DEVICE FOR TESTING STRENGTH AND SEALING PERFORMANCE OF CEMENT SHEATH AFTER PERFORATION AND USING METHOD THEREOF

Abstract

The invention discloses a device for testing strength and sealing performance of cement sheath after perforation, comprising a cement sheath curing maintenance simulation component, a perforation operation simulation component, and a cement sheath performance test component. By simulating the detonation effect and fluid-solid coupling effect, quantitatively testing the internal transverse crack and longitudinal crack propagation size, compressive strength and tensile strength, permeability, blowby pressure, blowby velocity and other parameters of the cement sheath, drawing the relation curve between different perforation distances and the maximum blowby pressure and permeability of the cement sheath, determining the perforation distance H.sub.p where the blowby of the cement sheath does not occur, determining the perforation distance H.sub.K to ensure the sealing of the cement sheath, and using min (H.sub.p, H.sub.K), the critical perforation distance that the cement sheath has sufficient strength to prevent blowby and meet the sealing requirements can be determined.

Claims

1. A device for testing strength and sealing performance of cement sheath after perforation, comprising a cement sheath curing maintenance simulation component, a perforation operation simulation component, and a cement sheath performance test component; wherein the cement sheath curing maintenance simulation component comprises: a casing (1); stratum rocks (8), which are arranged outside the casing (1), and the casing (1) and the stratum rocks (8) enclose a closed annular space; a cement sheath (7) is in curing maintenance in the closed annular space; the perforation operation simulation component comprises: a perforation gun, and a gun body (29) thereof is provided inside the casing (1); the gun body (29) is provided with a plurality of perforation bullets (30); the plurality of perforation bullets (30) are connected in series via a detonating cord (31) and pass through the top of the casing (1); a kill fluid (36), which is tanked between the casing (1) and the gun body (29); the cement sheath performance test component comprises: a channeling verification booster pump (17); the channeling verification pressure is applied to the lower end surface of the cement sheath (7) through a channeling verification pipeline (15) and a gas-permeable cement isolation ring (14); a channeling verification pressure sensor (16), which is provided on the channeling verification pipeline (15); a temperature and pressure control system (27), which is electrically connected to the channeling verification pressure sensor (16), and is used to draw the blowby pressure curve under perforation parameters and perforation distance to test the strength and sealing performance of the cement sheath after perforation.

2. The device for testing strength and sealing performance of cement sheath after perforation according to claim 1, wherein a casing sealing ring (2) and a lower plug (4) are sequentially provided between the casing (1) and the bottom of the stratum rocks (8) from the inside to the outside; an upper sealing head (5) and an upper plug (4) are sequentially provided between the casing (1) and the top of the stratum rocks (8) from the inside to the outside.

3. The device for testing strength and sealing performance of cement sheath after perforation according to claim 2, wherein the cement sheath curing maintenance simulation component further comprises: a casing booster pump (20), which is communicated with the casing (1) through a casing pressure pipeline (18); a casing internal pressure control valve (19), which is provided on the casing pressure pipeline (18) close to the casing booster pump (20).

4. The device for testing strength and sealing performance of cement sheath after perforation according to claim 3, wherein the cement sheath curing maintenance simulation component further comprises: a casing heating device, which is provided in the casing (1); a casing temperature and pressure sensor (6), which is provided in the casing (1) and is electrically connected to the temperature and pressure control system (27).

5. The device for testing strength and sealing performance of cement sheath after perforation according to claim 1, wherein the cement sheath curing maintenance simulation component further comprises: a rubber cylinder (9), which is surrounded outside the stratum rocks (8); a hydraulic chamber (10), which is surrounded outside the rubber cylinder (9); a hydraulic cylinder (11), which is surrounded outside the hydraulic chamber (10); a stratum heating jacket (12), which is surrounded outside the hydraulic cylinder (11); a confining pressure booster pump (24), which is communicated with the top of the hydraulic chamber (10) through a confining pressure booster pipeline (22); a confining pressure sensor (23), which is provided on the confining pressure booster pipeline (22) and is electrically connected to the temperature and pressure control system (27); a confining pressure relief valve (26), which is connected to the bottom of the hydraulic chamber (10) through a confining pressure relief pipeline (25).

6. The device for testing strength and sealing performance of cement sheath after perforation according to claim 1, wherein the perforation gun comprises: a gun body (29); a gun head (28), which is provided at the top of the gun body (29) and is located in the casing (1); a gun tail (32), which is provided at the bottom of the gun body (29) and is located in the casing (1); a gun body upper plug (33), which is provided outside the casing (1) and located directly above the gun body (29), and is used to guide the detonating cord (31); a gun body lower plug (34), which is provided at the bottom of the gun tail (32) and located in the casing (1); a gun body handle (35), which is provided at the top of the gun body upper plug (33).

7. The device for testing strength and sealing performance of cement sheath after perforation according to claim 1, wherein the perforation operation simulation component comprises: an inner iron sleeve (37), which is surrounded outside the stratum rocks (8); an outer iron sleeve (39), which is surrounded outside the inner iron sleeve (37), and concrete (38) is cured between the space enclosed by the inner iron sleeve (37) and the outer iron sleeve (39).

8. A using method of the device for testing strength and sealing performance of cement sheath after perforation according to claim 1, comprising: according to the curing maintenance parameters, a cement sheath (7) is in curing maintenance in the closed annular space enclosed by the casing (1) and the stratum rocks (8); according to the perforation operation parameters, perforating with a perforation gun and a detonator equipped with perforation bullets (30) and a detonating cord (31); connecting the channeling verification pressure sensor (16) and the channeling verification booster pump (17) to the channeling verification pipeline (15), selecting an initial pressure P.sub.0 to start the channeling verification, and observing the channeling verification curve of the temperature and pressure control system (27); if the temperature and pressure within 30 minutes are within the range of P.sub.0×(1±10%), then selecting the next pressure P.sub.1, P.sub.2, P.sub.3 . . . for channeling verification; monitoring and drawing the relation curve between the blowby pressure curve and time, increasing the pressure until the blowby of the cement sheath (7) occurs, recording the maximum pressure before the blowby occurs as P.sub.C0, and calculating the blowby velocity v.sub.0; taking out the cement sheath, measuring the propagation direction of the crack and the size of the crack at different positions from the perforation hole, and drawing the relation curve between the distance of the perforation hole and the crack size; processing the cement stone tensile specimens, compressive specimens and permeability test specimens at different positions away from the perforation hole; testing the compressive strength, tensile strength σ.sub.t0 to and permeability K.sub.0 of the cement stone after perforation, and drawing the relation curve between the perforation distance and the tensile strength σ.sub.t0, compressive strength σ.sub.R0 and permeability K.sub.0; selecting the next perforation distance H.sub.1, H.sub.1<H.sub.0, and measuring the maximum pressure P.sub.C1 under this perforation distance and the blowby velocity v.sub.1, until the designed perforation distances H.sub.2, H.sub.3 . . . are all tested; drawing the pressure blowby curve at different perforation distances; drawing the relation curves between different perforation distances H.sub.0, H.sub.1, H.sub.2, H.sub.3 . . . and the maximum blowby pressure P.sub.C0, P.sub.C1, P.sub.C2, P.sub.C3 . . . , permeability K.sub.0, K.sub.1, K.sub.2, K.sub.3 . . . ; according to the target stratum pressure P.sub.p, determining the critical blowby pressure P.sub.C of the cement sheath; when setting the target stratum pressure P.sub.p, ensuring that the perforation distance that the blowby of the cement sheath does not occur is greater than or equal to H.sub.p; determining the critical permeability K.sub.C of the cement sheath according to the annulus pressure P.sub.A control requirements; under the setting of the annulus pressure P.sub.A control requirements, ensuring that the perforation distance of the cement sheath sealing is greater than or equal to H.sub.K; selecting the minimum perforation distance (H.sub.p, H.sub.K) as the critical perforation distance to ensure the strength and sealing performance of the cement sheath.

9. The using method of the device for testing strength and sealing performance of cement sheath after perforation according to claim 8, wherein the curing maintenance parameters comprise: according to the cementing and perforation operating conditions of the target well, determining the cement slurry system, casing temperature, internal pressure, stratum temperature, confining pressure, temperature and pressure changes during cementing, and waiting on cement setting time during the cementing operation.

10. The using method of the device for testing strength and sealing performance of cement sheath after perforation according to claim 8, wherein the perforation operation parameters comprise: aperture, phase, hole density, penetration depth, and explosive payload during the perforation operation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0064] FIG. 1 is a schematic diagram of the structure of the device for testing strength and sealing performance of cement sheath after perforation provided by an embodiment of the invention;

[0065] FIG. 2 is a schematic diagram of the structure of the perforation device;

[0066] FIG. 3 is a test curve and a method for determining the critical perforation distance provided by an embodiment of the invention.

DESCRIPTION OF REFERENCE SIGNS

[0067] 1 refers to the casing; 2 refers to the casing sealing ring; 3 refers to the upper plug; 4 refers to the lower plug; 5 refers to the upper sealing head; 6 refers to the casing temperature and pressure sensor; 7 refers to the cement sheath; 8 refers to the stratum rocks; 9 refers to the rubber cylinder; 10 refers to the hydraulic chamber; 11 refers to the hydraulic cylinder; 12 refers to the stratum heating jacket; 13 refers to the casing heating device; 14 refers to the gas-permeable cement isolation ring; 15 refers to the channeling verification pipeline; 16 refers to the channeling verification pressure sensor; 17 refers to the channeling verification booster pump; 18 refers to the casing pressure pipeline; 19 refers to the casing internal pressure control valve; 20 refers to the casing booster pump; 21 refers to the channeling verification device lifting ring; 22 refers to the confining pressure booster pipeline; 23 refers to the confining pressure sensor; 24 refers to the confining pressure booster pump; 25 refers to the confining pressure relief pipeline; 26 refers to the confining pressure relief valve; 27 refers to the temperature and pressure control system; 28 refers to the gun head; 29 refers to the gun body; 30 refers to the perforation bullets; 31 refers to the detonation cord; 32 refers to the gun tail; 33 refers to the gun body upper plug; 34 refers to the gun body lower plug; 35 refers to the gun body handle; 36 refers to the kill fluid; 37 refers to the inner iron sleeve; 38 refers to the concrete; 39 refers to the outer iron sleeve.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0068] In order to make the purpose, technical solutions, and advantages of the invention clearer, the invention will be further described in detail hereinafter with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the invention, and not used to limit the invention.

[0069] One embodiment of the invention discloses a device for testing strength and sealing performance of cement sheath after perforation, wherein the device specifically comprises:

[0070] a cement sheath curing maintenance simulation component, a perforation operation simulation component, and a cement sheath performance test component. The invention can simulate the cyclic and alternating conditions of casing temperature, casing internal pressure, stratum temperature, and stratum confining pressure during cementing operations, to realize the solidification and maintenance of the cement sheath, and can simulate parameters such as aperture, phase, hole density, penetration depth, explosive payload, and other parameters during the perforation operation to realize the impact of detonation energy flow on the casing-cement sheath-stratum and complete the perforation. The invention provides a reliable experimental device and data support for cement slurry system design and perforation parameter optimization by quantitatively evaluating the size, strength and sealing performance of the internal cracks of the cement sheath under different perforation parameters.

[0071] With reference to FIG. 1, specifically, the cement sheath curing maintenance simulation component comprises: a casing 1, a casing sealing ring 2, an upper plug 3, a lower plug 4, an upper sealing head 5, a casing temperature and pressure sensor 6, a cement sheath, stratum rocks 8, a rubber cylinder 9, a hydraulic chamber 10, a hydraulic cylinder 11, a stratum heating jacket 12, a casing heating device 13, a casing pressure pipeline 18, a casing internal pressure control valve 19, a casing booster pump 20, a confining pressure booster pipeline 22, a confining pressure sensor 23, a confining pressure booster pump 24, a confining pressure relief pipeline 25, a confining pressure relief valve 26, and a temperature and pressure control system 27, which can simulate the cyclic and alternating conditions of casing temperature, casing internal pressure, stratum temperature, and stratum confining pressure during cementing operations, to realize the solidification and maintenance of the cement sheath.

[0072] Further, cement sheath curing maintenance simulation component encloses a closed annular space by the casing 1, the casing sealing ring 2, the upper plug 3, the lower plug 4, and the stratum rocks 8; the casing 1 is connected to the upper plug 3 and the lower plug 4 by threaded connection; the upper sealing head 5 and the casing sealing ring 2 are used for sealing; the inside of the casing 1 is provided with a casing heating device 13, which can heat the casing and simulate the casing temperature of the target wellbore.

[0073] Further, the upper plug 3 is provided with an upper sealing head 5 and a casing pressure pipeline 18, which is connected to a casing internal pressure control valve 19 and a casing booster pump 20, which can pressurize the inside of the casing and simulate the internal pressure of the target wellbore.

[0074] Further, the inside of the casing 1 is provided with a casing temperature and pressure sensor 6, which can monitor and record the temperature and pressure in real time; the outside of the stratum rocks 8 is provided with a stratum heating jacket 12; the rubber cylinder 9, the hydraulic chamber 10, the hydraulic cylinder 11, the confining pressure booster pipeline 22, the confining pressure sensor 23, the confining pressure booster pump 24, the confining pressure relief pipeline 25, the confining pressure relief valve 26 can heat and pressurize the stratum rocks 8 to simulate the stratum temperature and pressure near the target wellbore.

[0075] Further, the cement slurry system to be evaluated is tanked in a closed annular space, and the temperature and pressure control system 27 is used to control the temperature and pressure of the casing and the stratum respectively, which can simulate the cyclic alternating conditions of casing temperature, casing internal pressure, stratum temperature, and stratum confining pressure during the cementing operation, and wait until the cement sheath 7 is cured and maintained.

[0076] Further, the casing cement sheath stratum assembly preparation components comprise: a casing 2, a cement sheath 3, stratum rocks 4, a copper sleeve 5, a core plug 6, a casing core plug sealing component 7, a copper sleeve fixing flange 8, an assembly tightening flange 9, a pulling rod 10, a copper sleeve core plug sealing component 11, a tightening flange core plug sealing component 12, a tightening flange sealing flange 13, a tightening flange sealing flange bolt 14, and an assembly tightening flange pulling rod 15, which can realize the curing maintenance and preparation of the canned cement slurry system and the casing cement sheath stratum assembly.

[0077] With reference to FIG. 2, specifically, the perforation operation simulation component comprises: a gun head 28, a gun body 29, perforation bullets 30, a detonation cord 31, a gun tail 32, a gun body upper plug 33, a gun body lower plug 34, a gun body handle 35, a kill fluid 36, an inner iron sleeve 37, and concrete 38, which can simulate parameters such as aperture, phase, hole density, penetration depth, explosive payload, and other parameters during the perforation operation to realize the impact of detonation energy flow on the casing-cement sheath-stratum and complete the perforation.

[0078] That is, the perforation operation simulation component is composed of a gun head 28, a gun body 29, a gun tail 32, a gun body upper plug 33, a gun body lower plug 34, and a gun body handle 35; the gun body 29 is provided with perforation bullets 30, and the explosive payload, arrangement phase, aperture, hole density, and penetration depth are consistent with the perforation parameters of the target wellborn. The detonating cord 31 connects all the perforating bullets in series and passes through the gun body upper plug 33. A kill fluid 36 is tanked between the casing 1 and the gun body 29. A certain thickness of concrete 38 is cured between the inner iron sleeve 37 and the outer iron sleeve 39 to simulate the damage of the cement sheath 7 caused by the fluid-solid coupling effect under the detonation effect of perforation operation.

[0079] Specifically, the cement sheath performance test component comprises: a gas-permeable cement isolation ring 14, a channeling verification pipeline 15, a channeling verification pressure sensor 16, a channeling verification booster pump 17, and a channeling verification device lifting ring 21, which can quantitatively evaluate the internal crack size, strength and sealing performance of the cement sheath under different perforation parameters, and provide data support for cement slurry system design and perforation parameter optimization.

[0080] That is, the cement sheath performance test component applies the channeling pressure by the channeling verification booster pump 17 to the lower end surface of the cement sheath 7 through the channeling verification pipeline 15 and the gas-permeable cement isolation ring 14. Through the channeling verification pressure sensor 16, the change of the blowby pressure can be monitored in real time, and the blowby pressure curve under the perforation parameters and perforation distance can be drawn.

[0081] One embodiment discloses a using method of the device for testing strength and sealing performance of cement sheath after perforation, wherein the method comprises:

[0082] according to the cementing and perforation operating conditions of the target well, determining the cement slurry system, casing temperature, internal pressure, stratum temperature, confining pressure, temperature and pressure changes during cementing, waiting on cement setting time, and other curing parameters during the cementing operation; determining the parameters such as aperture, phase, hole density, penetration depth, explosive payload and so on during perforation operation.

[0083] S2: placing the lower plug 4 steadily, applying sealing grease and connecting the casing 1 and the lower plug 4 through the threaded connection through the casing sealing ring 2; according to the installation and positioning of the steps set by the stratum rocks 8 and the lower plug 4, installing the rubber cylinder 9, the hydraulic cavity 10, the hydraulic cylinder 11, the stratum heating jacket 12, the gas-permeable cement isolation ring 14, the confining pressure booster pipeline 22, the confining pressure sensor 23, the confining pressure booster pump 24, the confining pressure relief pipeline 25, and the confining pressure relief valve 26 in sequence; installing the casing temperature and pressure sensor 6 and the casing heating device 13 inside the casing.

[0084] S3: preparing the cement slurry system and slowly and steadily pouring into the annular space between the casing 1 and the stratum rocks 8 along the casing wall, and installing the upper plug 3 using the channeling verification device lifting ring 21, then installing the upper sealing head 5, the casing pressure pipeline 18, the casing internal pressure control valve 19, and the casing booster pump 20 in sequence.

[0085] S4: connecting the temperature and pressure control system 27 to the casing temperature and pressure sensor 6 and the confining pressure sensor 23 in sequence; when the casing internal pressure and temperature and the stratum confining pressure and temperature reach the cementing operating conditions, the temperature and pressure control system 27 starts to monitor and record the temperature and pressure curve of the cement sheath 7 curing maintenance; the temperature and pressure control system 27 can be used to set the temperature and pressure alternation amplitude and alternation time to simulate the characteristics of wellbore conditions during cementing operations.

[0086] S5: after the cement sheath 7 is cured and maintained, removing the upper sealing head 5, the casing pressure pipeline 18, the casing internal pressure control valve 19, the casing booster pump 20, the rubber cylinder 9, the hydraulic chamber 10, the hydraulic cylinder 11, and the stratum heating jacket 12, etc.; according to the aperture, phase, hole density, penetration depth, and explosive payload, processing and manufacturing the perforating gun, and installing the perforating bullets 30 in the gun body 29; preliminarily determining a larger perforation distance H.sub.0 that can guarantee the sealing performance of the cement sheath, then the height of the gun tail 32 is H.sub.0; installing the gun head 28, the gun body upper plug 33, the gun body lower plug 34, and the gun body handle 35 in sequence; using the detonating cord 31 to connect all perforating bullets in series and pass through the upper plug 33, and injecting the kill fluid 36 into the annular space between the gun body 29 and the casing 1.

[0087] S6: a certain thickness of concrete 38 is cured between the inner iron sleeve 37 and the outer iron sleeve 39 to prevent the stratum rocks 8 from crushing damage.

[0088] S7: connecting the detonating cord 31 to the detonator, determining a sufficient safety distance, and detonating the perforating bomb on the premise of confirming safety to complete the perforation simulation operation.

[0089] S8: connecting the channeling verification pressure sensor 16 and the channeling verification booster pump 17 to the channeling verification pipeline 15, selecting an initial pressure P.sub.0 to start the channeling verification, and observing the channeling verification curve of the temperature and pressure control system 27; if the temperature and pressure within 30 minutes are within the range of P.sub.0×(1±10%), then selecting the next pressure P.sub.1, P.sub.2, P.sub.3 . . . for channeling verification; monitoring and drawing the relation curve between the blowby pressure curve and time, increasing the pressure until the blowby of the cement sheath 7 occurs, recording the maximum pressure before the blowby occurs as P.sub.C0, and calculating the blowby velocity v.sub.0.

[0090] S9: taking out the cement sheath, measuring the propagation direction of the crack and the size of the crack at different positions from the perforation hole, and drawing the relation curve between the distance of the perforation hole and the crack size.

[0091] S10: processing the cement stone tensile specimens, compressive specimens and permeability test specimens at different positions away from the perforation hole; testing the compressive strength, tensile strength σ.sub.t0 to and permeability K.sub.0 of the cement stone after perforation, and drawing the relation curve between the perforation distance and the tensile strength σ.sub.t0, compressive strength σ.sub.R0 and permeability K.sub.0.

[0092] S11: selecting the next perforation distance H.sub.1, H.sub.1<H.sub.0, and measuring the maximum pressure P.sub.C1 under this perforation distance and the blowby velocity v.sub.1, until the designed perforation distances H.sub.2, H.sub.3 . . . are all tested.

[0093] S12: drawing the pressure blowby curve at different perforation distances; drawing the relation curves between different perforation distances H.sub.0, H.sub.1, H.sub.2, H.sub.3 . . . and the maximum blowby pressure P.sub.C0, P.sub.C1, P.sub.C2, P.sub.C3 . . . , permeability K.sub.0, K.sub.1, K.sub.2, K.sub.3 . . . .

[0094] S13: according to the target stratum pressure P.sub.p, determining the critical blowby pressure P.sub.C of the cement sheath; when setting the target stratum pressure P.sub.p, ensuring that the perforation distance that the blowby of the cement sheath does not occur is greater than or equal to H.sub.p.

[0095] S14: determining the critical permeability K.sub.C of the cement sheath according to the annulus pressure P.sub.A control requirements; under the setting of the annulus pressure P.sub.A control requirements, ensuring that the perforation distance of the cement sheath sealing is greater than or equal to H.sub.K.

[0096] S15: selecting the minimum perforation distance (H.sub.p, H.sub.K) as the critical perforation distance to ensure the strength and sealing performance of the cement sheath.

[0097] In summary, by simulating the detonation effect and fluid-solid coupling effect on the casing-cement sheath-stratum under perforating operation parameters, quantitatively testing the internal transverse crack and longitudinal crack propagation size, compressive strength and tensile strength, permeability, blowby pressure, blowby velocity and other parameters of the cement sheath, drawing the relation curve between different perforation distances and the maximum blowby pressure and permeability of the cement sheath, determining the perforation distance H.sub.p where the blowby of the cement sheath does not occur according to the target stratum pressure P.sub.p, determining the perforation distance H.sub.K to ensure the sealing of the cement sheath according to the annulus pressure P.sub.A, and using min (H.sub.p, H.sub.K), the critical perforation distance that the cement sheath has sufficient strength to prevent blowby and meet the sealing requirements can be determined, which provides data support for the optimization of cement slurry additives and perforation parameter design under complex conditions.

[0098] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, it should be regarded as the scope of the invention. The above embodiments only express several implementation modes of the invention; the descriptions are more specific and detailed, but should not be interpreted as limiting the scope of the invention. It should be pointed out that for those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the invention, which shall all fall within the protection scope of the invention. Therefore, the protection scope of the invention shall be subject to the appended claims.