Pipe column and method for water-polymer layered simultaneous injection of chemical flooding well
By designing a chemical well-driving column with a layered structure, using the combination of multiple packers and water distributors/polymerizers, the simultaneous stratification of water injection and polymerization is achieved, which solves the problem of water injection and polymerization in the prior art, and improves the development efficiency of oil and gas fields and the utilization level of oil layer.
Patent Information
- Application Number
- CN202311667345.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-06
- Publication Date
- 2025-06-06
AI Technical Summary
The prior art cannot achieve water injection and accumulation in the same pipe column at the same time, which limits the development efficiency of oil and gas fields and the utilization degree of oil layers.
A pipe column with chemically driven well water accumulation and layered injection is designed, including an outer pipe column and an inner pipe column. The outer pipe column is divided into multiple parts through multiple packers. The water dispenser and the injection container are respectively arranged in the upper and lower pipe columns. The inner pipe column is connected to the lower pipe column to realize the layering of water injection and injection.
Without changing the column structure, water injection and replenishment are carried out simultaneously, which simplifies operations, improves well driving efficiency, and greatly improves the utilization rate and production increase effect of chemically driving old wells.
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Figure CN120100330A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of chemical flooding injection in oil and gas field development, and in particular to a pipe string for chemical flooding well water aggregation and stratification injection, and also to a chemical flooding well water aggregation and stratification injection method. Background Art
[0002] As the global demand for oil increases year by year, the original secondary oil recovery technology is no longer sufficient to meet the needs of the times. Tertiary oil recovery technology has emerged. It uses the combined effects of physical and chemical reactions to achieve the purpose of improving oil recovery and displacement efficiency. Polymer flooding technology is one of the tertiary oil recovery technologies. It introduces some soluble polymers into water, reduces its permeability on the basis of increasing the viscosity of the water phase, thereby optimizing the oil-water mobility ratio to expand the sweep coefficient, thereby achieving the purpose of increasing oil recovery.
[0003] In the process of polymer flooding development, after a cycle of polymer flooding, the oil layer will gradually enter the water recovery stage or the subsequent water flooding stage. In order to further tap the potential and improve efficiency, most polymer flooding wells will implement back-layer replacement measures at this stage. In the process of implementing back-layer replacement measures, in view of the relatively simple development of the reservoir strata, general water injection is often used in the upper back-layer, and general water flooding development or blank water flooding before polymer flooding is carried out on the upper back-layer, while the lower polymer flooding layer continues to be exploited by general polymer injection to further exploit the remaining oil in the reservoir. For this upper back-layer replacement method, the mature concentric double-tube injection technology is used to meet the on-site needs, and the lower layer is generally injected with polymer through the inner pipe, and the upper layer is generally injected with water through the annulus of the inner pipe and the outer pipe.
[0004] There is currently no method that can be applied to the development of chemical flooding wells with a large number of reservoir layers and wells that require both stratified water injection and stratified polymer injection. This makes it impossible to effectively develop such wells, limits the utilization of the oil layer, and seriously affects the stable production of oil and gas. Summary of the invention
[0005] A technical problem to be solved by the present disclosure is that water injection and polymer injection cannot be carried out simultaneously on the same pipe string.
[0006] In order to solve the above technical problems, an embodiment of the present disclosure provides a tubing string for water-polymer injection in chemical drive wells, which includes an outer tubing string and an inner tubing string, the outer tubing string includes an upper tubing string and a lower tubing string with an inner diameter smaller than that of the upper tubing string, the inner tubing string can be inserted into the upper tubing string to be connected with the lower tubing string, a plurality of packers are arranged on the outer tubing string to divide the outer tubing string into a plurality of parts corresponding to the water injection layer and the polymer injection layer, the upper tubing string is provided with a water distributor, and the lower tubing string is provided with a polymer injector.
[0007] In some embodiments, the water distributor is a wave code intelligent water distributor, and the water distributor is configured to open the water distributor by transmitting a pressure wave code signal to the annulus between the upper tubing string and the inner tubing string.
[0008] In some embodiments, an annular seal is disposed at the lower portion of the upper tubular string, the lower end of the inner tubular string can be inserted into the seal, and the seal forms a seal between the inner tubular string and the upper tubular string.
[0009] In some embodiments, the upper end of the seal is provided with a tapered inner circumferential surface.
[0010] In some embodiments, the inner diameters of the inner tubular string and the lower tubular string are the same.
[0011] In some embodiments, the upper tubular string is provided with an upper packer, and the lower tubular string is provided with a lower packer, and the diameter of the lower packer is smaller than the diameter of the upper packer.
[0012] In some embodiments, the lower tubing string is provided with a lower packer located on its upper part, and the upper tubing string is provided with an upper packer located on its upper part, wherein the tubing string for chemical drive well water-polymer injection can be configured as follows: the lower packer is located between the water injection layer and the polymer injection layer, and the upper packer is located on the upper side of the water injection layer.
[0013] In some embodiments, the water distributor is located at a lower side of the upper packer, and the polymer injector is located at a lower side of the lower packer.
[0014] In some embodiments, the lower tubing string is provided with a plurality of the lower packers which is the same number as the polymer injection layers, and the upper tubing string is provided with a plurality of the upper packers which is the same number as the water injection layers, wherein the tubing string for the chemical drive well water polymer layer injection can be configured as follows: the uppermost upper packer is located on the upper side of the water injection layer, the other upper packers are located between two adjacent water injection layers, the uppermost lower packer is located between the water injection layer and the polymer injection layer, and the other lower packers are located between adjacent polymer injection layers.
[0015] In some embodiments, one water distributor is disposed on the lower side of each upper packer, and one polymer injector is disposed on the lower side of each lower packer.
[0016] In some embodiments, the lower tubing string is provided with a lower packer located on its upper part, and the upper tubing string is provided with a plurality of upper packers which is the same number as the water injection layers, wherein the tubing string for chemical drive well water-polymerization layer injection can be configured as follows: the lower packer is located between the water injection layer and the polymer injection layer, the uppermost upper packer is located on the upper side of the water injection layer, and the other upper packers are located between two adjacent water injection layers.
[0017] In some embodiments, one water distributor is disposed on the lower side of each upper packer, and the polymer injector is located on the lower side of the lower packer.
[0018] In some embodiments, the upper tubing string is provided with an upper packer located on its upper part, and the lower tubing string is provided with a plurality of lower packers which are the same in number as the polymer injection layers, wherein the tubing string for water injection in chemical drive wells can be configured as follows: the uppermost lower packer is located between the water injection layer and the polymer injection layer, and the other lower packers are located between adjacent polymer injection layers.
[0019] In some embodiments, the water distributor is located at the lower side of the upper packer, and one polymer injector is disposed at the lower side of each lower packer.
[0020] In some embodiments, a ball seat, a screen tube and a wire plug are provided at the lower end of the lower pipe string.
[0021] In some embodiments, the upper tubular string includes an oil pipe with an inner diameter of 110-120 mm, and the lower tubular string includes an oil pipe with an inner diameter of 70-80 mm.
[0022] On the other hand, the present invention also provides a method for chemical flooding well water polymerization and stratification co-injection, which comprises:
[0023] An outer tubing string is lowered to a designed depth, wherein a plurality of packers are arranged on the outer tubing string, the outer tubing string comprises an upper tubing string and a lower tubing string having an inner diameter smaller than that of the upper tubing string, the upper tubing string is provided with a water distributor, and the lower tubing string is provided with a polymer injector;
[0024] Sealing a plurality of said packers;
[0025] An inner pipe string is lowered into the upper pipe string so that the inner pipe string is butted and connected with the lower pipe string.
[0026] The water distributor and the polymer injector are respectively started to inject water into the water injection layer and polymer into the polymer injection layer.
[0027] In some embodiments, an annular seal is disposed at the lower portion of the upper tubular string, the lower end of the inner tubular string can be inserted into the seal, and the seal forms a seal between the inner tubular string and the upper tubular string.
[0028] In some embodiments, the plurality of packers divide the annulus between the outer tubing string and the wellbore into a plurality of sections corresponding to each water injection zone and each polymer injection zone to perform stratified water injection and stratified polymer injection.
[0029] In some embodiments, the multiple packers separate the annulus between the outer tubing and the wellbore into a water injection section corresponding to multiple water injection layers for general water injection; and / or, the multiple packers separate the annulus between the outer tubing and the wellbore into a polymer injection section corresponding to multiple polymer injection layers for general polymer injection.
[0030] Through the above technical solution, water injection and polymer injection can be carried out simultaneously without changing the tubing structure, which simplifies the operation, improves the well flooding efficiency, greatly increases the utilization rate of old chemical flooding wells, and improves the chemical flooding production increase effect. BRIEF DESCRIPTION OF THE DRAWINGS
[0031] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0032] Figure 1 This is a schematic diagram of the structure of a pipe string for chemical flooding well water polymerization and stratification co-injection in one implementation mode of the present scheme;
[0033] Figure 2 This is a schematic diagram of the structure of a pipe string for chemical flooding well water polymerization and stratification co-injection in another implementation manner of the present scheme;
[0034] Figure 3 This is a schematic diagram of the structure of a pipe string for chemical flooding well water polymerization and stratification injection in another implementation manner of the present scheme.
[0035] Description of reference numerals:
[0036] 1Outer pipe string 2Inner pipe string
[0037] 3 upper pipe string 4 lower pipe string
[0038] 5 Upper packer 6 Lower packer
[0039] 7 seal 8 reducer
[0040] 9 water distributor 10 injection device DETAILED DESCRIPTION
[0041] The following is a further detailed description of the embodiments of the present disclosure in conjunction with the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to exemplarily illustrate the principles of the present disclosure, but cannot be used to limit the scope of the present disclosure. The present disclosure can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.
[0042] The present disclosure provides these embodiments to make the present disclosure thorough and complete, and to fully express the scope of the present disclosure to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of the parts and steps, the composition of the materials, the numerical expressions and the numerical values set forth in these embodiments should be interpreted as being merely exemplary, and not as limiting.
[0043] It should be noted that, in the description of the present disclosure, unless otherwise specified, the meaning of "multiple" is greater than or equal to two; the terms "upper", "lower", "left", "right", "inner", "outer", etc., indicating the orientation or positional relationship, are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present disclosure. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.
[0044] In addition, the words "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different parts. "Vertical" does not mean vertical in the strict sense, but is within the tolerance range. "Parallel" does not mean parallel in the strict sense, but is within the tolerance range. "Include" or "comprising" and similar words mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of including other elements.
[0045] It should also be noted that in the description of the present disclosure, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present disclosure can be understood according to the specific circumstances. When a specific device is described as being located between a first device and a second device, there may or may not be an intermediate device between the specific device and the first device or the second device.
[0046] All terms used in the present disclosure have the same meanings as those understood by those of ordinary skill in the art to which the present disclosure belongs, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries, for example, should be interpreted as having meanings consistent with their meanings in the context of the relevant technology, and should not be interpreted in an idealized or extremely formal sense, unless explicitly defined as such herein.
[0047] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.
[0048] refer to Figure 1-Figure 3 As shown, the present scheme provides a tubing string for chemical drive well water polymer layered co-injection, wherein the tubing string comprises an outer tubing string 1 and an inner tubing string 2, wherein the outer tubing string 1 comprises an upper tubing string 3 and a lower tubing string 4 having an inner diameter smaller than that of the upper tubing string 3, the inner tubing string 2 can be inserted into the upper tubing string 3 to be docked and connected with the lower tubing string 4, a plurality of packers are arranged on the outer tubing string 1 to divide the outer tubing string 1 into a plurality of parts corresponding to the water injection layer and the polymer injection layer, the upper tubing string 3 is provided with a water distributor 9, and the lower tubing string 4 is provided with a polymer injector 10.
[0049] The tubing string for water stratification and simultaneous injection in chemical flooding wells mainly includes an outer tubing string 1 and an inner tubing string 2.
[0050] The outer tubular string 1 includes multiple sections of tubing and packers, and the outer tubular string 1 is divided into an upper tubular string 3 and a lower tubular string 4. The inner diameter of the upper tubular string 3 is larger than the inner diameter of the lower tubular string 4. Packers are respectively provided on the upper tubular string 3 and the lower tubular string 4 to seal the outer tubular string 1 in the wellbore. In addition, the annulus between the outer tubular string 1 and the wellbore is divided into multiple sections by the packers. By designing the position of the packers, the multiple sections of the annulus can be connected to different formations, that is, connected to different water injection layers and polymer injection layers.
[0051] The inner tubing string 2 can be inserted into the upper tubing string 3, thereby forming an annulus between the two. After the inner tubing string 2 is inserted into the upper tubing string 3, it can be connected with the lower tubing string 4. As a result, the inner tubing string 2 and the lower tubing string 4 together form a fluid channel, and the annulus between the inner tubing string 2 and the upper tubing string 4 forms another fluid channel. These two fluid channels are relatively independent of each other and can be injected with fluids separately.
[0052] In addition, the upper tubing string 3 is provided with a water distributor 9, and the lower tubing string 4 is provided with a polymer injector 10. When polymer is injected into the inner tubing string 2, it can be injected into the corresponding polymer injection layer through the polymer injector 10, and the water injected through the annulus between the inner tubing string 2 and the upper tubing string 3 can be injected into the corresponding water injection layer through the water distributor 9. The water injection operation and the polymer injection operation are relatively independent of each other and will not affect each other, thereby realizing the simultaneous water injection and polymer injection in layers.
[0053] In this scheme, without changing the tubing structure, water injection and polymer injection can be carried out simultaneously in layers, which simplifies the operation, improves the well flooding efficiency, greatly increases the utilization rate of old chemical flooding wells, and improves the chemical flooding production increase effect.
[0054] In some embodiments, the water distributor 9 is a wave code intelligent water distributor, and the water distributor is configured to open the water distributor by transmitting a pressure wave code signal to the annulus between the upper tubing string 3 and the inner tubing string 2. The water distributor 9 can be a wave code intelligent water distributor, and the ground control system transmits a pressure wave code signal to the annulus between the inner tubing string 2 and the upper tubing string 3, so that the water nozzle of the wave code intelligent water distributor is opened, and water injection into the injection layer can be started. Therefore, it is not necessary to physically connect the water distributor 9 to the ground control system, nor is it necessary to lower an opening device for the water distributor into the annulus between the upper tubing string 3 and the inner tubing string 2.
[0055] In some embodiments, the upper pipe string 3 and the lower pipe string 4 are connected via a reducer 8. Figure 1-Figure 3 As shown, the outer diameter of the reducer 8 gradually decreases from top to bottom to form a roughly truncated cone shape, connecting the upper pipe column 3 with a larger inner diameter and the lower pipe column 4 with a smaller inner diameter. In other embodiments, the upper pipe column 3 and the lower pipe column 4 may also be connected by an annular plate, wherein the outer diameter of the annular plate corresponds to the inner diameter of the upper pipe column 3, and the inner diameter of the annular plate corresponds to the outer diameter of the lower pipe column 4.
[0056] In some embodiments, an annular seal 7 is provided at the lower portion of the upper tubular string 3, and the lower end of the inner tubular string 2 can be inserted into the seal 7, and the seal 7 forms a seal between the inner tubular string 2 and the upper tubular string 3. The seal 7 is annular, and its outer circumference is sealed and engaged with the inner circumference of the upper tubular string 3. After the inner tubular string 2 is inserted into the seal 7, the outer circumference of the inner tubular string 2 is sealed and engaged with the inner circumference of the seal 7, and the seal 7 seals the lower end of the inner tubular string 2 and the lower end of the upper tubular string 3 to each other, that is, the lower end of the annulus between the inner tubular string 2 and the upper tubular string 3 is sealed to prevent it from communicating with the lower tubular string 4.
[0057] Further, in some embodiments, a tapered inner circumference is provided at the upper end of the seal 7. The large end of the tapered inner circumference is connected to the outer circumference of the upper end of the seal 7, and the inner diameter of the small end is substantially the same as the outer diameter of the inner pipe string 2. The tapered inner circumference can be used to guide the inner pipe string 2, so that the inner pipe string 2 is more easily inserted into the center hole of the seal 7.
[0058] In some embodiments, the inner diameter of the inner pipe string 2 and the lower pipe string 4 are the same. The inner diameter of the inner pipe string 2 and the lower pipe string 4 are the same, and the two have the same flow area, and can be smoothly docked, ensuring that the fluid can smoothly pass through the docking position, reducing the impact on the fluid. In other embodiments, the inner diameter of the inner pipe string 2 can be smaller than the inner diameter of the lower pipe string 4, in particular, the outer diameter of the inner pipe string 2 is approximately equal to the inner diameter of the lower pipe string 4, so as to allow the inner pipe string 2 to be inserted into the lower pipe string 4, so as to achieve docking and connection between the two.
[0059] In some embodiments, the upper tubular string 3 is provided with an upper packer 5, and the lower tubular string 4 is provided with a lower packer 6, and the diameter of the lower packer 6 is smaller than the diameter of the upper packer 5. Since the inner diameter of the upper tubular string 3 is larger than the inner diameter of the lower tubular string 4, it is necessary to correspondingly provide packers with different inner diameters, that is, the diameter of the upper packer 5 is larger than the diameter of the lower packer 6, and in particular, the diameter of the upper packer 5 is large enough to avoid a bottleneck in the flow area of the annulus between the upper tubular string 3 and the inner tubular string 2 at the upper packer 5.
[0060] In some embodiments, the lower tubular string 4 is provided with a lower packer 6 located at its upper part, and the upper tubular string 3 is provided with an upper packer 5 located at its upper part, wherein the tubular string for chemical flooding well water-polymer layer co-injection can be configured as follows: the lower packer 6 is located between the water injection layer and the polymer injection layer, and the upper packer 5 is located at the upper side of the water injection layer. That is to say, the lower tubular string 4 and the upper tubular string 3 are respectively provided with only one packer, and after being lowered into the wellbore, the annulus between the upper packer 5 and the lower packer 6 corresponds to one or more water injection layers, and the annulus below the lower packer 6 corresponds to one or more polymer injection layers.
[0061] Further, in some embodiments, a water distributor 9 is provided on the lower side of the upper packer 5, and a polymer injector 10 is provided on the lower side of the lower packer 6. The water distributor 9 corresponds to the annulus between the upper packer 5 and the lower packer 6 to inject water into the water injection layer. Only one water distributor 9 may be provided, and there may be multiple water injection layers, that is, one water distributor 9 is used to inject water into multiple water injection layers to achieve general water injection; similarly, the polymer injector 10 corresponds to the annulus on the lower side of the lower packer 6 to inject polymer into the polymer injection layer. Only one polymer injector 10 may be provided, and there may be multiple polymer injection layers, that is, one polymer injector 10 is used to inject polymer into multiple polymer injection layers to achieve general polymer injection. Of course, multiple water distributors 9 or polymer injectors 10 may also be provided.
[0062] In some embodiments, the lower tubing string 4 is provided with a plurality of lower packers 6, which is the same number as the injection layers, and the upper tubing string 3 is provided with a plurality of upper packers 5, which is the same number as the water injection layers, wherein the tubing string for the chemical drive well water injection layer can be set as follows: the uppermost upper packer 5 is located on the upper side of the water injection layer, the other upper packers 5 are located between two adjacent water injection layers, the uppermost lower packer 6 is located between the water injection layer and the injection layer, and the other lower packers 6 are located between adjacent injection layers. That is to say, when there are multiple water injection layers, the multiple water injection layers are separated by the upper packer 5, and there is an upper packer 5 between two adjacent water injection layers; when there are multiple injection layers, the multiple injection layers are separated by the lower packer 6, and there is a lower packer 6 between adjacent injection layers, and the adjacent injection layers and the water injection layer are separated by the lower packer 6.
[0063] Further, in some embodiments, a water distributor 9 is provided at the lower side of each upper packer 5, and a polymer injector 10 is provided at the lower side of each lower packer 6. That is, each water injection layer is correspondingly provided with a water distributor 9, and each polymer injection layer is correspondingly provided with a polymer injector 10, thereby realizing stratified water injection and stratified polymer injection.
[0064] In some embodiments, the lower tubular string 4 is provided with a lower packer 6 located at its upper part, and the upper tubular string 3 is provided with a plurality of upper packers 5 having the same number as the water injection layers, wherein the tubular string for the chemical drive well water polymerization layer injection can be set as follows: the lower packer 6 is located between the water injection layer and the polymer injection layer, the uppermost upper packer 5 is located on the upper side of the water injection layer, and the other upper packers 5 are located between two adjacent water injection layers. The lower packer 6 forms only one annulus at the lower tubular string 4 to correspond to one or more polymer injection layers; the upper packer 5 separates and forms multiple annuli at the upper tubular string 3 to correspond to multiple water injection layers one by one; the adjacent polymer injection layers and water injection layers are separated by the lower packer 6.
[0065] Further, in some embodiments, a water distributor 9 is provided on the lower side of each upper packer 5, and a polymer injector 10 is provided on the lower side of the lower packer 6. That is, a water distributor 9 is provided in each annulus corresponding to the water injection layer to realize stratified water injection; and a polymer injector 10 is provided in the annulus below the lower packer 6 to realize general polymer injection of multiple polymer injection layers. Of course, multiple polymer injectors 10 can also be provided on the lower side of the lower packer 6.
[0066] In some embodiments, the upper tubing string 3 is provided with an upper packer 5 located on the upper part thereof, and the lower tubing string 4 is provided with a plurality of lower packers 6 having the same number as the polymer injection layers, wherein the tubing string for the chemical drive well water polymer layer injection can be configured as follows: the uppermost lower packer 6 is located between the water injection layer and the polymer injection layer, and the other lower packers 6 are located between adjacent polymer injection layers. An annulus is formed between the upper packer 5 and the uppermost lower packer 6 to correspond to multiple water injection layers; and multiple lower packers 6 are separated to form multiple annuli to correspond to multiple polymer injection layers one by one. Adjacent water injection layers and polymer injection layers are separated by the uppermost lower packer 6.
[0067] Furthermore, in some embodiments, a water distributor 9 is provided at the lower side of the upper packer 5, and an injector 10 is provided at the lower side of each lower packer 6. That is, water is injected into multiple water injection layers through one water distributor 9 to achieve general water injection; and each water injection layer is injected with water through a corresponding injector 10 to achieve layered injection. Of course, in other embodiments, multiple water distributors 9 can also be used to inject water into multiple water injection layers.
[0068] In some embodiments, a ball-dropping seat, a screen tube, and a plug are provided at the lower end of the lower tubular column 4. The ball-dropping seat, the screen tube, and the plug are sequentially connected from top to bottom, and the plug can block the lower end of the screen tube. After a ball is dropped into the ball-dropping seat, the lower end of the lower tubular column 4 can be blocked, so as to allow pressure to be applied to the outer tubular column 1, thereby achieving the sealing of each packer.
[0069] In some embodiments, the upper tubular string 3 includes an oil pipe with an inner diameter of 110-120 mm, and the lower tubular string 4 includes an oil pipe with an inner diameter of 70-80 mm.
[0070] On the other hand, the present invention also provides a method for chemical flooding well water polymerization and stratification co-injection, which comprises:
[0071] An outer tubular string 1 is lowered to a designed depth, wherein the outer tubular string 1 is provided with a plurality of packers, wherein the outer tubular string 1 comprises an upper tubular string 3 and a lower tubular string 4 having an inner diameter smaller than that of the upper tubular string 3, wherein the upper tubular string 3 is provided with a water distributor 9, and the lower tubular string 4 is provided with a polymer injector 10;
[0072] Sealing a plurality of said packers;
[0073] The inner pipe string 2 is lowered into the upper pipe string 3 so that the inner pipe string 2 is connected to the lower pipe string 4.
[0074] The water distributor 9 and the polymer injector 10 are respectively started to inject water into the water injection layer and polymer into the polymer injection layer.
[0075] The outer pipe string 1 is lowered to the designed depth as required, so that the packer can separate the various water injection layers and polymer injection layers, and the water distributor 9 and polymer injection device 10 are located at the corresponding water injection layers and polymer injection layers.
[0076] The sealing of the packer can be achieved by pressure. For example, as mentioned above, the lower end of the outer pipe string 1 is provided with a ball-dropping seat, a screen tube and a wire plug, and after the ball is dropped, pressure can be applied to achieve sealing.
[0077] After the sealing is completed, the inner tubular string 2 is lowered into the upper tubular string 3 so that the inner tubular string 2 is docked with the lower tubular string 4 to form a fluid channel for polymer injection, and a water injection channel is formed between the inner tubular string 2 and the upper tubular string 3.
[0078] The polymer injector 10 may be a concentrically adjustable polymer injector. A downhole measuring and adjusting instrument is lowered into the inner layer pipe string 2 and connected to the concentrically adjustable polymer injector, so that the water nozzle of the concentrically adjustable polymer injector is opened, and polymer can be injected into the polymer injection layer.
[0079] In some embodiments, an annular seal 7 is provided at the lower portion of the upper tubular string 3, and the lower end of the inner tubular string 2 can be inserted into the seal 7, and the seal 7 forms a seal between the inner tubular string 2 and the upper tubular string 3. When the inner tubular string 2 is lowered into the upper tubular string 3, its lower end is inserted into the seal 7 to form a seal between the inner tubular string 2 and the upper tubular string 3, thereby preventing the inner and outer parts of the inner tubular string 2 from being connected.
[0080] In some embodiments, the plurality of packers divide the annulus between the outer tubing string 1 and the wellbore into multiple sections corresponding to each water injection layer and each polymer injection layer to perform stratified water injection and stratified polymer injection. As described above, the upper tubing string 3 may be provided with a plurality of upper packers 5 equal to the number of water injection layers to form a plurality of annuli corresponding to the plurality of water injection layers, and the lower tubing string 4 may be provided with a plurality of lower packers 6 equal to the number of polymer injection layers to form a plurality of annuli corresponding to the plurality of polymer injection layers, thereby achieving stratified water injection and stratified polymer injection.
[0081] In other embodiments, the plurality of packers separate the annulus between the outer tubular string 1 and the wellbore into a water injection section corresponding to a plurality of water injection layers for general water injection; and / or, the plurality of packers separate the annulus between the outer tubular string 1 and the wellbore into a polymer injection section corresponding to a plurality of polymer injection layers for general polymer injection. As described above, the upper tubular string 3 may be provided with only one upper packer 5, and only one annulus corresponding to a plurality of water injection layers is formed at the upper tubular string 3 to achieve general water injection; similarly, the lower tubular string 4 may be provided with only one lower packer 6, and only one annulus corresponding to a plurality of polymer injection layers is formed at the lower tubular string 4 to achieve general polymer injection.
[0082] The method of chemical flooding well water and polymer layered simultaneous injection in this scheme effectively solves the problem that the concentric double-tube injection technology can only meet the requirements of simultaneous upper formation general water injection and lower formation general polymer injection. Without moving the tubing, the upper layer water injection and lower layer polymer injection can be realized, which can meet the requirements of simultaneous layered water drive and layered polymer drive; it subverts the traditional process that a well cannot adopt multiple development methods at the same time, and realizes the combination of water drive and polymer drive in the same well while saving the construction and production costs of a well, improving the utilization rate of old wells and saving nearly 10 million yuan in construction and production costs; while the lower layer\general polymer is not stopped, the layered\general blank water drive before the upper polymer drive is completed at the same time, realizing water / polymer layered\general simultaneous injection, greatly shortening the return layer replacement time.
[0083] So far, various embodiments of the present disclosure have been described in detail. In order to avoid obscuring the concept of the present disclosure, some details known in the art are not described. Based on the above description, those skilled in the art can fully understand how to implement the technical solution disclosed here.
[0084] Although some specific embodiments of the present disclosure have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present disclosure. It should be understood by those skilled in the art that the above embodiments may be modified or some technical features may be replaced by equivalents without departing from the scope and spirit of the present disclosure. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there is no structural conflict.
Claims
1. A pipe string for chemical flooding well water polymerization and stratification injection, It is characterized in that The invention comprises an outer tubular string (1) and an inner tubular string (2), wherein the outer tubular string (1) comprises an upper tubular string (3) and a lower tubular string (4) having an inner diameter smaller than that of the upper tubular string (3), the inner tubular string (2) can be inserted into the upper tubular string (3) to be connected to the lower tubular string (4), a plurality of packers are arranged on the outer tubular string (1) to divide the outer tubular string (1) into a plurality of parts corresponding to water injection layers and polymer injection layers, the upper tubular string (3) is provided with a water distributor (9), and the lower tubular string (4) is provided with a polymer injector (10).
2. The pipe string for chemical flooding well water polymerization and simultaneous injection according to claim 1, It is characterized in that The water distributor (9) is a wave code intelligent water distributor, and the water distributor is configured to open the water distributor by transmitting a pressure wave code signal to the annulus between the upper tubing string (3) and the inner tubing string (2).
3. The pipe string for chemical flooding well water polymerization and stratification injection according to claim 1, It is characterized in that An annular sealing member (7) is provided at the lower part of the upper tubular column (3), and the lower end of the inner tubular column (2) can be inserted into the sealing member (7). The sealing member (7) forms a seal between the inner tubular column (2) and the upper tubular column (3).
4. The pipe string for chemical flooding well water polymerization and stratification injection according to claim 3, It is characterized in that The upper end of the sealing member (7) is provided with a tapered inner circumferential surface.
5. The pipe string for chemical flooding well water polymerization and simultaneous injection according to claim 1, It is characterized in that The inner diameters of the inner tube column (2) and the lower tube column (4) are the same.
6. The pipe string for chemical flooding well water polymerization and stratification injection according to claim 1, It is characterized in that The upper tubular column (3) is provided with an upper packer (5), and the lower tubular column (4) is provided with a lower packer (6), and the diameter of the lower packer (6) is smaller than the diameter of the upper packer (5).
7. The pipe string for chemical flooding well water polymerization and stratification injection according to claim 6, It is characterized in that The lower tubing string (4) is provided with a lower packer (6) located at its upper part, and the upper tubing string (3) is provided with an upper packer (5) located at its upper part, wherein the tubing string for chemical drive well water polymer layer co-injection can be configured as follows: the lower packer (6) is located between the water injection layer and the polymer injection layer, and the upper packer (5) is located on the upper side of the water injection layer.
8. The pipe string for chemical flooding well water polymerization and stratification injection according to claim 7, It is characterized in that The water distributor (9) is located at the lower side of the upper packer (5), and the polymer injector (10) is located at the lower side of the lower packer (6).
9. The pipe string for chemical flooding well water polymerization and stratification injection according to claim 6, It is characterized in that The lower tubing string (4) is provided with a plurality of the lower packers (6) whose number is the same as the number of the polymer injection layers, and the upper tubing string (3) is provided with a plurality of the upper packers (5) whose number is the same as the number of the water injection layers, wherein the tubing string for the chemical drive well water polymer injection layer can be arranged as follows: the uppermost upper packer (5) is located on the upper side of the water injection layer, the other upper packers (5) are located between two adjacent water injection layers, the uppermost lower packer (6) is located between the water injection layer and the polymer injection layer, and the other lower packers (6) are located between adjacent polymer injection layers.
10. The pipe string for chemical flooding well water polymerization and simultaneous injection according to claim 9, It is characterized in that A water distributor (9) is disposed on the lower side of each upper packer (5), and a polymer injector (10) is disposed on the lower side of each lower packer (6).
11. The pipe string for chemical flooding well water polymerization and stratification injection according to claim 6, It is characterized in that The lower tubing string (4) is provided with a lower packer (6) located at the upper part thereof, and the upper tubing string (3) is provided with a plurality of upper packers (5) which are the same in number as the water injection layers, wherein the tubing string for water-polymer injection in chemical drive wells can be configured as follows: the lower packer (6) is located between the water injection layer and the polymer injection layer, the uppermost upper packer (5) is located on the upper side of the water injection layer, and the other upper packers (5) are located between two adjacent water injection layers.
12. The pipe string for chemical flooding well water polymerization and simultaneous injection according to claim 11, It is characterized in that A water distributor (9) is provided on the lower side of each upper packer (5), and the polymer injector (10) is located on the lower side of the lower packer (6).
13. The pipe string for chemical flooding well water polymerization and simultaneous injection according to claim 6, It is characterized in that The upper tubing string (3) is provided with an upper packer (5) located at the upper part thereof, and the lower tubing string (4) is provided with a plurality of lower packers (6) which are the same in number as the polymer injection layers, wherein the tubing string for water-polymer injection in chemical drive wells can be arranged such that the uppermost lower packer (6) is located between the water injection layer and the polymer injection layer, and the other lower packers (6) are located between adjacent polymer injection layers.
14. The pipe string for chemical flooding well water polymerization and simultaneous injection according to claim 13, It is characterized in that The water distributor (9) is located at the lower side of the upper packer (5), and one of the polymer injectors (10) is provided at the lower side of each of the lower packers (6).
15. The pipe string for chemical flooding well water polymerization and simultaneous injection according to claim 1, It is characterized in that The lower end of the lower pipe column (4) is provided with a ball pitching seat, a screen pipe and a thread plug.
16. The pipe string for chemical flooding well water polymerization and simultaneous injection according to claim 1, It is characterized in that The upper tubular column (3) comprises an oil pipe with an inner diameter of 110-120 mm, and the lower tubular column (4) comprises an oil pipe with an inner diameter of 70-80 mm.
17. A method for chemical flooding well water polymerization and stratification injection, It is characterized in that include: An outer tubular column (1) is lowered to a designed depth, wherein a plurality of packers are arranged on the outer tubular column (1), wherein the outer tubular column (1) comprises an upper tubular column (3) and a lower tubular column (4) having an inner diameter smaller than that of the upper tubular column (3), wherein the upper tubular column (3) is provided with a water distributor (9), and the lower tubular column (4) is provided with a polymer injector (10); Sealing a plurality of said packers; An inner pipe string (2) is lowered into the upper pipe string (3) so that the inner pipe string (2) is butted and connected with the lower pipe string (4). The water distributor (9) and the polymer injector (10) are respectively started to inject water into the water injection layer and polymer into the polymer injection layer.
18. The method for simultaneous injection of chemical flooding well water in layers according to claim 17, It is characterized in that An annular sealing member (7) is provided at the lower part of the upper tubular column (3), and the lower end of the inner tubular column (2) can be inserted into the sealing member (7). The sealing member (7) forms a seal between the inner tubular column (2) and the upper tubular column (3).
19. The method for simultaneous injection of chemical flooding well water in layers according to claim 17, It is characterized in that The plurality of packers divide the annulus between the outer tubing string (1) and the wellbore into a plurality of sections corresponding to each water injection layer and each polymer injection layer, so as to perform stratified water injection and stratified polymer injection.
20. The method for chemical flooding well water polymerization and stratification co-injection according to claim 17, It is characterized in that The plurality of said packers separate the annulus between the outer tubing string (1) and the wellbore into a water injection section corresponding to the plurality of water injection layers for general water injection; and / or, the plurality of said packers separate the annulus between the outer tubing string (1) and the wellbore into a polymer injection section corresponding to the plurality of polymer injection layers for general polymer injection.