A similarity transformation method based on laboratory study of fractured vugular bodies

Abstract

The application provides a similarity conversion method based on a fault-fold-fracture body laboratory research, relates to the oil and gas field production technical field and contains: for the fault-fold-fracture body gas reservoir with non-single medium reservoir, a long core physical simulation model is established;Through the long core physical simulation model, the corresponding channeling coefficients of different medium reservoirs in the fault-fold-fracture body gas reservoir are simulated;Based on the similarity criterion, the corresponding similarity criterion of the fault-fold-fracture body gas reservoir is determined, the channeling coefficient is introduced, and the calculation expression of the production dynamic data of the mine gas well is established.The application can determine the conversion relationship between the laboratory physical simulation and the production rate and the production time of the actual gas well in the dual medium reservoir, is favorable to improving the accuracy and the representativeness of the laboratory physical simulation, and has important significance for the efficient exploitation of the gas field.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field production technology, and more specifically, to a similar transformation method based on laboratory research on fractured bodies. Background Technology

[0002] Compared to the abundant resource reserves of gas reservoirs, our current understanding and exploitation capabilities are still insufficient. Therefore, physical simulation methods are often used to study gas reservoirs. A multifunctional long core radial multi-point dynamic monitoring and displacement system includes a displacement system, a resistivity measurement system, and metering devices. The displacement system includes gas displacement devices, foam displacement devices, and fluid displacement devices. By measuring the pressure changes inside the long core in real time throughout the entire extraction process, the pressure distribution curve over time can be obtained, and the crossflow coefficient can be further calculated.

[0003] In order to better apply the results of physical simulation experiments to gas fields and provide theoretical guidance for the design of gas field development plans, it is necessary to derive similarity criteria for physical simulation of gas reservoir development based on the characteristics of gas reservoirs. However, the derivation process usually only considers a single medium reservoir. When there are dual medium reservoirs in the gas reservoir, the similarity criteria will be inaccurate.

[0004] To address the problems of existing technologies, this invention provides a similar transformation method based on laboratory research of fractured and folded bodies. Summary of the Invention

[0005] To address the problems of existing technologies, the present invention aims to provide a similarity theory conversion method for the gas production rate and extraction time of laboratory and actual gas reservoirs based on multi-point monitoring long core physical simulation experiments, in order to solve the problem of inaccurate similarity criteria for multi-medium reservoirs.

[0006] This invention provides a similarity transformation method based on laboratory research of fractured and folded bodies, the method comprising:

[0007] For fault-fold fracture gas reservoirs with non-single-medium reservoirs, a long core physical simulation model is established;

[0008] The crossflow coefficients of different media reservoirs in the fault-fold fracture gas reservoir were obtained by simulating the physical simulation model of the long core.

[0009] Based on the similarity criterion, the similarity index corresponding to the fractured gas reservoir is determined, and the crossflow coefficient is introduced to establish a calculation expression for the dynamic production data of gas wells in the mining area.

[0010] According to an embodiment of the present invention, the physical simulation model of the long core is established through the following steps:

[0011] Sampling was carried out on fault-folded fracture gas reservoirs with non-single-medium reservoirs to obtain core samples of different media reservoirs;

[0012] The core samples from different reservoir media are combined to form a long core, which is then used to obtain a physical simulation model of the long core. The different reservoir media include fractures and matrix.

[0013] According to an embodiment of the present invention, the crossflow coefficients corresponding to different medium reservoirs are obtained by simulation through the following steps:

[0014] For the core samples of different media reservoirs, the basic parameters corresponding to the different media reservoirs were measured respectively, wherein the basic parameters include porosity and permeability;

[0015] Based on the physical simulation model of the long core, a depletion mining experiment was conducted, and multiple pressure measurement points were selected to obtain the pressure distribution curve during the mining process.

[0016] The crossflow coefficients corresponding to different medium reservoirs are calculated by fitting the pressure distribution curve.

[0017] According to one embodiment of the present invention, the similarity criterion corresponding to a fractured gas reservoir is determined by the following steps:

[0018] The physical quantities and dimensions involved in the exploitation of fault-fold fracture gas reservoirs are statistically analyzed, and the basic dimensions are classified and determined.

[0019] Determine the dimensionless π-term exponential form of the physical quantity, and determine the linear equation system corresponding to each of the basic dimensions;

[0020] Solving the linear equations yields the similarity criterion for physical simulation experiments of development similarity of fractured gas reservoirs with non-single-medium reservoirs.

[0021] According to one embodiment of the present invention, the similarity criteria include, but are not limited to: a similarity criterion π9 for determining the model gas extraction rate, and a similarity criterion π for establishing time conversion relationships. 10 ,in:

[0022]

[0023]

[0024] Where: q is the gas production velocity; b is the seepage surface width; h is the thickness; K is the permeability; K rg T represents the relative permeability of the gas phase. sc Standard temperature; p i ρ is the original formation pressure; a is the discharge radius; μ is the gas viscosity; Z is the gas compressibility factor; T is the reservoir temperature; p sc Standard atmospheric pressure; t is time; Porosity; Sg This represents the gas saturation level.

[0025] According to an embodiment of the present invention, the calculation expression for the dynamic production data of the gas wells in the mining area is established through the following steps:

[0026] Considering the influence of crossflow coefficients in different reservoir media, the calculation expression is obtained based on the simulation experimental parameters of the long core physical simulation model and the similarity criterion, wherein the dynamic production data of the mine gas well includes the gas production rate and the gas production time of the mine gas well.

[0027] According to one embodiment of the present invention, considering that the gas leakage radius in a fractured gas reservoir with a non-single-medium reservoir is determined by the channeling coefficient and the matrix zone radius, based on the similarity criterion π9 and the core gas production rate q in the simulation experimental parameters. m Calculate the gas production rate q of the gas well in the mine. g :

[0028]

[0029] Where: b is the seepage surface width; h is the thickness; K is the permeability; K rg T represents the relative permeability of the gas phase. sc Standard temperature; p i λ is the original formation pressure; λ is the channeling coefficient; r1 is the matrix radius; μ is the gas viscosity; Z is the gas compressibility factor; T is the reservoir temperature; p sc The pressure is standard atmosphere; the parameter in parentheses is the parameter of the simulation experiment; q is the gas production rate.

[0030] According to one embodiment of the present invention, considering that the gas leakage radius in a fractured gas reservoir with a non-single-medium reservoir is determined by the channeling coefficient and the matrix region radius, based on the similarity criterion π 10 And the core gas production time t in the simulation experiment parameters m Calculate the gas production time t of the gas well in the mine. g :

[0031]

[0032] Where: λ is the crossflow coefficient; r1 is the radius of the matrix region; b is the width of the seepage surface; h is the thickness; Porosity; S g T represents gas saturation. sc Standard temperature; p i q represents the original formation pressure; g Z is the gas production rate of the gas well in the mining area; Z is the gas compressibility factor; T is the reservoir temperature; p sc The pressure is standard atmosphere; the parameter in parentheses is the parameter of the simulation experiment; q is the gas production rate.

[0033] According to another aspect of the invention, a storage medium is also provided, which includes instructions for performing the methods described in any of the preceding claims.

[0034] According to another aspect of the invention, a similar conversion system based on laboratory studies of fractured fracture bodies is also provided, performing the method as described in any of the preceding claims, the system comprising:

[0035] The physical simulation model of long cores is designed for fault-fold fracture gas reservoirs with non-single-medium reservoirs.

[0036] The exhaustion-type mining experimental equipment is used to simulate the crossflow coefficients of different media reservoirs in the fractured gas reservoir through the physical simulation model of the long core.

[0037] The similarity conversion module, based on the similarity criterion, determines the similarity criterion corresponding to the fractured gas reservoir, introduces the crossflow coefficient, and establishes a calculation expression for the dynamic production data of the gas well in the mining area.

[0038] This invention provides a similarity conversion method based on laboratory research of fractured bodies. Compared with the prior art, it has the following advantages: This invention can determine the conversion relationship between laboratory physical simulation and actual gas well development production rate and production time in dual-medium reservoirs, which is conducive to improving the accuracy and representativeness of laboratory physical simulation and is of great significance to the efficient development of gas fields.

[0039] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0040] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0041] Figure 1 A flowchart illustrating the steps of a similar transformation method based on laboratory research of fractured fracture bodies according to an embodiment of the present invention is shown.

[0042] Figure 2 A schematic diagram of a long core physical simulation model according to an embodiment of the present invention is shown;

[0043] Figure 3 A pressure distribution curve during the mining process according to an embodiment of the present invention is shown;

[0044] Figure 4 A graph showing the recovery rate of a dual-medium reservoir according to an embodiment of the present invention is displayed.

[0045] In the accompanying drawings, the same parts use the same reference numerals. Also, the drawings are not drawn to scale. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0047] The existing technology (Derivation and Application of Similarity Criteria for Physical Simulation of Water-Drive in Ultra-Low Permeability Reservoirs, Science & Technology Review, 2013.09) is based on similarity theory and uses equation analysis to derive similarity criteria for physical simulation of water-drive in fractured reservoirs under constant pressure and production conditions. These criteria consider gravity, viscosity, and the seepage effect between matrix fractures. The criteria are: fractured seepage systems must satisfy geometric similarity, have the same permeability ratio in all three axes, the same oil-water viscosity ratio, the same ratio of movable oil in the matrix to that in fractures, the same dimensionless seepage half-cycle, the same ratio of gravity pressure difference to injection-production pressure difference, and the same dimensionless initial and boundary conditions. Therefore, at the same dimensionless spatial point and dimensionless time point, producing wells will have the same dimensionless oil and water production, as well as the same production variation patterns. However, this existing technology has many and stringent application conditions, making its application inconvenient.

[0048] Existing technology (Similarity Criteria for Dynamic Physical Simulation Experiments in Low-Permeability Tight Gas Reservoirs, Daqing Petroleum Geology and Development, 2019.02) for two-fracture seepage systems assumes that the ratio of movable oil in the matrix to the fractures and the dimensionless adsorption half-cycle are equal, thus achieving similar adsorption phenomena during water-drive oil flow. However, this existing technology assumes that the reservoir is homogeneous, and therefore only applies to ideal conditions where fractures and matrix are uniformly distributed, which is inconsistent with the characteristics of actual gas reservoirs. When applied to gas reservoirs with dual-medium reservoirs, this existing technology leads to inaccurate similarity criteria. This invention addresses fault-fold fractured gas reservoirs with non-single-medium reservoirs by establishing a long core physical simulation model to obtain the channeling coefficients of different media reservoirs through physical simulation experiments. In other words, this invention introduces a channeling coefficient parameter, making the gas leakage radius parameter accurate and solving the problem of inaccurate application of the similarity criteria in the existing technology.

[0049] Existing technology (Similarity Criteria for Three-Dimensional Quantitative Physical Simulation of Two-Phase Flow in Heterogeneous Reservoirs, Oil & Gas Well Testing, 2014.02) employs finite vacuum saturation technology and natural sandstone selection methods to quantitatively control the ratio of movable oil in matrix fractures and the matrix-permeation coupling half-cycle through experimental calculations. By quantitatively controlling the ratio of movable fluid in the matrix to that in fractures, the ratio of movable oil in matrix fractures and the matrix-permeation coupling half-cycle are controlled to achieve comprehensive physical similarity in the simulation. However, this existing technology is limited by experimental simulation conditions and is difficult to simulate tight sandstone gas reservoirs under reservoir temperature and pressure conditions, thus its applicability is limited.

[0050] Existing technology (Research on Similarity Theory of Physical Simulation for the Development of Abnormally High-Pressure Gas Reservoirs, Science Technology and Engineering, 2013.12) assumes a two-pore, single-permeability fractured seepage medium, neglects rock and fluid compressibility, and ignores capillary forces in fractures. It derives a two-phase seepage mathematical model for fractured reservoirs under different conditions, using boundary conditions as the solution. Based on this, 15 similarity criterions are derived, enabling quantitative simulation and prediction of reservoir development dynamics and various development indicators. Although this existing technology has wide applicability, its computational accuracy is low, and improvements are needed to address the reservoir characteristics of tight sandstone gas reservoirs.

[0051] To address the shortcomings of the existing technologies, this invention provides a similarity theory conversion method for the gas production rate and extraction time of laboratory and actual gas reservoirs based on multi-point monitoring long core physical simulation experiments. This method can solve the problems of unclear seepage patterns and difficulty in predicting early development dynamics in low-permeability tight gas reservoirs.

[0052] Figure 1 A flowchart illustrating the steps of a similar transformation method based on laboratory research of fractured fracture bodies according to an embodiment of the present invention is shown.

[0053] like Figure 1 As shown, in step S1, a long core physical simulation model is established for fault-folded fractured gas reservoirs with non-single-medium reservoirs.

[0054] In one embodiment, step S1 involves establishing a long core physical simulation model through the following steps: sampling a fault-folded fractured gas reservoir with non-single-medium reservoirs to obtain core samples of different media reservoirs; combining the core samples of different media reservoirs into a long core to obtain a long core physical simulation model (e.g., Figure 2 ), where different media reservoirs include fractures and matrix.

[0055] like Figure 1 As shown, in step S2, the crossflow coefficients corresponding to different media reservoirs in the fault-fold fractured gas reservoir are simulated using the long core physical simulation model.

[0056] In one embodiment, step S2 involves simulating the channeling coefficients corresponding to different reservoir media through the following steps: For core samples from different reservoir media, the basic parameters corresponding to each media reservoir are measured, including porosity and permeability; based on a long core physical simulation model, a depletion-type mining experiment is conducted, selecting multiple pressure measurement points to obtain the pressure distribution curves during the mining process (e.g., ...). Figure 3 The flow coefficients corresponding to different medium reservoirs are calculated by fitting the pressure distribution curves.

[0057] Specifically, for fault-fractured gas reservoirs with dual-medium reservoirs, samples are taken from the reservoir layers separately, and basic parameters, including porosity, are measured in both matrix-type and fracture-type cores. and permeability K; combining matrix-type cores and fracture-type cores into long cores for depletion mining experiments (e.g.) Figure 2 Six pressure measuring points were selected to obtain the pressure distribution curve during the mining process (e.g., Figure 3 Based on the pressure distribution curve, the flow coefficient λ of the fracture zone and the matrix zone was calculated. The experimental results of the flow coefficient λ are shown in Table 1.

[0058] Table 1. Dual-medium cross-flow coefficients

[0059]

[0060]

[0061] like Figure 1 As shown, in step S3, based on the similarity criterion, the similarity criterion corresponding to the fractured gas reservoir is determined, the crossflow coefficient is introduced, and the calculation expression of the dynamic production data of the gas well in the mine is established.

[0062] In one embodiment, in step S3, the similarity criterion corresponding to the fractured gas reservoir is determined by the following steps: statistically analyzing the physical quantities and dimensions involved in the exploitation process of the fractured gas reservoir, and classifying and determining the basic dimensions; determining the dimensionless π-term exponential form of the physical quantities, and determining the linear equation set corresponding to each basic dimension; and solving the equation set to obtain the similarity criterion of the physical simulation experiment for the development similarity of the fractured gas reservoir with non-single medium reservoir.

[0063] Specifically, similarity criteria include, but are not limited to: the similarity criterion π9 used to determine the gas extraction rate of the model, and the similarity criterion π used to establish time conversion relationships. 10 ,in:

[0064]

[0065]

[0066] Where: q is the gas production velocity; b is the seepage surface width; h is the thickness; K is the permeability; K rg T represents the relative permeability of the gas phase. sc Standard temperature; p i ρ is the original formation pressure; a is the discharge radius; μ is the gas viscosity; Z is the gas compressibility factor; T is the reservoir temperature; p sc Standard atmospheric pressure; t is time; Porosity; S g This represents the gas saturation level.

[0067] In one embodiment, in step S3, the calculation expression for the dynamic production data of the gas well in the mine is established through the following steps: considering the influence of the crossflow coefficient of different medium reservoirs, the calculation expression is obtained based on the simulation experimental parameters and similarity criterion of the long core physical simulation model, wherein the dynamic production data of the gas well in the mine includes the gas production rate of the gas well and the gas production time of the gas well in the mine.

[0068] Specifically, considering that the gas leakage radius in a fractured gas reservoir with a non-single-medium reservoir is determined by the channeling coefficient and the matrix radius, based on the similarity criterion π9 and the core gas production rate q in the simulation experimental parameters... m Calculate the gas production rate q of the gas well in the mine. g :

[0069]

[0070] Where: b is the seepage surface width; h is the thickness; K is the permeability; K rg T represents the relative permeability of the gas phase. sc Standard temperature; p i λ is the original formation pressure; λ is the channeling coefficient; r1 is the matrix radius; μ is the gas viscosity; Z is the gas compressibility factor; T is the reservoir temperature; p sc The pressure is standard atmosphere; the parameters in parentheses are simulation parameters; q is the gas production rate.

[0071] Specifically, considering a fault-fractured gas reservoir with a non-single-medium reservoir structure, the gas leakage radius is determined by the channeling coefficient and the matrix radius, based on the similarity criterion π. 10 And the core gas production time t in the simulation experiment parameters m Calculate the gas production time t of the gas well in the mining area. g :

[0072]

[0073] Where: λ is the crossflow coefficient; r1 is the radius of the matrix region; b is the width of the seepage surface; h is the thickness; Porosity; S g T represents gas saturation.sc Standard temperature; p i q represents the original formation pressure; g Z is the gas production rate of the gas well in the mining area; Z is the gas compressibility factor; T is the reservoir temperature; p sc The pressure is standard atmosphere; the parameters in parentheses are simulation parameters; q is the gas production rate.

[0074] Dimensional analysis arose from the study of similar phenomena by examining the dimensions of various physical quantities. Its theoretical foundation lies in the mathematical theory of homogeneous equations. Generally speaking, equations used to explain physical phenomena are homogeneous, which is the basis for the derivation of theorems through dimensional analysis.

[0075] However, once the π theorem is derived, it is no longer limited to physical phenomena with equations. At this point, by examining the dimensions of the correctly selected parameters through dimensional analysis, a functional relationship consistent with the π theorem can be obtained, and similar phenomena can be generalized accordingly.

[0076] Specifically, in step S3, the quantitative relationship between the actual gas well development parameters and the simulated experimental parameters is solved as follows:

[0077] Step S31, a complete description of the physical quantities and dimensions in the mining process:

[0078] (1) Permeability K, with dimensions [L] 2 ];

[0079] (2) Porosity Dimensionless;

[0080] (3) Gas saturation S g Its dimension is 1;

[0081] (4) The discharge radius a has the dimension of [L];

[0082] (5) The seepage surface width b, with dimensions [L];

[0083] (6) Thickness h, dimensionless [L], the product of thickness and seepage surface width corresponds to the seepage cross-sectional area of ​​the model core;

[0084] (7) Original formation pressure P i The dimension is [M·T] -2 ·L -1 ];

[0085] (8) Gas production rate q, dimensionless [L] 3 ·T -1 It should be noted that the flow rate here is 1 / 2n of the gas well flow rate, where n is the number of fractures, and for a fractured vertical well, n = 1;

[0086] (9) Time t, dimensionless [T];

[0087] (10) Gas compressibility factor Z, dimensionless;

[0088] (11) Reservoir temperature T, dimension [K];

[0089] (12) Standard temperature T sc Its dimension is [K];

[0090] (13) Standard atmospheric pressure P sc The dimension is [M·T] -2 ·L -1 ].

[0091] The above are 13 independent variables (when using simulated gas reservoir cores, the relative permeability of the gas phase K). rg Only the water saturation S w (The function is not an independent variable and is not considered) plus the dependent variable P w There are a total of 14 variables.

[0092] After classifying the 14 variables, there are 4 basic dimensions: length [L], mass [M], time [T], and temperature [K]. According to similarity theory, there are 10 similarity criteria, therefore, an expression for any similarity criterion π can be derived:

[0093] Step S32, dimensionless exponential expression for the π term:

[0094]

[0095] According to the homogeneity principle, the corresponding system of linear equations is as follows:

[0096] When the length dimension is 1, the equation is:

[0097] 2x1+x4+x5+x6-x7+3x8-x 13 -x 14 =0

[0098] The equation is as follows when the mass dimension is 1:

[0099] x7+x 13 +x 14 =0

[0100] When the time dimension is 1, the equation is as follows:

[0101] -2x7-x8+x9-2x 13 -2x 14 =0

[0102] When the temperature dimension is 1, the equation is as follows:

[0103] x 11 +x 12 =0

[0104] Step S33: According to matrix theory, there are 10 fundamental solution sets, that is, there are 10 independent similarity criteria. Solve the equations to obtain the similarity criteria of the physical simulation experiment of dual-medium gas reservoir development similarity, as shown in Table 2.

[0105] Table 2 Similarity Criteria in Gas Reservoir Physical Simulation

[0106]

[0107]

[0108] When the reservoir seepage is Darcy flow, the similarity criterion π9 is expressed with the gas well free flow rate as the denominator. π9 represents the ratio of gas production rate to free flow rate, which aligns with the production allocation principle of 1 / 3 to 1 / 6 of the free flow rate. This reflects kinematic similarity, and subsequent experiments will demonstrate that π9 is an important similarity criterion in similarity experiments. According to mine production statistics, the prototype value is generally 1 / 3 to 1 / 10. Due to its low permeability, the free flow rate of low-permeability tight cores is relatively small. At a flow pressure of 30 MPa, the free flow rate of a full-diameter core is approximately 10,000 mL / min. For the physical model experiment, a flow rate of 1,000–3,000 mL / min is sufficient to ensure consistency between the model and prototype similarity criterion, making the experiment experimentally feasible.

[0109] Similarity coefficient π 10 The denominator is the geological reserves of natural gas, and the numerator is the cumulative gas production, i.e., the similarity criterion π. 10 The cumulative gas production to reserves ratio reflects the degree of gas reservoir recovery. According to statistics, the prototype similarity criterion π for low-permeability tight gas reservoirs... 10 The similarity criterion π is between 0 and 0.6. 10 With a similarity criterion of 0 to 0.95, the model can achieve consistency with the prototype.

[0110] Step S34: The physical model experiment can obtain key development dynamic data such as the inlet pressure p1, outlet pressure p2, cumulative gas production, and recovery rate of the physical model core. Among them, the outlet pressure p2 of the physical model core corresponds to the bottom hole pressure p of the gas reservoir. w The inlet pressure p1 of the physical model core corresponds to the gas reservoir boundary pressure p. e Therefore, dynamic production data of gas wells in the mining area can be obtained based on the experimental results of the physical model and the similarity conversion of the similarity criterion, where the similarity criterion π9 and the gas production rate q of the physical model core are used as the basis. m Calculate the gas production rate q of a gas well in a mining area. g The formula is:

[0111]

[0112] In the formula: m is the parameter inside the parentheses, which is the physical model parameter; a is the venting radius.

[0113] Unlike single-medium systems, this invention considers that the gas leakage radius in dual-medium systems is determined by the crossflow coefficient λ and the matrix zone radius r1. Therefore, the gas production rate q of the well in the mining area is... g Gas production rate q from the core sample m The conversion relationship is as follows:

[0114]

[0115] Based on the similarity criterion π 10 Gas generation time t in physical model experiment m Calculate the mine production time t g The formula is:

[0116]

[0117] Unlike single-medium systems, this invention considers that the gas leakage radius in dual-medium systems is determined by the crossflow coefficient λ and the matrix zone radius r1. Therefore, the gas production time t of the well in the oilfield is... g Gas production time t of the core sample m The conversion relationship is as follows:

[0118]

[0119] In summary, this invention establishes a laboratory-based physical simulation model for multi-point monitoring of long core samples; it obtains the crossflow coefficients between fracture zones and matrix zones in dual-medium environments using simulation experiments; it uses dimensional analysis in similarity criteria to obtain a functional relationship consistent with the π theorem, introduces the crossflow coefficient, and derives the similarity relationship between actual gas well development parameters and simulation experimental parameters, thus solving the problem of inaccurate similarity criteria for multi-medium reservoirs.

[0120] In one embodiment, an experiment on the gas supply and exhaust mechanism of a fractured gas reservoir, conducted using a multi-point monitoring long core device, calculates the actual gas production rate and production time corresponding to the experimentally obtained gas production rate and production time based on the similarity between actual gas well production parameters and physical simulation experimental parameters. This allows for realistic simulation of gas well production in researching related scientific issues, solving the difficulty of using laboratory physical simulations of dual-medium reservoir gas wells to guide actual gas well development, and calculating the gas supply and exhaust efficiency of gas wells in different reservoirs during actual development. Specific implementation steps and results are as follows:

[0121] Combining the simulation realism of the experimental equipment with the characteristics of actual gas reservoirs, a gas supply and displacement experiment was designed for fractured-matrix type reservoirs. The displacement inlet simulated the well control outer boundary, the displacement outlet established back pressure to simulate the bottom of the gas well, and the confining pressure simulated the pressure of the overlying strata (e.g., Figure 2 (Schematic diagram of physical simulation of dual-medium reservoir shown).

[0122] Based on similarity criteria, a similarity conversion between the experimental model and actual gas wells is established, thereby determining the conversion relationship between gas production rate and production time:

[0123]

[0124]

[0125] Based on motion similarity and extraction degree similarity, the similarity parameter table for this experimental model is obtained, as shown in Table 3:

[0126] Table 3 Similarity parameters for dual-medium reservoir models

[0127] Similarity Criteria Similar attributes Experimental parameter values Actual gas well parameter values <![CDATA[π9]]> Similar gas extraction speed 1200~3000mL / min 2～5％ <![CDATA[π 10 ]]> Similar production time 1400-2000min 12-17.14a

[0128] Based on the actual gas well production rate and development life calculated using similarity parameters, the recovery rate curves of the actual gas wells corresponding to the experimental model in the matrix zone and fracture zone can be calculated under different reservoir characteristics, as shown in the following figure. Figure 4 The calculation results are shown in Table 4.

[0129] Table 4. Recovery Calculation Results of Dual-Media Reservoir Model

[0130] Location matrix region crack zone Recovery rate (%) 30.26 76.68

[0131] The calculation results based on the similarity criterion can be used to evaluate the gas supply and exhaust efficiency of gas wells with different physical properties and reservoir types during development. The similarity calculation method provided by this invention can classify and convert relevant parameters such as pore throat development characteristics and physical properties of different types of fault-fold fractured gas reservoirs, and apply the calculation results to different types of gas wells. The converted results were applied to the EUR calculation of actual gas wells, and the results were compared with the parameter fitting calculations and pressure drop curve method of actual gas wells. The calculation accuracy was over 90%, verifying the accuracy of the gas venting radius calculated by the multi-point monitoring long core device and the reliability of the similarity relationship corrected experimentally.

[0132] The similarity transformation method based on laboratory research of fractured and folded bodies provided by this invention can also be used in conjunction with a computer-readable storage medium. The storage medium stores a computer program, which is executed to run the similarity transformation method based on laboratory research of fractured and folded bodies. The computer program can execute computer instructions, which include computer program code. The computer program code can be in the form of source code, object code, executable file, or some intermediate form.

[0133] Computer-readable storage media can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc.

[0134] It should be noted that the contents of computer-readable storage media may be appropriately added to or subtracted from the contents according to the requirements of legislation and patent practice in a jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable storage media may not include electrical carrier signals and telecommunication signals.

[0135] According to another aspect of the present invention, a similarity conversion system based on laboratory research of fractured and folded bodies is also provided, which performs a similarity conversion method based on laboratory research of fractured and folded bodies.

[0136] In one embodiment, a similarity conversion system based on laboratory research of fractured bodies includes: a long core physical simulation model, a depletion-based production experimental device, and a similarity conversion module. The long core physical simulation model is designed for fractured gas reservoirs with non-single-medium reservoirs; the depletion-based production experimental device is used to simulate the channeling coefficients corresponding to different media reservoirs in the fractured gas reservoir using the long core physical simulation model; the similarity conversion module determines the similarity criterion corresponding to the fractured gas reservoir based on similarity criteria, introduces the channeling coefficient, and establishes a calculation expression for the dynamic production data of gas wells in the mining area.

[0137] In summary, this invention provides a similarity conversion method based on laboratory research of fractured bodies. Compared with the prior art, it has the following advantages: This invention can determine the conversion relationship between laboratory physical simulation and actual gas well development production rate and production time in dual-medium reservoirs, which is conducive to improving the accuracy and representativeness of laboratory physical simulation and is of great significance to the efficient development of gas fields.

[0138] It should be understood that the embodiments disclosed herein are not limited to the specific structures, processing steps, or materials disclosed herein, but should be extended to equivalent substitutions of these features as understood by those skilled in the art. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0139] In the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0140] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0141] Certain terms are used throughout this application to refer to specific system components. As those skilled in the art will recognize, the same components may often be referred to by different names, and therefore this application is not intended to distinguish those components that differ only in name and not in function. In this application, the terms “comprise,” “include,” and “have” are used in an open-ended manner and should therefore be interpreted as meaning “including, but not limited to…”. Furthermore, the terms “substantially,” “materially,” or “approximately” as used herein refer to industry-accepted tolerances for the corresponding terms. The term “coupling,” as may be used herein, includes direct coupling and indirect coupling via additional components, elements, circuits, or modules, wherein, for indirect coupling, the intermediate component, element, circuit, or module does not alter the information of the signal but may adjust its current level, voltage level, and / or power level. Inferred coupling (e.g., one element is inferredly coupled to another element) includes direct and indirect coupling between two elements in the same manner as “coupling.”

[0142] The phrase "an embodiment" or "an embodiment" used in this specification means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Therefore, the phrase "an embodiment" or "an embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0143] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

[0144] While the embodiments disclosed in this invention are as described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and variations in form and detail of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection for this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A similarity transformation method based on laboratory research of fractured and folded bodies, characterized in that, The method includes: For fault-fold fracture gas reservoirs with non-single-medium reservoirs, a long core physical simulation model is established; The crossflow coefficients of different media reservoirs in the fault-fold fracture gas reservoir were obtained by simulating the physical simulation model of the long core. Based on the similarity criterion, the similarity criterion number corresponding to the fractured gas reservoir is determined, and the crossflow coefficient is introduced to establish a calculation expression for the dynamic production data of the gas well in the field. The calculation expression for the dynamic production data of the gas wells in the mining area is established through the following steps: Considering the influence of crossflow coefficients in different reservoir media, the calculation expression is obtained based on the simulation experimental parameters of the long core physical simulation model and the similarity criterion. The dynamic production data of the gas wells in the mining area includes the gas production rate and the gas production time of the gas wells. The similarity criterion includes: a similarity criterion π9 used to determine the gas production rate of the model, and a similarity criterion π used to establish the time conversion relationship. 10 ,but: Considering that the gas leakage radius in a fractured gas reservoir with a non-single-medium reservoir is determined by the channeling coefficient and the matrix radius, based on the similarity criterion π9 and the core gas production rate q in the simulation experimental parameters... m Calculate the gas production rate q of the gas well in the mine. g : Considering that the gas leakage radius in a fractured gas reservoir with a non-single-medium reservoir is determined by the channeling coefficient and the matrix region radius, according to the similarity criterion π 10 And the core gas production time t in the simulation experiment parameters m Calculate the gas production time t of the gas well in the mine. g : Where: q is the gas production velocity; b is the seepage surface width; h is the thickness; K is the permeability; K rg T represents the relative permeability of the gas phase. sc Standard temperature; p i ρ is the original formation pressure; a is the discharge radius; μ is the gas viscosity; Z is the gas compressibility factor; T is the reservoir temperature; p sc Standard atmospheric pressure; t is time; Porosity; S g λ represents the gas saturation; λ represents the crossflow coefficient; r1 represents the matrix region radius; and m represents the parameters in parentheses from the simulation experiment.

2. The similarity transformation method based on laboratory research of fractured and folded bodies as described in claim 1, characterized in that, The physical simulation model of the long core is established through the following steps: Sampling was carried out on fault-folded fracture gas reservoirs with non-single-medium reservoirs to obtain core samples of different media reservoirs; The core samples from different reservoir media are combined to form a long core, which is then used to obtain a physical simulation model of the long core. The different reservoir media include fractures and matrix.

3. The similarity transformation method based on laboratory research of fractured and folded bodies as described in claim 2, characterized in that, The crossflow coefficients corresponding to different medium reservoirs are obtained through simulation using the following steps: For the core samples of different media reservoirs, the basic parameters corresponding to the different media reservoirs were measured respectively, wherein the basic parameters include porosity and permeability; Based on the physical simulation model of the long core, a depletion mining experiment was conducted, and multiple pressure measurement points were selected to obtain the pressure distribution curve during the mining process. The crossflow coefficients corresponding to different medium reservoirs are calculated by fitting the pressure distribution curve.

4. A similarity conversion method based on laboratory research of fractured and folded bodies as described in any one of claims 1-3, characterized in that, The similarity criterion corresponding to the fault-fold fracture gas reservoir is determined by the following steps: The physical quantities and dimensions involved in the exploitation of fault-fold fracture gas reservoirs are statistically analyzed, and the basic dimensions are classified and determined. Determine the dimensionless π-term exponential form of the physical quantity, and determine the linear equation system corresponding to each of the basic dimensions; Solving the linear equations yields the similarity criterion for physical simulation experiments of development similarity of fractured gas reservoirs with non-single-medium reservoirs.

5. A storage medium, characterized in that, It contains instructions for performing the method as described in any one of claims 1-4.

6. A similarity conversion system based on laboratory research of fractured and folded bodies, characterized in that, The system, which performs the method as described in any one of claims 1-4, comprises: The physical simulation model of long cores is designed for fault-fold fracture gas reservoirs with non-single-medium reservoirs. The exhaustion-type mining experimental equipment is used to simulate the crossflow coefficients of different media reservoirs in the fractured gas reservoir through the physical simulation model of the long core. The similarity conversion module, based on the similarity criterion, determines the similarity criterion corresponding to the fractured gas reservoir, introduces the crossflow coefficient, and establishes a calculation expression for the dynamic production data of the gas well in the mining area.

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