Fracture-vug type gas reservoir key parameter calculation method and device, computer equipment and storage medium

Abstract

The invention provides a fractured-vuggy gas reservoir key parameter calculation method and device, computer equipment and a storage medium, and the method comprises the steps: building a basic hypothesis based on a continuum mechanics theory; constructing a well-cave-fracture-cave-fracture calculation model by using the basic hypothesis; obtaining dimensionless variables; curve characteristics of the typical flow stage are obtained; solving the well-cave-fracture-cave-fracture calculation model through dimensionless variables and curve characteristics of the typical flow stage to obtain a dimensionless bottom hole pressure progressive solution of the typical flow stage; performing dimensionalization on the dimensionless bottom hole pressure progressive solution of the typical flow stage to obtain a dimensioned pressure derivative progressive solution of the typical flow stage; and calculating the fracture-cavity gas reservoir key parameters by using the progressive solution of the dimensioned pressure derivative of the typical flow stage. According to the method for calculating the key parameters of the fracture-vug gas reservoir, the key parameters of the fracture-vug gas reservoir are calculated, the multiplicity of solutions of pressure recovery well test interpretation of the fracture-vug gas reservoir is effectively overcome, and the interpretation precision of stratum parameters is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas exploration, and particularly to a method, device, computer equipment and storage medium for calculating key parameters of a fractured-vuggy gas reservoir. Background Art

[0002] As an important means of understanding gas reservoirs, pressure buildup well test interpretation has also become an essential and important link in oil and gas exploration and development work. It is the most direct means of clarifying underground formation parameters, related to the ultimate oil and gas evaluation prospects of a structure or a region, and is also the key to guiding further drilling, development and formulating stimulation measures. Pressure buildup well test interpretation is also known as pressure buildup test interpretation.

[0003] However, pressure buildup well test interpretation has multiple solutions. If the existing well test interpretation methods directly perform well test automatic fitting, the fitting is slow and the fitting accuracy is low, and the effect is not ideal. Therefore, a key parameter interpretation method for fractured-vuggy gas reservoirs based on the analysis of pressure buildup characteristic lines is proposed, which combines the characteristic solutions of typical flow stages to improve the accuracy of formation parameter interpretation. A fractured-vuggy gas reservoir is a complex type of geological reservoir, in which there are wellbores, fracture zones and solution cavities at the same time.

[0004] This paper proposes a key parameter interpretation method for fractured-vuggy gas reservoirs based on the analysis of pressure buildup curve characteristic lines, so as to improve the interpretation accuracy of wellbore, fracture zone and solution cavity parameters. From the establishment of the well-cavity-fracture-cavity-fracture calculation model, the characteristic solutions of each typical flow stage are obtained, and finally, combined with the well test data of an example well in a fractured-vuggy gas reservoir, the formation parameter interpretation and analysis are carried out. Summary of the Invention

[0005] Based on this, in view of the above technical problems, it is necessary to provide a method, device, computer equipment and storage medium for calculating key parameters of a fractured-vuggy gas reservoir.

[0006] A method for calculating key parameters of a fractured-vuggy gas reservoir includes:

[0007] Based on the theory of continuum mechanics, establish basic assumptions;

[0008] Using the basic assumptions, construct a well-cavity-fracture-cavity-fracture calculation model;

[0009] Obtain dimensionless variables;

[0010] Obtain the curve characteristics of typical flow stages;

[0011] Through the dimensionless variables and the curve characteristics of the typical flow stages, solve the well-cavity-fracture-cavity-fracture calculation model to obtain the dimensionless bottom-hole pressure asymptotic solution of the typical flow stage;

[0012] Dimensionlessize the asymptotic solution of the dimensionless bottom-hole pressure for the typical flow stage to obtain the asymptotic solution of the dimensional pressure derivative for the typical flow stage;

[0013] Use the asymptotic solution of the dimensional pressure derivative for the typical flow stage to calculate the key parameters of the fracture-cavity gas reservoir.

[0014] In one embodiment, the step of solving the well-cavity-fracture-cavity-fracture calculation model through the dimensionless variables and the curve characteristics of the typical flow stage to obtain the asymptotic solution of the dimensionless bottom-hole pressure for the typical flow stage includes:

[0015] Based on the dimensionless variables, perform dimensionless processing on the well-cavity-fracture-cavity-fracture calculation model to obtain the dimensionless processed well-cavity-fracture-cavity-fracture calculation model;

[0016] Use the curve characteristics of the typical flow stage to solve the dimensionless processed well-cavity-fracture-cavity-fracture calculation model to obtain the asymptotic solution of the dimensionless bottom-hole pressure for the typical flow stage.

[0017] In one embodiment, the typical flow stage includes wellbore storage flow, first cavern storage flow, fracture zone linear flow, and second cavern storage flow;

[0018] The step of obtaining the curve characteristics of the typical flow stage includes:

[0019] Obtain the curve characteristics of the wellbore storage flow;

[0020] Obtain the curve characteristics of the first cavern storage flow;

[0021] Obtain the curve characteristics of the fracture zone linear flow;

[0022] Obtain the curve characteristics of the second cavern storage flow;

[0023] The step of using the curve characteristics of the typical flow stage to solve the dimensionless processed well-cavity-fracture-cavity-fracture calculation model to obtain the asymptotic solution of the dimensionless bottom-hole pressure for the typical flow stage includes:

[0024] Use the curve characteristics of the wellbore storage flow to solve the dimensionless processed well-cavity-fracture-cavity-fracture calculation model to obtain the asymptotic solution of the dimensionless bottom-hole pressure for the wellbore storage flow;

[0025] Use the curve characteristics of the first cavern storage flow to solve the dimensionless processed well-cavity-fracture-cavity-fracture calculation model to obtain the asymptotic solution of the dimensionless bottom-hole pressure for the first cavern storage flow;

[0026] Using the curve characteristics of the linear flow in the fracture zone, solve the dimensionless well-cave-fracture-cave-fracture calculation model to obtain the dimensionless bottom-hole pressure asymptotic solution of the linear flow in the fracture zone;

[0027] Using the curve characteristics of the second cave storage flow, solve the dimensionless well-cave-fracture-cave-fracture calculation model to obtain the dimensionless bottom-hole pressure asymptotic solution of the second cave storage flow.

[0028] In one embodiment, the dimensional pressure derivative asymptotic solutions of the typical flow stages include the dimensional pressure derivative asymptotic solution of the wellbore storage flow, the dimensional pressure derivative asymptotic solution of the first cave storage flow, the dimensional pressure derivative asymptotic solution of the linear flow in the fracture zone, and the dimensional pressure derivative asymptotic solution of the second cave storage flow;

[0029] The steps of dimensionalizing the dimensionless bottom-hole pressure asymptotic solutions of the typical flow stages to obtain the dimensional pressure derivative asymptotic solutions of the typical flow stages include:

[0030] Dimensionalize the dimensionless bottom-hole pressure asymptotic solution of the wellbore storage flow to obtain the dimensional pressure derivative asymptotic solution of the wellbore storage flow;

[0031] Dimensionalize the dimensionless bottom-hole pressure asymptotic solution of the first cave storage flow to obtain the dimensional pressure derivative asymptotic solution of the first cave storage flow;

[0032] Dimensionalize the dimensionless bottom-hole pressure asymptotic solution of the linear flow in the fracture zone to obtain the dimensional pressure derivative asymptotic solution of the linear flow in the fracture zone;

[0033] Dimensionalize the dimensionless bottom-hole pressure asymptotic solution of the second cave storage flow to obtain the dimensional pressure derivative asymptotic solution of the second cave storage flow;

[0034] The key parameters of the fractured-vuggy gas reservoir include the wellbore storage coefficient, the first cave storage coefficient, the fracture zone permeability and fracture zone width, and the second cave storage coefficient;

[0035] The steps of calculating the key parameters of the fractured-vuggy gas reservoir by using the dimensional pressure derivative asymptotic solutions of the typical flow stages include:

[0036] Calculate the wellbore storage coefficient by using the dimensional pressure derivative asymptotic solution of the wellbore storage flow;

[0037] Calculate the first cave storage coefficient by using the dimensional pressure derivative asymptotic solution of the first cave storage flow;

[0038] Calculate the fracture zone permeability and fracture zone width by using the dimensional pressure derivative asymptotic solution of the linear flow in the fracture zone;

[0039] Calculate the wellbore storage coefficient by using the dimensional pressure derivative asymptotic solution of the second karst cave storage flow.

[0040] In one embodiment, after the step of dimensionless processing of the well-cave-fracture-cave-fracture calculation model based on the dimensionless variables to obtain the dimensionless well-cave-fracture-cave-fracture calculation model, the method further includes:

[0041] Perform Laplace transform on the dimensionless well-cave-fracture-cave-fracture calculation model to obtain the well-cave-fracture-cave-fracture calculation model in Laplace space;

[0042] The step of using the curve characteristics of the typical flow stage to solve the dimensionless well-cave-fracture-cave-fracture calculation model to obtain the dimensionless bottom-hole pressure asymptotic solution in the typical flow stage includes:

[0043] Use the curve characteristics of the typical flow stage to solve the well-cave-fracture-cave-fracture calculation model in Laplace space to obtain the dimensionless bottom-hole pressure asymptotic solution in Laplace space of the typical flow stage;

[0044] Based on the Laplace transform principle, convert the dimensionless bottom-hole pressure asymptotic solution in Laplace space of the typical flow stage into the dimensionless bottom-hole pressure asymptotic solution in real space of the typical flow stage;

[0045] The step of dimensionalizing the dimensionless bottom-hole pressure asymptotic solution in the typical flow stage to obtain the dimensional pressure derivative asymptotic solution in the typical flow stage includes:

[0046] Dimensionalize the dimensionless bottom-hole pressure asymptotic solution in real space of the typical flow stage to obtain the dimensional pressure derivative asymptotic solution in the typical flow stage.

[0047] In one embodiment, the step of dimensionless processing of the well-cave-fracture-cave-fracture calculation model based on the dimensionless variables to obtain the dimensionless well-cave-fracture-cave-fracture calculation model includes:

[0048] Obtain the typical flow characteristics in stages;

[0049] Based on the typical flow characteristics in stages, perform a preliminary solution on the well-cave-fracture-cave-fracture calculation model to obtain the preliminarily solved well-cave-fracture-cave-fracture calculation model;

[0050] Based on the dimensionless variables, perform dimensionless processing on the preliminarily processed well-cave-fracture-cave-fracture calculation model to obtain the dimensionless well-cave-fracture-cave-fracture calculation model.

[0051] A device for calculating key parameters of a fracture-vug gas reservoir, comprising:

[0052] A basic assumption establishment module for establishing basic assumptions based on the theory of continuum mechanics;

[0053] A model calculation module for constructing a well-fracture-vug-fracture-vug calculation model by using the basic assumptions;

[0054] A dimensionless variable acquisition module for acquiring dimensionless variables;

[0055] A characteristic acquisition module for acquiring the curve characteristics of typical flow stages;

[0056] A dimensionless asymptotic solution solving module for solving the well-fracture-vug-fracture-vug calculation model through the dimensionless variables and the curve characteristics of the typical flow stages to obtain the dimensionless bottom-hole pressure asymptotic solution of the typical flow stage;

[0057] A dimensionalization module for dimensionalizing the dimensionless bottom-hole pressure asymptotic solution of the typical flow stage to obtain the dimensional pressure derivative asymptotic solution of the typical flow stage;

[0058] A parameter calculation module for calculating the key parameters of the fracture-vug gas reservoir by using the dimensional pressure derivative asymptotic solution of the typical flow stage.

[0059] In one embodiment, the dimensionless asymptotic solution solving module includes:

[0060] A dimensionless processing unit for performing dimensionless processing on the well-fracture-vug-fracture-vug calculation model based on the dimensionless variables to obtain a dimensionless processed well-fracture-vug-fracture-vug calculation model;

[0061] A dimensionless asymptotic solution solving unit for solving the dimensionless processed well-fracture-vug-fracture-vug calculation model by using the curve characteristics of the typical flow stage to obtain the dimensionless bottom-hole pressure asymptotic solution of the typical flow stage.

[0062] A computer device includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements the steps of the method for calculating key parameters of the fracture-vug gas reservoir described in any of the above embodiments.

[0063] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, it implements the steps of the method for calculating key parameters of the fracture-vug gas reservoir described in any of the above embodiments.

[0064] The above-mentioned calculation method, device, computer equipment and storage medium for the key parameters of the fracture-vug gas reservoir calculate the key parameters of the fracture-vug gas reservoir by using the curve characteristics of typical flow stages. That is to say, the key parameters of the fracture-vug gas reservoir are reduced from the traditional parameter group to specific parameter values, effectively overcoming the multi-solution problem in the pressure build-up well test interpretation of the fracture-vug gas reservoir and improving the interpretation accuracy of formation parameters. Brief Description of the Drawings

[0065] Figure 1 It is a schematic diagram of the well-cave-fracture-cave-fracture mode in any embodiment;

[0066] Figure 2a It is the wellbore storage flow characteristic line in the calculation method of the key parameters of the fracture-vug gas reservoir in one embodiment;

[0067] Figure 2b It is the first cave storage flow characteristic line in the calculation method of the key parameters of the fracture-vug gas reservoir in one embodiment;

[0068] Figure 2c It is the fracture zone linear flow characteristic line in the calculation method of the key parameters of the fracture-vug gas reservoir in one embodiment;

[0069] Figure 2d It is the second cave storage flow characteristic line in the calculation method of the key parameters of the fracture-vug gas reservoir in one embodiment;

[0070] Figure 3 It is the characteristic line analysis diagram of the key parameter interpretation method for the fracture-vug gas reservoir based on the pressure build-up characteristic line analysis in another embodiment;

[0071] Figure 4 It is the internal structure diagram of the computer equipment in one embodiment;

[0072] Figure 5 It is the structural block diagram of the calculation device for the key parameters of the fracture-vug gas reservoir in one embodiment;

[0073] Figure 6 It is the flow schematic diagram of the calculation method for the key parameters of the fracture-vug gas reservoir in one embodiment. Detailed Embodiments

[0074] In order to make the objectives, technical solutions and advantages of the present application clearer and more understandable, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0075] Embodiment 1

[0076] In this embodiment, as Figure 6 shown, a calculation method for the key parameters of a fracture-vug gas reservoir includes:

[0077] Step 110: Based on the theory of continuum mechanics, establish basic assumptions.

[0078] In this embodiment, the basic assumptions are as follows: (1) The production of a single well is at a constant rate; (2) Consider the wellbore storage effect; (3) Consider the pressure loss between the first solution cavity and the fracture zone, the pressure loss within the fracture zone, and the pressure loss between the second solution cavity and the fracture zone; (4) The first solution cavity flows into the wellbore or the fracture zone in a storage flow (pseudo-steady state); (5) The outer fracture zone supplies the second solution cavity with a finite-conductivity linear flow.

[0079] In this embodiment, the pressure loss between the wellbore and the first solution cavity is caused by the fracture zone.

[0080] In this embodiment, due to the extremely complex internal storage space of the fractured-vuggy gas reservoir, basic assumptions need to be made to simplify the model while ensuring the fitting accuracy of the well-cavity-fracture-cavity-fracture calculation model constructed in the subsequent Step 120.

[0081] Step 120: Use the basic assumptions to construct a well-cavity-fracture-cavity-fracture calculation model.

[0082] In this embodiment, as Figure 1 shown, the storage space of the fractured-vuggy gas reservoir is mainly composed of fracture zones and solution cavities, and its development and distribution are extremely irregular. It is considered that the wellbore is drilled on a solution cavity, that is, the first solution cavity, and is connected to another solution cavity through the fracture zone, that is, connected to the second solution cavity, forming a well-cavity-fracture-cavity-fracture pattern.

[0083] In this embodiment, the well-cavity-fracture-cavity-fracture calculation model includes a partial differential equation, which is used to describe the linear flow of gas in the fracture zone (x a ≤x≤x b ). The calculation formula of the partial differential equation is as follows:

[0084]

[0085] Among them, p f is the fracture zone pressure, and the unit of p f is MPa; φ f is the fracture porosity, and the fracture porosity is dimensionless; t is the test time, and the unit of t is h; μ g is the gas viscosity, and the unit of μ g is mPa·s; c tf is the comprehensive fracture compressibility, and the unit of c tf is 1 / MPa; k f is the fracture permeability, and the unit of k f is μm 2 .

[0086] Step 130: Obtain dimensionless variables.

[0087] In this embodiment, the basic assumptions of the dimensionless variables are as follows:

[0088]

[0089]

[0090]

[0091]

[0092]

[0093]

[0094] Among them, p fD is the dimensionless fracture pressure; t D is the dimensionless time; F CD is the dimensionless conductivity; C vD is the dimensionless cavern storage coefficient; x D is the dimensionless length; r w is the wellbore radius, m; k r is the reference permeability, and the unit of k r is μm 2 ; μ r is the reference viscosity, and the unit of μ r is mPa·s; φ r is the reference porosity, dimensionless; c tr is the reference comprehensive compressibility, and the unit of c tr is 1 / MPa.

[0095] In this embodiment, dimensionless variables are introduced to process the mathematical model. The main function of dimensionless processing is to convert variables with different dimensions into dimensionless relative values for comparison and analysis in data analysis. Step 140, obtain the curve characteristics of the typical flow stage.

[0096] Step 150, solve the well-cavern-fracture-cavern-fracture calculation model through the dimensionless variables and the curve characteristics of the typical flow stage to obtain the asymptotic solution of the dimensionless bottom-hole pressure in the typical flow stage.

[0097] Step 160, dimensionalize the asymptotic solution of the dimensionless bottom-hole pressure in the typical flow stage to obtain the asymptotic solution of the dimensional pressure derivative in the typical flow stage.

[0098] Step 170, calculate the key parameters of the fracture-cavern gas reservoir by using the asymptotic solution of the dimensional pressure derivative in the typical flow stage.

[0099] In one embodiment, the step of solving the well-cavity-fracture-cavity-fracture calculation model through the dimensionless variables and the curve characteristics of the typical flow stages to obtain the asymptotic solution of the dimensionless bottom-hole pressure in the typical flow stages includes:

[0100] Based on the dimensionless variables, perform dimensionless processing on the well-cavity-fracture-cavity-fracture calculation model to obtain the dimensionless well-cavity-fracture-cavity-fracture calculation model after dimensionless processing;

[0101] Utilize the curve characteristics of the typical flow stages to solve the dimensionless well-cavity-fracture-cavity-fracture calculation model after dimensionless processing to obtain the asymptotic solution of the dimensionless bottom-hole pressure in the typical flow stages.

[0102] In this embodiment, the dimensionless well-cavity-fracture-cavity-fracture calculation model after dimensionless processing is as follows:

[0103]

[0104] In one embodiment, the typical flow stages include wellbore storage flow, first cavern storage flow, fracture zone linear flow, and second cavern storage flow;

[0105] The step of obtaining the curve characteristics of the typical flow stages includes:

[0106] Obtain the curve characteristics of the wellbore storage flow;

[0107] Obtain the curve characteristics of the first cavern storage flow;

[0108] Obtain the curve characteristics of the fracture zone linear flow;

[0109] Obtain the curve characteristics of the second cavern storage flow;

[0110] The step of utilizing the curve characteristics of the typical flow stages to solve the dimensionless well-cavity-fracture-cavity-fracture calculation model after dimensionless processing to obtain the asymptotic solution of the dimensionless bottom-hole pressure in the typical flow stages includes:

[0111] Utilize the curve characteristics of the wellbore storage flow to solve the dimensionless well-cavity-fracture-cavity-fracture calculation model after dimensionless processing to obtain the asymptotic solution of the dimensionless bottom-hole pressure in the wellbore storage flow;

[0112] Utilize the curve characteristics of the first cavern storage flow to solve the dimensionless well-cavity-fracture-cavity-fracture calculation model after dimensionless processing to obtain the asymptotic solution of the dimensionless bottom-hole pressure in the first cavern storage flow;

[0113] Utilize the curve characteristics of the fracture zone linear flow to solve the dimensionless well-cavity-fracture-cavity-fracture calculation model after dimensionless processing to obtain the asymptotic solution of the dimensionless bottom-hole pressure in the fracture zone linear flow;

[0114] Using the curve characteristics of the second cavern storage flow, solve the dimensionless well-cavern-fracture-cavern-fracture calculation model to obtain the dimensionless bottom-hole pressure asymptotic solution of the second cavern storage flow.

[0115] In this embodiment, the curve characteristics of each typical flow stage are the curve characteristics on the characteristic lines of each typical flow stage. Specifically as follows:

[0116] As Figure 2a shown, in this embodiment, the curve characteristic of the wellbore storage flow is that the pressure curve coincides with the pressure derivative curve and the slope is 1, and the dimensionless bottom-hole pressure asymptotic solution of the wellbore storage flow is In this embodiment, combined with the well storage characteristics, the dimensionless bottom-hole pressure asymptotic solution of the wellbore storage flow is obtained. The well storage characteristics in this embodiment are the wellbore storage flow characteristics.

[0117] As Figure 2b shown, in this embodiment, the curve characteristic of the first cavern storage flow is that the slope of the pressure derivative curve is 1. Only considering the wellbore and the first cavern, since the pressure wave has not propagated to the far end, the fracture zone has not participated in the seepage for the time being.

[0118] As Figure 2c shown, in this embodiment, the curve characteristic of the fracture zone linear flow is that the slope of the pressure curve and the slope of the pressure derivative curve are both Only considering the wellbore, the first cavern, and the fracture zone participating in the flow, since the pressure wave has not propagated to the far end, the second cavern at the far end has not participated in the seepage for the time being.

[0119] As Figure 2d shown, in this embodiment, the curve characteristic of the second cavern storage flow is that the slope of the pressure derivative curve is 1. Since the intercept of the second cavern storage flow is the superposition effect of the wellbore, the first cavern, and the second cavern storage flows, only the storage flows of the wellbore, the first cavern, and the second cavern are considered.

[0120] In one embodiment, the dimensional pressure derivative asymptotic solutions of the typical flow stages include the dimensional pressure derivative asymptotic solution of the wellbore storage flow, the dimensional pressure derivative asymptotic solution of the first cavern storage flow, the dimensional pressure derivative asymptotic solution of the fracture zone linear flow, and the dimensional pressure derivative asymptotic solution of the second cavern storage flow;

[0121] The steps of dimensionalizing the dimensionless bottom-hole pressure asymptotic solutions of the typical flow stages to obtain the dimensional pressure derivative asymptotic solutions of the typical flow stages include:

[0122] Dimensionalize the dimensionless bottom-hole pressure asymptotic solution of the wellbore storage flow to obtain the dimensional pressure derivative asymptotic solution of the wellbore storage flow;

[0123] Dimensionlessize the asymptotic solution of the bottom-hole pressure of the first karst reservoir flow to obtain the asymptotic solution of the dimensional pressure derivative of the first karst reservoir flow;

[0124] Dimensionlessize the asymptotic solution of the bottom-hole pressure of the fracture zone linear flow to obtain the asymptotic solution of the dimensional pressure derivative of the fracture zone linear flow;

[0125] Dimensionlessize the asymptotic solution of the bottom-hole pressure of the second karst reservoir flow to obtain the asymptotic solution of the dimensional pressure derivative of the second karst reservoir flow;

[0126] The key parameters of the fracture-cavity gas reservoir include the wellbore storage coefficient, the first karst reservoir coefficient, the fracture zone permeability, the fracture zone width, and the second karst reservoir coefficient;

[0127] The steps of calculating the key parameters of the fracture-cavity gas reservoir by using the asymptotic solution of the dimensional pressure derivative of the typical flow stage include:

[0128] Calculate the wellbore storage coefficient by using the asymptotic solution of the dimensional pressure derivative of the wellbore storage flow;

[0129] Calculate the first karst reservoir coefficient by using the asymptotic solution of the dimensional pressure derivative of the first karst reservoir flow;

[0130] Calculate the fracture zone permeability and the fracture zone width by using the asymptotic solution of the dimensional pressure derivative of the fracture zone linear flow;

[0131] Calculate the wellbore storage coefficient by using the asymptotic solution of the dimensional pressure derivative of the second karst reservoir flow.

[0132] In this embodiment, the asymptotic solution of the dimensional pressure derivative of the wellbore storage flow is:

[0133]

[0134] The asymptotic solution of the dimensional pressure derivative of the first karst reservoir flow is:

[0135]

[0136] The asymptotic solution of the dimensional pressure derivative of the fracture zone linear flow is:

[0137]

[0138] The asymptotic solution of the dimensional pressure derivative of the second karst reservoir flow is:

[0139]

[0140] In this embodiment, the asymptotic solution of the dimensional pressure derivative of the wellbore storage flow can explain the wellbore storage coefficient C w; The dimensional pressure derivative asymptotic solution of the first karst reservoir flow can explain the first karst reservoir storage coefficient C v1 ; The dimensional pressure derivative asymptotic solution of the fracture zone linear flow can explain the fracture zone permeability and the fracture zone width related to the fracture zone permeability k f and the fracture zone width w f . After solving the fracture zone permeability k through the overall fitting of the parameter group f , the fracture zone width w can be obtained f ; The dimensional pressure derivative asymptotic solution of the second karst reservoir flow can explain the second karst reservoir storage coefficient C v2 . The application of the characteristic line analysis method greatly reduces the multi-solution problem and improves the interpretation efficiency, with an average of interpreting single well parameters within 2 minutes

[0141] In this embodiment, the fracture zone permeability and the fracture zone width include the fracture zone width and the permeability

[0142] In this embodiment, the key parameters of the fracture-cave gas reservoir are explained through the dimensional pressure derivative asymptotic solutions of each typical flow stage. The key parameters of the fracture-cave gas reservoir include the determined values or initial values of the parameters and the parameter group. The parameters include the wellbore storage coefficient, the volume of the first karst cave, and the volume of the second karst cave. The parameter group includes the fracture zone width and permeability, and the fracture zone length and permeability

[0143] In one embodiment, after the step of performing dimensionless processing on the well-cave-fracture-cave-fracture calculation model based on the dimensionless variables to obtain the dimensionless well-cave-fracture-cave-fracture calculation model, it further includes:

[0144] Performing Laplace transform on the dimensionless well-cave-fracture-cave-fracture calculation model to obtain the well-cave-fracture-cave-fracture calculation model in the Laplace space;

[0145] The step of using the curve characteristics of the typical flow stage to solve the dimensionless well-cave-fracture-cave-fracture calculation model after dimensionless processing to obtain the dimensionless bottom-hole pressure asymptotic solution of the typical flow stage includes:

[0146] Using the curve characteristics of the typical flow stage to solve the well-cave-fracture-cave-fracture calculation model in the Laplace space to obtain the dimensionless bottom-hole pressure asymptotic solution in the Laplace space of the typical flow stage;

[0147] Based on the Laplace transform principle, converting the dimensionless bottom-hole pressure asymptotic solution in the Laplace space of the typical flow stage into the dimensionless bottom-hole pressure asymptotic solution in the real space of the typical flow stage;

[0148] The step of dimensionalizing the dimensionless bottom-hole pressure asymptotic solution of the typical flow stage to obtain the asymptotic solution of the dimensional pressure derivative of the typical flow stage includes:

[0149] Dimensionalize the dimensionless bottom-hole pressure asymptotic solution in the real space of the typical flow stage to obtain the asymptotic solution of the dimensional pressure derivative of the typical flow stage.

[0150] In this embodiment, the calculation formula of the well-cavity-fracture-cavity-fracture calculation model in the Laplace space is as follows:

[0151]

[0152] In this embodiment, the dimensionless bottom-hole pressure asymptotic solution in the Laplace space of the wellbore storage flow is:

[0153]

[0154] The dimensionless bottom-hole pressure asymptotic solution in the real space of the wellbore storage flow is:

[0155]

[0156] The dimensionless bottom-hole pressure asymptotic solution in the Laplace space of the first cavity storage flow is:

[0157]

[0158] The dimensionless bottom-hole pressure asymptotic solution in the real space of the first cavity storage flow is:

[0159]

[0160] The dimensionless bottom-hole pressure asymptotic solution in the Laplace space of the fracture zone linear flow is:

[0161]

[0162] The dimensionless bottom-hole pressure asymptotic solution in the real space of the fracture zone linear flow is:

[0163]

[0164] The dimensionless bottom-hole pressure asymptotic solution in the Laplace space of the second cavity storage flow is:

[0165]

[0166] The dimensionless bottom-hole pressure asymptotic solution in the real space of the second cavity storage flow is:

[0167]

[0168] In this embodiment, according to the definitions of dimensionless variables such as pressure, time, storage coefficient, etc., the dimensional pressure derivative solutions for each typical flow stage are solved.

[0169] In one embodiment, the step of performing dimensionless treatment on the well-cavity-fracture-cavity-fracture calculation model based on the dimensionless variables to obtain the dimensionless well-cavity-fracture-cavity-fracture calculation model includes:

[0170] Obtain the typical flow characteristics in stages;

[0171] Based on the typical flow characteristics in stages, perform a preliminary solution on the well-cavity-fracture-cavity-fracture calculation model to obtain the preliminarily solved well-cavity-fracture-cavity-fracture calculation model;

[0172] Based on the dimensionless variables, perform dimensionless treatment on the preliminarily processed well-cavity-fracture-cavity-fracture calculation model to obtain the dimensionless well-cavity-fracture-cavity-fracture calculation model.

[0173] In this embodiment, the process of the preliminary solution is as follows:

[0174] The fracture zone is connected to the wellbore at x = x a Ignoring wellbore storage and skin effect for the time being, that is:

[0175]

[0176] In the formula, q is the gas well production rate, and the unit of q is m 3 / d; B is the volume coefficient, and the unit of B is m 3 / m 3 ; w f is the width of the fracture zone, and the unit of w f is m; h is the effective thickness of the oil layer, and the unit of h is m.

[0177] The connection between the cavity and the fracture is the connection between the second cavity and the fracture zone. Considering that the second cavity is an equipotential body completely filled with gas and ignoring the loss of the pressure wave at the connection between the fracture zone and the second cavity, that is, at x = x b the internal pressure p v of the second cavity is equal to the pressure at the connection between the cavity and the fracture, that is:

[0178]

[0179] Due to considering the elastic expansion of the gas in the cavity, the flow continuity at the connection between the cavity and the fracture (x = x b ) can be considered as:

[0180]

[0181] In the formula, p vis the pressure of the karst cave, p v The unit of which is MPa; R v is the radius of the karst cave, R v The unit of which is m; φ v is the porosity of the karst cave, φ v is dimensionless; c tv is the comprehensive compressibility of the karst cave, c tv The unit of which is 1 / MPa;

[0182] The bottom hole is the bottom of the wellbore. At the initial moment, the pressures at the bottom hole, the fracture zone, the first karst cave and the second karst cave are equal, that is:

[0183] p f | t＝0 = p w | t＝0 = p v | t＝0 = 0

[0184] For the traditional method of fitting the key parameter group of the fracture-cavity gas reservoir, what is obtained is the parameter group, which has a series of pressures and pressure derivatives. By continuously iterating the parameter group, the measured pressure and pressure derivative are fitted to the typical chart, and a series of values of the parameter group are interpreted. However, the number of such parameter groups is large and the multi-solution property is very strong. To solve the problem of multi-solution of parameters, the above-mentioned method for calculating the key parameters of the fracture-cavity gas reservoir directly calculates the parameters. First, the linear characteristics are demonstrated, and the parameters are calculated through the intercept of the linear characteristics or its time, so that the number of parameter groups will be greatly reduced.

[0185] The above-mentioned method for calculating the key parameters of the fracture-cavity gas reservoir calculates the key parameters of the fracture-cavity gas reservoir by using the curve characteristics of the typical flow stage. That is to say, the key parameters of the fracture-cavity gas reservoir are reduced from the traditional parameter group to specific parameter values, effectively overcoming the multi-solution property of the pressure build-up well test interpretation of the fracture-cavity gas reservoir and improving the interpretation accuracy of formation parameters.

[0186] It should be understood that although Figure 6 each step in the flowchart of Figure 6 is shown in sequence according to the indication of the arrow, these steps are not necessarily executed in the order indicated by the arrow. Unless there is a clear indication in this article, the execution of these steps has no strict order limit, and these steps can be executed in other orders. Moreover,

[0187] Embodiment 2

[0188] In this embodiment, a method for interpreting key parameters of a fractured-vuggy gas reservoir based on pressure build-up characteristic line analysis is provided, including constructing a well-cavity-fracture-cavity-fracture calculation model, solving the bottom-hole dimensionless pressure solution in typical flow stages, solving the pressure derivative characteristic line solution in typical flow stages, and forming a characteristic line analysis method. Among them,

[0189] (1) Construction of the well-cavity-fracture-cavity-fracture calculation model: The storage space of a fractured-vuggy gas reservoir is mainly composed of fracture zones and cavities, and their development and distribution are extremely irregular. Considering that the wellbore is drilled on a cavity, that is, the first cavity, and is connected to another cavity through a fracture zone, that is, connected to the second cavity, a well-cavity-fracture-cavity-fracture pattern is formed, as Figure 1 shown. In this embodiment, it is not limited to constructing a well-cavity-fracture-cavity-fracture calculation model, and a well-cavity-fracture-cavity-fracture interpretation model can also be constructed. One cavity in this embodiment is the first cavity in the above embodiment, and the other cavity in this embodiment is the second cavity in the above embodiment.

[0190] The basic assumptions of the model are as follows: (1) The single well produces at a constant rate; (2) The wellbore storage effect is considered; (3) The pressure losses between the well and the cavity, and between the cavity and the fracture, as well as the pressure loss in the fracture, are considered; (4) The cavity flows into the wellbore or fracture zone in a storage flow (pseudo-steady state); (5) The outer fracture zone supplies the cavity with a finite-conductivity linear flow.

[0191] Based on the basic assumptions, a mathematical model is constructed to describe the partial differential equation of the linear flow of gas in the fracture zone (x a ≤x≤x b ) as follows:

[0192]

[0193] In the formula: p f is the pressure in the fracture zone, and the unit of p f is MPa; φ f is the fracture porosity, and φ f is dimensionless; t is the test time, and the unit of t is h; μ g is the gas viscosity, and the unit of μ g is mPa·s; c tf is the comprehensive compressibility of the fracture, and the unit of c tf is 1 / MPa; k f is the fracture permeability, and the unit of k f is μm 2 .

[0194] The model and mathematical model in this embodiment are both the well-cavity-fracture-cavity-fracture calculation model in the above embodiment.

[0195] The fracture is at x = xa is connected to the wellbore. The fracture in this embodiment is the fracture zone in the above embodiment. The wellbore storage and skin effect are not considered for the time being, that is:

[0196]

[0197] In the formula, q is the gas well production, and the unit of q is m 3 / d; B is the volume coefficient, and the unit of B is m 3 / m 3 ; w f is the width of the fracture zone, and the unit of w f is m; h is the effective thickness of the oil reservoir, and the unit of h is m.

[0198] The connection between the cave and the fracture is the connection between the second cave and the fracture zone. Considering that the second cave is an equipotential body completely filled with gas, the loss of the pressure wave at the connection between the fracture zone and the second cave is not considered. That is, at x = x b , the internal pressure p v of the second cave is equal to the pressure at the connection between the cave and the fracture, that is:

[0199]

[0200] Due to considering the elastic expansion of the gas in the cave, the flow continuity at the connection between the cave and the fracture (x = x b ) can be considered as:

[0201]

[0202] In the formula, p v is the pressure of the cave, and the unit of p v is MPa; R v is the radius of the cave, and the unit of R v is m; φ v is the porosity of the cave, and φ v is dimensionless; c tv is the comprehensive compressibility of the cave, and the unit of c tv is 1 / MPa;

[0203] The bottom hole is the bottom of the wellbore. At the initial moment, the pressures at the bottom hole, the fracture zone, the first cave and the second cave are equal, that is:

[0204] p f | t＝0 = p w | t＝0 = p v | t＝0 = 0

[0205] To facilitate the solution of the mathematical model, dimensionless variables are introduced to process the mathematical model. The basic assumptions of the dimensionless variables are as follows:

[0206]

[0207]

[0208]

[0209]

[0210]

[0211]

[0212] In the formula, p fD is the dimensionless fracture pressure; t D is the dimensionless time; F CD is the dimensionless conductivity; C vD is the dimensionless solution coefficient of the karst cave reservoir; x D is the dimensionless length; r w is the wellbore radius, the unit of r w is m; k r is the reference permeability, the unit of k r is μm 2 ; μ r is the reference viscosity, the unit of μ r is mPa·s; φ r is the reference porosity, dimensionless; c tr is the reference comprehensive compressibility coefficient, the unit of c tr is 1 / MPa.

[0213] Substitute the above dimensionless variables into the mathematical model, and the dimensionless mathematical model after processing is as follows:

[0214]

[0215] After Laplace transform, the mathematical model in the Laplace space can be obtained as:

[0216]

[0217] The mathematical model in the Laplace space in this embodiment is the well-cave-fracture-cave-fracture calculation model in the Laplace space in the above embodiment. The Laplace transform in this embodiment is the above Laplace transform.

[0218] (2) Solution of the dimensionless bottom-hole pressure in the typical flow stage: For the problem of multiple solutions in well test interpretation, combined with the typical flow stage of the well-cave-fracture-cave-fracture model, the asymptotic solution of the dimensionless bottom-hole pressure is solved. The derivation idea is as follows:

[0219] For wellbore storage flow: The curve characteristics are that the pressure and pressure derivative curves coincide and the slope is 1. Combining with the characteristics of fixed well storage, the characteristic solution of wellbore storage flow is:

[0220]

[0221] For cavern 1 storage flow: The curve characteristic is that the slope of the pressure derivative curve is 1. Only considering the wellbore and cavern 1, since the pressure wave has not propagated to the far end, the fracture zone has not participated in the seepage for the time being. Solve the bottom hole pressure by coupling the cavern pressure:

[0222]

[0223] The dimensionless bottom hole pressure solution of cavern 1 storage flow in Laplace space is:

[0224]

[0225] The dimensionless bottom hole pressure solution of cavern 1 storage flow in real space is:

[0226]

[0227] For fracture zone linear flow: The curve characteristics are that the slopes of the pressure and pressure derivative curves are 1 / 2. Only considering the wellbore, cavern 1, and fracture zone participating in the flow, since the pressure wave has not propagated to the far end, the far-end cavern 2 has not participated in the seepage for the time being. Solve the bottom hole pressure by coupling the fracture pressure and cavern pressure:

[0228]

[0229] The dimensionless bottom hole pressure solution of fracture zone linear flow in Laplace space is:

[0230]

[0231] The dimensionless bottom hole pressure solution of fracture zone linear flow in real space is:

[0232]

[0233] For cavern 2 storage flow: The curve characteristic is that the slope of the pressure derivative curve is 1. Since the intercept of cavern 2 storage flow is the superposition effect of the wellbore, cavern 1, and cavern 2 storage flows, only consider the storage flows of the wellbore, cavern 1, and cavern 2. Solve the bottom hole pressure by coupling the wellbore and cavern pressures:

[0234]

[0235] The dimensionless bottom hole pressure solution of cavern 2 storage flow in Laplace space is:

[0236]

[0237] The dimensionless bottom-hole pressure solution in real space for the storage flow in karst cave 2 is as follows:

[0238]

[0239] Through the above solution of the bottom-hole pressure based on the well-cave-fracture-cave-fracture model, the typical flow stages can be obtained as wellbore storage flow, storage flow in cave 1, fracture linear flow, and the asymptotic solution of the pressure for the storage flow in karst cave 2, as shown in Table 1.

[0240] Table 1 Asymptotic solutions of pressure for typical flow stages

[0241]

[0242] (3) Characteristic line solution of pressure derivative for typical flow stages: Based on the dimensionless bottom-hole pressure solution, the asymptotic solution of the dimensional pressure derivative is further solved. The determined values or initial values of the parameters (well storage coefficient, karst cave volume) and parameter groups (fracture zone width and fracture zone permeability, fracture zone length and fracture zone permeability) are explained through four characteristic lines.

[0243] According to the definitions of dimensionless variables such as pressure, time, and storage coefficient, the dimensional pressure derivative solutions for each typical flow stage are solved.

[0244] The dimensional pressure derivative solution for wellbore storage flow is as follows:

[0245]

[0246] The dimensional pressure derivative solution for the storage flow in karst cave 1 is as follows:

[0247]

[0248] The dimensional pressure derivative solution for fracture zone linear flow is as follows:

[0249]

[0250] The dimensional pressure derivative solution for the storage flow in karst cave 2 is as follows:

[0251]

[0252] (4) Characteristic line analysis method: The asymptotic solution of the dimensional pressure derivative for wellbore storage flow can explain the wellbore storage coefficient C w ; the asymptotic solution of the dimensional pressure derivative for the storage flow in karst cave 1 can explain the storage coefficient C of cave 1 v1 ; the asymptotic solution of the dimensional pressure derivative for fracture zone linear flow can explain the fracture zone width and permeability The asymptotic solution of the dimensional pressure derivative for the storage flow in karst cave 2 can explain the storage coefficient C of cave 2 v2 . The application of the characteristic line analysis method greatly reduces the multi-solution problem and improves the interpretation efficiency, with an average of explaining single-well parameters within 2 minutes.

[0253] The karst cave 1 and cave 1 in this embodiment are both the first karst caves in the above embodiment, and the karst cave 2 and cave 2 in this embodiment are both the second karst caves in the above embodiment. The dimensional pressure derivative solution in this embodiment is the dimensional pressure derivative asymptotic solution in the above embodiment. The typical stage of this embodiment is the typical flow stage in the above embodiment. The pressure asymptotic solution in this embodiment is the dimensionless bottom-hole pressure asymptotic solution in the above embodiment. The dimensional pressure derivative solution in this embodiment is the dimensional pressure derivative asymptotic solution in the above embodiment.

[0254] The application of the characteristic line analysis method in the present invention greatly reduces the multi-solution problem and improves the interpretation efficiency, and can interpret single-well parameters within an average of 2 minutes.

[0255] For the traditional method of fitting the key parameter group for interpreting fractured-vuggy gas reservoirs, what is obtained is a parameter group with a series of pressures and pressure derivatives. By continuously iterating the parameter group, the measured pressure and pressure derivative are fitted to the typical chart, and a series of parameter group values are interpreted. However, there are many such parameter groups and the multi-solution problem is very strong. To solve the multi-solution problem of parameters, the above-mentioned method for interpreting key parameters of fractured-vuggy gas reservoirs based on pressure build-up characteristic line analysis directly calculates the parameters. First, the linear characteristics are demonstrated, and the parameters are calculated through the intercept of the linear characteristics or its time, so that the number of parameter groups will be greatly reduced.

[0256] Embodiment III

[0257] In this embodiment, another method for interpreting key parameters of fractured-vuggy gas reservoirs based on pressure build-up characteristic line analysis is provided, which includes:

[0258] An example well conforming to the well-cave-fracture-cave-fracture pattern is selected. By dragging the characteristic line to the corresponding flow stage, the parameters of the wellbore, fracture zone and karst cave are effectively interpreted, such as the wellbore storage coefficient, fracture zone length, karst cave volume, etc.

[0259] Select a typical well conforming to the well-cave-fracture-cave-fracture distribution for characteristic line analysis. First, by dragging the characteristic line, it is corresponded to the corresponding flow stage, such as Figure 3 as shown.

[0260] Using the characteristic line analysis method, the key parameter interpretation values of the wellbore, fracture zone and karst cave can be obtained, which are respectively: well storage coefficient Cw = 2.16 m 3 / MPa; skin factor S = 0.6863; volume of karst cave 1

[0261] V V1 = 6.53×10 4 m 3 ; fracture zone permeability k f= 0.52D; the width of the fracture zone wf = 47.85 m; the length of the fracture zone x f = 245.99 m; the volume of the second cavern V V2 = 39.4×10 4 m 3 。

[0262] The characteristic line in this embodiment is the characteristic line of the typical flow stage in the above embodiment, including the characteristic line of wellbore storage flow, the characteristic line of the first cavern storage flow, the characteristic line of fracture zone linear flow, and the characteristic line of the second cavern storage flow. The characteristic line of wellbore storage flow in this embodiment has the curve characteristics of wellbore storage flow in the above embodiment. The characteristic line of the first cavern storage flow in this embodiment has the curve characteristics of the first cavern storage flow in the above embodiment. The characteristic line of fracture zone linear flow in this embodiment has the curve characteristics of fracture zone linear flow in the above embodiment. The characteristic line of the second cavern storage flow in this embodiment has the curve characteristics of the second cavern storage flow in the above embodiment. The V in this embodiment V1 is V1 in the above embodiment. The V in this embodiment V2 is V2 in the above embodiment.

[0263] The application of the characteristic line analysis method in the present invention greatly reduces the multi-solution problem and improves the interpretation efficiency, with the average interpretation of single well parameters within 2 minutes.

[0264] For the traditional method of fitting the key parameter group for interpreting fractured-vuggy gas reservoirs, what is obtained is a parameter group, with a series of pressures and pressure derivatives. By continuously iterating the parameter group, the measured pressures and pressure derivatives are fitted to the typical chart, and a series of values of the parameter group are interpreted. However, there are a large number of such parameter groups and the multi-solution problem is very strong. To solve the problem of multi-solution of parameters, the above-mentioned method for interpreting key parameters of fractured-vuggy gas reservoirs based on pressure buildup characteristic line analysis directly calculates the parameters. First, the linear characteristics are demonstrated, and the parameters are calculated through the intercept of the linear characteristics or its time, so that the number of parameter groups will be greatly reduced.

[0265] Embodiment 4

[0266] In this embodiment, as Figure 5 shown, a device for calculating key parameters of a fractured-vuggy gas reservoir is provided, including:

[0267] A basic assumption establishment module 210, configured to establish basic assumptions based on the theory of continuous medium mechanics;

[0268] A model calculation module 220, configured to construct a well-cavern-fracture-cavern-fracture calculation model by using the basic assumptions;

[0269] A variable acquisition module 230, configured to acquire dimensionless variables;

[0270] A feature acquisition module 240, configured to acquire curve features of typical flow stages;

[0271] A dimensionless asymptotic solution solving module 250, configured to solve the well-cavity-fracture-cavity-fracture calculation model by using the dimensionless variables and the curve features of the typical flow stages, so as to obtain a dimensionless bottom-hole pressure asymptotic solution of the typical flow stage;

[0272] A dimensionalization module 260, configured to perform dimensionalization on the dimensionless bottom-hole pressure asymptotic solution of the typical flow stage, so as to obtain a dimensional pressure derivative asymptotic solution of the typical flow stage;

[0273] A parameter calculation module 270, configured to calculate key parameters of a fractured-vuggy gas reservoir by using the dimensional pressure derivative asymptotic solution of the typical flow stage.

[0274] In one embodiment, the dimensionless asymptotic solution solving module includes:

[0275] A dimensionless processing unit, configured to perform dimensionless processing on the well-cavity-fracture-cavity-fracture calculation model based on the dimensionless variables, so as to obtain a dimensionless processed well-cavity-fracture-cavity-fracture calculation model;

[0276] A dimensionless asymptotic solution solving unit, configured to solve the dimensionless processed well-cavity-fracture-cavity-fracture calculation model by using the curve features of the typical flow stage, so as to obtain a dimensionless bottom-hole pressure asymptotic solution of the typical flow stage.

[0277] In one embodiment, the feature acquisition module is further configured to:

[0278] Acquire curve features of wellbore storage flow;

[0279] Acquire curve features of the first vug storage flow;

[0280] Acquire curve features of fracture zone linear flow;

[0281] Acquire curve features of the second vug storage flow;

[0282] The dimensionless asymptotic solution solving unit is further configured to:

[0283] Solve the dimensionless processed well-cavity-fracture-cavity-fracture calculation model by using the curve features of the wellbore storage flow, so as to obtain a dimensionless bottom-hole pressure asymptotic solution of the wellbore storage flow;

[0284] Solve the dimensionless processed well-cavity-fracture-cavity-fracture calculation model by using the curve features of the first vug storage flow, so as to obtain a dimensionless bottom-hole pressure asymptotic solution of the first vug storage flow;

[0285] Using the curve characteristics of the linear flow in the fracture zone, solve the dimensionless well-cavity-fracture-cavity-fracture calculation model to obtain the dimensionless bottom-hole pressure asymptotic solution of the linear flow in the fracture zone;

[0286] Using the curve characteristics of the second cavern storage flow, solve the dimensionless well-cavity-fracture-cavity-fracture calculation model to obtain the dimensionless bottom-hole pressure asymptotic solution of the second cavern storage flow.

[0287] In this embodiment, the typical flow stages include wellbore storage flow, the first cavern storage flow, linear flow in the fracture zone, and the second cavern storage flow.

[0288] In one embodiment, the dimensionalization module is further configured to:

[0289] Dimensionalize the dimensionless bottom-hole pressure asymptotic solution of the wellbore storage flow to obtain the dimensional pressure derivative asymptotic solution of the wellbore storage flow;

[0290] Dimensionalize the dimensionless bottom-hole pressure asymptotic solution of the first cavern storage flow to obtain the dimensional pressure derivative asymptotic solution of the first cavern storage flow;

[0291] Dimensionalize the dimensionless bottom-hole pressure asymptotic solution of the linear flow in the fracture zone to obtain the dimensional pressure derivative asymptotic solution of the linear flow in the fracture zone;

[0292] Dimensionalize the dimensionless bottom-hole pressure asymptotic solution of the second cavern storage flow to obtain the dimensional pressure derivative asymptotic solution of the second cavern storage flow;

[0293] The key parameters of the fractured-vuggy gas reservoir include wellbore storage coefficient, the first cavern storage coefficient, fracture zone permeability, fracture zone width, and the second cavern storage coefficient;

[0294] The parameter calculation module is further configured to:

[0295] Calculate the wellbore storage coefficient using the dimensional pressure derivative asymptotic solution of the wellbore storage flow;

[0296] Calculate the first cavern storage coefficient using the dimensional pressure derivative asymptotic solution of the first cavern storage flow;

[0297] Calculate the fracture zone permeability and fracture zone width using the dimensional pressure derivative asymptotic solution of the linear flow in the fracture zone;

[0298] Calculate the wellbore storage coefficient using the dimensional pressure derivative asymptotic solution of the second cavern storage flow.

[0299] In this embodiment, the dimensional pressure derivative asymptotic solutions of the typical flow stages include the dimensional pressure derivative asymptotic solution of wellbore storage flow, the dimensional pressure derivative asymptotic solution of the first cavern storage flow, the dimensional pressure derivative asymptotic solution of fracture zone linear flow, and the dimensional pressure derivative asymptotic solution of the second cavern storage flow.

[0300] In one embodiment, the device further includes:

[0301] A Laplace transform module, configured to perform Laplace transform on the dimensionless processed well-cavern-fracture-cavern-fracture calculation model to obtain a well-cavern-fracture-cavern-fracture calculation model in Laplace space;

[0302] The dimensionless asymptotic solution solving unit includes:

[0303] A solving subunit, configured to solve the well-cavern-fracture-cavern-fracture calculation model in Laplace space by using the curve characteristics of the typical flow stages to obtain a dimensionless bottom-hole pressure asymptotic solution in Laplace space of the typical flow stages;

[0304] A conversion subunit, configured to convert the dimensionless bottom-hole pressure asymptotic solution in Laplace space of the typical flow stages into a dimensionless bottom-hole pressure asymptotic solution in real space of the typical flow stages based on the Laplace transform principle;

[0305] The dimensioning module is further configured to:

[0306] Perform dimensioning on the dimensionless bottom-hole pressure asymptotic solution in real space of the typical flow stages to obtain a dimensional pressure derivative asymptotic solution of the typical flow stages.

[0307] In one embodiment, the dimensionless processing unit includes:

[0308] A flow characteristic acquisition subunit, configured to acquire staged typical flow characteristics;

[0309] A preliminary solving subunit, configured to perform preliminary solution on the well-cavern-fracture-cavern-fracture calculation model based on the staged typical flow characteristics to obtain a well-cavern-fracture-cavern-fracture calculation model after preliminary solution;

[0310] A dimensionless processing subunit, configured to perform dimensionless processing on the well-cavern-fracture-cavern-fracture calculation model after preliminary processing based on the dimensionless variables to obtain a dimensionless processed well-cavern-fracture-cavern-fracture calculation model.

[0311] The traditional device for fitting key parameter groups of fractured-vuggy gas reservoirs calculates parameter groups, which include a series of pressures and pressure derivatives. By continuously iterating the parameter groups, the measured pressures and pressure derivatives are fitted to the typical graph, and a series of values of parameter groups are interpreted. However, the number of parameter groups is large and the multi-solution problem is strong. To solve the problem of multi-solution of parameters, the above-mentioned device for calculating key parameters of fractured-vuggy gas reservoirs directly calculates the parameters. First, the linear characteristics are demonstrated, and the parameters are calculated through the intercept of the linear characteristics or its time, so that the number of parameter groups will be greatly reduced.

[0312] For the specific limitations of the device for calculating key parameters of fractured-vuggy gas reservoirs, reference can be made to the limitations of the method for calculating key parameters of fractured-vuggy gas reservoirs in the above text, which will not be elaborated here. Each unit in the above-mentioned device for calculating key parameters of fractured-vuggy gas reservoirs can be implemented in whole or in part by software, hardware, and their combinations. The above-mentioned units can be embedded in the processor of the computer device in hardware form or be independent of it, or can be stored in the memory of the computer device in software form, so as to facilitate the processor to call and execute the operations corresponding to each of the above units.

[0313] Example Five

[0314] In this example, a computer device is provided. Its internal structure diagram can be as Figure 4 shown. The computer device includes a processor, a memory, a network interface, a display screen, and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program, and a database is deployed on the non-volatile storage medium, and the database is used to store the curve characteristics of typical flow stages. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The network interface of the computer device is used to communicate with other computer devices on which application software is deployed. When the computer program is executed by the processor, it realizes a method for calculating key parameters of fractured-vuggy gas reservoirs. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen. The input device of the computer device can be a touch layer covered on the display screen, or a button, a trackball, or a touchpad set on the shell of the computer device, or an external keyboard, a touchpad, or a mouse, etc.

[0315] Those skilled in the art can understand that Figure 4 the structure shown in

[0316] In one embodiment, a computer device is provided, including a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, the steps of the method for calculating key parameters of a fractured-vuggy gas reservoir described in any of the above embodiments are implemented.

[0317] For a traditional computer device for interpreting the fitting of key parameter groups of a fractured-vuggy gas reservoir, what is obtained is a parameter group, which has a series of pressures and pressure derivatives. By continuously iterating the parameter group, the measured pressures and pressure derivatives are fitted to a typical chart, and a series of values of the parameter group are interpreted. However, in this way, the number of parameter groups is large and the multi-solution property is very strong. To solve the problem of the multi-solution property of parameters, the above computer device directly calculates the parameters. First, the linear characteristics are demonstrated, and the parameters are calculated through the intercept of the linear characteristics or its time, so that the number of parameter groups will be greatly reduced.

[0318] Embodiment Six

[0319] In this embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the method for calculating key parameters of a fractured-vuggy gas reservoir described in any of the above embodiments are implemented.

[0320] For a traditional computer-readable storage medium for interpreting the fitting of key parameter groups of a fractured-vuggy gas reservoir, what is obtained is a parameter group, which has a series of pressures and pressure derivatives. By continuously iterating the parameter group, the measured pressures and pressure derivatives are fitted to a typical chart, and a series of values of the parameter group are interpreted. However, in this way, the number of parameter groups is large and the multi-solution property is very strong. To solve the problem of the multi-solution property of parameters, the above computer-readable storage medium directly calculates the parameters. First, the linear characteristics are demonstrated, and the parameters are calculated through the intercept of the linear characteristics or its time, so that the number of parameter groups will be greatly reduced.

[0321] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, storage, database, or other medium used in the various embodiments provided in the present application can include non-volatile and / or volatile memories. Non-volatile memories can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memories can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and Rambus dynamic RAM (RDRAM), etc.

[0322] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0323] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A calculation method for key parameters of a fracture-vuggy gas reservoir, characterized in that including: Based on the theory of continuum mechanics, establish basic assumptions; Using the basic assumptions, construct a well-cave-fracture-cave-fracture calculation model; Obtain dimensionless variables; Obtain the curve characteristics of typical flow stages; Through the dimensionless variables and the curve characteristics of the typical flow stages, solve the well-cave-fracture-cave-fracture calculation model to obtain the dimensionless bottom-hole pressure asymptotic solution of the typical flow stage; Dimensionalize the dimensionless bottom-hole pressure asymptotic solution of the typical flow stage to obtain the dimensional pressure derivative asymptotic solution of the typical flow stage; Using the dimensional pressure derivative asymptotic solution of the typical flow stage, calculate the key parameters of the fractured-vuggy gas reservoir.

2. The method according to claim 1, characterized in that The step of solving the well-cave-fracture-cave-fracture calculation model through the dimensionless variables and the curve characteristics of the typical flow stages to obtain the dimensionless bottom-hole pressure asymptotic solution of the typical flow stage includes: Based on the dimensionless variables, perform dimensionless treatment on the well-cave-fracture-cave-fracture calculation model to obtain the dimensionless-treated well-cave-fracture-cave-fracture calculation model; Using the curve characteristics of the typical flow stage, solve the dimensionless-treated well-cave-fracture-cave-fracture calculation model to obtain the dimensionless bottom-hole pressure asymptotic solution of the typical flow stage.

3. The method according to claim 2, wherein The typical flow stages include wellbore storage flow, first vug storage flow, fracture zone linear flow, and second vug storage flow; The step of obtaining the curve characteristics of the typical flow stage includes: Obtain the curve characteristics of the wellbore storage flow; Obtain the curve characteristics of the first vug storage flow; Obtain the curve characteristics of the fracture zone linear flow; Obtain the curve characteristics of the second vug storage flow; The step of using the curve characteristics of the typical flow stage to solve the dimensionless-treated well-cave-fracture-cave-fracture calculation model to obtain the dimensionless bottom-hole pressure asymptotic solution of the typical flow stage includes: Using the curve characteristics of the wellbore storage flow, solve the dimensionless-treated well-cave-fracture-cave-fracture calculation model to obtain the dimensionless bottom-hole pressure asymptotic solution of the wellbore storage flow; Using the curve characteristics of the first vug storage flow, solve the dimensionless-treated well-cave-fracture-cave-fracture calculation model to obtain the dimensionless bottom-hole pressure asymptotic solution of the first vug storage flow; Using the curve characteristics of the fracture zone linear flow, solve the dimensionless-treated well-cave-fracture-cave-fracture calculation model to obtain the dimensionless bottom-hole pressure asymptotic solution of the fracture zone linear flow; Using the curve characteristics of the second vug storage flow, solve the dimensionless-treated well-cave-fracture-cave-fracture calculation model to obtain the dimensionless bottom-hole pressure asymptotic solution of the second vug storage flow.

4. The method according to claim 3, wherein The dimensional pressure derivative asymptotic solution of the typical flow stage includes the dimensional pressure derivative asymptotic solution of the wellbore storage flow, the dimensional pressure derivative asymptotic solution of the first vug storage flow, the dimensional pressure derivative asymptotic solution of the fracture zone linear flow, and the dimensional pressure derivative asymptotic solution of the second vug storage flow; The step of dimensionalizing the dimensionless bottom-hole pressure asymptotic solution of the typical flow stage to obtain the dimensional pressure derivative asymptotic solution of the typical flow stage includes: Dimensionalize the dimensionless bottom-hole pressure asymptotic solution of the wellbore storage flow to obtain the dimensional pressure derivative asymptotic solution of the wellbore storage flow; Dimensionalize the dimensionless bottom-hole pressure asymptotic solution of the first vug storage flow to obtain the dimensional pressure derivative asymptotic solution of the first vug storage flow; Dimensionalize the dimensionless bottom-hole pressure asymptotic solution of the fracture zone linear flow to obtain the dimensional pressure derivative asymptotic solution of the fracture zone linear flow; Dimensionalize the dimensionless bottom-hole pressure asymptotic solution of the second vug storage flow to obtain the dimensional pressure derivative asymptotic solution of the second vug storage flow; The key parameters of the fracture-vug gas reservoir include the wellbore storage coefficient, the first vug storage coefficient, the fracture zone permeability, the fracture zone width, and the second vug storage coefficient; The steps of calculating the key parameters of the fracture-vug gas reservoir by using the dimensional pressure derivative asymptotic solution of the typical flow stage include: Calculate the wellbore storage coefficient by using the dimensional pressure derivative asymptotic solution of the wellbore storage flow; Calculate the first vug storage coefficient by using the dimensional pressure derivative asymptotic solution of the first vug storage flow; Calculate the fracture zone permeability and the fracture zone width by using the dimensional pressure derivative asymptotic solution of the fracture zone linear flow; Calculate the wellbore storage coefficient by using the dimensional pressure derivative asymptotic solution of the second vug storage flow.

5. The method according to claim 2, wherein After the step of dimensionless processing the well-hole-fracture-vug-fracture calculation model based on the dimensionless variables to obtain the dimensionless processed well-hole-fracture-vug-fracture calculation model, it further includes: Perform Laplace transform on the dimensionless processed well-hole-fracture-vug-fracture calculation model to obtain the well-hole-fracture-vug-fracture calculation model in the Laplace space; The steps of solving the dimensionless processed well-hole-fracture-vug-fracture calculation model by using the curve characteristics of the typical flow stage to obtain the dimensionless bottom-hole pressure asymptotic solution of the typical flow stage include: Solve the well-hole-fracture-vug-fracture calculation model in the Laplace space by using the curve characteristics of the typical flow stage to obtain the dimensionless bottom-hole pressure asymptotic solution in the Laplace space of the typical flow stage; Based on the Laplace transform principle, convert the dimensionless bottom-hole pressure asymptotic solution in the Laplace space of the typical flow stage into the dimensionless bottom-hole pressure asymptotic solution in the real space of the typical flow stage; The steps of dimensionalizing the dimensionless bottom-hole pressure asymptotic solution of the typical flow stage to obtain the dimensional pressure derivative asymptotic solution of the typical flow stage include: Dimensionalize the dimensionless bottom-hole pressure asymptotic solution in the real space of the typical flow stage to obtain the dimensional pressure derivative asymptotic solution of the typical flow stage.

6. The method according to claim 2, wherein The steps of dimensionless processing the well-hole-fracture-vug-fracture calculation model based on the dimensionless variables to obtain the dimensionless processed well-hole-fracture-vug-fracture calculation model include: Obtain the typical flow characteristics in stages; Based on the typical flow characteristics in stages, perform a preliminary solution on the well-hole-fracture-vug-fracture calculation model to obtain the preliminarily solved well-hole-fracture-vug-fracture calculation model; Based on the dimensionless variables, the preliminarily processed well-cavity-fracture-cavity-fracture calculation model is dimensionless processed to obtain a dimensionless processed well-cavity-fracture-cavity-fracture calculation model.

7. A device for calculating key parameters of a fracture-vug gas reservoir, characterized in that Including: A basic assumption establishment module for establishing basic assumptions based on the theory of continuum mechanics; A model calculation module for constructing a well-cavity-fracture-cavity-fracture calculation model by using the basic assumptions; A variable acquisition module for acquiring dimensionless variables; A characteristic acquisition module for acquiring the curve characteristics of typical flow stages; A dimensionless asymptotic solution solving module for solving the well-cavity-fracture-cavity-fracture calculation model through the dimensionless variables and the curve characteristics of the typical flow stages to obtain the dimensionless bottom-hole pressure asymptotic solution of the typical flow stage; A dimensionalization module for dimensionalizing the dimensionless bottom-hole pressure asymptotic solution of the typical flow stage to obtain the dimensional pressure derivative asymptotic solution of the typical flow stage; A parameter calculation module for calculating the key parameters of the fracture-cavity gas reservoir by using the dimensional pressure derivative asymptotic solution of the typical flow stage.

8. The device according to claim 7, characterized in that, The dimensionless asymptotic solution solving module includes: A dimensionless processing unit for dimensionless processing the well-cavity-fracture-cavity-fracture calculation model based on the dimensionless variables to obtain a dimensionless processed well-cavity-fracture-cavity-fracture calculation model; A dimensionless asymptotic solution solving unit for solving the dimensionless processed well-cavity-fracture-cavity-fracture calculation model by using the curve characteristics of the typical flow stage to obtain the dimensionless bottom-hole pressure asymptotic solution of the typical flow stage.

9. A computer device, comprising a memory and a processor, the memory storing a computer program, characterized in that, When the processor executes the computer program, the steps of the method according to any one of claims 1 to 6 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, the steps of the method according to any one of claims 1 to 6 are implemented.

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