A well formation structure and process for geological storage test of carbon dioxide in saline water layer

Abstract

The invention discloses a well-forming structure and process for a saline carbon dioxide geological storage test, which belongs to the technical field of carbon dioxide geological storage; it comprises: a surface casing, the surface casing is arranged in a borehole, a cement ring is arranged between the surface casing and the borehole; a technical casing is arranged in the surface casing; a monitoring pipe, the monitoring pipe is arranged between the surface casing and the technical casing, and is arranged adjacent to the technical casing; a carbon dioxide injection device, the carbon dioxide injection device comprises a carbon dioxide injection pipe and a double-stage packer; the double-stage packer is sleeved in the annular gap between the bottom of the carbon dioxide injection pipe and the technical casing. The saline carbon dioxide geological storage test well-forming structure and process provided by the invention realizes the injection of carbon dioxide into the saline water layer, the monitoring of carbon dioxide injected into the saline water layer, and the monitoring of the sealing condition of the double-stage separator.

Description

Technical Field

[0001] The present invention relates to the technical field of geological storage of carbon dioxide, and in particular to a well-forming structure and process for a geological storage test of carbon dioxide in a saline layer. Background Art

[0002] Saline layer carbon dioxide geological storage refers to the technology of capturing carbon dioxide generated in the production process of large emission source enterprises through engineering and technical means and injecting it into deep underground saline layers for storage, thereby achieving long-term isolation of carbon dioxide from the atmosphere. It is a new emission reduction technology and one of the key technologies for addressing global climate change.

[0003] In the saline aquifer carbon dioxide geological storage test, carbon dioxide needs to be injected into the saline aquifer designed deep underground and monitored and studied. The test well is the channel for injecting carbon dioxide into the target formation. It is the basis and key to long-term monitoring and research of carbon dioxide injected into the formation and its impact on the formation. The well structure and process are the key to whether the test well can meet the project requirements. At present, the geological storage of carbon dioxide in saline aquifers is still in the test stage, and the relevant process technology is not familiar. There is no mature well structure and process for the geological storage of carbon dioxide in saline aquifers. The existing well structures and processes in other industries cannot meet the requirements of the project in terms of carbon dioxide injection and monitoring research in saline aquifers.

[0004] Therefore, there is an urgent need for a saline layer carbon dioxide geological storage test well structure and process to realize carbon dioxide injection and monitoring research in the saline layer to ensure that the entire device can maintain a stable state for a long time. Summary of the invention

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A well formation structure for a saline layer carbon dioxide geological storage test, comprising:

[0007] A surface casing, which is arranged in the borehole, and a cement ring is arranged between the surface casing and the borehole; a technical casing is arranged in the surface casing, and the technical casing extends downward from the ground to the bottom of the borehole; a detachable wellhead sealing device is installed on the top of the technical casing;

[0008] A monitoring pipe, which is arranged between the surface casing and the technical casing, and is arranged adjacent to the technical casing, and extends downward from the ground to the monitoring target layer;

[0009] The carbon dioxide injection device comprises a carbon dioxide injection pipe and a double-stage packer. The carbon dioxide injection pipe extends downward from the ground to the upper part of the perforation position, and the carbon dioxide injection device is higher than the ground terminal wellhead sealing device; the double-stage packer is sleeved in the annular gap between the bottom of the carbon dioxide injection pipe and the technical casing.

[0010] Furthermore, the surface casing, the technical casing, the carbon dioxide injection pipe and the cement ring are coaxially arranged.

[0011] Furthermore, the process of forming a well structure for a saline layer carbon dioxide geological storage test comprises:

[0012] S1, drilling

[0013] After the surface drilling reaches the designed depth, the surface casing is lowered, and the drilling is stopped after the drilling reaches the designed target layer;

[0014] S2, electrical logging;

[0015] S3, casing lowering

[0016] Install the side monitoring device on the technical casing and lower it along with the technical casing, apply sealing and fastening glue to the connecting threads; after the technical casing is lowered to the designed depth, circulate and adjust the drilling fluid performance, flush the technical casing and the borehole annulus;

[0017] S4, cementing with cement slurry

[0018] During cementing operation, the pressure is pumped into the monitoring tube to the designed value through the pressure equipment, so that the rubber bag at the bottom of the monitoring tube expands, and the rubber bag forms a cavity without cement slurry between the technical casing and the borehole wall;

[0019] S5, scraper

[0020] Run the scraper to remove the cement remaining on the inner wall of the technical casing above the depth of the double-stage separator;

[0021] S6, perforation connection

[0022] The casing and the target formation are connected by perforation technology to form a CO2 injection channel;

[0023] S7, installation of carbon dioxide injection device

[0024] Install the wellhead sealing device shell on the top of the technical casing, lower the double-stage packer and the CO2 injection pipe to the designed depth, hang and seal the CO2 injection pipe on the wellhead sealing device shell, and fix it with screws; use the pressure equipment to pressurize the double-stage packer through the CO2 injection pipe, so that the double-stage separator expands and anchors on the technical casing, and seals the annular gap between the CO2 injection pipe and the technical casing;

[0025] S8, installing the wellhead device and the side monitoring device and pressurizing the side pipe to connect with the monitoring formation.

[0026] Furthermore, step S8 specifically includes the following steps:

[0027] S81, connect the plug valve and the pressure equipment manifold at the top of the CO2 injection pipe, pressurize the CO2 injection pipe for test injection, and check the sealing condition of the double-stage packer through the monitoring instrument on the wellhead sealing device;

[0028] S82, pressurize the side monitoring pipe to the designed value and fracture the rubber bag at the bottom to achieve the connection between the monitoring pipe and the monitoring formation, and achieve the goal of monitoring the sealing conditions of the formation and cement sheath interface from the perforation position to the monitoring position, the technical casing and cement sheath interface, and the impact of carbon dioxide injection on the overlying formation;

[0029] S83, install monitoring instruments on the top of the monitoring pipe, check the on-site equipment and facilities, and inject carbon dioxide into the designed formation through the ground injection equipment, wellhead sealing device, carbon dioxide injection pipe, technical casing, and perforation communication channel;

[0030] S84, close the stopcock on the wellhead sealing device, install monitoring instruments on the top of the wellhead sealing device, monitor the status of carbon dioxide injected into the target layer through the instrument on the top of the wellhead sealing device, monitor the annulus status of the carbon dioxide injection pipe and the technical casing through the instrument on the side of the wellhead sealing device, and monitor the impact of carbon dioxide injection on the overlying formation through the instrument on the top of the side monitoring pipe.

[0031] The present invention has the following beneficial effects:

[0032] 1. The well formation structure designed in the present invention realizes the injection of carbon dioxide into the saline layer, the monitoring of carbon dioxide injected into the saline layer, and the monitoring of the sealing condition of the double-stage separator through the technical casing, the double-stage packer, the carbon dioxide injection pipe and the wellhead sealing device. At the same time, the wellhead sealing device enhances the processing capability when abnormal conditions occur in the annulus between the carbon dioxide injection pipe and the technical casing;

[0033] 2. The side monitoring device is used to monitor the sealing performance of the interface between the formation and the cement sheath, the interface between the cement sheath and the technical casing, and the influence of carbon dioxide injection on the overlying formation of the target layer;

[0034] 3. All the design components in the well formation structure are made of stainless steel, which has good anti-carbon dioxide corrosion performance, ensuring that the entire device can maintain a stable state for a long time;

[0035] 4. The well-forming structure of the saline carbon dioxide geological storage test designed by the present invention is combined with the well-forming process flow of the saline carbon dioxide geological storage test, which is highly operable and easy to implement, and improves the well-forming process of the saline carbon dioxide geological storage test, laying a foundation for the saline carbon dioxide geological storage test;

[0036] 5. The well formation structure and process flow designed by the present invention achieve the purpose of easy operation and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A schematic diagram of a well-forming structure and process for a saline layer carbon dioxide geological storage test provided by the present invention;

[0038] Figure 2 A schematic diagram of the wellbore structure after the casing and the side monitoring device are lowered for a well formation structure and process for a geological storage test of carbon dioxide in a saline layer provided by the present invention;

[0039] Figure 3 A schematic diagram of a wellbore structure after cementing for a well formation structure and process for a saline layer carbon dioxide geological storage test provided by the present invention;

[0040] Figure 4 A schematic diagram of a wellbore structure after perforation for a well formation structure and process for a saline layer carbon dioxide geological storage test provided by the present invention;

[0041] Figure 5 A schematic diagram of the structure and process for the experimental well formation of carbon dioxide geological storage in a saline layer provided by the present invention, showing the installation of a carbon dioxide injection device and a wellhead sealing device;

[0042] Figure 6 A schematic diagram of the structure after the packer is opened and the rubber bag is fractured in a well-forming structure and process for a geological storage test of carbon dioxide in a saline layer provided by the present invention;

[0043] Figure 7 A schematic diagram of a carbon dioxide injection operation for a well-forming structure and process for a saline water layer carbon dioxide geological storage test provided by the present invention;

[0044] Figure 8 A schematic diagram of the structure during the monitoring process of a well formation structure and process for a saline layer carbon dioxide geological storage test provided by the present invention.

[0045] Among them: 1. Surface casing; 2. Cement ring; 3. Borehole; 4. Monitoring pipe; 5. Technical casing; 6. Wire mesh; 7. Rubber bag; 8. Carbon dioxide injection pipe; 9. Double-stage packer; 10. Wellhead sealing device; 11. Overlying formation; 12. Cap layer; 13. Target layer; 14. Perforation. DETAILED DESCRIPTION

[0046] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0047] Example 1

[0048] Reference Figure 1-4 In this embodiment, a well formation structure for a saline layer carbon dioxide geological storage test comprises:

[0049] A surface casing 1 is arranged in a borehole 3, and a cement ring 2 is arranged between the surface casing 1 and the borehole 3; a technical casing 5 is arranged in the surface casing 1, and the technical casing 5 extends downward from the ground to the bottom of the borehole 3; a wellhead sealing device 10 is detachably arranged on the top of the technical casing 5;

[0050] A monitoring pipe 4, which is arranged between the surface casing 1 and the technical casing 5, and is arranged adjacent to the technical casing 5;

[0051] The carbon dioxide injection device includes a carbon dioxide injection pipe 8 and a dual-stage packer 9. The carbon dioxide injection pipe 8 is installed in the technical casing 5 and extends downward from the ground to the upper part of the perforation 14; the dual-stage packer 9 is sleeved in the annular gap between the bottom of the carbon dioxide injection pipe 8 and the technical casing 5.

[0052] The surface casing 1, the technical casing 5, the carbon dioxide injection pipe 8 and the cement sheath 2 are coaxially arranged.

[0053] Example 2

[0054] This embodiment is a detailed configuration based on the embodiment 1.

[0055] The well formation structure of the saline layer carbon dioxide geological storage test mainly consists of an underground well formation casing, a cement ring 2, a carbon dioxide injection device, a side monitoring device and a ground wellhead sealing device 10.

[0056] The well casing is divided into a surface casing 1 and a technical casing 5; the surface casing 1 mainly plays the role of surface wall protection during drilling construction and reinjection when the surface is vacant after cementing the technical casing 5, and conventional oil casing is used; the technical casing 5 forms an installation space for the carbon dioxide injection device on the one hand, and on the other hand, it seals the upper formation together with the cement ring 2 to prevent the injected carbon dioxide from affecting the overlying formation 11. It needs to contact with carbon dioxide, and adopts acid-corrosion-resistant steel and air-tight threads to ensure sealing performance and meet long-term use requirements. The lowering length of the technical casing 5 is determined by the design, and the bottom is connected to cementing tools such as floating collars and floating shoes. The top is higher than the ground end and is connected to the shell of the wellhead sealing device 10 through threads.

[0057] Acid corrosion resistant cement slurry is injected into the gap between the technical casing 5 and the borehole 3. After the cement slurry solidifies, a cement ring 2 is formed to isolate the upper formation and prevent the injected carbon dioxide from affecting the overlying formation 11.

[0058] The carbon dioxide injection device consists of a carbon dioxide injection pipe 8 and a double-stage packer 9, which is installed in the technical casing 5; the carbon dioxide injection pipe 8 adopts an oil pipe with an acid-resistant corrosion coating to ensure long-term performance, is connected to the wellhead sealing device 10 at the top and the double-stage separator 9 at the bottom, and is connected to the ground carbon dioxide injection equipment and the perforation 14 to the target formation to form a carbon dioxide injection channel; the double-stage packer 9 is made of acid-resistant corrosion steel to ensure long-term performance, and is installed at the bottom of the carbon dioxide injection pipe 8 to isolate the annular space between the carbon dioxide injection pipe 8 and the technical casing 5, thereby preventing the carbon dioxide injected into the target formation 13 from moving upward along the annular space between the carbon dioxide injection pipe 8 and the technical casing 5.

[0059] The side monitoring device consists of a monitoring tube 4, a wire mesh 6 and a rubber bag 7, which is installed on one side of the technical casing 5 and goes down with the technical casing 5 to the designed monitoring layer in the hole; the monitoring tube 4 connects the designed monitoring layer with the ground monitoring instrument, and adopts a high-strength aluminum alloy round tube with good corrosion resistance, with dimensions of 40mm in outer diameter and 30mm in inner diameter. The top of the monitoring tube 4 is above the ground and connected to the ground monitoring instrument, and the bottom is made into a horseshoe shape and connected to the wire mesh 6 and the rubber bag 7; the wire mesh 6 has a wire diameter of 1mm and a hole size of 5X5mm, which is welded to the horseshoe-shaped bottom surface of the monitoring tube 4, so as to prevent the rubber bag 7 from being pressed into the monitoring tube 4 or even crushed during the lowering of the monitoring tube.

[0060] The rubber bag 7 is made of special rubber, and its bursting pressure is designed according to the designed insertion depth, drilling fluid density, and cementing cement slurry density. Its constant pressure expansion volume is designed according to the designed borehole diameter at the deepest depth and the outer diameter of the technical casing. When cementing and injecting cement slurry, the monitoring pipe 4 is connected to the ground pressure-pressurizing equipment and pressurized to the designed value to expand the rubber bag 7 and form a cavity without cement slurry in the annulus between the technical casing 5 and the borehole 3. After the cement slurry solidifies, it is pressurized again through the monitoring pipe 4 to rupture the rubber bag 7, so that the monitoring pipe 4 is connected to the monitoring formation, and the purpose of monitoring the interface between the formation and the cement ring 2 at the monitoring position, the sealing condition of the interface between the technical casing 5 and the cement ring 2, and the influence of carbon dioxide injection on the overlying formation is achieved.

[0061] The wellhead sealing device 10 is made of stainless steel and has good acid corrosion resistance. Its outer shell is connected to the top of the technical casing 5 by threads. The internal device is connected to the carbon dioxide injection pipe 8 at the bottom and the carbon dioxide injection equipment manifold and monitoring instruments at the top to realize the functions of hanging the carbon dioxide injection pipe 8, sealing the annulus of the carbon dioxide injection pipe 8 and the technical casing 5 at the wellhead, and monitoring the inner cavity of the carbon dioxide injection pipe 8 and the annulus of the technical casing 5. If the annulus between the carbon dioxide injection pipe 8 and the technical casing 5 is abnormal, back pressure treatment can be carried out in time through the back pressure end of the wellhead sealing device 10.

[0062] Example 3

[0063] This embodiment is a detailed configuration based on the second embodiment.

[0064] In this embodiment, a process for forming a well structure for a saline layer carbon dioxide geological storage test includes:

[0065] S1, drilling 3

[0066] After the surface layer is drilled to the designed depth, the surface casing 1 is lowered, and the drilling is continued to the designed target layer 13 and then stopped;

[0067] S2, electrical logging;

[0068] S3, casing lowering

[0069] Install the side monitoring device on the technical casing 5 and lower it along with the technical casing 5, and apply sealing and fastening glue to the connecting threads; after the technical casing 5 is lowered to the designed depth, circulate and adjust the drilling fluid performance, and flush the annulus between the technical casing 5 and the borehole 3;

[0070] S4, cementing with cement slurry

[0071] During the cementing operation, the pressure is pumped into the monitoring tube 4 to the designed value through the pressure pumping equipment, so that the rubber bag 7 at the bottom of the monitoring tube 4 expands, and a cavity without cement slurry is formed between the technical casing 5 and the wall of the borehole 3;

[0072] S5, scraper

[0073] Run the scraper to remove the cement remaining on the inner wall of the technical casing 5 above the depth of the double-stage separator;

[0074] S6, perforation 14 connected

[0075] Connecting the technical casing 5 with the target layer to form a carbon dioxide injection channel;

[0076] S7, installation of carbon dioxide injection device

[0077] Install the shell of the wellhead sealing device 10 on the top of the technical casing 5, lower the double-stage packer 9 and the carbon dioxide injection pipe 8 to the designed depth, hang and seal the carbon dioxide injection pipe 8 on the shell of the wellhead sealing device 10, and fix it with screws;

[0078] S8, installing the wellhead device and the side monitoring device and pressurizing the side pipe to connect with the monitoring formation.

[0079] Example 4

[0080] This embodiment is a detailed configuration based on the embodiment 3.

[0081] In this embodiment, after the surface drilling reaches the designed depth, the surface casing is lowered, and the electric logging operation is performed after drilling through the cap layer 12 to the designed target layer. According to the electric logging data and the logging data during the drilling process, the technical casing 5 is lowered into the depth, the carbon dioxide injection target layer depth and the side monitoring target layer depth and other data are determined, and then the technical casing 5 is lowered into the pipe. The side monitoring device is installed on the technical casing 5 and lowered with the technical casing. The sealing and fastening glue is applied to the connecting thread to ensure sealing.

[0082] After the technical casing 5 is lowered to the designed depth, the drilling fluid performance is adjusted in a cycle, the technical casing and the borehole annulus are flushed, and then cementing operations are performed. During the cementing operation, the pressure is pumped into the monitoring pipe 4 to the designed value through the pressure equipment, so that the rubber bag 7 at the bottom of the monitoring pipe 4 expands, and a cavity without cement slurry is formed between the technical casing 5 and the wall of the borehole 3; after the cementing operation is completed, wait for the curing, and lower the scraper to remove the cement remaining on the inner wall of the technical casing 5 above the designed lowering depth of the double-stage separator 9, and then perform perforation operations to connect the technical casing 5 with the target formation to form a carbon dioxide injection channel;

[0083] After the perforation 14 is connected to the technical casing 5 and the target layer 13 is injected, the shell of the wellhead sealing device 10 is installed on the top of the technical casing 5, the double-stage packer 9 and the carbon dioxide injection pipe 8 are lowered to the designed depth, and the carbon dioxide injection pipe 8 is suspended and sealed on the shell of the wellhead sealing device 10 and fixed with screws;

[0084] After the CO2 injection device and the wellhead sealing device 10 are installed, a plug valve and a pressure equipment manifold are connected to the top of the CO2 injection pipe 8, the CO2 injection pipe 8 is pressurized to the design value, the double-stage packer 9 is opened, and then a test injection is performed, and the sealing condition of the double-stage packer 9 is checked by the monitoring instrument on the wellhead sealing device 10, and then the side monitoring pipe 4 is pressurized to the design value, and the rubber bag 7 at the bottom thereof is fractured, so that the monitoring pipe 4 is connected to the monitoring formation, and the sealing condition of the interface between the monitoring formation and the cement ring, the interface between the technical casing 5 and the cement ring, and the influence of the CO2 injection on the overlying formation 11 are achieved;

[0085] After the double-stage packer 9 is opened and the rubber bag 7 is fractured, a monitoring instrument is installed on the top of the monitoring pipe 4, and the on-site equipment and facilities are checked. When everything is ready, the carbon dioxide injection operation is started, and carbon dioxide is injected into the designed formation through the ground injection equipment, the wellhead sealing device 10, the carbon dioxide injection pipe 8, the technical casing 5, and the perforation 14 connecting channel; after the carbon dioxide injection operation is completed, the stopcock on the wellhead sealing device 10 is closed, and a monitoring instrument is installed on the top of the wellhead sealing device 10. The status of the carbon dioxide injected into the target layer 13 is monitored through the instrument on the top of the wellhead sealing device 10, the status of the annulus between the carbon dioxide injection pipe and the technical casing is monitored through the instrument on the side of the wellhead sealing device 10, and the impact of the carbon dioxide injection on the overlying formation 11 is monitored through the instrument on the top of the side monitoring pipe 4.

[0086] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A well formation structure for a saline layer carbon dioxide geological storage test, characterized in that: include: A surface casing, the surface casing is arranged in the borehole, a cement ring is arranged between the surface casing and the borehole; a technical casing is arranged in the surface casing, the technical casing extends downward from the ground to the bottom of the borehole; the technical casing is terminated on the ground with a detachable wellhead sealing device; A monitoring pipe, which is arranged between the surface casing and the technical casing, and is arranged adjacent to the technical casing, and extends downward from the ground to the monitoring target layer; A carbon dioxide injection device, the carbon dioxide injection device comprising a carbon dioxide injection pipe and a dual-stage packer, the carbon dioxide injection pipe is installed in the technical casing and extends downward from the ground to the upper part of the perforation position, the carbon dioxide injection device is higher than the ground terminal wellhead sealing device; the dual-stage packer is sleeved in the annular gap between the bottom of the carbon dioxide injection pipe and the technical casing; The process of the well formation structure for the saline water layer carbon dioxide geological storage test includes: S1, drilling After the surface drilling reaches the designed depth, the surface casing is lowered, and the drilling is stopped after the drilling reaches the designed target layer; S2, electrical logging; S3, casing lowering Install the side monitoring device on the technical casing and lower it along with the technical casing, apply sealing and fastening glue to the connecting threads; after the technical casing is lowered to the designed depth, circulate and adjust the drilling fluid performance, flush the technical casing and the borehole annulus; S4, cementing with cement slurry During cementing operation, the pressure is pumped into the monitoring tube to the designed value through the pressure equipment, so that the rubber bag at the bottom of the monitoring tube expands, and the rubber bag forms a cavity without cement slurry between the technical casing and the borehole wall; S5, Scraper Run the scraper to remove the cement remaining on the inner wall of the technical casing above the depth of the double-stage separator; S6, perforation connection The casing and the target formation are connected by perforation technology to form a CO2 injection channel; S7, installation of carbon dioxide injection device Install the wellhead sealing device shell on the top of the technical casing, lower the double-stage packer and the CO2 injection pipe to the designed depth, hang and seal the CO2 injection pipe on the wellhead sealing device shell, and fix it with screws; use the pressure equipment to pressurize the double-stage packer through the CO2 injection pipe, so that the double-stage separator expands and anchors on the technical casing, and seals the annular gap between the CO2 injection pipe and the technical casing; S8, installing the wellhead device and the side monitoring device and pressurizing the side pipe to connect with the monitoring formation; Step S8 specifically includes the following steps: S81, connect the plug valve and the pressure equipment manifold at the top of the CO2 injection pipe, pressurize the CO2 injection pipe for test injection, and check the sealing condition of the double-stage packer through the monitoring instrument on the wellhead sealing device; S82, pressurize the side monitoring pipe to the designed value and fracture the rubber bag at the bottom to achieve the connection between the monitoring pipe and the monitoring formation, and achieve the goal of monitoring the sealing conditions of the formation and cement sheath interface from the perforation position to the monitoring position, the technical casing and cement sheath interface, and the impact of carbon dioxide injection on the overlying formation; S83, install monitoring instruments on the top of the monitoring pipe, check the on-site equipment and facilities, and inject carbon dioxide into the designed formation through the ground injection equipment, wellhead sealing device, carbon dioxide injection pipe, technical casing, and perforation communication channel; S84, close the stopcock on the wellhead sealing device, install monitoring instruments on the top of the wellhead sealing device, monitor the status of carbon dioxide injected into the target layer through the instrument on the top of the wellhead sealing device, monitor the annulus status of the carbon dioxide injection pipe and the technical casing through the instrument on the side of the wellhead sealing device, and monitor the impact of carbon dioxide injection on the overlying formation through the instrument on the top of the side monitoring pipe.

2. The well-forming structure for the geological storage test of carbon dioxide in a saline layer according to claim 1, characterized in that: The surface casing, the technical casing, the carbon dioxide injection pipe and the cement ring are coaxially arranged.

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