CO2 huff and puff injection and production system and anti-CO2 packer and using method thereof

Abstract

The invention discloses a CO2 huff and puff injection and production system and an anti-CO2 packer and a using method thereof, the CO2 huff and puff injection and production system comprises ground equipment, the ground equipment is arranged on the ground and connected with a wellhead, and the CO2 huff and puff injection and production system further comprises a hydraulic control airtight injection and production pipe column; the upper end of the hydraulic control airtight injection-production pipe column is connected with a wellhead; a double-injection-production-device integrated separating device and a CO2-resistant packer are arranged in the hydraulic-control airtight injection-production pipe column. The anti-CO2 packer comprises a setting mechanism, a bidirectional sequential pressure transmission mechanism, an anchoring mechanism and a deblocking mechanism which are connected in sequence. According to the CO2 huff and puff injection and production system, other reservoirs in the same well can be exploited while soaking is carried out, the defect that oil cannot be exploited while soaking is carried out is overcome, and the production time rate is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of oil extraction, and specifically relates to a CO 2 huff and puff injection-production system, its anti-CO 2 packer and usage method. Background Art

[0002] CO 2 huff and puff technology is an important measure to improve the oil recovery rate in oil fields. This process injects supercritical CO 2 into the reservoir to reduce the viscosity of crude oil, improve the mobility ratio, and reduce the interfacial tension, so as to achieve the purpose of increasing the oil recovery rate. The injection methods include general injection, dual-tubing layered injection, and single-tubing multi-layer injection. The traditional CO 2 injection process mostly uses the general gas injection method. For reservoirs with a relatively uniform gas intake profile, general gas injection can meet the effective displacement needs of the oil layer. For reservoirs with large interlayer differences, layered injection is more conducive to expanding the swept volume of carbon dioxide. The oil production method generally selects rod pump oil production. After the gas injection shut-in is completed, a pump is lowered for production. With the expansion of the process application scale and the increase of application environments, the current process cannot meet the on-site requirements in the following two aspects.

[0003] First of all, after CO 2 is injected, in order to increase the reaction time with the crude oil in the injected reservoir and the huff and puff effect, it is necessary to carry out a shut-in for several weeks or even longer. During the shut-in period, due to the high downhole pressure, production cannot be carried out, and the well is in a shut-down state, delaying production. In order to increase the production, the on-site is more in need of a development process that can carry out production in other reservoirs of the same well while shutting in. Secondly, since there is an optimal temperature range for CO 2 to strip crude oil, when injecting liquid carbon dioxide into the reservoir, too high pressure and too low temperature will cause reservoir damage or directly lead to the failure of the process. Therefore, during the injection process, it is particularly important to real-time monitor the temperature and pressure of carbon dioxide in the wellbore and make on-line adjustments. However, the current huff and puff string cannot meet the requirements of real-time and accurate parameter monitoring, or only tests at the wellhead, and calculates the temperature and pressure of carbon dioxide when it enters the reservoir, resulting in large errors during on-site application.

[0004] Publication (Announcement) No.: CN214997593U discloses a CO 2 huff and puff well injection-production integrated string, which includes an in-well tubing, an in-well sucker rod, a hydraulic anchor drainer, a long plunger injection-production pump, an inserted oil production bridge plug, an oil production insert pipe, a flared port, a pump barrel, a plunger assembly, an upper joint, a lower joint, a fixed valve assembly, and an injection hole. This prior art adopts the general injection method, and the long plunger injection-production pump plays a role in providing a channel during the CO 2 injection link, and CO 2It flows through the injection hole into the annulus between the pump barrel and the outer pipe, reaches the formation after flowing to the tubing string production tool. It serves the purpose of lifting the formation-produced fluid during the oil production process, and the anti-kickoff distance needs to be adjusted during oil production. The hydraulic anchor drain valve serves the purpose of anchoring the pipe string and preventing the pipe string from creeping during the oil production process. If the moving pipe string operation is carried out, it plays the role of draining the tubing, which can prevent pollution, and the channel formed by cutting the pin after draining can also be used for positive and reverse well killing.

[0005] This prior art can realize injection, production, and soaking well with one trip of the tubing string, but oil production can only be carried out after the soaking well is completed. It cannot use the soaking well time to alternately produce other reservoirs, nor can it monitor the downhole carbon dioxide status in real time to make adjustments to the injection rate.

[0006] Publication (Announcement) No.: CN113863907A discloses a carbon dioxide composite stratified huff and puff tubing string, which includes a tubing body whose top end can be connected to a ground injection device, and also includes a carbon dioxide composite stratified injection part connected in series on the tubing body. The carbon dioxide composite stratified injection part can perform two switching operations through secondary ball dropping to inject carbon dioxide and steam in layers; an upper packer is strung on the tubing body, and the upper packer is used to seal the annulus between the upper oil layer and above the upper oil layer; a hydraulic type interlayer packer is sleeved on the tubing body, and the interlayer packer is used to seal the annulus between the lower oil layer and the upper oil layer; the bottom end of the tubing body is connected with a screen pipe that can be connected to the lower oil layer, and the bottom of the screen pipe is closed; a constant pressure ball seat is arranged at the position between the interlayer packer and the screen pipe in the tubing body. This invention can realize the stratified injection of carbon dioxide injection and steam huff and puff, can accurately control the injection volume of each layer, and increase the utilization degree of the injected fluid in the vertical direction of the oil well.

[0007] Although this prior art can realize stratified injection, during the injection and soaking well process, it can only wait until the injection pressure is completely absorbed by the reservoir. During this period, it is impossible to lower the pump to produce other reservoirs, nor can it conduct long-term monitoring of the temperature and pressure of the injected gas in the reservoir.

[0008] Publication (Announcement) No.: CN110159234A discloses a concentric dual-tube separate injection CO 2 tubing string and its use method, which includes a casing, an outer pipe, and an inner pipe, which are sleeved in sequence. An outer side gate, an upper packer, a gas separation valve, a lower packer, and an injection valve are sequentially connected on the outer pipe; the lower end of the inner pipe is first connected with an inner side gate and then connected to the gas separation valve. An insertion sealing mechanism, a locking mechanism, and an anti-backflow mechanism are arranged in the gas separation valve. This invention has inner and outer side gates, which solves the problem of the well killing channel; has an anti-backflow mechanism, ensuring production safety; has an insertion sealing and locking mechanism to prevent seal failure. A gas-tight packer with anchoring but without a washable well channel is used, ensuring reliable segmentation and preventing seal failure caused by the excessive lower pressure difference causing the packer to move upward.

[0009] This prior art only has an injection function, no production function, and cannot monitor the downhole carbon dioxide status in real time.

[0010] In summary, the technical solutions, the technical problems to be solved, and the beneficial effects of the above-disclosed technologies are all different from those of the present invention. Regarding more technical features, technical problems to be solved, and beneficial effects of the present invention, there is no technical inspiration in the above-disclosed technical documents. Summary of the Invention

[0011] In view of the above-mentioned defects existing in the prior art, the object of the present invention is to provide a CO 2 huff and puff injection-production system, its anti-CO 2 packer and usage method. This system uses an anti-carbon dioxide packer to separate the reservoir, and a hydraulic control airtight injection-production device to realize the opening and closing control of each reservoir section and the tubing channel. After the injection is completed, the injection-production device closes the injection layer for soaking the well, and at the same time opens the production layer. A sucker rod is used to drive a rod pump into a working barrel pre-installed on the tubing, and the pump is fixed with a circlip. The sucker rod drives the plunger to produce, achieving the purpose of producing other reservoirs during the soaking period. The entire process uses fiber optic monitoring technology to provide accurate real-time testing of downhole parameters, and the injection parameters can be adjusted in real time according to the data to avoid damage to the reservoir.

[0012] To achieve the above object, the present invention adopts the following technical solutions:

[0013] A CO 2 huff and puff injection-production system, including surface equipment, the surface equipment is arranged on the ground and connected to the wellhead, and also includes a hydraulic control airtight injection-production string; the upper end of the hydraulic control airtight injection-production string is connected to the wellhead; a double injection-production device integrated separation device and an anti-CO 2 packer are arranged in the hydraulic control airtight injection-production string; the anti-CO 2 packer includes a setting mechanism, a two-way sequential pressure transmission mechanism, an anchoring mechanism, and a releasing mechanism connected in sequence.

[0014] Furthermore, the double injection-production device integrated separation device includes an upper hydraulic control airtight injection-production device, a separation cylinder, and a lower hydraulic control airtight injection-production device;

[0015] Specifically, the upper end of the upper hydraulic control airtight injection-production device is connected to the lower end of the rod pump, and the lower end of the upper hydraulic control airtight injection-production device is connected to the lower end of the separation cylinder;

[0016] Specifically, the lower hydraulic control airtight injection-production device is arranged in the separation cylinder, and a blind plug and a fiber optic temperature and pressure sensor are sequentially arranged at the lower end of the lower hydraulic control airtight injection-production device.

[0017] Furthermore, the separation cylinder includes a double-tight joint, a coupling, a third upper joint, an outer sealing sleeve, and a third lower joint connected in sequence from top to bottom;

[0018] Specifically, a fastening pin hole is provided between the connection collar and the third upper sub to prevent relative rotation between the connection collar and the third upper sub;

[0019] Specifically, the third upper sub is provided with at least two liquid control pipeline through holes;

[0020] Specifically, the upper end female thread of the double connection sub is reverse thread, and the lower end male thread is straight thread; the male thread of the third lower sub is reverse thread, and another double connection sub is connected below the third lower sub.

[0021] Further, the upper layer liquid control airtight injection-production device or the lower layer liquid control airtight injection-production device includes an upper housing, an outer sleeve, a piston, and a lower housing;

[0022] Specifically, both the upper housing and the lower housing are hollow housings, and the lower end of the upper housing is connected to the upper end of the lower housing;

[0023] Specifically, the upper housing is provided with at least two inner injection-production holes that are evenly distributed circumferentially;

[0024] Specifically, an upper step is provided on the outer wall of the upper housing, a lower step is provided on the outer wall of the lower housing, the upper end of the outer sleeve is connected to the large-diameter surface of the upper step, and the lower end is connected to the large-diameter surface of the lower step;

[0025] Specifically, the annulus between the small-diameter surface of the upper step, the small-diameter surface of the lower step, and the outer sleeve is the piston cylinder, and the piston is arranged in the piston cylinder and can slide up and down;

[0026] Specifically, the outer sleeve is provided with outer injection-production holes corresponding to the inner injection-production holes, and the piston is provided with communication holes having the same number as the inner injection-production holes;

[0027] Specifically, an upper liquid control channel communicating with the piston cylinder is provided on the side wall of the upper housing, and a lower liquid control channel communicating with the piston cylinder is provided on the lower housing.

[0028] Further, seals are provided between the upper housing and the outer sleeve, between the lower housing and the outer sleeve, between the outer sleeve and the piston, between the upper housing and the piston, and between the lower housing and the piston by "O" - rings;

[0029] Specifically, the "O" - rings are successively provided with a first sheath, a second sheath, and a third sheath outside;

[0030] Further, the liquid control airtight injection-production pipe string further includes an oil pipe and a constant pressure sliding sleeve;

[0031] Specifically, the upper end of the oil pipe is connected to the wellhead, the double injection-production device integral separation device is arranged on the oil pipe, and the lower end of the double injection-production device integral separation device is connected to the anti - CO 2The upper end of the packer is connected to the CO 2 The lower end of the packer is connected to the upper end of the constant pressure sliding sleeve.

[0032] Furthermore, the hydraulically controlled gas-tight injection-production string also includes a rod pump, and the rod pump is arranged between the wellhead and the dual-injection-production device integrated separation device.

[0033] Furthermore, the above-ground equipment includes a wireless data transmission system, an optical fiber monitoring device, a CO 2 Injection equipment and monitoring system, pressure gauge and control valve of lower hydraulic control pipeline, pressure gauge and control valve of upper hydraulic control pipeline;

[0034] Specifically, the optical fiber monitoring device is connected to the optical fiber temperature and pressure sensor via an optical cable;

[0035] Specifically, the upper hydraulic control pipeline pressure gauge and control valve are connected to the upper hydraulic control gas-tight injection and extraction device through the upper hydraulic control pipeline;

[0036] Specifically, the pressure gauge and control valve of the lower hydraulic control pipeline are connected to the lower hydraulic control gas-tight injection and extraction device through the lower hydraulic control pipeline;

[0037] Specifically, the CO 2 The injection equipment and monitoring system are connected to the wellhead injection valve;

[0038] Specifically, the data wireless transmission system is connected to the optical fiber monitoring equipment.

[0039] Further, the upper end of the upper shell is provided with a first upper joint, and the lower end of the lower shell is provided with a first lower joint;

[0040] Specifically, the first upper joint of the lower hydraulically controlled airtight injector is connected to the lower end of the inner wall of the third upper joint, and the first lower joint of the upper hydraulically controlled airtight injector is connected to the upper end of the double-tight joint;

[0041] Specifically, the lower layer hydraulic control pipeline passes through the hydraulic control pipeline outlet hole and is inserted into the upper hydraulic control channel or the lower hydraulic control channel of the lower layer hydraulic control gas-tight injector;

[0042] Specifically, the upper hydraulic control pipeline is inserted into the upper hydraulic control channel or the lower hydraulic control channel of the upper hydraulic control gas-tight injector.

[0043] In order to achieve the above object, the present invention adopts the following technical solutions:

[0044] A CO 2 CO2 resistance of the Huff-and-Puff injection-production system 2 The packer comprises an inner central pipe, and also comprises a sealing mechanism, a bidirectional sequential pressure transmission mechanism, an anchoring mechanism, and a releasing mechanism which are arranged in sequence from top to bottom outside the inner central pipe.

[0045] Further, a second upper joint is provided at the upper end of the inner central tube;

[0046] Specifically, the setting mechanism includes a balance cylinder sleeve, a balance piston, a rubber cylinder, a spacer ring, and an outer central tube;

[0047] Specifically, the upper end of the balance cylinder sleeve is connected to the second upper joint by a releasing shear pin, and balance holes are provided in the corresponding area of the inner central tube in the balance cylinder sleeve;

[0048] Specifically, a limiting convex ring is provided on the outer wall of the inner central tube below the balance holes, and the piston is arranged in the annulus between the inner central tube and the balance cylinder sleeve and above the limiting convex ring;

[0049] Specifically, the outer central tube is sleeved on the outer wall of the inner central tube and below the limiting convex ring;

[0050] Specifically, an upper pressing ring is connected to the lower end of the balance cylinder sleeve, the lower end of the upper pressing ring is connected to the outer central tube, a lower pressing ring is provided on the outer central tube below the upper pressing ring, at least two rubber cylinders are provided between the upper pressing ring and the lower pressing ring, and a spacer ring is arranged between every two rubber cylinders.

[0051] Further, the two-way sequential pressure transmission mechanism includes a cylinder sleeve, an upper piston, a piston locking block, and a lower piston;

[0052] Specifically, the upper end of the cylinder sleeve contacts the lower pressing ring, a bayonet joint is also provided between the upper end of the cylinder sleeve and the lower pressing ring, and a setting shear pin is provided between the lower pressing ring and the outer central tube;

[0053] Specifically, a first pressure transmission hole is provided in the corresponding area of the inner central tube in the cylinder sleeve, a second pressure transmission hole is provided in the corresponding area of the outer central tube in the cylinder sleeve, and the annulus formed between the cylinder sleeve and the outer central tube is a pressure transmission annulus;

[0054] Specifically, the upper piston and the lower piston are both arranged in the piston annulus, the upper piston is above the second pressure transmission hole, and the lower piston is below the second pressure transmission hole;

[0055] Specifically, the upper end of the upper piston is engaged with the cylinder sleeve, a protruding arm is provided at the lower end of the upper piston, and the lower end of the protruding wall contacts the lower piston;

[0056] Specifically, a piston locking groove is provided in the outer central tube at the corresponding position of the protruding arm, the piston locking block is arranged in the piston locking groove and contacts the protruding arm, and the piston locking block and the piston arm seal the piston annulus.

[0057] Further, the anchoring mechanism includes an upper cone, slips, and a lower cone;

[0058] Specifically, the upper cone is engaged with the lower piston, the lower cone is arranged below the upper cone, the slips are arranged between the upper cone and the lower cone, and a buttress thread is arranged between the lower cone and the outer central tube.

[0059] Further, the releasing mechanism includes a releasing lock ring seat, a lock ring, a releasing lock block, a lock block seat, and a second lower sub;

[0060] Specifically, the lower end of the releasing lock ring seat is connected to the second lower sub, a claw is arranged at the upper end of the releasing lock ring seat, and the upper end of the claw contacts the lower cone;

[0061] Specifically, the lock ring is arranged at the lower end of the outer central tube, and the lock ring can cooperate with the claw;

[0062] Specifically, the lock block seat is arranged on the inner wall of the second lower sub, the releasing lock block is placed at the upper end of the lock block seat, the releasing lock block is engaged and connected with the lock ring and can slide radially, and the releasing lock block is inserted and connected with the second lower sub;

[0063] Specifically, the lower end of the inner central tube is inserted into the inner wall of the second lower sub, and a locking groove is arranged on the outer wall of the lower end of the inner central tube.

[0064] Further, sealing rings are arranged between the second upper sub and the balance cylinder sleeve, between the balance piston and the inner central tube and the balance cylinder sleeve, between the upper and lower ends of the outer central tube and the inner central tube, between the upper piston and the outer central tube and the cylinder sleeve, between the lower piston and the outer central tube and the cylinder sleeve, and between the second lower sub and the inner central tube.

[0065] In order to achieve the above object, the present invention adopts the following technical solutions:

[0066] A method for using a CO 2 huff and puff injection and production system, including the following steps,

[0067] S1. Connect the hydraulic control airtight injection and production string with the surface equipment and lower it into the well;

[0068] S2. Set the CO 2 packer;

[0069] S3. Carbon dioxide injection stage: Select surface equipment matching the injection pressure during design, fix the wellhead to the ground anchor with a wire rope to ensure high-pressure safety protection; pressurize or depressurize through the lower-layer hydraulic control pipeline pressure gauge and control valve, and the upper-layer hydraulic control pipeline pressure gauge and control valve, open the target layer hydraulic control switch to connect the target oil layer; through the CO 2The injection device and the monitoring system inject carbon dioxide and conduct process monitoring to control the injection pressure within the rated pressure, and real-time monitor the downhole temperature and pressure data through the fiber optic monitoring device; appropriately adjust the carbon dioxide injection rate according to the real-time monitoring data, so as to adjust the temperature and pressure of the pay zone and improve the huff and puff effect;

[0070] S4. Oil production stage: After the carbon dioxide injection is completed, soak the well. Pressurize or depressurize through the lower layer liquid control pipeline pressure gauge and control valve, and the upper layer liquid control pipeline pressure gauge and control valve, close the injection layer, and open the production layer;

[0071] Lower a rod pump for production. While soaking the injection layer, alternately produce another layer. Use the fiber optic monitoring device to test the production layer data, and remotely monitor the pay zone parameters through the data wireless transmission system;

[0072] S5. Anti-CO 2 Release the packer and pull out the tubing string.

[0073] Furthermore, when the anti-CO 2 packer is set, the setting shear pin is cut off by pressurizing at the wellhead. The upper piston moves upward, driving the cylinder sleeve upward, causing the rubber barrel to expand to complete the seal. At the same time, the buttress thread between the cylinder sleeve and the lower retaining ring is locked; after the upper piston moves upward, the piston lock block disengages from the piston groove, and the lower piston moves downward under pressure, pushing the upper cone downward, causing the slips to pop out. At the same time, the buttress thread between the upper cone and the outer center pipe is locked;

[0074] Specifically, when the anti-CO 2 packer is released and the tubing string is pulled out, lift the tubing string to cut off the release shear pin. The second upper joint and the inner center pipe move upward, causing the release lock block to enter the lock groove. The second lower joint moves downward and hooks on the lock ring through the claw. At this time, the space above the setting mechanism is vacated, and the space below the anchoring mechanism is vacated. Under the action of the rubber barrel elasticity and the slips elasticity, the setting is released and the anchoring is released, and the tubing string is pulled out. The present invention has the following beneficial effects compared with the prior art:

[0075] 1. The CO 2 huff and puff injection-production system realizes the exploitation of other reservoirs in the same well while soaking the well, eliminates the drawback that oil cannot be produced simultaneously during soaking, and improves the production time efficiency;

[0076] 2. In the case of downhole layering, the innovative design of the separating cylinder eliminates the structure of multiple pipelines passing through the packer, saving costs and eliminating the weak points of passing through the packer;

[0077] 3. It has the function of accurately monitoring and real-time adjusting the downhole CO 2 parameters, protecting the reservoir while improving the CO 2 huff and puff effect;

[0078] 4. When designing the pipe string, the lower-layer hydraulic control airtight injection-production device is moved above the packer so that it works at a relatively low wellbore temperature, expanding the temperature range for the application of the pipe string.

[0079] 5. It has an independent hydraulic system. Layers can be changed by pressurizing and depressurizing through the surface hydraulic control pipeline. The operation is convenient and the reliability is high. The on-off state of the downhole injection-production device can be judged by the pressure of the surface hydraulic control pipeline, which is simple, intuitive and cost-saving. Description of the Drawings

[0080] Figure 1 is a schematic diagram of the pipe string structure of a CO 2 huff and puff injection-production system of the present invention;

[0081] Figure 2 is a schematic diagram of the structure of the separating cylinder of a CO 2 huff and puff injection-production system of the present invention;

[0082] Figure 3 is a schematic diagram of the structure of the hydraulic control airtight injection-production device of a CO 2 huff and puff injection-production system of the present invention;

[0083] Figure 4 is a schematic diagram of the structure of the CO 2 resistant packer of the huff and puff injection-production system of the present invention; 2

[0084] In the figure: 1. Data wireless transmission system; 2. Optical fiber monitoring equipment; 3. Rod pump; 4. Upper-layer hydraulic control airtight injection-production device; 5. Optical cable; 6. Separating cylinder; 7. Lower-layer hydraulic control airtight injection-production device; 8. Blind plug; 9. Safety joint; 10. CO 2 resistant packer; 11. Constant pressure sliding sleeve; 12. Optical fiber temperature and pressure sensor; 13. Lower-layer hydraulic control pipeline; 14. Upper-layer hydraulic control pipeline; 15. CO 2 injection equipment and monitoring system; 16. Lower-layer hydraulic control pipeline pressure gauge and control valve; 17. Upper-layer hydraulic control pipeline pressure gauge and control valve;

[0085] 401. Upper housing; 402. Outer sleeve; 403. Piston; 404. First sheath; 405. Second sheath; 406. Third sheath; 407. "O" ring; 408. Lower housing;

[0086] 601. Double-tight joint; 602. Connecting hoop; 603. Fastening pin hole; 604. Third upper joint; 605. Hydraulic control pipeline through hole; 606. Outer seal sleeve; 609. Third lower joint;

[0087] 1001. Second upper joint; 1002. Balance cylinder sleeve; 1003. Balance piston; 1004. Rubber cylinder; 1005. Spacer ring; 1006. Outer central tube; 1007. Inner central tube; 1008. Cylinder sleeve; 1009. Upper piston; 1010. Piston locking block; 1011. Lower piston; 1012. Upper cone; 1013. Spring; 1014. Unlocking ring seat; 1015. Unlocking block; 1016. Second lower joint; 1017. Locking block seat. Detailed implementation manner

[0088] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0089] Embodiment 1:

[0090] Please refer to Figures 1 to 4 , a CO 2 huff and puff injection and production system provided by the present invention, including a liquid-controlled airtight injection and production string and wellhead equipment. The anti-CO 2 packer string is arranged in the well. The upper end of the liquid-controlled airtight injection and production string is connected to the wellhead, and the wellhead equipment is arranged on the ground and connected to the wellhead;

[0091] The liquid-controlled airtight injection and production string includes a tubing, a rod pump 3, a double injection and production device integrated separation device, an anti-CO 2 packer 10, and a constant pressure sliding sleeve 11. The upper end of the tubing is connected to the wellhead. The rod pump 3 is arranged below the wellhead. The double injection and production device integrated separation device is arranged below the rod pump 3. The lower end of the double injection and production device integrated separation device is connected to the upper end of the anti-CO 2 packer 10 through a safety joint 9. The lower end of the anti-CO 2 packer 10 is connected to the upper end of the constant pressure sliding sleeve 11.

[0092] The double injection and production device integrated separation device includes an upper liquid-controlled airtight injection and production device 4, a separation cylinder 6, and a lower liquid-controlled airtight injection and production device 7. The upper end of the upper liquid-controlled airtight injection and production device 4 is connected to the lower end of the rod pump 3. The lower end of the upper liquid-controlled airtight injection and production device 4 is connected to the lower end of the separation cylinder 6. The lower liquid-controlled airtight injection and production device 7 is arranged in the separation cylinder 6. A blind plug 8 and an optical fiber temperature and pressure sensor 12 are sequentially arranged at the lower end of the lower liquid-controlled airtight injection and production device 7.

[0093] The separation cylinder 6 includes a double-tight joint 601, a coupling 602, a third upper joint 604, an outer sealing sleeve 606, and a third lower joint 607, which are connected in sequence from top to bottom; a fastening pin hole 603 is provided between the coupling 602 and the third upper joint 604 to prevent relative rotation between the coupling 602 and the third upper joint 604. The third upper joint 604 is provided with at least two liquid control pipeline through holes 605 as the through channels for multiple liquid control pipelines and optical cables; the upper end female thread of the double-tight joint 601 is a left-handed thread (reverse thread), and the lower end male thread is a right-handed thread (positive thread) for connecting the upper end pipe string and the lower end coupling 602. When connecting, the upper and lower threads are tightened simultaneously; the male thread of the third lower joint 607 is a left-handed thread (reverse thread), and another double-tight joint 601 is connected below the third lower joint 607, which can avoid the problem that the pre-laid pipeline cannot be screwed onto the pipe string.

[0094] The wellhead equipment includes a data wireless transmission system 1, an optical fiber monitoring device 2, CO 2 injection equipment and monitoring system 15, a lower-layer liquid control pipeline pressure gauge and control valve 16, and an upper-layer liquid control pipeline pressure gauge and control valve 17; the optical fiber monitoring device 2 is connected to an optical fiber temperature and pressure sensor 12 through an optical cable 5. The upper-layer liquid control pipeline pressure gauge and control valve 17 are connected to an upper-layer liquid control airtight injection and production device 4 through an upper-layer liquid control pipeline 14. The lower-layer liquid control pipeline pressure gauge and control valve 16 are connected to a lower-layer liquid control airtight injection and production device 7 through a lower-layer liquid control pipeline 13. The CO 2 injection equipment and monitoring system 15 is connected to a wellhead injection valve, and the data wireless transmission system 1 is connected to the optical fiber monitoring device 2.

[0095] Among them, the upper-layer liquid control airtight injection and production device 4 is used for injection and production above the CO 2 packer 10;

[0096] The lower-layer liquid control airtight injection and production device 7 is used for injection and production below the CO 2 packer 10;

[0097] The constant-pressure sliding sleeve 11 is used for pressure relief after setting;

[0098] The CO 2 packer 10 is used for separating the reservoir;

[0099] The safety joint 9 is used for disconnecting the tubing when encountering sand sticking during later operations;

[0100] The sucker rod of the rod pump 3 is lowered into the internal designed position of the tubing for oil production.

[0101] It should be noted that the constant-pressure sliding sleeve 11, the rod pump 3, and the wellhead equipment are all prior arts and can be purchased. Those skilled in the art are clear about this.

[0102] The hydraulic control airtight injection-production device of the present invention, as Figure 2 shown, includes an upper housing 401, an outer sleeve 402, a piston 403, and a lower housing 408;

[0103] Both the upper housing 401 and the lower housing 408 are hollow housings. The lower end of the upper housing 401 is connected to the upper end of the lower housing 408. The upper housing 401 is provided with at least two inner injection-production holes evenly distributed along the circumferential direction. The outer wall of the upper housing 401 is provided with an upper step, and the outer wall of the lower housing 408 is provided with a lower step. The upper end of the outer sleeve 402 is connected to the large-diameter surface of the upper step, and the lower end is connected to the large-diameter surface of the lower step. The annulus between the small-diameter surface of the upper step, the small-diameter surface of the lower step, and the outer sleeve 402 is a piston cylinder. The piston 403 is arranged in the piston cylinder and can slide up and down. The outer sleeve 402 is provided with outer injection-production holes corresponding to the inner injection-production holes. The piston 403 is provided with communication holes having the same number as the inner injection-production holes. The side wall of the upper housing 401 is provided with an upper hydraulic control channel communicating with the piston cylinder, and the lower housing 408 is provided with a lower hydraulic control channel communicating with the piston cylinder.

[0104] A first upper joint is arranged at the upper end of the upper housing 401, and a first lower joint is arranged at the lower end of the lower housing 408.

[0105] Between the upper housing 401 and the outer sleeve 402, between the lower housing 408 and the outer sleeve 402, between the outer sleeve 402 and the piston 403, between the upper housing 401 and the piston 403, and between the lower housing and the piston 403, they are all sealed by an "O" - ring 407. The outer of the "O" - ring 407 is successively a first sheath 404, a second sheath 405, and a third sheath 406.

[0106] Specifically, the lower end inner wall of the first upper joint of the lower - layer hydraulic control airtight injection - production device 7 is connected to the inner wall of the third upper joint 604. The first lower joint of the upper - layer hydraulic control airtight injection - production device 4 is connected to the upper end of the double - tight joint 602. The lower - layer hydraulic control pipeline 13 passes through the hydraulic control pipeline through - hole 605 and is inserted into the upper hydraulic control channel or the lower hydraulic control channel of the lower - layer hydraulic control airtight injection - production device 7. The upper - layer hydraulic control pipeline 14 passes through the hydraulic control pipeline through - hole 605 and is inserted into the upper hydraulic control channel or the lower hydraulic control channel of the upper - layer hydraulic control airtight injection - production device 4. By pressurizing or depressurizing through the upper - layer hydraulic control pipeline 14 and the lower - layer hydraulic control pipeline 13, the piston 403 moves upward or downward, so that the inner injection - production holes are communicated with or closed to the outer injection - production holes.

[0107] To solve the problem of limited space, the lower - layer hydraulic control airtight injection - production device 7 is eccentrically installed inside the third upper joint 604.

[0108] Embodiment 2:

[0109] This embodiment also provides the CO - resistant 2 packer 10 of the present invention, asFigure 4 As shown, it includes an inner central tube 1007. A second upper joint 1001 is provided at the upper end of the inner central tube 1007. The inner central tube 1007 is successively sleeved with a setting mechanism, a two-way sequential pressure transmission mechanism, an anchoring mechanism, a releasing mechanism, and a second lower joint 1016 from top to bottom.

[0110] The setting mechanism includes a balance cylinder sleeve 1002, a balance piston 1003, a rubber cylinder 1004, a spacer ring 1005, and an outer central tube 1006. The upper end of the balance cylinder sleeve 1002 is connected to the second upper joint 1001 by a releasing shear pin. The inner central tube 1007 is provided with a balance hole in the corresponding area of the balance cylinder sleeve 1002. A limiting convex ring is provided on the outer wall of the inner central tube 1007 below the balance hole. The piston 1003 is arranged in the annulus between the inner central tube 1007 and the balance cylinder sleeve 1002. The outer central tube 1006 is sleeved on the outer wall of the inner central tube 1007 and is located below the limiting convex ring. The lower end of the balance cylinder sleeve 1002 is connected with an upper pressure ring, and the lower end of the upper pressure ring is connected to the outer central tube 1006. The outer central tube 1006 is provided with a lower pressure ring below the upper pressure ring. At least two rubber cylinders are arranged between the upper pressure ring and the lower pressure ring of the rubber cylinder 1004, and a spacer ring 1005 is arranged between every two rubber cylinders.

[0111] The two-way sequential pressure transmission mechanism includes a cylinder sleeve 1008, an upper piston 1009, a piston locking block 1010, and a lower piston 1011. The upper end of the cylinder sleeve 1008 contacts the lower pressure ring, and a bayonet joint is also arranged between the upper end of the cylinder sleeve 1008 and the lower pressure ring. A setting shear pin is arranged between the lower pressure ring and the outer central tube. The inner central tube 1007 is provided with a first pressure transmission hole in the corresponding area of the cylinder sleeve 1008, and the outer central tube 1006 is provided with a second pressure transmission hole in the corresponding area of the cylinder sleeve 1008. The annulus formed between the cylinder sleeve 1008 and the outer central tube 1006 is a pressure transmission annulus. The upper piston 1009 and the lower piston 1011 are both arranged in the piston annulus. The upper piston 1009 is located above the second pressure transmission hole, and the lower piston 1011 is located below the second pressure transmission hole. The upper end of the upper piston 1009 is engaged with the cylinder sleeve 1008. A protruding arm is arranged at the lower end of the upper piston 1009, and the lower end of the protruding wall contacts the lower piston 1011. A piston locking groove is arranged on the outer central tube 1006 at the corresponding position of the protruding arm. The piston locking block 1010 is arranged in the piston locking groove and contacts the protruding arm. The piston locking block 1010 and the piston arm seal the piston annulus. Only when the upper piston 1009 moves upward to make room and the piston locking block 1010 disengages from the piston locking groove to conduct the piston annulus, can the lower piston 1011 be pushed.

[0112] The anchoring mechanism includes an upper cone 1012, slips 1013, and a lower cone; the upper cone 1012 is engaged with the lower piston 1011, the lower cone is arranged below the upper cone, the slips 1013 are arranged between the upper cone 1012 and the lower cone, and a buttress thread is arranged between the lower cone and the outer central tube 1006.

[0113] The releasing mechanism includes a release locking ring seat 1014, a release locking block 1015, and a lock block seat 1017; the lower end of the release locking ring seat 1014 is connected to the second lower sub 1016, a claw is arranged at the upper end of the release locking ring seat 1014, the upper end of the claw contacts the lower cone, a lock ring is arranged at the lower end of the outer central tube 1006, and the lock ring can cooperate with the claw; the lock block seat 1017 is arranged on the inner wall of the second lower sub 1016, the release locking block 1015 is placed at the upper end of the lock block seat 1017, the release locking block 1015 is engaged and connected with the lock ring and can slide radially, the release locking block 1015 is inserted and connected with the second lower sub 1016, the lower end of the inner central tube 1007 is inserted into the inner wall of the second lower sub 1016, and a lock groove is arranged on the outer wall of the lower end of the inner central tube 1007. When the inner central tube 1007 is lifted to make the release locking block 1015 enter the lock groove, the inner central tube cannot move downward anymore.

[0114] Sealing rings are arranged between the second upper sub 1001 and the balance cylinder sleeve 1002, between the balance piston 1003 and the inner central tube 1007 and the balance cylinder sleeve 1002, between the upper and lower ends of the outer central tube 1006 and the inner central tube 1007, between the upper piston 1009 and the outer central tube 1006 and the cylinder sleeve 1008, between the lower piston and the outer central tube 1006 and the cylinder sleeve 1008, and between the second lower sub 1016 and the inner central tube 1007.

[0115] Embodiment 3:

[0116] S1. Connect the hydraulic control airtight injection-production string with the wellhead equipment and lower it into the well; at this time, the balance cylinder sleeve 1002, the balance piston 1003, the upper pressure ring, the outer central tube, the lock ring, the release locking ring seat, the release locking block, the second lower sub, and the lock block seat are integrated and fixed through the limit ring between the balance piston 1003 and the inner central tube 1007.

[0117] S2. Set the packer string. Cut the setting shear pin by pumping pressure at the wellhead. The upper piston 1009 moves upward, driving the cylinder sleeve 1008 to move upward, so that the rubber cylinder 1004 expands to complete the sealing. At the same time, the buttress thread between the cylinder sleeve 1008 and the lower retaining ring is locked.

[0118] After the upper piston 1009 moves upward, the piston lock block 1010 disengages from the piston groove, and the lower piston 1011 moves downward under pressure, pushing the upper cone 1012 downward to eject the slips 1013. At the same time, the buttress thread between the upper cone 1012 and the outer central pipe 1006 is locked.

[0119] S3. Carbon dioxide injection stage: Select wellhead equipment matching the injection pressure during design, fix the wellhead to the ground anchor with a wire rope to ensure high-pressure safety protection; pressurize or depressurize through the lower-layer hydraulic control pipeline pressure gauge and control valve 16 and the upper-layer hydraulic control pipeline pressure gauge and control valve 17, and open the target layer hydraulic control switch to connect the target oil layer; 2 Inject carbon dioxide through the injection equipment and monitoring system 15 and conduct process monitoring to control the injection pressure within the rated pressure. Real-time monitor the downhole temperature and pressure data through the fiber optic monitoring equipment 2; appropriately adjust the carbon dioxide injection rate according to the real-time monitoring data, thereby adjusting the temperature and pressure at the pay zone position to improve the huff and puff effect.

[0120] S4. Oil production stage: After the carbon dioxide injection is completed, shut in the well. Pressurize or depressurize through the lower-layer hydraulic control pipeline pressure gauge and control valve 16 and the upper-layer hydraulic control pipeline pressure gauge and control valve 17 to close the injection layer and open the production layer.

[0121] Lower the rod pump 3 for production. While shutting in the injection layer, alternately produce another layer. Use the fiber optic monitoring equipment 2 to test the production layer data and remotely monitor the pay zone parameters through the data wireless transmission system 1.

[0122] S5. Unseal and pull out. Lift the tubing string to cut the unsealing shear pin. The second upper joint 1001 and the inner central pipe 1007 move upward, making the unsealing lock block 1015 enter the lock groove. The second lower joint 1016 moves downward and hangs on the lock ring through the claw. At this time, the space above the setting mechanism is vacated, and the space below the anchoring mechanism is vacated. Under the elastic force of the rubber barrel 1004 and the elastic force of the slips 1013, the setting and anchoring are released, and the tubing string is pulled out.

[0123] In this application, any parts that are not elaborated on themselves and the connection methods of each part in this application belong to the well-known technologies in this technical field. They can be directly applied and will not be elaborated further.

[0124] In the present invention, the term "plurality" means two or more, unless otherwise clearly defined. Terms such as "install", "connect", "join", "fix" and other terms should be understood in a broad sense. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; "join" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0125] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "front", "rear", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0126] In the description of this specification, the descriptions of the terms "one embodiment", "some embodiments", "specific embodiments", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or instance. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0127] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A CO 2 huff and puff injection and production system, comprising surface equipment, wherein the surface equipment is arranged on the ground and connected to the wellhead. It is characterized in that it further includes a hydraulically controlled airtight injection-production pipe string; The upper end of the liquid-controlled airtight injection-production pipe string is connected to the wellhead; a double injection-production device integrated separation device and an anti-CO 2 packer are arranged in the liquid-controlled airtight injection-production pipe string. The anti-CO 2 The packer comprises a sealing mechanism, a bidirectional sequential pressure transmission mechanism, an anchoring mechanism and a releasing mechanism which are connected in sequence.

2. A CO 2 huff and puff injection-production system It is characterized in that the double injection-production device integrated separation device includes an upper hydraulically controlled airtight injection-production device, a separation cylinder, and a lower hydraulically controlled airtight injection-production device; the upper end of the upper hydraulically controlled airtight injection-production device is connected to the lower end of the rod pump, and the lower end of the upper hydraulically controlled airtight injection-production device is connected to the lower end of the separation cylinder; the lower hydraulically controlled airtight injection-production device is arranged in the separation cylinder, and a blind plug and an optical fiber temperature and pressure sensor are sequentially arranged at the lower end of the lower hydraulically controlled airtight injection-production device.

3. The CO 2 huff and puff injection and production system It is characterized in that the separation cylinder includes a double-joint, a coupling, a third upper joint, an outer seal sleeve, and a third lower joint, which are sequentially connected from top to bottom; a fastening pin hole is arranged between the coupling and the third upper joint to prevent the coupling from rotating relative to the third upper joint; the third upper joint is provided with at least two liquid control pipeline through holes; the upper end female thread of the double-joint is a reverse thread, and the lower end male thread is a normal thread; the male thread of the third lower joint is a reverse thread, and another double-joint is connected below the third lower joint.

4. A CO 2 huff and puff injection-production system It is characterized in that the upper hydraulically controlled airtight injection-production device or the lower hydraulically controlled airtight injection-production device includes an upper housing, an outer sleeve, a piston, and a lower housing; both the upper housing and the lower housing are hollow housings, and the lower end of the upper housing is connected to the upper end of the lower housing; the upper housing is provided with at least two inner injection-production holes that are evenly distributed circumferentially; an upper step is arranged on the outer wall of the upper housing, a lower step is arranged on the outer wall of the lower housing, the upper end of the outer sleeve is connected to the large-diameter surface of the upper step, and the lower end is connected to the large-diameter surface of the lower step; the annular space between the small-diameter surface of the upper step, the small-diameter surface of the lower step, and the outer sleeve is a piston cylinder, and the piston is arranged in the piston cylinder and can slide up and down; the outer sleeve is provided with outer injection-production holes corresponding to the inner injection-production holes, and the piston is provided with communication holes with the same number as the inner injection-production holes; an upper liquid control channel communicating with the piston cylinder is arranged on the side wall of the upper housing, and a lower liquid control channel communicating with the piston cylinder is arranged on the lower housing.

5. A CO 2 huff and puff injection-production system It is characterized in that between the upper housing and the outer sleeve, between the lower housing and the outer sleeve, between the outer sleeve and the piston, between the upper housing and the piston, and between the lower housing and the piston are all sealed by "O" rings; the outer side of the "O" ring is successively a first sheath, a second sheath, and a third sheath.

6. A CO 2 huff and puff injection-production system It is characterized in that the hydraulically controlled airtight injection-production pipe string further includes an oil pipe and a constant pressure sliding sleeve; The upper end of the tubing is connected to the wellhead. The dual injection-production integrally separated device is arranged on the tubing. The lower end of the dual injection-production integrally separated device is connected to the anti-CO 2 packer through a safety joint. The upper end of the anti-CO 2 packer is connected to the upper end of the constant pressure sliding sleeve.

7. A CO 2 huff and puff injection-production system It is characterized in that the hydraulically controlled airtight injection-production pipe string further includes a rod pump, and the rod pump is arranged between the wellhead and the double injection-production device integrated separation device.

8. A CO 2 huff and puff injection and production system It is characterized in that The aboveground equipment includes a data wireless transmission system, an optical fiber monitoring device, a CO 2 injection device and monitoring system, a pressure gauge and control valve for the lower-layer liquid control pipeline, and a pressure gauge and control valve for the upper-layer liquid control pipeline; the optical fiber monitoring device is connected to the optical fiber temperature and pressure sensor through an optical cable; the upper liquid control pipeline pressure gauge and control valve are connected to the upper hydraulically controlled airtight injection-production device through the upper liquid control pipeline; the lower liquid control pipeline pressure gauge and control valve are connected to the lower hydraulically controlled airtight injection-production device through the lower liquid control pipeline; The CO 2 injecting device and the monitoring system are connected to the wellhead injection valve; the data wireless transmission system is connected to the optical fiber monitoring device.

9. A CO 2 huff and puff injection and production system It is characterized in that a first upper joint is arranged at the upper end of the upper housing, and a first lower joint is arranged at the lower end of the lower housing; The lower end of the inner wall of the first upper joint of the lower liquid-controlled airtight injection-production device is connected to the third upper joint, and the upper end of the double adapter is connected to the first lower joint of the upper liquid-controlled airtight injection-production device; The lower liquid control pipeline passes through the liquid control pipeline through-hole and is inserted into the upper liquid control channel or the lower liquid control channel of the lower liquid-controlled airtight injection-production device; The upper liquid control pipeline is inserted into the upper liquid control channel or the lower liquid control channel of the upper liquid-controlled airtight injection-production device.

10. A CO 2 packer for CO 2 huff and puff injection and production system, comprising an inner central tube, It is characterized in that It further includes a setting packer mechanism, a two-way sequential pressure transmission mechanism, an anchoring mechanism, and a releasing mechanism, which are arranged from top to bottom outside the inner central tube.

11. A CO 2 packer for a CO 2 huff and puff injection and production system It is characterized in that A second upper joint is arranged at the upper end of the inner central tube; The setting packer mechanism includes a balance cylinder sleeve, a balance piston, a rubber barrel, a spacer ring, and an outer central tube; The upper end of the balance cylinder sleeve is connected to the second upper joint by a releasing shear pin, and a balance hole is arranged in the inner central tube corresponding to the balance cylinder sleeve; A limiting convex ring is arranged on the outer wall of the inner central tube below the balance hole, and the piston is arranged in the annular space between the inner central tube and the balance cylinder sleeve, above the limiting convex ring; The outer central tube is sleeved on the outer wall of the inner central tube, below the limiting convex ring; The lower end of the balance cylinder sleeve is connected with an upper pressure ring, the lower end of the upper pressure ring is connected with the outer central tube, a lower pressure ring is arranged on the outer central tube below the upper pressure ring, and at least two rubber barrels are arranged between the upper pressure ring and the lower pressure ring, and a spacer ring is arranged between every two rubber barrels.

12. A CO 2 packer for the anti-CO 2 huff and puff injection and production system It is characterized in that The two-way sequential pressure transmission mechanism includes a cylinder sleeve, an upper piston, a piston locking block, and a lower piston; The upper end of the cylinder sleeve contacts the lower pressure ring, a bayonet is also arranged between the upper end of the cylinder sleeve and the lower pressure ring, and a setting shear pin is arranged between the lower pressure ring and the outer central tube; A first pressure transmission hole is arranged in the inner central tube corresponding to the cylinder sleeve, a second pressure transmission hole is arranged in the outer central tube corresponding to the cylinder sleeve, and the annular space formed between the cylinder sleeve and the outer central tube is a pressure transmission annular space; The upper piston and the lower piston are both arranged in the piston annular space, the upper piston is above the second pressure transmission hole, and the lower piston is below the second pressure transmission hole; The upper end of the upper piston is engaged with the cylinder sleeve, a protruding arm is arranged at the lower end of the upper piston, and the lower end of the protruding wall contacts the lower piston; A piston locking groove is arranged on the outer central tube corresponding to the protruding arm, the piston locking block is arranged in the piston locking groove and contacts the protruding arm, and the piston locking block and the piston arm seal the piston annular space.

13. A CO 2 packer for the anti-CO 2 huff and puff injection and production system according to claim 12 It is characterized in that The anchoring mechanism includes an upper cone, a slip, and a lower cone; The upper cone is engaged with the lower piston, the lower cone is arranged below the upper cone, the slip is arranged between the upper cone and the lower cone, and a bayonet is arranged between the lower cone and the outer central tube.

14. A CO 2 packer for the anti-CO 2 huff and puff injection and production system It is characterized in that The releasing mechanism includes a releasing lock ring seat, a lock ring, a releasing lock block, a lock block seat, and a second lower joint; The lower end of the releasing lock ring seat is connected to the second lower joint, a hook is arranged at the upper end of the releasing lock ring seat, and the upper end of the hook contacts the lower cone; The lock ring is arranged at the lower end of the outer central tube, and the lock ring can cooperate with the hook; The lock block seat is arranged on the inner wall of the second lower sub, the unlocking block is placed at the upper end of the lock block seat, the unlocking block is engaged and connected with the lock ring and can slide radially, and the unlocking block is inserted and connected with the second lower sub; The lower end of the inner central tube is inserted into the inner wall of the second lower sub, and a lock groove is arranged on the outer wall of the lower end of the inner central tube.

15. A CO 2 packer for anti-CO 2 in the Huff and Puff injection and production system It is characterized in that Sealing rings are arranged between the second upper sub and the balance cylinder sleeve, between the balance piston and the inner central tube and the balance cylinder sleeve, between the upper and lower ends of the outer central tube and the inner central tube, between the upper piston and the outer central tube and the cylinder sleeve, between the lower piston and the outer central tube and the cylinder sleeve, and between the second lower sub and the inner central tube.

16. A method for using a CO 2 huff and puff injection and production system It is characterized in that It includes the following steps S1. Connect the hydraulic control airtight injection-production pipe string with the wellhead equipment and lower it into the well; S2. Anti-CO 2 Packer setting; S3. Carbon dioxide injection stage: Select wellhead equipment matching the injection pressure during design, fix the wellhead to the ground anchor with wire ropes to ensure high-pressure safety protection; pressurize or depressurize through the pressure gauges and control valves of the lower-layer hydraulic control pipelines and the pressure gauges and control valves of the upper-layer hydraulic control pipelines, open the hydraulic control switch of the target layer to connect the target oil layer; inject carbon dioxide through the 2 injection equipment and monitoring system, and conduct process monitoring to control the injection pressure within the rated pressure, and real-time monitor the downhole temperature and pressure data through the fiber optic monitoring equipment; Adjust the carbon dioxide injection rate appropriately according to the real-time monitoring data, so as to adjust the temperature and pressure of the pay zone and improve the huff and puff effect; S4. Oil production stage: After the carbon dioxide injection is completed, soak the well. Pressurize or depressurize through the pressure gauge and control valve of the lower layer hydraulic control pipeline and the pressure gauge and control valve of the upper layer hydraulic control pipeline, close the injection layer, and open the production layer; Lower a rod pump for production. While soaking the injection layer, alternately produce another layer. Use an optical fiber monitoring device to test the data of the production layer, and remotely monitor the pay zone parameters through a data wireless transmission system; S5. Anti-CO 2 The packer is released and the tubing string is retrieved.

17. The usage method of a CO 2 huff and puff injection-production system It is characterized in that Anti-CO 2 When the packer is set, the setting shear pin is cut by applying pressure at the wellhead. The upper piston moves upward, driving the cylinder sleeve upward, causing the rubber barrel to expand and complete the sealing. At the same time, the buttress threads between the cylinder sleeve and the lower retaining ring are locked. After the upper piston moves upward, the piston lock block disengages from the piston groove, and the lower piston moves downward under pressure, pushing the upper cone downward, causing the slips to pop out. At the same time, the buttress threads between the upper cone and the outer central tube are locked. Anti-CO 2 When the packer is released and the pipe string is pulled out, lift the pipe string to cut the release shear pin. The second upper joint and the inner central pipe move upward, allowing the release locking block to enter the locking groove. The second lower joint moves downward and hangs on the locking ring through the claw. At this time, the space above the setting mechanism is vacated, and the space below the anchoring mechanism is vacated. Under the action of the elastic force of the rubber cylinder and the elastic force of the slips, the setting is released and the anchoring is released, and the pipe string is pulled out.

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