked with the drill pipe limiting base A81 and the drill pipe limiting base B91 respectively through bolts, so as to realize the fixation of the drill pipe 6 in the radial direction, and the axis of the fixed drill pipe 6 coincides with the axis of the top end of the curved wellbore 1;

[0099] Step S7, the rubber plug 42 at the threaded hole of the wellbore top plate 14 is removed, and then the two flow meters 5 are connected with the two threaded holes of the wellbore top plate 14 to record the value changes of the two flow meters 5 in real time;

[0100] Step S8, the rubber plug 42 at the threaded hole of the wellbore bottom plate 13 is removed, and then the two gas injection pipes 10 are connected with the two threaded holes of the wellbore bottom plate 13;

[0101] Step S9, the two gas injection pipes 10 are connected with the external detection gas cylinder, and the detection gas cylinder injects the gas with a pressure of 1 MPa into the two gas injection pipes 10;

[0102] Step S10, the external transient impact generator is used to apply a pulse impact pressure (peak value of 10 kN and frequency of 10 kHz) to the left end of the drill pipe 6 to push the drill pipe 6 to move slowly towards the bottom end of the curved wellbore 1, and the displacement speed of the drill pipe 6 is controlled to be 0.2 m / s, until the centralizer 7 contacts with the inner wall of the curved wellbore 1, the displacement speed of the drill pipe 6 is adjusted to be 0.1 m / s, the drill pipe 6 is continuously pushed to move into the curved wellbore 1, until the centralizer 7 reaches the bottom end of the curved wellbore 1;

[0103] Step S11, the external transient impact generator is used to apply a pulse impact tension (peak value of 10 kN and frequency of 10 kHz) to the left end of the drill pipe 6 to pull the drill pipe 6 to move towards the top end of the curved wellbore 1, and the moving speed of the drill pipe 6 is controlled to be 0.1 m / s, until the centralizer 7 is separated from the inner wall of the curved wellbore 1, the moving speed of the drill pipe 6 is adjusted to be 0.2 m / s, until the centralizer 7 is completely removed from the curved wellbore 1;

[0104] Step S12, steps S10 and S11 are repeated, and the values of the multiple flow meters in the test process are recorded, in this embodiment, there are two flow meters, and the values of the two flow meters are both zero, which indicates that the cement sheath has good sealing performance, and at least one of the values of the two flow meters is not zero, which indicates that the sealing performance of the cement sheath is damaged.

[0105] Through the method, the impact damage of the drill pipe 6 and the centralizer 7 to the cement sheath of the curved wellbore can be evaluated.

[0106] While the preferred embodiments of the application have been described, additional variations and modifications can be made to these embodiments by those skilled in the art once they have the benefit of the present disclosure. Therefore, the appended claims are intended to encompass all such variations and modifications as falling within the scope of the application.

[0107] The preferred embodiments of the application described hereinabove are therefore to be considered in all respects as illustrative only and not restrictive in character, since the scope of the application includes any modifications and variations that come within the scope of the appended claims.

Claims

1. A cement ring seal failure test apparatus, characterized in that, include: The curved wellbore comprises an inner and outer cylinder arranged coaxially to form an annular space, and is closed at both ends by a top plate and a bottom plate, with through holes provided on the top plate and the bottom plate. A wellbore fixing unit is used to fix a bent wellbore. An impact simulation unit, used to simulate impact loads; A cement ring forming unit, wherein the cement ring forming unit is used to form a cement ring within an annular space; A sealing detection unit, connected to an annular space, is used to sample when the impact simulation unit simulates an impact; the wellbore fixing unit includes a limiter for fixing the bent wellbore; The impact simulation unit includes a drill pipe that runs through a curved wellbore and a centralizer mounted on the drill pipe; The cement ring forming unit includes a grouting device that communicates with the top slab; The sealing detection unit includes an injection pipe and a flow meter that communicate with the annular space.

2. The cement ring seal failure test device according to claim 1, characterized in that: The drill pipe is connected to a drill pipe guide unit, which includes at least two limiters spaced apart on the drill pipe. The inner diameter of the limiters is smaller than the diameter of the drill pipe to constrain radial displacement and allow axial sliding.

3. The cement ring seal failure test device according to claim 1, characterized in that: The limiter consists of a top limiter and a bottom limiter, which are used to fix the top and bottom of the wellbore respectively. Both the top limiter and the bottom limiter adopt a split base and cover plate, and the base and cover plate are connected by bolts.

4. The cement ring seal failure test device according to claim 1, characterized in that: The stabilizer has helical side wings and a central hole for connecting the drill rod.

5. The cement ring seal failure test device according to claim 1, characterized in that: Both the top plate and the bottom plate are provided with at least one interface for connecting a grouting device, a flow meter, or an air injection pipe.

6. A test method for cement ring seal failure, characterized in that: The method includes using the cement ring seal failure test apparatus according to any one of claims 1-5, with the following specific steps: Secure the top and bottom ends of the curved well shaft; Cement grout is injected into the annular space and cured to form a cement ring; Install drill pipes with stabilizers to constrain radial displacement of the drill pipes; Test gas is introduced into the bottom of the curved well shaft, and multiple flow meters are connected to the top to detect the flow rate of the gas. A pulse impact load is applied to the drill pipe, which pushes the centralizer to move at a first speed to contact the inner wall of the wellbore, and then moves at a second speed to the bottom of the wellbore; Apply a reverse pulse impact load and pull the drill pipe back at the third speed until the centralizer is removed from the inner wall of the wellbore, and then remove the centralizer at the fourth speed; The values ​​of multiple flow meters were recorded throughout the test to determine the sealing performance of the cement ring.

7. The cement ring seal failure test method according to claim 6, characterized in that: The first speed is greater than the second speed, and the fourth speed is greater than the third speed.

8. The cement ring seal failure test method according to claim 6, characterized in that: The fixed drill pipe axis coincides with the axis of the top of the curved wellbore.

9. The test method for cement ring seal failure according to claim 8, characterized in that: The test method described above evaluates the impact damage of drill pipe and centralizer on the wellbore cement sheath when passing through curved well sections. Multiple flow meter values ​​of zero indicate that the cement sheath is in good sealing condition, while at least one flow meter value of non-zero indicates that the cement sheath is damaged.

Images