Method for determining fracture-vuggy multi-reservoir gas reservoir parameters based on production dynamic analysis

Abstract

The invention discloses a method for determining fracture-vug type multi-reservoir gas reservoir parameters based on production dynamic analysis, and belongs to the technical field of oil and gas reservoir development. Establishing a theoretical Blasingame yield decline calculation model and a theoretical bottomhole flowing pressure model of the internal reservoir body; the method comprises the following steps of: dividing production dynamics into two stages by taking supply starting of an external reservoir body as a demarcation point, adjusting parameters of each reservoir body in a theoretical bottom hole flowing pressure model and a theoretical Blasingame yield decline model, respectively fitting actual flowing pressure data and an actual Blasingame yield decline chart in the two stages, and determining parameters of the internal and external reservoir bodies according to a fitting effect. According to the method, fitting is conducted from the two aspects of the flowing bottomhole pressure and the Blasingame chart in stages, the multiplicity of solutions of calculation results is reduced, and identification of parameters such as the external reservoir body supply starting time and the reserves is achieved.

Description

Technical Field

[0001] This invention relates to the field of oil and gas reservoir development technology, specifically a method for determining parameters of fractured-vuggy multi-reservoir gas reservoirs based on production dynamic analysis. Background Technology

[0002] Fractured-vuggy oil and gas reservoirs are an important type of carbonate reservoir, characterized by large caverns, fractures, and fracture systems, exhibiting strong heterogeneity and complex fluid flow characteristics. Taking a carbonate reservoir in an oilfield in Xinjiang as an example, some production wells show a significant slowdown in production and pressure reduction rates after a certain period of operation, even remaining stable for extended periods. This phenomenon is caused by continuous recharge from reservoirs connected to the outside of the fractured-vuggy reservoir. This external supply behavior makes it difficult for traditional dynamic analysis methods based on static geological models and closed material balance to accurately depict actual production dynamics. Currently, conventional oil and gas reservoir production dynamic analysis is generally based on Darcy's flow theory and homogeneous or layered heterogeneous reservoir models, assuming the reservoir is a constant-volume closed system and neglecting the injection of external fluids or energy during development. These conventional methods have significant shortcomings when dealing with fractured-vuggy multi-reservoir oil and gas reservoirs. The existence of external reservoirs (among the internal and external reservoirs, the reservoir directly connected to the wellbore is the internal reservoir, and the rest are external reservoirs) renders traditional material balance equations and dynamic prediction models ineffective. The inability to accurately determine the start time, amount, and level of communication of external supply leads to difficulties in reserve assessment, delays in development strategy adjustments, and large deviations in production capacity forecasts. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a method for determining parameters of fractured-vuggy multi-reservoir gas reservoirs based on production dynamic analysis. This invention considers the properties and dynamic changes of the internal and external reservoirs, enabling accurate acquisition of parameters for both internal and external reservoirs, thus providing support for predicting production dynamics.

[0004] To achieve the above objectives, the present invention provides the following solution: A method for determining parameters of fractured-vuggy multi-reservoir gas reservoirs based on production dynamics analysis includes the following steps: S1. Obtain basic data from multiple storage facilities, including production data and basic fluid data; S2. Establish a theoretical Blasingame production decline calculation model; S3. Establish a theoretical bottom-hole flowing pressure model for the internal reservoir based on the material balance equation and the production capacity formula; S4. Adjust the parameters of the inner reservoir in the theoretical bottom-hole flowing pressure model and the theoretical Blasingame production decline model respectively to fit the actual flowing pressure data and the actual Blasingame production decline chart before the outer reservoir starts supplying. Determine the parameters of the inner reservoir based on the fitting effect, including determining the reserves of the inner reservoir. The actual Blasingame production decline chart before the outer reservoir starts supplying is obtained by normalizing the reserves of the first reservoir in the theoretical Blasingame production decline model and the basic data of the multiple reservoirs obtained in step S1. S5. Adjust the parameters of each external reservoir in the theoretical bottom-hole flowing pressure model and the theoretical Blasingame production decline model respectively to fit the actual flowing pressure data and the actual Blasingame production decline chart after the external reservoir starts supplying. Determine the parameters of each external reservoir based on the fitting effect. The actual Blasingame production decline chart after the external reservoir starts supplying is obtained by normalizing the parameters of the internal reservoir determined in step S4 and the basic data of the multiple reservoirs obtained in step S1.

[0005] In this invention, the derivation process of the theoretical Blasingame yield decline calculation model is as follows: Assume the reservoir consists of different circular, closed gas reservoirs connected by fractures. Based on traditional seepage theory and the boundary condition of external reservoir supply, mathematical physics methods are used to derive the dimensionless production solution of the internal reservoir with external reservoir supply in Laplace space: In the formula, Represents the parameters in the Laplace space, such as Represents the dimensionless product solution in Laplace space; r eD Indicates the dimensionless well control radius of the internal storage group; s Representing time in real space t Operators after conversion to Laplace space; K 0( x ) represents the 0th-order modified Bessel function of the second kind; K 1( x () represents the first-order modified Bessel function of the second kind;I 0( x () represents the 0th-order modified Bessel function of the first kind; I 1( x ) represents the first-order modified Bessel function of the first kind; This indicates the dimensionless supply capacity of foreign exchange reserves under Laplace. t Dstart The dimensionless time at which the foreign exchange reserves collectively begin to be supplied; N pDd Indicates dimensionless cumulative output; r eD Indicates the dimensionless well control radius of the internal storage group; r e Indicates the control radius of the internal storage collective well, in meters; r w Indicates the well radius; q Dext This indicates that the foreign exchange reserves collectively lack the capacity for dimensionless supply. q ext Indicates the collective supply capacity of foreign exchange reserves, m 3 ; q g Indicates daily gas production; k Indicates reservoir permeability; μ The viscosity of the fluid is expressed in mPa·s. φ Indicates porosity; V The volume of the internal storage unit is expressed in m. 3 ; C t Represents the overall compression ratio, in MPa -1 ; t start Indicates the time when the foreign exchange reserves collectively begin to be supplied; h Indicates reservoir thickness; The dimensionless yield solution in real space can be obtained through Steshfest numerical inversion (refer to Stehfest H. Algorithm 368: Numerical inversion of Laplace transforms [D5][J]. Communications of the ACM, 1970, 13(1): 47-49.). Solution of dimensionless cumulative output .

[0006] The dimensionless mass equilibrium pseudo-time is defined as the dimensionless cumulative production solution. Solution of dimensionless production The ratio: The theoretical Blasingame yield decline calculation model can be determined based on the following definitions, including: The theoretically dimensional quasi-time of mass equilibrium is defined as the dimensionalization of the dimensionless quasi-time of mass equilibrium, and its calculation formula is as follows: Theoretical dimensional normalized output Defined as the dimensionalization of a dimensionless product solution, its calculation formula is: Theoretical normalized product integral Defined as theoretically normalized output Integrals of theoretical material equilibrium pseudotime and current theoretical material equilibrium pseudotime t ca The ratio (theoretical) is calculated as follows: Theoretical normalized product integral derivative Defined as the theoretically integrated product integral The derivative of the theoretical mass equilibrium time and the current theoretical mass equilibrium pseudotime t ca The negative value of the (theoretical) product is calculated as follows: In the formula, (*) Indicates the pressure in the original formation. p i The following parameters*; B This represents the volume coefficient.

[0007] In one specific embodiment of the present invention, step S3, the theoretical bottom-hole flowing pressure model includes: Material balance equation prior to the commencement of collective supply from foreign reserves: Material balance equations after the commencement of collective supply from foreign reserves: In the formula, n represents the number of each storage group, where the number of the internal storage group is 1, the number of the external storage group starts from 2, and N is the total number of all storage groups. p 1( t )express t Theoretical average pressure of the first storage group (internal storage group) at any given time; z (t ) indicates pressure p 1( t The corresponding gas deviation factor; p i Indicates the original formation pressure; z i This represents the gas deviation factor corresponding to the original formation pressure. G p ( t )express t Cumulative gas production at any given time; G 1 represents the reserves of the first reserve group; q 21 ( t This indicates the output supplied by the second storage collective to the first storage collective after the supply has begun; J 21 This represents the crossflow coefficient from the second storage group to the first storage group; q n(n-1) ( t ) represents the output supplied by the nth storage group to the (n-1)th storage group after the supply begins; q (n+1)n ( t ) represents the output supplied by the (n+1)th storage unit to the nth storage unit after the supply begins; J n(n-1) The crossflow coefficient is the supply from the nth storage group to the (n-1)th storage group. p n ( t () represents the average pressure of the nth storage group after the start of supply; p n-1 ( t () represents the average pressure of the (n-1)th storage unit after the start of supply; G n This represents the reserves of the nth storage group; The formula for calculating the theoretical bottom hole flowing pressure is: In the formula, p wf (Theoretical) refers to the theoretical bottom hole flowing pressure.

[0008] As a specific embodiment of the present invention, step S4 includes: S41. Parameters for estimating the total domestic reserves, including reserves. G 1. Control radius of internal storage collective wells r e reservoir permeability k reservoir thickness h Porosity ф When will the foreign exchange reserves begin to be supplied collectively? tstart ; S42. Substitute the estimated internal collective reserves into the theoretical bottom-hole flowing pressure model, and combine this with the data at each time point ( t < t start The cumulative gas production was used to calculate the theoretical average pressure of the internal gas storage tank. p 1(t); then combine each time step ( t < t start Gas production and estimated control radius of the internal storage collective well r e The theoretical bottom hole flowing pressure was calculated before the start of collective supply from the external storage. p wf (theory); S43, the estimated internal storage parameters ( r e , k , h , ф , t start Substituting these values ​​into the theoretical Blasingame production decline calculation model, the theoretical Blasingame chart before the external reserve collective begins supply is calculated; the estimated internal reserve collective reserves ( G 1) Substitute the production data and basic fluid data obtained in step S1 into the mathematical model of the actual Blasingame production decline chart to obtain the actual Blasingame production decline chart before the external reserve collective begins to supply. S44. Calculate the deviation between the theoretical bottom-hole flowing pressure and the actual bottom-hole flowing pressure before the external storage collective begins supply; calculate the deviation between the theoretical Blasingame chart and the actual Blasingame production decline chart before the external storage collective begins supply; if both deviations are less than a preset threshold, output the parameters of the internal storage collective. G 1. r e , k , h , ф , t start Otherwise, return to step S41 to recalculate.

[0009] As a specific embodiment of the present invention, step S5 includes: S51. Estimate the parameters of each foreign reserve group, including reserves ( G n (n≥2), cross-current coefficient ( J n(n-1) ) and the unified foreign exchange reserve collective supply capacity of the Blasingame curve ( qext ); S52. Substitute the estimated external collective reserves into the theoretical bottom-hole flowing pressure model, and combine it with each time step ( t > t start The cumulative gas production was used to calculate the theoretical average pressure of the internal gas storage tank. p 1( t ); and then combined with the control radius of the internal storage collective well determined in step S4 ( r e The theoretical bottom hole flowing pressure after the start of collective external storage supply was calculated. p wf (theory); S53. Substitute the estimated external reserve parameters and the internal reserve parameters determined in step S4 into the theoretical Blasingame production decline calculation model to calculate the theoretical Blasingame chart after the external reserve begins supply; calculate the internal reserve quantity determined in step S4 ( G 1) Substitute the production data and basic fluid data obtained in step S1 into the mathematical model of the actual Blasingame production decline chart to obtain the actual Blasingame production decline chart after the external reserve collective begins to supply. S54. Calculate the deviation between the theoretical bottomhole flowing pressure and the actual bottomhole flowing pressure after the start of external storage group supply; calculate the deviation between the theoretical Blasingame production decline chart and the actual Blasingame production decline chart after the start of external storage group supply; if both deviations are less than the preset threshold, output the parameters of each external storage group. G n , J n(n-1) , q ext Otherwise, return to step S51 to recalculate.

[0010] Compared with existing calculation methods, the present invention has the following advantages: (1) This invention can determine the start time of external reserve collective supply, the amount of external reserve collective supply and the degree of communication: This invention establishes a theoretical Blasingame production decline calculation model that considers external reserve collective supply, establishes a material balance equation that considers internal and external reserves, and combines bottom hole flowing pressure and Blasingame chart fitting. Based on the curve deviation of different fitting stages of the chart, the start time of external reserve collective supply, the amount of external reserve collective supply and the degree of communication can be accurately identified.

[0011] (2) This invention solves some problems in the assessment of reserves, forecasting of production capacity and adjustment of development strategies for multiple reserves: accurate identification of the start time of supply from external reserves, the amount of supply from external reserves and the degree of communication provides developers with a more comprehensive understanding of the real-time mobilization of multiple reserves; with a more accurate understanding of multiple reserves, adjustments to production development strategies and more accurate production capacity forecasts can be realized earlier. Attached Figure Description

[0012] Figure 1 This is a flowchart illustrating the method for determining parameters of fractured-vuggy multi-reservoir gas reservoirs based on production dynamics analysis in this embodiment. Figure 2 Fitting diagram of bottom-hole flowing pressure of the first reservoir before the start of supply to the external reservoir; Figure 3 A fitted graph of the declining production curve of Blasingame before the start of collective supply from foreign reserves; Figure 4 Fitting diagram of bottom flow pressure of the first reservoir after the start of external reservoir collective supply; Figure 5 A fitted graph of the decreasing production curve of Blasingame after the start of collective supply from foreign reserves. Detailed Implementation

[0013] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0014] The following examples involve creating a declining actual Blasingame production chart, which is a commonly used chart. The declining actual Blasingame production chart includes three curves: the X-axis represents the actual material equilibrium time, and the Y-axis represents the actual normalized production, the integral of the actual normalized production, and the derivative of the integral of the actual normalized production. Mathematical models for actual diminishing returns of Blasingame include: The formula for calculating the actual material equilibrium pseudo-time is: (1) In the formula, t ca (Actual) refers to the actual material balance time calculated based on actual production data; p i Indicates the original formation pressure; q g Indicates daily gas production; G 1 represents the reserves of the first reserve collective, i.e., the reserves of the inner reserve collective, m 3 ;(*) Indicates the pressure in the original formation. p iThe following parameters*; μ The viscosity of the fluid is expressed in mPa·s. C t Represents the overall compression ratio, in MPa -1 ; z Indicates the gas deviation factor; p wf( (Actual) represents the actual bottom hole flowing pressure; To facilitate the handling of parameters that vary with gas pressure, the pseudo-pressure is defined as follows: In the formula, It's pressure p The corresponding pseudo-pressure, MPa; Actual normalized production , defined as the ratio of output to the pseudo-pressure difference, is calculated as follows: In the formula, p pi This is the pseudo-pressure corresponding to the original formation pressure; p pwf This is the pseudo-pressure corresponding to the actual bottom hole pressure; Actual normalized production integral Defined as actual normalized output The integral of the actual material balance pseudo-time with the current actual material balance pseudo-time t ca The (actual) ratio is calculated as follows: Integral derivative of actual normalized output Defined as the integral of the totalized output The derivative of the mass equilibrium time with respect to the current actual mass equilibrium time t ca The negative value of the (actual) product is calculated as follows: .

[0015] As can be seen from the mathematical model of actual Blasingame production decline, apart from the reserves of the first reservoir, the other variables are all production data and basic fluid data, which can be measured. Therefore, once the reserves of the first reservoir are determined, the actual Blasingame production decline chart can be determined.

[0016] A method for determining parameters of fractured-vuggy multi-reservoir gas reservoirs based on production dynamics analysis, such as... Figure 1 As shown, it includes the following steps: S1. Obtain basic data from multiple storage facilities, including production data and basic fluid data; This step involves collecting and organizing basic data such as logging, well logging, and well testing reports from this well and adjacent wells to obtain production and basic fluid data for multiple reservoirs. Simultaneously, this process can also acquire formation data for multiple reservoirs. The production data obtained includes: daily gas production. q g Daily water production q w and actual bottom hole flowing pressure p wf( In practice, the basic fluid data obtained includes the fluid's viscosity. μ Overall compression coefficient C t and gas deviation factor z (and stress) p The relevant functions and specific calculation methods can be found in "Natural Gas Engineering" published by Petroleum Industry Press. These data are directly measured and used as real data. Simultaneously, formation data, such as reservoir thickness, can also be obtained during the above process. h Porosity φ Volume index B Original formation pressure p i reservoir permeability k and well radius r w These data are mostly calculated from known parameters, rather than actual measured values. They can be used as initial values ​​for subsequent parameter estimation, providing fitting parameters that conform to basic geological understanding for subsequent model historical fitting, reducing the possibility of invalid or multiple solutions in the model fitting process, and achieving a more accurate fitting of the collective reserves, supply start time, and supply capacity of internal and external reservoirs.

[0017] S2. Establish a theoretical Blasingame production decline calculation model; The theoretical Blasingame yield decline calculation model includes: The theoretically dimensional formula for calculating the pseudo-time of mass equilibrium is: Theoretical dimensional normalized output The formula for calculation is: Theoretical normalized product integral The formula for its calculation is: Theoretical normalized product integral derivative The formula for its calculation is: Among them, dimensionless material equilibrium pseudo-time t caDd The formula for calculation is: In the formula, Represents the parameter in Laplace space, such as Represents the dimensionless product solution in Laplace space; r eD Indicates the dimensionless well control radius of the internal storage group; s Representing time in real space t Operators after conversion to Laplace space; K 0( x ) represents the 0th-order modified Bessel function of the second kind; K 1( x () represents the first-order modified Bessel function of the second kind; I 0( x () represents the 0th-order modified Bessel function of the first kind; I 1( x ) represents the first-order modified Bessel function of the first kind; This indicates the dimensionless supply capacity of foreign exchange reserves within the Laplace space. t Dstart The dimensionless time at which the foreign exchange reserves collectively begin to be supplied; N pDd Indicates dimensionless cumulative output; r eD Indicates the dimensionless well control radius of the internal storage group; r e Indicates the control radius of the internal storage collective well, in meters; r w Indicates the well radius; q Dext This indicates that the foreign exchange reserves collectively lack the capacity for dimensionless supply. q ext Indicates the collective supply capacity of foreign exchange reserves, m 3 ; q g Indicates daily gas production; k Indicates reservoir permeability; μThe viscosity of the fluid is expressed in mPa·s. φ Indicates porosity; V The volume of the internal storage unit is expressed in m. 3 ; C t Represents the overall compression ratio, in MPa -1 ; t start Indicates the time when the foreign exchange reserves collectively begin to be supplied; h Indicates reservoir thickness; (*) Indicates the pressure in the original formation. p i The following parameters*; B Indicates the volume factor; S3. Establish a theoretical bottom-hole flowing pressure model for the internal reservoir based on the material balance equation and the production capacity formula; Material balance equation prior to the commencement of collective supply from foreign reserves: Material balance equations after the commencement of collective supply from foreign reserves: The formula for calculating the theoretical bottom hole flowing pressure is: In the formula, n represents the number of each storage group, where the number of the internal storage group is 1, the number of the external storage group starts from 2, and N is the total number of all storage groups. p 1( t )express t Theoretical average pressure of the first storage group (internal storage group) at any given time, in MPa; z ( t ) indicates pressure p 1( t The corresponding gas deviation factor; p i Indicates the original formation pressure; z i This represents the gas deviation factor corresponding to the original formation pressure. G p ( t )express t The cumulative gas production at any given time, i.e., the daily gas production. q g exist t The sum before time, m 3 ; G 1 represents the reserves of the first reservoir group, m 3; q 21 ( t (m) represents the output supplied by the second storage collective to the first storage collective after the supply begins. 3 / d; J 21 The term m represents the crossflow coefficient from the second storage group to the first storage group. 3 / d / MPa; q n(n-1) ( t Let m represent the output supplied by the nth storage group to the (n-1)th storage group after the supply begins. 3 / d; q (n+1)n ( t Let m represent the output supplied by the (n+1)th storage unit to the nth storage unit after the supply begins. 3 / d; J n(n-1) Let m be the crossflow coefficient from the nth storage group to the (n-1)th storage group. 3 / d / MPa; p n ( t () represents the average pressure of the nth storage unit after the start of supply, in MPa; p n-1 ( t () represents the average pressure of the (n-1)th storage unit after the start of supply, in MPa; G n Let m represent the reserves of the nth storage group. 3 ; p wf (Theoretical) refers to the theoretical bottom hole flowing pressure.

[0018] S4. Adjust the parameters of the inner reservoir in the theoretical bottom-hole flowing pressure model and the theoretical Blasingame production decline model respectively to fit the actual flowing pressure data and the actual Blasingame production decline chart before the outer reservoir starts supplying. Determine the parameters of the inner reservoir based on the fitting effect, including determining the reserves of the inner reservoir. The actual Blasingame production decline chart before the outer reservoir starts supplying is obtained by normalizing the reserves of the first reservoir in the theoretical Blasingame production decline model and the basic data of the multiple reservoirs obtained in step S1. S41. Parameters for estimating the total domestic reserves, including reserves. G 1. Control radius of internal storage collective wells r e reservoir permeability k reservoir thickness h Porosity ф When will the foreign exchange reserves begin to be supplied collectively? tstart ; S42. Substitute the estimated internal collective reserves into the theoretical bottom-hole flowing pressure model, and combine this with the data at each time point ( t < t start The cumulative gas production was used to calculate the theoretical average pressure of the internal gas storage tank. p 1(t); then combine each time step ( t < t start Gas production and estimated control radius of the internal storage collective well r e The theoretical bottom hole flowing pressure was calculated before the start of collective supply from the external storage. p wf (theory); S43, the estimated internal storage parameters ( r e , k , h , ф , t start Substituting these values ​​into the theoretical Blasingame production decline calculation model, the theoretical Blasingame chart before the external reserve collective begins supply is calculated; the estimated internal reserve collective reserves ( G 1) Substitute the production data and basic fluid data obtained in step S1 into the mathematical model of the actual Blasingame production decline chart to obtain the actual Blasingame production decline chart before the external reserve collective begins to supply. S44. Calculate the deviation between the theoretical bottom-hole flowing pressure and the actual bottom-hole flowing pressure before the external storage collective begins supply; calculate the deviation between the theoretical Blasingame chart and the actual Blasingame production decline chart before the external storage collective begins supply; if both deviations are less than a preset threshold, output the parameters of the internal storage collective. G 1. r e , k , h , ф , t start If not, return to step S41 to recalculate; The final fitted result is as follows Figure 2 and Figure 3 As shown; S5. Adjust the parameters of each external reservoir in the theoretical bottom-hole flowing pressure model and the theoretical Blasingame production decline model respectively to fit the actual flowing pressure data and the actual Blasingame production decline chart after the external reservoir starts supplying. Determine the parameters of each external reservoir based on the fitting effect. The actual Blasingame production decline chart after the external reservoir starts supplying is obtained by normalizing the parameters of the internal reservoir determined in step S5 and the basic data of the multiple reservoirs obtained in step S1.

[0019] S51. Estimate the parameters of each foreign reserve group, including reserves ( G n (n≥2), cross-current coefficient ( J n(n-1) ) and the unified foreign exchange reserve collective supply capacity of the Blasingame curve ( q ext ); S52. Substitute the estimated external collective reserves into the theoretical bottom-hole flowing pressure model, and combine it with each time step ( t > t start The cumulative gas production was used to calculate the theoretical average pressure of the internal gas storage tank. p 1( t ); and then combined with the control radius of the internal storage collective well determined in step S4 ( r e The theoretical bottom hole flowing pressure after the start of collective external storage supply was calculated. p wf (theory); S53. Substitute the estimated external reserve parameters and the internal reserve parameters determined in step S4 into the theoretical Blasingame production decline calculation model to calculate the theoretical Blasingame chart after the external reserve begins supply; calculate the internal reserve quantity determined in step S4 ( G 1) Substitute the production data and basic fluid data obtained in step S1 into the mathematical model of the actual Blasingame production decline chart to obtain the actual Blasingame production decline chart after the external reserve collective begins to supply. S54. Calculate the deviation between the theoretical bottomhole flowing pressure and the actual bottomhole flowing pressure after the start of external storage group supply; calculate the deviation between the theoretical Blasingame production decline chart and the actual Blasingame production decline chart after the start of external storage group supply; if both deviations are less than the preset threshold, output the parameters of each external storage group. G n , J n(n-1) , q ext Otherwise, return to step S51 to recalculate; The final fitted result is as follows Figure 4 and Figure 5 As shown.

[0020] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the embodiments of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for determining parameters of fractured-vuggy multi-reservoir gas reservoirs based on production dynamic analysis, characterized in that, Includes the following steps: S1. Obtain basic data from multiple storage facilities, including production data and basic fluid data; S2. Establish a theoretical Blasingame production decline calculation model; S3. Establish a theoretical bottom-hole flowing pressure model for the internal reservoir based on the material balance equation and the production capacity formula; S4. Adjust the parameters of the inner reservoir in the theoretical bottom-hole flowing pressure model and the theoretical Blasingame production decline model respectively to fit the actual flowing pressure data and the actual Blasingame production decline chart before the outer reservoir starts supplying. Determine the parameters of the inner reservoir based on the fitting effect, including determining the reserves of the inner reservoir. The actual Blasingame production decline chart before the outer reservoir starts supplying is obtained by normalizing the reserves of the first reservoir in the theoretical Blasingame production decline model and the basic data of the multiple reservoirs obtained in step S1. S5. Adjust the parameters of each external reservoir in the theoretical bottom-hole flowing pressure model and the theoretical Blasingame production decline model respectively to fit the actual flowing pressure data and the actual Blasingame production decline chart after the external reservoir starts supplying. Determine the parameters of each external reservoir based on the fitting effect. The actual Blasingame production decline chart after the external reservoir starts supplying is obtained by normalizing the parameters of the internal reservoir determined in step S4 and the basic data of the multiple reservoirs obtained in step S1.

2. The method for determining parameters of fractured-vuggy multi-reservoir gas reservoirs based on production dynamic analysis according to claim 1, characterized in that, Step S2, the theoretical Blasingame yield decline calculation model includes: In the formula, This represents the theoretically dimensional material equilibrium pseudotime. r e Indicates the control radius of the internal storage collective well; φ Indicates porosity; (*) Indicates the pressure in the original formation. p i The following parameters*; C t Indicates the overall compression ratio; μ Indicates fluid viscosity; B Indicates the volume factor; r eD Indicates the dimensionless well control radius of the internal storage group; k Indicates reservoir permeability; This represents the pseudo-time of dimensionless mass equilibrium. This represents the theoretically dimensional normalized output. h Indicates reservoir thickness; q Dd Indicates dimensionless output; Represents the theoretically normalized product integral; This represents the integral derivative of the theoretically normalized output. N pDd Indicates dimensionless cumulative output; Indicates the parameter in Laplace space*; s Representing time in real space t Operators after conversion to Laplace space; K 0( x ) represents the 0th-order modified Bessel function of the second kind; K 1( x ) represents the first-order modified Bessel function of the second kind; I 0( x ) represents the 0th-order modified Bessel function of the first kind; I 1( x () denotes a first-order modified Bessel function of the first kind; This indicates the dimensionless supply capacity of foreign exchange reserves within the Laplace space. q Dext This indicates that the foreign exchange reserves collectively lack the capacity for dimensionless supply. t Dstart The dimensionless time at which the foreign exchange reserves collectively begin to be supplied; r w Indicates the well radius; q ext This indicates the collective supply capacity of foreign exchange reserves; q g Indicates daily gas production; V Indicates the total volume of the internal storage; r w Indicates the well radius.

3. The method for determining parameters of fractured-vuggy multi-reservoir gas reservoirs based on production dynamic analysis according to claim 2, characterized in that, In step S3, the theoretical bottom-hole flowing pressure model includes: Material balance equation prior to the commencement of collective supply from foreign reserves: Material balance equations after the commencement of collective supply from foreign reserves: In the formula, n represents the number of each storage group, where the number of the internal storage group is 1, the number of the external storage group starts from 2, and N is the total number of all storage groups. p 1( t )express t The average pressure of the first storage group at any given moment; z ( t ) indicates pressure p 1( t The corresponding gas deviation factor; p i Indicates the original formation pressure; z i This represents the gas deviation factor corresponding to the original formation pressure. G p ( t )express t Cumulative gas production at any given time; G 1 represents the reserves of the first reserve group; q 21 ( t This indicates the output supplied by the second storage collective to the first storage collective after the supply has begun; J 21 This represents the crossflow coefficient from the second storage group to the first storage group; q n(n-1) ( t ) represents the output supplied by the nth storage group to the (n-1)th storage group after the supply begins; q (n+1)n ( t ) represents the output supplied by the (n+1)th storage unit to the nth storage unit after the supply begins; J n(n-1) The crossflow coefficient is the supply from the nth storage group to the (n-1)th storage group. p n ( t () represents the average pressure of the nth storage group after the start of supply; p n-1 ( t () represents the average pressure of the (n-1)th storage unit after the start of supply; G n This represents the reserves of the nth storage group; The formula for calculating the theoretical bottom hole flowing pressure is: In the formula, p wf (Theoretical) refers to the theoretical bottom hole flowing pressure.

4. The method for determining parameters of fractured-vuggy multi-reservoir gas reservoirs based on production dynamic analysis according to claim 2, characterized in that, Step S4 includes: S41. Estimate the parameters of the internal reservoir, including reserves, well control radius of the internal reservoir, reservoir permeability, reservoir thickness, porosity, and the time when the external reservoir begins supplying. S42. Substitute the estimated internal storage collective reserves into the theoretical bottom hole pressure model, and calculate the theoretical average pressure of the internal storage collective by combining the cumulative gas production at each time point; then calculate the theoretical bottom hole pressure before the external storage collective supply begins by combining the gas production at each time point with the estimated well control radius of the internal storage collective. S43. Substitute the estimated internal storage parameters into the theoretical Blasingame production decline calculation model to calculate the theoretical Blasingame chart before the external storage begins to supply; substitute the estimated internal storage volume, the production data and basic fluid data obtained in step S1 into the actual Blasingame production decline chart mathematical model to obtain the actual Blasingame production decline chart before the external storage begins to supply. S44. Calculate the deviation between the theoretical bottom-hole flowing pressure and the actual bottom-hole flowing pressure before the external storage collective starts supplying, and calculate the deviation between the theoretical Blasingame chart and the actual Blasingame production decline chart before the external storage collective starts supplying; if both deviations are less than the preset threshold, output the parameters of the internal storage collective; otherwise, return to step S41 to recalculate.

5. The method for determining parameters of fractured-vuggy multi-reservoir gas reservoirs based on production dynamic analysis according to claim 2, characterized in that, Step S5 includes: S51. Estimate the parameters of each foreign reserve group, including reserves, cross-flow coefficient, and supply capacity of the foreign reserve group; S52. Substitute the estimated external storage collective reserves into the theoretical bottom hole pressure model, and calculate the theoretical internal storage collective average pressure by combining the cumulative gas production at each moment; then calculate the theoretical bottom hole pressure after the external storage collective supply begins by combining the internal storage collective well control radius determined in step S4. S53. Substitute the estimated external storage parameters and the internal storage parameters determined in step S4 into the theoretical Blasingame production decline calculation model to calculate the theoretical Blasingame chart after the external storage begins to supply; substitute the internal storage quantity determined in step S4, the production data and basic fluid data obtained in step S1 into the actual Blasingame production decline chart mathematical model to obtain the actual Blasingame production decline chart after the external storage begins to supply. S54. Calculate the deviation between the theoretical bottomhole flowing pressure and the actual bottomhole flowing pressure after the external storage collective starts supplying. Calculate the deviation between the theoretical Blasingame production decline chart and the actual Blasingame production decline chart after the external storage collective starts supplying. If both deviations are less than the preset threshold, output the parameters of each external storage collective. Otherwise, return to step S51 to recalculate.

Images