Bushing system and prevention performance verification method thereof
By installing preventative components and a sandblasting layer in the casing system, the annular pressure problem caused by micro-gap in the cement sheath was solved, improving cementing quality and preventative effect, and ensuring safe production of the gas storage facility.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA NAT PETROLEUM CORP
- Filing Date
- 2024-11-21
- Publication Date
- 2026-05-22
Smart Images
Figure CN122071946A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of cementing operation technology, and in particular to a casing system and a method for verifying its preventive performance. Background Technology
[0002] Annular pressure in gas storage wells is one of the current challenges affecting the safe production of gas storage facilities. How to manage and prevent annular pressure has become a key focus and difficulty in gas storage operations. Among the causes of annular pressure is post-cementing annular gas channeling. While existing technologies have developed anti-gas channeling agents, packers, and other fixing materials and tools for oil and gas well cementing to prevent channeling, they have not fundamentally and effectively solved this problem. Furthermore, with the increasing number of natural gas wells, annular gas channeling is becoming increasingly serious. Specifically, analyzing the pathways of gas channeling, there are two main channels: one is micro-cracks in the cement sheath, caused by the influence of injection pressure, periodic temperature changes, well completion and pressure testing, and vibrations from subsequent operations, leading to micro-cracks and gas channeling; the other is annular gas channeling occurring when micro-gaps exist at the cement sheath interface.
[0003] For microcracks in the cement sheath, the periodic changes in well pressure during gas injection and production, coupled with plastic deformation of the cement sheath under stress, can lead to microcracks. Temperature variations during injection and production can also cause mismatches in the deformation of the cement sheath and casing wall, resulting in microcracks. Later operations, such as vibrations from drill plugs, can also cause microcracks in the cement sheath. Correspondingly, the cement sheath interface, consisting of a primary interface formed by the casing and cement sheath, and a secondary interface formed by the cement sheath and formation, can lead to annular gas channeling even with a micro-gap of only 0.01 mm. This can result in annular pressure buildup and inter-layer flow, increasing wellhead inspection and depressurization costs, reducing production, and even causing well shutdown or abandonment. In summary, micro-gap in the cement sheath is a significant factor causing gas channeling and annular pressure buildup. Preventing micro-gap formation, mitigating damage from casing deformation and other factors, ensuring preventative measures, and reducing the probability of annular pressure buildup are problems that need to be addressed in this field. Summary of the Invention
[0004] The purpose of this invention is to provide a casing system and its preventive performance verification method to prevent micro-gap in the cement sheath, reduce the damage to the cement sheath caused by factors such as casing deformation, ensure its preventive effect, and reduce the probability of annular pressure.
[0005] To achieve this objective, the present invention adopts the following technical solution:
[0006] A casing system, comprising:
[0007] The invention comprises a technical sleeve, a production sleeve, and a preventive component. Cement is injected into the annular space between the technical sleeve and the production sleeve to form a cement ring. The preventive component is fixed to the outside of the production sleeve and located in the annular space to prevent micro-gaps from forming in the cement ring within the annular space. The inner wall of the technical sleeve is provided with a first sandblasting layer, and the outer side of the preventive component is provided with a second sandblasting layer. The outer side of the cement ring contacts the first sandblasting layer and the second sandblasting layer.
[0008] Optionally, the prevention component includes an upper locking ring, an upper conical ring, an upper limit ring, a buffer cylinder, a protective cylinder, a lower limit ring, a lower conical ring, and a lower locking ring arranged sequentially along the direction from the upper end to the lower end of the production sleeve. The upper locking ring and the lower locking ring are sleeved on the outside of the production sleeve and located at both ends of the prevention component. The upper conical ring and the lower conical ring are respectively abutted against the upper locking ring and the lower locking ring, and both are sleeved on the outside of the production sleeve. The upper limit ring and the lower limit ring are respectively screwed to the outside of the upper locking ring and the lower locking ring, and respectively press against the outside of the upper conical ring and the lower conical ring. The buffer cylinder is elastically sleeved on the outside of the production sleeve and located between the upper limit ring and the lower limit ring. The protective cylinder is sleeved on the outside of the buffer cylinder and screwed to the upper limit ring and the lower limit ring. The second sandblasting layer is disposed on the outside of the protective cylinder.
[0009] Alternatively, the buffer cylinder may be configured as a V-shaped buffer sleeve, and the buffer cylinder may be able to expand radially when compressed axially to seal the annular space between the protective sleeve and the production sleeve.
[0010] Optionally, both the upper and lower conical rings have a notch at their midpoints, so that under the squeezing action of the upper and lower limit rings, both the upper and lower conical rings can contract radially and press against the outside of the production sleeve.
[0011] Optionally, it also includes a cleaning component that can be connected to the screw drill bit to clean the outer wall of the production casing and the inner wall of the technical casing. The cleaning component has a body that includes a tapered portion and a connecting portion for connecting to the screw drill bit. The connecting portion has a plurality of flexible steel wires on its outer side, and a plurality of nozzles are evenly arranged between the flexible steel wires for spraying flushing fluid or pre-fluid.
[0012] On the other hand, the method for verifying the preventive performance of the casing system uses a simulated casing device to test and verify the preventive performance of the casing system against the occurrence of micro-gap in the cement sheath, which includes the following steps:
[0013] S1. No preventive components of the casing system are installed in the simulated casing device, and no sandblasting layer is set on the inner wall of the simulated technical casing in the simulated casing device. After the simulated casing device simulates the conventional cementing conditions, the pressure is increased in increments at a certain step size, and the pressure value P1 when the simulated casing device leaks is recorded.
[0014] S2. The prevention component is not installed in the simulated casing device, and the inner wall of the simulated technical casing in the simulated casing device is not provided with a sandblasting layer. After the simulated casing device simulates the fracturing condition, the pressure is increased in increments at a certain step size, and the pressure value P2 when the simulated casing device leaks is recorded.
[0015] S3. Install the prevention component in the simulated casing device, and provide a sandblasting layer on the inner wall of the simulated technical casing and the outer side of the prevention component in the simulated casing device. Repeat step S1 and record the pressure value P3 when the simulated casing device leaks.
[0016] S4. Install the prevention component in the simulated casing device, and provide a sandblasting layer on the inner wall of the simulated technical casing and the outer side of the prevention component in the simulated casing device. Repeat step S2 and record the pressure value P4 when the simulated casing device leaks.
[0017] S5. The sealing pressure required for the cement ring in the gas storage is denoted as P. The corresponding prevention effect is obtained by comparing the values of P, P1, P2, P3, and P4.
[0018] Optionally, the simulated sleeve device includes a simulated technology sleeve and a simulated production sleeve. When the preventive component is installed in the simulated sleeve device, the preventive component is located outside the simulated production sleeve and inside the simulated technology sleeve. A simulated annulus is provided between the simulated technology sleeve and the simulated production sleeve, and a simulated cement ring can be formed after cement is injected into the simulated annulus.
[0019] Optionally, the simulated sleeve device further includes an upper connector, a lower connector, an upper sealing ring, and a lower sealing ring. The upper connector is screwed to the upper end of the simulated production sleeve, and the lower connector is screwed to the lower end of the simulated production sleeve. The upper sealing ring and the lower sealing ring are both sleeved on the outside of the simulated production sleeve and screwed to the upper and lower ends of the simulated technology sleeve, respectively.
[0020] Optionally, a pressure-holding piston is also provided in the simulated annular space, and an exhaust port is provided on the simulated sleeve, which can be sealed by a sealing screw. Both the pressure-holding piston and the exhaust port are located below the upper sealing ring.
[0021] Optionally, the simulated casing device further includes a cement injector capable of injecting cement into the simulated annulus. The cement injector includes an upper connector, a hydraulic cylinder, a compression piston, and a lower connector. The upper connector, the hydraulic cylinder, and the lower connector are connected by threads. The hydraulic cylinder is located between the upper connector and the lower connector. The compression piston is located in the hydraulic cylinder. The top of the upper connector is connected to the simulated annulus. A pressure inlet is provided on the side of the lower connector.
[0022] The beneficial effects of this invention are:
[0023] This invention utilizes a preventative component to prevent the formation of micro-gap in the cement sheath. The preventative component is positioned outside the production casing and within the annulus. Simultaneously, a first blasting layer and a second blasting layer are respectively formed on the inner wall of the production casing and the outer wall of the preventative component. This ensures that the cement sheath preferentially contacts the first and second blasting layers during subsequent cement sheath fabrication. Compared to the smooth casing wall used in existing technologies, this significantly improves the cementing quality of the casing system. Furthermore, the preventative component further prevents cement sheath damage, reduces micro-gap formation, and achieves its preventative function. On the other hand, comparative installation tests between the simulated casing assembly and the preventative component allow for accurate testing of the preventative performance of the casing system, verifying its operational effectiveness during use and ensuring the stability of the preventative measures in practical applications. Attached Figure Description
[0024] Figure 1 This is a schematic diagram of the casing system described in an embodiment of the present invention;
[0025] Figure 2 This is a partially enlarged schematic diagram of the first and second sandblasting layers in the casing system described in the embodiment of the present invention;
[0026] Figure 3 This is a schematic diagram of the structure of the cleaning component in the sleeve system described in an embodiment of the present invention;
[0027] Figure 4 This is a schematic diagram of the structure of the simulated sleeve device according to an embodiment of the present invention.
[0028] In the picture:
[0029] 100' - Cement ring; 200' - Technical sleeve; 300' - Production sleeve; 201 - First sandblasting layer; 301 - Second sandblasting layer; 10 - Upper locking ring; 20 - Upper conical ring; 30 - Upper limit ring; 40 - Buffer cylinder; 50 - Protective cylinder; 60 - Lower limit ring; 70 - Lower conical ring; 80 - Lower locking ring; 90 - Cleaning component; 91 - Body; 92 - Flexible steel wire; 93 - Nozzle;
[0030] 100 - Simulated cement ring; 200 - Simulated technical sleeve; 210 - Exhaust port; 220 - Sealing screw; 300 - Simulated production sleeve; 310 - Upper connector; 320 - Lower connector; 410 - Upper sealing ring; 420 - Lower sealing ring; 430 - Pressure-holding piston; 500 - Cement injector; 510 - Upper connector of cement injector; 520 - Hydraulic cylinder; 530 - Extrusion piston; 540 - Lower connector of cement injector. Detailed Implementation
[0031] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.
[0032] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.
[0033] In the description of this invention, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0034] The technical solution of this embodiment will be further described below with reference to the accompanying drawings and specific implementation methods.
[0035] like Figures 1-4As shown, this embodiment provides a casing system including a technical casing 200', a production casing 300', and a prevention component. Cement is injected into the annular space between the technical casing 200' and the production casing 300' to form a cement ring 100'. The prevention component is fixed to the outside of the production casing 300' and located in the annular space to prevent micro-gaps from forming in the cement ring 100' within the annular space. The inner wall of the technical casing 200' is provided with a first sandblasting layer 201, and the outer side of the prevention component is provided with a second sandblasting layer 301. The outer side of the cement ring 100' contacts the first sandblasting layer 201 and the second sandblasting layer 301.
[0036] On the other hand, the method for verifying the preventive performance of the casing system uses a simulated casing device to detect and verify the preventive performance of the casing system against the occurrence of micro-gap in the cement sheath, including the following steps:
[0037] S1. No preventive components of the casing system are installed in the simulated casing device, and no sandblasting layer is set on the inner wall of the simulated technical casing 200 in the simulated casing device. After the simulated casing device simulates the conventional cementing conditions, the pressure is increased in increments at a certain step size, and the pressure value P1 when the simulated casing device leaks is recorded.
[0038] S2. No preventive components are installed in the simulated casing device, and no sandblasting layer is provided on the inner wall of the simulated technical casing 200 in the simulated casing device. After simulating the fracturing condition in the simulated casing device, the pressure is increased in increments at a certain step size, and the pressure value P2 when the simulated casing device leaks is recorded.
[0039] S3. Install the prevention component in the simulated casing device, and set the sandblasting layer on the inner wall of the simulated technical casing 200 and the outer side of the prevention component in the simulated casing device. Repeat step S1 and record the pressure value P3 when the simulated casing device leaks.
[0040] S4. Install the prevention component in the simulated casing device, and set the sandblasting layer on the inner wall of the simulated technical casing 200 and the outer side of the prevention component in the simulated casing device. Repeat step S2 and record the pressure value P4 when the simulated casing device leaks.
[0041] S5. The sealing pressure required for the cement ring 100 in the gas storage tank is denoted as P. The corresponding prevention effect is obtained by comparing the values of P, P1, P2, P3, and P4.
[0042] Specifically, in this embodiment, a prevention component is used to prevent the formation of micro-gap in the cement sheath 100'. The prevention component is positioned outside the production casing 300' and within the annulus. A first blasting layer 201 and a second blasting layer 301 are respectively provided on the inner wall of the technical casing 200' and the outer side of the prevention component. This ensures that during the subsequent fabrication of the cement sheath 100', the cement sheath 100' preferentially contacts the first and second blasting layers 201 and 301. Compared to the use of smooth casing walls in existing technologies, this improves the cementing quality of the casing system. Furthermore, the prevention component further prevents damage to the cement sheath 100', reduces the formation of micro-gap, and achieves its preventative function. On the other hand, a comparative installation test between the simulated casing assembly and the prevention component allows for accurate testing of the preventative performance of the casing system, verifying its operational effectiveness during use, and ensuring the stability of the prevention measures in actual applications.
[0043] The specific structure of the casing system in this embodiment will be described below.
[0044] like Figures 1-3 As shown, in this embodiment, the casing system includes a technical casing 200', a production casing 300', a prevention component, and a cleaning component 90. An annulus exists between the technical casing 200' and the production casing 300', and a cement ring 100' is formed after cement is injected into the annulus. The prevention component is fixed to the outside of the production casing 300' and located within the annulus to prevent the formation of micro-gaps in the cement ring 100' within the annulus. Furthermore, a first blasting layer 201 is provided on the inner wall of the technical casing 200', and a second blasting layer 301 is provided on the outside of the prevention component. The outer side of the formed cement ring 100' can preferentially contact the first blasting layer 201 and the second blasting layer 301, thereby increasing the friction between the cement ring 100' and the technical casing 200' and the production casing 300' under the action of high friction, thus ensuring cementing quality. Specifically, in this embodiment, the prevention component includes an upper locking ring 10, an upper conical ring 20, an upper limit ring 30, a buffer cylinder 40, a protective cylinder 50, a lower limit ring 60, a lower conical ring 70, and a lower locking ring 80 arranged sequentially along the direction from the upper end to the lower end of the production sleeve 300'.
[0045] like Figure 1As shown, in this embodiment, both the upper locking ring 10 and the lower locking ring 80 are sleeved on the outside of the production sleeve 300' and are located at both ends of the prevention assembly to ensure the stable installation of the remaining components. Specifically, the upper conical ring 20 and the lower conical ring 70 are placed against the upper locking ring 10 and the lower locking ring 80 respectively, and both the upper conical ring 20 and the lower conical ring 70 are sleeved on the outside of the production sleeve 300' to ensure their stable installation. Further, the upper limit ring 30 and the lower limit ring 60 are screwed to the outside of the upper locking ring 10 and the lower locking ring 80 respectively, and press against the outside of the upper conical ring 20 and the lower conical ring 70 respectively, thereby ensuring the stable installation of both and further ensuring the stable installation of the upper conical ring 20 and the lower conical ring 70. For example, both the upper conical ring 20 and the lower conical ring 70 are configured as conical structures, and both have notches at their middle positions facing the production sleeve 300'. Under the squeezing action of the upper limit ring 30 and the lower limit ring 60, both the upper conical ring 20 and the lower conical ring 70 can shrink radially and press tightly against the outside of the production sleeve 300', thereby enabling the entire prevention assembly to be stably installed on the production sleeve 300'.
[0046] Optionally, in this embodiment, the buffer cylinder 40 is elastically sleeved on the outside of the production sleeve 300' and located between the upper limit ring 30 and the lower limit ring 60, thereby ensuring that the upper limit ring 30 and the lower limit ring 60 will not slide on the outside of the production sleeve 300'. Further, the protective cylinder 50 is sleeved on the outside of the buffer cylinder 40, and the upper and lower ends of the protective cylinder 50 are respectively screwed to the outside of the upper limit ring 30 and the lower limit ring 60, thereby ensuring the overall stability of the prevention assembly and allowing its various components to be stably connected. Further, the second sandblasting layer 301 is disposed on the outside of the protective cylinder 50 to improve the stability of the cement ring 100'. Specifically, in this embodiment, the buffer cylinder 30 is configured as a V-shaped buffer cylinder, and the buffer cylinder 40 can expand radially when subjected to axial compression, thereby ensuring that the annular space between the protective cylinder 50 and the production sleeve 300' is effectively sealed under its squeezing action, improving its sealing effect.
[0047] Furthermore, in this embodiment, a first sandblasting layer 201 is provided on the inner wall of the technical casing 200', and a second sandblasting layer 301 is provided on the outer side of the protective cylinder 50 in the prevention component. In this way, when cement is injected into the annulus between the technical casing 200' and the production casing 300' to form a cement ring 100', under the action of the first sandblasting layer 201 and the second sandblasting layer 301, the cementing quality of the annulus between the protective cylinder 50 and the technical casing 200' can be improved more effectively than the cementing operation with a smooth pipe wall in the prior art, resulting in a better sealing effect. For example, during fracturing operations, the inside of the production casing 300' needs to be pressurized. Under this pressure, the production casing 300' expands radially outward, which in turn squeezes the annulus between the production casing 300' and the technical casing 200'. Since a preventive component is provided on the outside of the production casing 300', and the buffer cylinder 40 in the preventive component has an elastic buffering effect, it can absorb the deformation of the production casing 300', thereby significantly reducing the radial force transmitted to the protective cylinder 50. This can prevent the cement annulus 100' on the outside of the protective cylinder 50 from being damaged, reduce the generation of micro-gap, and achieve its preventive function.
[0048] like Figure 3 As shown, in this embodiment, the cleaning component 90 can be connected to the screw drill bit to clean the outer wall of the production casing 300' and the inner wall of the technical casing 200', thereby preventing impurities such as mud, rock cuttings, oil film, and rust from affecting the smoothness of the outer surface of the production casing 300' and the inner surface of the technical casing. In this embodiment, the cleaning component 90, together with the dedicated drill rod and screw drill bit, can achieve the cleaning operation. In other embodiments, other mechanical cleaning or high-pressure cleaning methods can be used for cleaning, which will not be elaborated here. Specifically, in this embodiment, the cleaning component 90 is provided with a body 91, and the body 91 is provided with a flexible steel wire 92 and a nozzle 93. Specifically, in this embodiment, the body 91 includes a tapered part and a connecting part, wherein the tapered part has a tapered structure, which can quickly guide the direction. Further, the connecting part is set as a cylindrical structure, and the two ends of the connecting part are respectively connected to the screw drill bit and the tapered part. Furthermore, a number of flexible steel wires 92 are provided on the outer side of the connecting part, and a number of nozzles 93 are evenly arranged between the flexible steel wires 92 for spraying flushing fluid or pre-flushing fluid.
[0049] For example, in this embodiment, the outer diameter of the body 91 is the same as the outer diameter of the screw drill bit to avoid affecting subsequent downhole operations. Furthermore, the outer diameter of the flexible steel wire 92 is larger than the inner diameter of the technical casing 200', and after the cleaning assembly 90 is lowered into the well, the flexible steel wire 92 is bent to tightly abut against the inner wall of the technical casing 200'. Specifically, during cleaning operations, the screw drill bit can drive the cleaning assembly 90 to rotate and continuously lower it, thereby enabling the flexible steel wire 92 to effectively clean the inner wall of the technical casing 200'. Furthermore, under the action of the nozzle 93, flushing fluid or pre-flushing fluid can be efficiently sprayed onto the inner wall of the technical casing 200'. Combined with the dual action of the flexible steel wire 92, effective cleaning of the inner wall of the technical casing 200' can be ensured, improving the subsequent fixing quality. Correspondingly, under the action of the cleaning assembly 90, the outer side of the production casing 300' can also be effectively cleaned; the specific process will not be elaborated further.
[0050] For example, the cementing process of the casing system in this embodiment is as follows:
[0051] The inner surface of the technical casing 200' is sandblasted to form the first sandblasting layer 201, and the technical casing 200' is installed in a well section near the wellhead;
[0052] A cleaning component 90 is inserted into the technical sleeve 200' to clean the inner wall of the technical sleeve 200', in order to remove rust and other impurities and ensure the bonding quality between the surface of the technical sleeve 200' and the cement ring 100'.
[0053] Install the prevention component on the outside of the production sleeve 300', tighten all its threads, and ensure that the buffer cylinder 40 expands and seals, so that the entire prevention component is stably fixed on the outside of the production sleeve 300'.
[0054] The outer side of the protective sleeve 50 in the prevention component is sandblasted to form a second sandblasting layer 301. Then the prevention component and the production casing 300' are installed as a whole in the technical casing 200' with the first sandblasting layer 201 near the wellhead.
[0055] Cement is injected into the annulus between the technical sleeve 200' and the production sleeve 300', and the cement is allowed to solidify under a certain pressure environment to complete the fixing operation.
[0056] Specifically, during the fracturing operation after cementing, a high hydraulic pressure is applied to the inside of the production casing 300', causing it to expand radially. In well sections without a protective component, the production casing 300' will directly squeeze the cement sheath 100' outwards, resulting in micro-gap formations and causing the sealing effect of the cement sheath 100' to fail, leading to annular pressure issues. However, in locations with a protective component, the production casing 300' will expand radially and squeeze the buffer cylinder 40 outwards. The high elasticity of the buffer cylinder 40 absorbs the deformation of the production casing 300', thereby significantly reducing the pressure transmitted to the protective cylinder 50, thus protecting the cement sheath 100' and reducing micro-gap formations.
[0057] The specific steps of the preventive performance verification method for the casing system in this embodiment are described below.
[0058] Combination Figure 1 and Figure 4 As shown, the method for verifying the preventive performance of the casing system uses a simulated casing device to detect and verify the preventive performance of the casing system against the occurrence of micro-gap in the cement sheath, including the following steps:
[0059] S1. No preventive components of the casing system are installed in the simulated casing device, and no sandblasting layer is set on the inner wall of the simulated technical casing 200 in the simulated casing device. After the simulated casing device simulates the conventional cementing conditions, the pressure is increased in increments at a certain step size, and the pressure value P1 when the simulated casing device leaks is recorded.
[0060] S2. No preventive components are installed in the simulated casing device, and no sandblasting layer is provided on the inner wall of the simulated technical casing 200 in the simulated casing device. After simulating the fracturing condition in the simulated casing device, the pressure is increased in increments at a certain step size, and the pressure value P2 when the simulated casing device leaks is recorded.
[0061] S3. Install the prevention component in the simulated casing device, and set the sandblasting layer on the inner wall of the simulated technical casing 200 and the outer side of the prevention component in the simulated casing device. Repeat step S1 and record the pressure value P3 when the simulated casing device leaks.
[0062] S4. Install the prevention component in the simulated casing device, and set the sandblasting layer on the inner wall of the simulated technical casing 200 and the outer side of the prevention component in the simulated casing device. Repeat step S2 and record the pressure value P4 when the simulated casing device leaks.
[0063] S5. The sealing pressure required for the cement ring 100 in the gas storage tank is denoted as P. The corresponding prevention effect is obtained by comparing the values of P, P1, P2, P3, and P4.
[0064] Combination Figure 1 and Figure 4As shown, in this embodiment, the simulated casing device includes a simulated technical casing 200, a simulated production casing 300, an upper connector 310, a lower connector 320, an upper sealing ring 410, a lower sealing ring 420, a pressure-holding piston 430, and a cement injector 500. Specifically, the annulus between the simulated technical casing 200 and the simulated production casing 300 is a simulated annulus, and a simulated cement ring 100 can be formed after cement is injected into the simulated annulus. Optionally, when a preventive component is installed in the simulated casing device, the preventive component is located on the outside of the simulated production casing 300 and inside the simulated technical casing 200. Specifically, the inner wall of the simulated technical casing 200 and the outer side of the preventive component on the outside of the simulated production casing 300 can be sandblasted to form a sandblasted layer according to experimental needs, corresponding to the first abrasive layer 201 and the second abrasive layer 301 in the casing system.
[0065] like Figure 4 As shown, in this embodiment, the upper connector 310 is screwed to the upper end of the simulated production sleeve 300, and the lower connector 320 is screwed to the lower end of the simulated production sleeve 300, thereby ensuring the stable installation of the simulated production sleeve 300 with other equipment. Furthermore, both the upper sealing ring 410 and the lower sealing ring 420 are sleeved on the outside of the simulated production sleeve 300, and are respectively screwed to the upper and lower ends of the simulated technology sleeve 200, thereby sealing the annular space between the simulated technology sleeve 200 and the simulated production sleeve 300 to ensure the stability of the simulated cement ring 100. Furthermore, a pressure-blocking piston 430 is also provided in the annular space between the simulated technology sleeve 200 and the simulated production sleeve 300, that is, the pressure-blocking piston 430 is located between the upper sealing ring 410 and the lower sealing ring 420. Specifically, the simulation technology sleeve 200 is also provided with an exhaust port 210, which connects the annulus between the simulation technology sleeve 200 and the simulation production sleeve 300 with the external environment. Furthermore, the exhaust port 210 can be sealed by a sealing screw 220, allowing the opening and closing of the exhaust port 210 to be operated as needed. Specifically, both the pressure-holding piston 430 and the exhaust port 210 are located below the upper sealing ring 410 and above the lower sealing ring 420.
[0066] like Figure 4As shown, specifically, in this embodiment, to ensure the implementation of the preventive performance verification method, a cement injector 500 is provided, and the cement injector 500 includes an upper connector 510, a hydraulic cylinder 520, a compression piston 530, and a lower connector 540. Optionally, the upper connector 510, the hydraulic cylinder 520, and the lower connector 540 are connected by threads, and the hydraulic cylinder 520 is located between the upper connector 510 and the lower connector 540, thereby ensuring the overall stability of the cement injector 500 installation. Furthermore, the extrusion piston 530 is located in the liquid cylinder 520, and the top of the cement injector upper connector 510 can be connected to the simulation sleeve device to inject cement into the simulation annulus. The side of the cement injector lower connector 540 is provided with a pressure inlet, which can pressurize the inside of the liquid cylinder 520 so that the extrusion piston 530 can extrude the cement in the liquid cylinder 520 through the cement injector upper connector 510 into the simulation sleeve device.
[0067] Furthermore, in this embodiment, the pressure inlet on the side of the lower connector 540 of the cement injector is designated as port A, the output port of the upper connector 510 of the cement injector connected to the simulated casing device is designated as port B, the interface in the simulated casing device connected to the upper connector 510 of the cement injector is designated as port C, another interface on the top of the simulated technical casing 200 is designated as port D, and the top interface of the upper connector 310 is designated as port E. Specifically, port C is located near the lower sealing ring 420 and can connect the annulus between the simulated technical casing 200 and the simulated production casing 300 with the external environment. Port D is located near the upper sealing ring 410 and above the exhaust port 210, and connects the space above the pressure-holding piston 430 with the external environment. Furthermore, port E is connected to the internal space of the simulated production casing 300 for internal pressure testing and simulating fracturing and other working conditions.
[0068] For example, the method of using the simulated sleeve device is as follows:
[0069] First, assemble the lower connector 540 of the cement injector, the extrusion piston 530, and the liquid cylinder 520. Then, connect the upper connector 310, the lower connector 320, and the simulated production sleeve 300. Connect the upper sealing ring 410, the lower sealing ring 420, and the simulated technology sleeve 200 to form a simulated annulus between the simulated technology sleeve 200 and the simulated production sleeve 300. Then, install the pressure-holding piston 430 below the upper sealing ring 410. The prevention component can be installed on the outside of the production sleeve 300 as needed for the test, and positioned below the pressure-holding piston 430.
[0070] Then, cement slurry is added to the cylinder 520, and then the cement injector connector 510 is installed. Port A is connected to the pressure line, and ports B and C are connected, so that the exhaust port 210 is in the normally open state. Then, pressure is applied, so that the hydraulic pressure pushes the extrusion piston 530 to squeeze the cement slurry upward, so that the cement slurry can be discharged from the cement injector 500 through port B and enter the simulated annulus through port C, gradually filling the simulated annulus. At the same time, the air in the simulated annulus is discharged from the exhaust port 210.
[0071] When the cement slurry is discharged from the vent 210, it indicates that the simulated annulus has been filled. At this time, the sealing screw 220 is installed in the vent 210 to seal it, and a plug is installed at port C to seal the inlet of the cement slurry.
[0072] Then, connect port D to the pressure line to pressurize the simulated annulus. At this time, the pressure-holding piston 430 is pushed and squeezes the cement slurry in the simulated annulus downward, so as to ensure that the cement slurry solidifies under a certain pressure and ensures the setting quality of the simulated cement ring 100.
[0073] After the condensation is completed, port E is connected to the pressure testing pipeline to pressurize the inside of the simulated production casing 300. Then the simulated production casing 300 will expand radially to simulate the fracturing condition and create a crack in the simulated cement sheath 100.
[0074] Finally, remove the sealing screw 220, remove the plug from port C, and connect port C to the pressure line to pressurize the simulated annulus. By checking the results at the exhaust port 210, the sealing effect of the simulated cement ring 100 in the simulated annulus can be verified, and the preventive performance of the preventive component for micro-gap in the simulated cement ring 100 can be obtained.
[0075] Specifically, in step S1 of the casing system's preventive performance verification method, after assembling the simulated casing device, cement slurry is injected into the simulated annulus in the simulated casing device under the action of the cement injector 500, and pressure is held for more than 48 hours. After the pressure is held for more than 48 hours, the pressure is released, the pressure-pressurizing pipeline at port D is removed, and it is installed at port C. The sealing screw 220 is removed, the entire device is laid flat, with the exhaust port 210 facing downwards, and then pressure is applied through port C in increments of 5 MPa. After each increment of pressure is stabilized for 3 minutes, the pressure at which leakage occurs at the exhaust port 210 is observed, and the leakage pressure value at this time is recorded as P1.
[0076] Accordingly, after assembling the simulated casing device in step S2, cement slurry is injected into the simulated annulus under the action of the cement injector 500, and pressure is held for more than 48 hours for curing. After curing, the pressure is released, the pressure-pressurizing pipeline at port D is removed and installed at port E, the entire device is laid flat, and pressure is applied to the simulated production casing 300 at 70 MPa. After stabilizing the pressure for 3 minutes, the pressure is released to 0 MPa. This process is repeated 10 times to simulate fracturing conditions. Then, the pressure-pressurizing pipeline at port E is disconnected and connected to port C, and the sealing screw 220 is removed. The entire device is laid flat with the vent port 210 facing downwards, and then pressure is applied in increments of 5 MPa. After each increment of pressure, the pressure is stabilized for 3 minutes, and the pressure at which leakage occurs at the vent port 210 is observed. The leakage pressure value at this time is recorded as P2.
[0077] Furthermore, in step S5, if both P1 and P3 are greater than P, it indicates that the cementing quality is qualified; if P1≈P3, it indicates that the use of the prevention component has no impact on the cementing effect; if P4>P>P2, it indicates that the prevention tool is effective.
[0078] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.
Claims
1. A casing system, characterized in that, include: The system comprises a technical sleeve (200'), a production sleeve (300'), and a preventive component. Cement is injected into the annular space between the technical sleeve (200') and the production sleeve (300') to form a cement ring (100'). The preventive component is fixed to the outside of the production sleeve (300') and located in the annular space to prevent micro-gaps from forming in the cement ring (100') within the annular space. The inner wall of the technical sleeve (200') is provided with a first sandblasting layer (201), and the outer side of the preventive component is provided with a second sandblasting layer (301). The outer side of the cement ring (100') contacts the first sandblasting layer (201) and the second sandblasting layer (301).
2. The casing system according to claim 1, characterized in that, The prevention assembly includes an upper locking ring (10), an upper conical ring (20), an upper limit ring (30), a buffer cylinder (40), a protective cylinder (50), a lower limit ring (60), a lower conical ring (70), and a lower locking ring (80) arranged sequentially from the upper end to the lower end of the production sleeve (300'). The upper locking ring (10) and the lower locking ring (80) are sleeved on the outside of the production sleeve (300') and located at both ends of the prevention assembly. The upper conical ring (20) and the lower conical ring (70) are respectively abutted against the upper locking ring (10) and the lower locking ring (80), and both are sleeved on the production sleeve (300'). Outside the upper limit ring (30) and the lower limit ring (60), the upper limit ring (30) and the lower limit ring (60) are respectively screwed to the outside of the upper locking ring (10) and the lower locking ring (80), and respectively press against the outside of the upper conical ring (20) and the lower conical ring (70). The buffer cylinder (40) is elastically sleeved on the outside of the production sleeve (300') and located between the upper limit ring (30) and the lower limit ring (60). The protective cylinder (50) is sleeved on the outside of the buffer cylinder (40) and screwed to the upper limit ring (30) and the lower limit ring (60). The second sandblasting layer (301) is disposed on the outside of the protective cylinder (50).
3. The casing system according to claim 2, characterized in that, The buffer cylinder (40) is configured as a V-shaped buffer rubber cylinder, and the buffer cylinder (40) is capable of expanding radially when compressed in its axial direction to seal the annular space between the protective cylinder (50) and the production sleeve (300').
4. The casing system according to claim 2, characterized in that, Both the upper conical ring (20) and the lower conical ring (70) have notches at their midpoints. Under the squeezing action of the upper limit ring (30) and the lower limit ring (60), both the upper conical ring (20) and the lower conical ring (70) can shrink radially and press against the outside of the production sleeve (300').
5. The casing system according to claim 1, characterized in that, It also includes a cleaning component (90) that can be connected to the screw drill to clean the outer wall of the production casing (300') and the inner wall of the technical casing (200'). The cleaning component (90) is provided with a body (91), which includes a tapered portion and a connecting portion. The connecting portion is used to connect to the screw drill, and a plurality of flexible steel wires (92) are provided on the outside of the connecting portion. A plurality of nozzles (93) are evenly arranged between the plurality of flexible steel wires (92) for spraying flushing fluid or pre-fluid.
6. A method for verifying the preventive performance of a casing system, comprising using a simulated casing device to test and verify the preventive performance of the casing system according to any one of claims 1-5 against the occurrence of micro-gap in the cement sheath, characterized in that, Includes the following steps: S1. The preventive components of the casing system described in any one of claims 1-5 are not installed in the simulated casing device, and the inner wall of the simulated technical casing (200) in the simulated casing device is not provided with a sandblasting layer. After the simulated casing device simulates the conventional cementing working conditions, the pressure is increased step by step, and the pressure value P1 when the simulated casing device leaks is recorded. S2. The prevention component is not installed in the simulated casing device, and the inner wall of the simulated technical casing (200) in the simulated casing device is not provided with a sandblasting layer. After the simulated casing device simulates the fracturing condition, the pressure is increased in increments at a certain step size, and the pressure value P2 when the simulated casing device leaks is recorded. S3. Install the prevention component in the simulated casing device, and provide a sandblasting layer on the inner wall of the simulated technical casing (200) and the outer side of the prevention component in the simulated casing device. Repeat step S1 and record the pressure value P3 when the simulated casing device leaks. S4. Install the prevention component in the simulated casing device, and provide a sandblasting layer on the inner wall of the simulated technical casing (200) and the outer side of the prevention component in the simulated casing device. Repeat step S2 and record the pressure value P4 when the simulated casing device leaks. S5. The sealing pressure required for the cement ring (100) in the gas storage is denoted as P. The corresponding prevention effect is obtained by comparing the values of P, P1, P2, P3 and P4.
7. The method for verifying the preventive performance of a casing system according to claim 6, characterized in that, The simulated sleeve device includes a simulated technology sleeve (200) and a simulated production sleeve (300). When the preventive component is installed in the simulated sleeve device, the preventive component is located outside the simulated production sleeve (300) and inside the simulated technology sleeve (200). A simulated annulus is provided between the simulated technology sleeve (200) and the simulated production sleeve (300), and a simulated cement ring (100) can be formed after cement is injected into the simulated annulus.
8. The method for verifying the preventive performance of a casing system according to claim 7, characterized in that, The simulated sleeve device further includes an upper connector (310), a lower connector (320), an upper sealing ring (410), and a lower sealing ring (420). The upper connector (310) is screwed to the upper end of the simulated production sleeve (300), and the lower connector (320) is screwed to the lower end of the simulated production sleeve (300). The upper sealing ring (410) and the lower sealing ring (420) are both sleeved on the outside of the simulated production sleeve (300) and screwed to the upper and lower ends of the simulated technology sleeve (200), respectively.
9. The method for verifying the preventive performance of a casing system according to claim 8, characterized in that, A pressure-holding piston (430) is also provided in the simulated ring. An exhaust port (210) is provided on the simulated technology sleeve (200), and the exhaust port (210) can be blocked by a sealing screw (220). The pressure-holding piston (430) and the exhaust port (210) are both located below the upper sealing ring (410).
10. The method for verifying the preventive performance of a casing system according to claim 7, characterized in that, The simulated casing device also includes a cement injector (500) capable of injecting cement into the simulated annulus. The cement injector (500) includes an upper connector (510), a hydraulic cylinder (520), a compression piston (530), and a lower connector (540). The upper connector (510), the hydraulic cylinder (520), and the lower connector (540) are connected by threads. The hydraulic cylinder (520) is located between the upper connector (510) and the lower connector (540). The compression piston (530) is located in the hydraulic cylinder (520). The top of the upper connector (510) can communicate with the simulated annulus. The side of the lower connector (540) is provided with a pressure inlet.