Method for evaluating fluid sensitivity of tight sandstone reservoirs and related equipment

Abstract

The application discloses a kind of fluid sensitivity evaluation method and related equipment of compact sandstone reservoir, it is related to oil and gas development field, mainly to solve the problem of not enough comprehensive for the factor considered in the evaluation method of compact sandstone reservoir to fluid sensitivity, evaluation result is not accurate enough.The method comprises: determining target sample, wherein the target sample is artificial sanding fracture core, natural fracture core and base block core after series connection;Determine the recovery before fluid invasion and the recovery after fluid invasion of target sample;Determine fluid sensitivity degree based on the recovery before fluid invasion and the recovery after fluid invasion.The application is used in the fluid sensitivity evaluation process of compact sandstone reservoir.

Description

Technical Field

[0001] This invention relates to the field of oil and gas development, and more particularly to a method and related equipment for evaluating the fluid sensitivity of tight sandstone reservoirs. Background Technology

[0002] During gas reservoir exploration and development, foreign sensitive fluids introduced during drilling, completion, and other operations have varying degrees of salinity and pH. Upon contact with reservoir rocks, these fluids can easily induce reservoir damage, reduce reservoir permeability, and lead to a decline in reservoir recovery. Currently, most assessments of damage to tight sandstone gas reservoirs are based on the industry standard SY / T 5358-2010, "Evaluation Methods for Reservoir Sensitivity Flow Tests," which specifies the basic methods for water-sensitive, salt-sensitive, acid-sensitive, and alkali-sensitive tests. This method simulates the invasion of foreign fluids into the formation, using the permeability damage rate before and after fluid invasion as the evaluation index. However, it still does not consider in-situ temperature, overlying formation pressure, and the gas's occurrence state under in-situ conditions. Furthermore, it cannot simulate the depletion-type exploitation process of tight sandstone gas reservoirs, cannot establish a reliable relationship with reservoir recovery, and cannot obtain more accurate evaluation results. Summary of the Invention

[0003] In view of the above problems, the present invention provides a method and related equipment for evaluating the fluid sensitivity of tight sandstone reservoirs. The main purpose is to solve the problem that the current evaluation methods for the fluid sensitivity of tight sandstone reservoirs do not consider all factors and the evaluation results are not accurate enough.

[0004] To address at least one of the aforementioned technical problems, in a first aspect, the present invention provides a method for evaluating the fluid sensitivity of tight sandstone reservoirs, the method comprising:

[0005] The target samples were identified, which included artificially sand-filled fracture cores, natural fracture cores, and basement cores arranged in series.

[0006] Determine the pre-intrusion and post-intrusion recovery rates of the target sample;

[0007] Fluid sensitivity is determined based on the pre-intrusion and post-intrusion recovery rates described above. Optionally, determining the pre-intrusion and post-intrusion recovery rates of the target sample includes:

[0008] Determine the methane content of the target sample in a first state, wherein the first state is a state in which the target sample is fully saturated with methane;

[0009] Determine the methane content of the target sample in the second state, wherein the second state is the state of the target sample after depletion mining;

[0010] Based on the methane content of the target sample in the first state and the methane content of the target sample in the second state, the pre-intrusion recovery rate of the target sample is determined.

[0011] Optionally, the above-mentioned pre-intrusion recovery rate of the target sample based on the methane content of the target sample in the first state and the methane content of the target sample in the second state includes:

[0012] The pre-intrusion recovery rate R of the above target sample is determined based on the following formula. f :

[0013]

[0014] In the above formula, Q... f1 The methane content of the target sample in the first state is given by Q. f2 The methane content of the target sample in the second state is given.

[0015] Optionally, the determination of the pre-intrusion recovery rate and post-intrusion recovery rate of the target sample includes:

[0016] The sensitive liquid is pumped into the target sample in reverse and continued for a preset time.

[0017] Based on the backflow pressure differential value, methane is used to positively displace the aforementioned sensitive liquid in the target sample;

[0018] With all the sensitive liquid in the target sample removed, the target sample is fully saturated with methane, wherein the state in which the target sample is fully saturated with methane is the third state.

[0019] Determine the methane content of the target sample in the fourth state, wherein the fourth state is the state after depletion mining in the third state.

[0020] The recovery rate of the target sample after fluid intrusion is determined based on the methane content of the target sample in the third state and the methane content of the target sample in the fourth state.

[0021] Optionally, determining the post-intrusion recovery rate of the target sample based on the methane content of the target sample in the third state and the methane content of the target sample in the fourth state includes:

[0022] The post-intrusion recovery rate R of the target sample is determined based on the following formula. E :

[0023]

[0024] In the above formula, Q... E1The methane content of the target sample in the third state is given by Q. E2 The methane content of the target sample in the fourth state is given.

[0025] Optionally, the above methods also include:

[0026] The above-mentioned backflow pressure difference value P is determined based on the following formula. b :

[0027] P b =(P p -P f )×l / L+P r

[0028] In the above formula, P... p For reservoir pore pressure, the above P f The bottom-hole flowing pressure of the reservoir is given by P, where l is the length of the target sample, L is the width of the pressure drop funnel formed after the tight sandstone reservoir is opened, and P is the bottom-hole flowing pressure of the reservoir. r This is back pressure.

[0029] Optionally, the determination of fluid sensitivity based on the pre-invasion recovery rate and the post-invasion recovery rate includes:

[0030] The fluid sensitivity level I is determined based on the following formula:

[0031]

[0032] In the above formula, R... f For the aforementioned pre-intrusion recovery rate of fluid, the aforementioned R E The recovery rate after the aforementioned fluid intrusion.

[0033] Secondly, embodiments of the present invention also provide a fluid sensitivity evaluation device for tight sandstone reservoirs, comprising:

[0034] The first determining unit is used to prepare the target sample, wherein the target sample is a series of artificially sand-filled fracture core, natural fracture core and base block core;

[0035] The second determining unit is used to determine the pre-intrusion recovery rate and post-intrusion recovery rate of the target sample.

[0036] The third determining unit is used to determine the fluid sensitivity based on the aforementioned pre-invasion recovery rate and post-invasion recovery rate.

[0037] To achieve the above objectives, according to a third aspect of the present invention, a computer-readable storage medium is provided, the computer-readable storage medium comprising a stored program, wherein, when the program is executed by a processor, the steps of the above-described method for evaluating the fluid sensitivity of tight sandstone reservoirs are implemented.

[0038] To achieve the above objectives, according to a fourth aspect of the present invention, an electronic device is provided, comprising at least one processor and at least one memory connected to the processor; wherein the processor is configured to invoke program instructions in the memory to execute the steps of the above-described method for evaluating the fluid sensitivity of tight sandstone reservoirs.

[0039] By employing the above technical solution, the fluid sensitivity evaluation method and related equipment for tight sandstone reservoirs provided by this invention address the problem that current evaluation methods for the fluid sensitivity of tight sandstone reservoirs do not consider all factors comprehensively and the evaluation results are not accurate enough. This invention identifies target samples, which are tandem artificially padded fracture cores, natural fracture cores, and matrix cores; determines the pre-intrusion and post-intrusion recovery rates of the target samples; and determines the degree of fluid sensitivity based on the pre-intrusion and post-intrusion recovery rates. In this scheme, the gas occurrence state of the tight sandstone gas reservoir is considered. By evaluating the gas production capacity of the cores before and after fluid damage, the degree of reservoir sensitivity caused by fluid intrusion is evaluated, forming an evaluation method for the fluid sensitivity of tight sandstone under in-situ conditions. This provides a basis for optimizing the protective reservoir-sensitive fluid system and efficiently developing tight sandstone gas reservoirs.

[0040] Correspondingly, the fluid sensitivity evaluation device, equipment, and computer-readable storage medium for tight sandstone reservoirs provided in the embodiments of the present invention also have the above-mentioned technical effects.

[0041] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0042] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0043] Figure 1 A schematic flowchart of a method for evaluating the fluid sensitivity of tight sandstone reservoirs provided in an embodiment of the present invention is shown.

[0044] Figure 2 A schematic diagram of the composition of a fluid sensitivity detection device provided in an embodiment of the present invention is shown;

[0045] Figure 3This diagram illustrates the composition of a fluid sensitivity evaluation device for tight sandstone reservoirs provided in an embodiment of the present invention.

[0046] Figure 4 This diagram illustrates the composition of an electronic device for evaluating the fluid sensitivity of tight sandstone reservoirs, as provided in an embodiment of the present invention. Detailed Implementation

[0047] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0048] To address the shortcomings of current methods for evaluating the fluid sensitivity of tight sandstone reservoirs, which often lack comprehensive consideration of factors and result in inaccurate assessments, this invention provides a method for evaluating the fluid sensitivity of tight sandstone reservoirs. Figure 1 As shown, the method includes:

[0049] S101. Determine the target samples, wherein the target samples are artificially sand-filled fracture cores, natural fracture cores and base block cores connected in series;

[0050] For example, in this embodiment, downhole cores from tight sandstone gas wells are selected and processed into artificially padded fracture cores, natural fracture cores, and matrix cores. These cores are connected in series to form a target sample used to simulate the multi-scale mass transfer pathways in tight sandstone. The target sample is placed in a core holder, and a confining pressure pump and a resistance wire wound around the core holder are used to subject the core to reservoir temperature and overlying formation pressure. A vacuum pump is used to extract gas from the pipeline and core holder for 12 hours, maintaining the experimental system under vacuum conditions. It is understood that the vacuuming time can be adjusted according to specific circumstances. Based on the above operations, the original formation conditions of the core in the reservoir can be reconstructed, including formation temperature, pressure, and the gas occurrence state in the core under reservoir conditions.

[0051] It should be noted that the embodiments of this application classify the permeability based on the level of gas permeability measured under effective reservoir stress and temperature. The classification criteria are as follows: permeability 1mD>K>0.1mD is natural fracture core, and permeability K≤0.1mD is matrix core. The artificial sand-filled fracture core is prepared by creating artificial fractures through the Brazilian splitting method, and the appropriate sand-filling concentration and sand-filling type are selected through on-site sand-filling system. The reservoir temperature and the pressure of the overlying formation can be set based on the on-site closed core data.

[0052] S102. Determine the pre-intrusion and post-intrusion recovery rates of the target sample.

[0053] The steps in S102 above include S1021-S1024:

[0054] S1021. The determination of the pre-intrusion recovery rate and post-intrusion recovery rate of the target sample includes:

[0055] S1022. Determine the methane content of the target sample in the first state, wherein the first state is the state of fully saturated methane in the target sample;

[0056] For example, in this embodiment of the application, methane gas is introduced into the core holder to make the pore pressure in the target sample reach the reservoir pore pressure. After stabilizing for a certain period of time, the target sample is fully saturated with methane. The methane gas content in the core is then analyzed by nuclear magnetic resonance on the core holder, i.e., the methane content Q of the target sample in the first state. f1 .

[0057] It is important to note that the methane gas must be fully heated to the reservoir temperature using a gas heating device before injection. This process allows for the reconstruction of the gas state within the core at the formation temperature.

[0058] S1023. Determine the methane content of the target sample in the second state, wherein the second state is the state of the target sample after depletion mining.

[0059] For example, in this embodiment of the application, back pressure is set at the outlet end of the core holder to obtain the extraction volume through depletion mining within the production time. After mining is completed, the methane content in the core holder is analyzed by nuclear magnetic resonance, that is, the methane content Q of the target sample in the second state. f2 Since the embodiments of this application simulate the depletion-type exploitation process of tight sandstone gas reservoirs, the evaluation of the fluid sensitivity of the reservoir is more accurate.

[0060] It is important to note that the back pressure setting described above simulates the depletion-type extraction process of tight sandstone gas under the pressure difference between reservoir pore pressure and surface pressure. Specifically, it represents the spontaneous production of methane gas from the core under the production pressure difference between the pore pressure and the back pressure. The production pressure difference is the difference between the core pore pressure and the back pressure. By changing the magnitude of the back pressure, the changes in production pressure difference caused by different production nozzle regimes in the field can be simulated. The above production pressure difference is based on the field drainage regime setting, and the above production time is set based on the production curves from the daily field production reports.

[0061] S1024. Based on the methane content of the target sample in the first state and the methane content of the target sample in the second state, the pre-intrusion recovery rate of the target sample.

[0062] The steps in S1024 above include S10241:

[0063] S10241, the fluid intrusion recovery rate of the target sample based on the methane content of the target sample in the first state and the methane content of the target sample in the second state includes:

[0064] The pre-intrusion recovery rate R of the above target sample is determined based on the following formula. f :

[0065]

[0066] In the above formula, Q... f1 The methane content of the target sample in the first state is given by Q. f2 R represents the methane content of the target sample in the second state. f It is a dimensionless quantity.

[0067] The steps in S102 above also include S1025-S1029:

[0068] S1025. Pump the sensitive liquid into the target sample in reverse and continue for a preset time.

[0069] For example, in this embodiment of the application, a vacuum pump is used to evacuate the target sample, and then a sensitive liquid with a mass fraction of 5% Mn2+ is pumped in from the outlet end of the core holder in the opposite direction to damage the target sample core. The damage to the target sample core needs to be sustained for a certain period of time.

[0070] It is important to note that the duration of the damage target sample core is based on the time the injected fluid remains underground. The aforementioned sensitive fluids refer to drilling and fracturing fluids, such as drilling fluid and fracturing fluid, pumped underground during drilling and fracturing. These fluids cause reservoir-sensitive damage upon contact with the reservoir, hence the term "sensitive fluids." Before being pumped into the core, these sensitive fluids must be fully heated to the reservoir temperature using a fluid heating device. This process allows for the reconstruction of the gas state within the core at formation temperature.

[0071] S1026. Based on the backflow pressure difference value, use methane to positively displace the aforementioned sensitive liquid in the target sample.

[0072] For example, by setting a certain backflow pressure differential, methane is used for forward displacement to backflow sensitive fluids. Because this embodiment simulates the actual operation process of backflowing sensitive fluids after intrusion in a tight sandstone gas reservoir during depletion-type extraction, the evaluation of the reservoir's fluid sensitivity is more accurate.

[0073] The steps in S1026 above include S10261:

[0074] S10261. Determine the above-mentioned backflow pressure difference value P based on the following formula. b MPa:

[0075] P b =(P p -P f )×l / L+P r

[0076] In the above formula, P... p The reservoir pore pressure is given in MPa; the above P f The bottom-hole flowing pressure of the reservoir is MPa; l is the length of the target sample, cm; L is the width of the pressure drop funnel formed after the tight sandstone reservoir is opened, cm; P r The back pressure is measured in MPa.

[0077] S1027. After all the sensitive liquid in the target sample is discharged, the target sample is fully saturated with methane, wherein the state in which the target sample is fully saturated with methane is the third state.

[0078] For example, in this embodiment of the application, after the liquid flow ceases, methane gas is continuously introduced to fully saturate the core with methane for a period of time. Then, the outlet end of the core holder is closed, and nuclear magnetic resonance analysis is used to analyze the methane gas content at this time, i.e., the methane content Q of the target sample in the third state. E1 .

[0079] S1028. Determine the methane content of the target sample in the fourth state, wherein the fourth state is the state after depletion mining in the third state.

[0080] For example, a certain back pressure is maintained at the outlet of the core holder, and depletion mining is carried out over a certain period of time. After gas extraction is completed, the methane content Q in the core holder is analyzed by nuclear magnetic resonance. E2 .

[0081] S1029. Determine the post-intrusion recovery rate of the target sample based on the methane content of the target sample in the third state and the methane content of the target sample in the fourth state.

[0082] The steps in S1029 above include S10291:

[0083] S10291. Determine the post-intrusion recovery rate R of the above target sample based on the following formula. E :

[0084]

[0085] In the above formula, Q...E1 The methane content of the target sample in the third state is given by Q. E2 R represents the methane content of the target sample in the fourth state. E It is a dimensionless quantity.

[0086] S103. Determine the fluid sensitivity based on the recovery rate before fluid invasion and the recovery rate after fluid invasion.

[0087] The above-mentioned step S103 also includes S1031:

[0088] S1031. The determination of fluid sensitivity based on the pre-invasion recovery rate and the post-invasion recovery rate includes:

[0089] The fluid sensitivity level I is determined based on the following formula:

[0090]

[0091] In the above formula, R... f For the aforementioned pre-intrusion recovery rate of fluid, the aforementioned R E I represents the recovery rate after the aforementioned fluid intrusion, where I is a dimensionless quantity.

[0092] For example, since this application does not use permeability as the evaluation standard, but uses the gas recovery rate before and after the invasion of sensitive liquids as the evaluation index to evaluate the reservoir's sensitivity to fluids, it is more in line with the actual situation in the mine than the current standard which uses permeability before and after damage as the evaluation index, and it closely links the laboratory experiment on the fluid sensitivity of tight sandstone gas reservoirs with the well site productivity evaluation.

[0093] For example, the following illustrates a reservoir fluid sensitivity evaluation standard provided by an embodiment of this application:

[0094] When I ≤ 5%, the reservoir fluid sensitivity is zero;

[0095] When 5% < I ≤ 30%, the reservoir fluid sensitivity is weak;

[0096] When 30% < I ≤ 50%, the reservoir fluid sensitivity is moderate to weak.

[0097] When 50% < I ≤ 70%, the reservoir fluid sensitivity is moderately strong.

[0098] When 70% < I ≤ 90%, the reservoir fluid sensitivity is strong;

[0099] When I > 90%, the reservoir fluid sensitivity is extremely high.

[0100] In summary, this application's embodiments first screen and prepare core samples from base blocks, natural fractures, and artificial fractures. These core samples are then saturated with methane gas, and an external fluid is used to reverse-invade and damage the core. By evaluating the gas production capacity of the core before and after fluid damage, the degree of reservoir sensitivity induced by fluid intrusion is obtained. Because this application's embodiments consider in-situ temperature, overlying formation pressure, and the gas's occurrence state under in-situ conditions, it simulates the depletion-type exploitation process of tight sandstone gas reservoirs and establishes a good relationship with reservoir recovery. Therefore, the resulting method for evaluating the fluid sensitivity of tight sandstone under in-situ conditions can provide a basis for the optimal selection of sensitive fluids in tight sandstone, ensuring the efficient development of tight sandstone gas reservoirs.

[0101] By employing the above technical solution, the fluid sensitivity evaluation method for tight sandstone reservoirs provided by this invention addresses the problem that current evaluation methods for the fluid sensitivity of tight sandstone reservoirs do not consider all factors comprehensively and the evaluation results are not accurate enough. This invention identifies target samples, which are tandem artificially padded fracture cores, natural fracture cores, and matrix cores; determines the pre-intrusion and post-intrusion recovery rates of the target samples; and determines the degree of fluid sensitivity based on the pre-intrusion and post-intrusion recovery rates. In this scheme, the gas occurrence state of the tight sandstone gas reservoir is considered. By evaluating the gas production capacity of the cores before and after fluid damage, the degree of reservoir sensitivity induced by fluid intrusion is evaluated, forming an evaluation method for the fluid sensitivity of tight sandstone under in-situ conditions. This provides a basis for optimizing the reservoir-sensitive fluid system for protecting tight sandstone gas reservoirs and for the efficient development of the reservoir.

[0102] Furthermore, Figure 2 The diagram shows the composition of a fluid sensitivity detection device provided in an embodiment of the present invention: 1 is a methane cylinder; 2 and 12 are heating devices; 3 and 11 are temperature sensors; 4, 7, 10, and 16 are valves; 5 is a core holder; 6 and 15 are pressure sensors; 8 is a back pressure valve; 9 is a measuring cylinder; 13 is a sensitive liquid container; 14 is a vacuum pump; 17 is a confining pressure pump; and 18 is a nuclear magnetic resonance system.

[0103] For example, the following illustrates one scenario implemented by an embodiment of this application:

[0104] S1. First, select downhole core samples from a tight sandstone gas well in a certain block. Screen and process them into one each of artificially fractured, naturally fractured, and basement core samples, each approximately 3-5 cm long and 2.5 cm wide. Dry the three core samples at 60℃ for 24 hours, then connect them in series in a core holder 5 to form the target sample, used to simulate the multi-scale mass transfer pathway in tight sandstone. Use a confining pressure pump 17 and a resistance wire wound on the core holder to bring the core samples to a reservoir temperature of 50℃ and an overlying formation pressure of 60 MPa. Use a vacuum pump to extract gas from the pipeline and core holder for 12 hours to maintain the experimental system under vacuum conditions.

[0105] S2. Open valve 4 and close valves 7 and 10. Use methane cylinder 1 to introduce methane gas into the core holder 5 until the pore pressure reaches the reservoir pore pressure of 35 MPa. Stabilize for a certain period of time to allow the target sample to be fully saturated with methane. Use a nuclear magnetic resonance system 18 to analyze the methane gas content Q in the core holder. f1 (i.e., the methane content of the target sample in the first state);

[0106] S3. At the outlet end of the core holder, the back pressure is set to 5 MPa through the back pressure valve 8, and the extraction volume is obtained through depletion mining within 24 hours. After mining is completed, the methane content Q in the core holder is analyzed by the nuclear magnetic resonance system 18. f2 (i.e., the methane content of the target sample in the second state), the recovery rate is calculated using the following formula:

[0107]

[0108] In the above formula, Q... f1 The methane content of the target sample in the first state is given by Q. f2 R represents the methane content of the target sample in the second state. f It is a dimensionless quantity.

[0109] S4. Use vacuum pump 14 to evacuate the experimental system, then close valves 4 and 7, open valve 10, and pump in 5% Mn by mass into the sensitive liquid container 13. 2+ The sensitive liquid was injected into the damaged rock core after passing through the heating device 12, and the damage lasted for 12 hours.

[0110] S5. Open valves 4 and 7, and close valve 10. Set the backflow pressure differential to 3.5 MPa, use the methane forward backflow sensitive fluid, collect the liquid using graduated cylinder 9, and displace until no liquid flows out. Continue to introduce methane gas until saturation is achieved, then close the core holder outlet and analyze the methane gas content Q at this time using nuclear magnetic resonance. E1 (i.e., the methane content of the target sample in the third state);

[0111] S6. Repeat steps S3. After mining is completed, analyze the methane content Q in the core holder using a nuclear magnetic resonance system. E2 (i.e., the methane content of the target sample in the fourth state), the recovery rate after fluid intrusion and flowback is calculated using the following formula:

[0112]

[0113] In the above formula, Q... E1 The methane content of the target sample in the third state is given by Q. E2 R represents the methane content of the target sample in the fourth state. E It is a dimensionless quantity.

[0114] S7. The sensitivity of the reservoir to external fluids is evaluated using the methane recovery rate before and after damage as the evaluation standard. The sensitivity of the reservoir to external fluids is evaluated using the following formula:

[0115]

[0116] In the above formula, R... f For the aforementioned pre-intrusion recovery rate of fluid, the aforementioned R E I represents the recovery rate after the aforementioned fluid intrusion, where I is a dimensionless quantity.

[0117] The final experimental results show that the sensitivity of the reservoir to external fluid contact is 64%, which is moderate to strong.

[0118] Furthermore, as a response to the above Figure 1 In addition to the method shown, this embodiment of the invention also provides another fluid sensitivity evaluation device for tight sandstone reservoirs, used for evaluating the above-mentioned... Figure 1 The method shown is implemented accordingly. This device embodiment corresponds to the foregoing method embodiment. For ease of reading, this device embodiment will not repeat the details of the foregoing method embodiment, but it should be clear that the device in this embodiment can implement all the contents of the foregoing method embodiment. Figure 3 As shown, the device includes: a first determining unit 21, a second determining unit 22, and a third determining unit 23, wherein:

[0119] The first determining unit 21 is used to prepare the target sample, wherein the target sample is a series of artificially sand-filled fracture core, natural fracture core and base block core;

[0120] The second determining unit 22 is used to determine the pre-fluid infiltration recovery rate and post-fluid infiltration recovery rate of the target sample.

[0121] The third determining unit 23 is used to determine the fluid sensitivity based on the above-mentioned pre-invasion recovery rate and the above-mentioned post-invasion recovery rate.

[0122] The processor contains a kernel, which retrieves the corresponding program units from memory. One or more kernels can be configured, and by adjusting kernel parameters, a fluid sensitivity evaluation method for tight sandstone reservoirs can be implemented. This method addresses the shortcomings of current fluid sensitivity evaluation methods for tight sandstone reservoirs, which do not consider all factors comprehensively and produce inaccurate results.

[0123] This invention provides a computer-readable storage medium including a stored program that, when executed by a processor, implements the aforementioned method for evaluating the fluid sensitivity of tight sandstone reservoirs.

[0124] This invention provides a processor for running a program, wherein the program executes the fluid sensitivity evaluation method for tight sandstone reservoirs.

[0125] This invention provides an electronic device, which includes at least one processor and at least one memory connected to the processor; wherein the processor is used to call program instructions in the memory to execute the fluid sensitivity evaluation method for tight sandstone reservoirs as described above.

[0126] This invention provides an electronic device 30, such as... Figure 4 As shown, the electronic device includes at least one processor 301, and at least one memory 302 and bus 303 connected to the processor; wherein, the processor 301 and the memory 302 communicate with each other through the bus 303; the processor 301 is used to call program instructions in the memory to execute the above-mentioned fluid sensitivity evaluation method for tight sandstone reservoirs.

[0127] The smart electronic devices mentioned in this article can be PCs, tablets, mobile phones, etc.

[0128] This application also provides a computer program product that, when executed on a process management electronic device, is suitable for executing a program that initializes the steps of the fluid sensitivity evaluation method for the aforementioned tight sandstone reservoir.

[0129] It should be noted that the descriptions of each embodiment in the above embodiments have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0130] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0131] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create a machine for implementing the flowchart illustrations. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0132] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0133] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0134] This application also provides a computer program product, which includes computer software instructions that, when executed on a processing device, cause the processing device to perform actions such as... Figure 1 The control flow of the memory in the corresponding embodiment.

[0135] A computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the flow or function according to the embodiments of this application is generated. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium may be any available medium that a computer can store or a data storage device such as a server or data center that integrates one or more available media. The available medium may be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid-state disk (SSD)).

[0136] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0137] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces, or indirect coupling or communication connection between apparatuses or units, and may be electrical, mechanical, or other forms.

[0138] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0139] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0140] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0141] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A method for evaluating the fluid sensitivity of tight sandstone reservoirs, characterized in that, include: The target samples are determined, wherein the target samples are artificially sand-filled fracture cores, natural fracture cores and base block cores connected in series; Determine the pre-intrusion and post-intrusion recovery rates of the target sample; Fluid sensitivity is determined based on the pre-intrusion recovery rate and the post-intrusion recovery rate. Determining the pre-intrusion and post-intrusion recovery rates of the target sample includes: The sensitive liquid is pumped into the target sample in reverse and continued for a preset time. Based on the backflow pressure differential value, methane is used to positively displace the sensitive liquid in the target sample; With all the sensitive liquid in the target sample removed, the target sample is fully saturated with methane, wherein the state in which the target sample is fully saturated with methane is the third state; Determine the methane content of the target sample in the fourth state, wherein the fourth state is the state after depletion mining in the third state; The recovery rate of the target sample after fluid intrusion is determined based on the methane content of the target sample in the third state and the methane content of the target sample in the fourth state. The backflow pressure difference value P is determined based on the following formula. b : In the above formula, P p The P is the reservoir pore pressure. f The bottom-hole flowing pressure is the reservoir bottom pressure, l is the length of the target sample, L is the width of the pressure drop funnel formed after the tight sandstone reservoir is opened, and P is the bottom-hole flowing pressure. r Back pressure; Determining the pre-intrusion and post-intrusion recovery rates of the target sample includes: Determine the methane content of the target sample in a first state, wherein the first state is a state in which the target sample is fully saturated with methane; Determine the methane content of the target sample in a second state, wherein the second state is the state of the target sample after depletion mining; The pre-intrusion recovery rate of the target sample is determined based on the methane content of the target sample in the first state and the methane content of the target sample in the second state.

2. The method according to claim 1, characterized in that, The pre-intrusion recovery rate of the target sample based on the methane content of the target sample in a first state and the methane content of the target sample in a second state includes: The pre-intrusion recovery rate R of the target sample is determined based on the following formula. f : In the above formula, Q f1 Q represents the methane content of the target sample in its first state. f2 The methane content of the target sample in the second state.

3. The method according to claim 1, characterized in that, The determination of the post-intrusion recovery rate of the target sample based on the methane content of the target sample in the third state and the methane content of the target sample in the fourth state includes: The post-intrusion recovery rate R of the target sample is determined based on the following formula. E : In the above formula, Q E1 Q represents the methane content of the target sample in the third state. E2 The methane content of the target sample in the fourth state is given.

4. The method according to claim 1, characterized in that, The determination of fluid sensitivity based on the pre-invasion recovery rate and the post-invasion recovery rate includes: The fluid sensitivity I is determined based on the following formula: In the above formula, R f R is the pre-intrusion recovery rate of the fluid. E The recovery rate after the fluid intrusion is denoted as .

5. A fluid sensitivity evaluation device for tight sandstone reservoirs, characterized in that, include: The first determining unit is used to prepare the target sample, wherein the target sample is a series of artificially sand-filled fracture core, natural fracture core and base block core; The second determining unit is used to determine the pre-intrusion recovery rate and post-intrusion recovery rate of the target sample. The third determining unit is used to determine the fluid sensitivity based on the pre-invasion recovery rate and the post-invasion recovery rate. Determining the pre-intrusion and post-intrusion recovery rates of the target sample includes: The sensitive liquid is pumped into the target sample in reverse and continued for a preset time. Based on the backflow pressure differential value, methane is used to positively displace the sensitive liquid in the target sample; With all the sensitive liquid in the target sample removed, the target sample is fully saturated with methane, wherein the state in which the target sample is fully saturated with methane is the third state; Determine the methane content of the target sample in the fourth state, wherein the fourth state is the state after depletion mining in the third state; The recovery rate of the target sample after fluid intrusion is determined based on the methane content of the target sample in the third state and the methane content of the target sample in the fourth state. The backflow pressure difference value P is determined based on the following formula. b : In the above formula, P p The P is the reservoir pore pressure. f The bottom-hole flowing pressure is the reservoir bottom pressure, l is the length of the target sample, L is the width of the pressure drop funnel formed after the tight sandstone reservoir is opened, and P is the bottom-hole flowing pressure. r Back pressure; Determining the pre-intrusion and post-intrusion recovery rates of the target sample includes: Determine the methane content of the target sample in a first state, wherein the first state is a state in which the target sample is fully saturated with methane; Determine the methane content of the target sample in a second state, wherein the second state is the state of the target sample after depletion mining; The pre-intrusion recovery rate of the target sample is determined based on the methane content of the target sample in the first state and the methane content of the target sample in the second state.

6. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored program, wherein, when the program is executed by a processor, it implements the method for evaluating the fluid sensitivity of tight sandstone reservoirs as described in any one of claims 1 to 4.

7. An electronic device, characterized in that, The electronic device includes at least one processor and at least one memory connected to the processor; wherein the processor is used to call program instructions in the memory to execute the fluid sensitivity evaluation method for tight sandstone reservoirs as described in any one of claims 1 to 4.

Images