Method, device, equipment and medium for determining closed reservoir reserves of multi-well production

Abstract

The application discloses a kind of closed reservoir reserves determination methods, device, equipment and medium of multi-well production, comprising: obtaining the oil reservoir basic parameters of target closed reservoir, and the production dynamic data of production well in target closed reservoir;Based on production dynamic data, calculate standardization production related parameters, and draw measured standardization characteristic curve according to standardization production related parameters;Percolation theory model of circular closed reservoir is constructed, and theoretical standardization characteristic curve is drawn according to percolation theory model;Determine target reservoir fitting parameters based on measured standardization characteristic curve and theoretical standardization characteristic curve;According to target reservoir fitting parameters, determine the dynamic geological reserves corresponding to target closed reservoir.It is realized that intelligent automatic analysis is realized by drawing measured standardization characteristic curve and theoretical standardization characteristic curve, and the scientificity and efficiency of analysis work are improved.

Description

Technical Field

[0001] This invention relates to the field of oil and gas reservoir development technology, and in particular to a method, apparatus, equipment and medium for determining the reserves of a closed oil reservoir produced by multiple wells. Background Technology

[0002] In oilfield development, one often encounters reservoirs that are completely shielded by impermeable faults on all sides, or purely lithological pinch-out reservoirs. These reservoirs are characterized by relatively small geological reserves and lack of connection to external water bodies, forming entirely independent development units. The development of these reservoirs or sand bodies generally depends on the geological reserve size and project economics, optimizing the total number of development wells and considering whether to implement artificial water injection to replenish formation energy.

[0003] However, methods for calculating the geological reserves of closed oil reservoirs are divided into static and dynamic methods. The static method, also known as the volumetric method, mainly calculates the original static geological reserves based on multiple parameters such as the oil-bearing area, oil layer thickness, porosity, original oil saturation, and formation crude oil volume factor. When an oil field reaches a certain stage of development and has acquired a relatively long period of abundant production dynamic data, dynamic methods are sometimes needed to further verify the geological reserves in order to clarify the material basis of underground reserves. This is called dynamic geological reserves. Through research on published literature and the functions of commercial software, the Blasingame method can currently provide variable production analysis in single-well models, which can be used to determine the dynamic geological reserves of closed oil reservoirs.

[0004] However, in practice, single-well development of a single reservoir is relatively rare. More often, two or more development wells simultaneously develop a single closed reservoir. Currently, commercial software does not have the function of calculating the dynamic geological reserves of the entire reservoir in such cases. Summary of the Invention

[0005] This invention provides a method, apparatus, equipment, and medium for determining the reserves of closed oil reservoirs produced by multiple wells. By calculating the standardized production integral and the standardized production integral derivative curve from actual test data, and then theoretically plotting the standardized production integral and the standardized production integral derivative curve for the same time period, the radius parameter of the closed circular oil reservoir when the actual data and theoretical data have a high degree of fit is obtained from the above curves. Dynamic geological reserves are calculated based on the radius parameter of the closed circular oil reservoir, thereby realizing intelligent automatic analysis and improving the scientificity and efficiency of the analysis work.

[0006] According to one aspect of the present invention, a method for determining the reserves of a closed oil reservoir produced by multiple wells is provided, comprising:

[0007] Obtain the reservoir basic parameters of the target closed reservoir, as well as the production dynamic data of the production wells within the target closed reservoir;

[0008] Calculate standardized output-related parameters based on production dynamic data, and plot measured standardized characteristic curves based on standardized output-related parameters;

[0009] A seepage theory model for a circular closed reservoir was constructed, and a theoretically standardized characteristic curve was plotted based on the seepage theory model.

[0010] The fitting parameters for the target reservoir are determined based on the measured standardized characteristic curves and the theoretical standardized characteristic curves.

[0011] The dynamic geological reserves corresponding to the target closed reservoir are determined based on the fitting parameters of the target reservoir.

[0012] According to another aspect of the present invention, a device for determining the reserves of a closed oil reservoir produced by multiple wells is provided, comprising:

[0013] The data acquisition module is used to acquire the basic reservoir parameters of the target closed reservoir, as well as the production dynamic data of the production wells within the target closed reservoir;

[0014] The measured standardized characteristic curve plotting module is used to calculate standardized output-related parameters based on production dynamic data and plot the measured standardized characteristic curve based on the standardized output-related parameters.

[0015] The theoretically standardized characteristic curve plotting module is used to construct a seepage theory model for a circular closed reservoir and plot theoretically standardized characteristic curves based on the seepage theory model.

[0016] The reservoir fitting parameter determination module is used to determine the target reservoir fitting parameters based on measured standardized characteristic curves and theoretical standardized characteristic curves.

[0017] The dynamic geological reserves calculation module is used to determine the dynamic geological reserves corresponding to the target closed reservoir based on the fitting parameters of the target reservoir.

[0018] According to another aspect of the present invention, an electronic device is provided, the electronic device comprising:

[0019] At least one processor; and

[0020] A memory that is communicatively connected to at least one processor; wherein,

[0021] The memory stores a computer program that can be executed by at least one processor, such that the at least one processor is able to perform the method for determining the reserves of a closed reservoir produced by a multi-well process according to any embodiment of the present invention.

[0022] According to another aspect of the present invention, a computer-readable storage medium is provided, which stores computer instructions for causing a processor to execute a method for determining the reserves of a closed oil reservoir produced by multi-well production according to any embodiment of the present invention.

[0023] The technical solution of this invention involves acquiring the basic reservoir parameters of a target closed reservoir and the production dynamic data of the production wells within the target closed reservoir; calculating standardized production-related parameters based on the production dynamic data, and plotting measured standardized characteristic curves based on these parameters; constructing a seepage theory model for a circular closed reservoir, and plotting theoretical standardized characteristic curves based on the seepage theory model; determining the target reservoir fitting parameters based on the measured and theoretical standardized characteristic curves; and determining the dynamic geological reserves corresponding to the target closed reservoir based on the target reservoir fitting parameters. By calculating the standardized production integral and its derivative curve from the actual test data, and then theoretically plotting the standardized production integral and its derivative curves for the same time period, the radius parameter of the closed circular reservoir when the actual data and theoretical data have a high degree of fit is obtained from the above curves. The dynamic geological reserves are then calculated based on the radius parameter of the closed circular reservoir, thereby achieving intelligent and automatic analysis and improving the scientific rigor and efficiency of the analysis work.

[0024] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a flowchart of a method for determining the reserves of a closed oil reservoir produced by multiple wells, provided in an embodiment of the present invention.

[0027] Figure 2 This is a schematic diagram of the interface for plotting the standardized output integral and the relationship curve between the standardized output integral derivative and the standardized time of actual data, provided by an embodiment of the present invention.

[0028] Figure 3 This is a schematic diagram of the interface for plotting the theoretical standardized output integral and the relationship curve between the derivative of the standardized output integral and the standardized time, provided in an embodiment of the present invention.

[0029] Figure 4This is a schematic diagram of the automatic fitting interface between measured data and theoretical data provided in an embodiment of the present invention;

[0030] Figure 5 This is a flowchart of a method for determining the reserves of a closed oil reservoir produced by multiple wells, provided in an embodiment of the present invention.

[0031] Figure 6 This is a schematic diagram of a device for determining the reserves of a closed oil reservoir produced by multi-well production, provided in an embodiment of the present invention.

[0032] Figure 7 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0033] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0034] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0035] Figure 1 This is a flowchart illustrating a method for determining the reserves of a closed oil reservoir produced by multiple wells, provided in an embodiment of the present invention. This embodiment is applicable to closed oil reservoirs where multiple production wells are simultaneously producing the reservoir. The method calculates the dynamic geological reserves of the closed oil reservoir using production dynamic data. This method can be executed by a device for determining the reserves of a closed oil reservoir produced by multiple wells. This device can be implemented in hardware and / or software and can be configured in an electronic device. Figure 1 As shown, the method specifically includes the following steps:

[0036] S110. Obtain the reservoir basic parameters of the target closed reservoir, as well as the production dynamic data of the production wells within the target closed reservoir.

[0037] In this context, a target closed reservoir can be an independent development reservoir unit that is shielded by impermeable faults or formed by lithological pinch-out and is not connected to external water bodies. Reservoir basic parameters can be a set of fundamental parameters characterizing the reservoir's geological and fluid properties, including reservoir thickness, porosity, formation crude oil viscosity, and volume index. Production dynamic data can be understood as the actual production operation data of production wells within the reservoir, including daily production per well, cumulative production, and bottomhole flowing pressure.

[0038] Specifically, the basic parameters of the target closed reservoir and the production dynamic data of the production wells within the target closed reservoir can be obtained. For example, the geological and fluid-related basic parameters of the target closed reservoir can be collected through the oilfield development database, historical production data of all production wells in the reservoir can be retrieved, and core production dynamic data such as single well production and bottom hole pressure can be extracted. After being organized into a standardized format, the data can be imported into the supporting analysis software to collect and organize reservoir-related parameters and production dynamic data, such as wellhead production and bottom hole flowing pressure data of all single wells.

[0039] S120. Calculate standardized output-related parameters based on production dynamic data, and plot the measured standardized characteristic curve based on the standardized output-related parameters.

[0040] Standardized production-related parameters can be a set of dimensionless parameters calculated based on dynamic production data, used to eliminate the impact of production fluctuations and uniformly characterize the dynamic features of reservoir production. The measured standardized characteristic curve can be understood as a double logarithmic curve reflecting the reservoir's seepage characteristics, plotted based on actual production data.

[0041] Specifically, standardized production-related parameters are calculated based on production dynamic data, and measured standardized characteristic curves are plotted based on these parameters. For example, the processed production dynamic data can be substituted into a preset formula to calculate the standardized production-related parameters for each production well in sequence. With standardized time as the horizontal axis and standardized production integral and standardized production integral derivative as the vertical axis, corresponding relationship curves are plotted in a double logarithmic coordinate system to form measured standardized characteristic curves.

[0042] For example, such as Figure 2 As shown, clicking the button in the middle of the software interface will automatically load the raw test pressure data, calculate the standardized production integral and the derivative of the standardized production integral, and then plot them in a double logarithmic coordinate system. Figure 2 The curve at the top center represents the relationship between the standardized production integral of a single well and the derivative of the standardized production integral with the standardized time.

[0043] Based on the above technical solution, standardized production-related parameters are calculated based on production dynamic data, and measured standardized characteristic curves are plotted based on the standardized production-related parameters. This includes: calculating standardized production-related parameters for each production well within the target closed reservoir based on production dynamic data; and plotting measured standardized characteristic curves in a double logarithmic coordinate system based on the standardized production-related parameters.

[0044] The standardized output parameters include standardized time, standardized output, standardized output integral, and the derivative of the standardized output integral. The measured standardized characteristic curves include the curves showing the relationship between the standardized output integral and standardized time, and the curves showing the relationship between the derivative of the standardized output integral and standardized time.

[0045] Specifically, for each production well within the target closed reservoir, the corresponding standardized production-related parameters can be calculated based on its production dynamic data. Using standardized time as the unified horizontal axis, the curves showing the relationship between the standardized production integral, the derivative of the standardized production integral, and the standardized time can be plotted for each well. The measured standardized characteristic curves for each well can then be generated in a double logarithmic coordinate system.

[0046] The technical solution of this invention realizes the independent characterization of the production dynamics of each production well in the reservoir by calculating and plotting each well separately, providing a single-well curve basis for subsequent single-well fitting and well-controlled reserve calculation.

[0047] Based on the above technical solution, the standardized production parameters of each production well in the target closed reservoir are calculated based on production dynamic data, including: calculating standardized time based on the cumulative production and daily production of a single well; calculating standardized production based on the daily production of a single well, the difference between the initial pressure of the reservoir and the bottom-hole flowing pressure; calculating the standardized production integral based on the daily production and cumulative production of a single well; and calculating the derivative of the standardized production integral with respect to standardized time, the daily production and the cumulative production of a single well.

[0048] Standardized time can be a dimensionless time parameter calculated based on the cumulative production and daily production of a single well. Standardized production can be understood as a dimensionless production parameter calculated based on the daily production and production pressure difference of a single well. The standardized production integral is an integral parameter used to characterize the dynamic features of cumulative production. The derivative of the standardized production integral can be the derivative of the standardized production integral with respect to standardized time.

[0049] Specifically, the cumulative production and daily production of a single well can be substituted into the formula to calculate the standardized time; the standardized production can be calculated by using the daily production of a single well as the numerator and the difference between the initial pressure of the reservoir and the bottom-hole flowing pressure as the denominator; the standardized production can be integraled by integrating the process of the standardized production change with the standardized time, and the standardized production integral can be obtained by combining the single-well production data; the derivative of the standardized production integral with respect to the standardized time can be calculated to obtain the derivative of the standardized production integral.

[0050] For example, plot the standardized production integral and the relationship curve between the standardized production integral derivative and standardized time corresponding to the actual production data of the production well.

[0051] Define the standardized time parameter as follows: ;

[0052] Define the standardized production parameter as follows: ;

[0053] Define the standardized output integral parameter as follows: ;

[0054] Define the parameter of the standardized product integral derivative as: ;

[0055] In the above formula, q represents the cumulative production of a single well, in cubic meters; q represents the daily production of a single well, in cubic meters per day. This is the initial pressure of the reservoir, in MPa. This is the bottom-hole flowing pressure, in MPa. In a log-log coordinate system, the standardized production integral and the relationship curve between the standardized production integral derivative and standardized time corresponding to the actual production data of the production well can be plotted.

[0056] The technical solution of this invention fully quantifies the dynamic characteristics of single-well production by calculating four types of standardized parameters step by step. The derivative parameters amplify the detailed characteristics of reservoir seepage law, effectively improving the accuracy and recognition of subsequent curve fitting.

[0057] S130. Construct a seepage theory model for a circular closed reservoir and plot the theoretically standardized characteristic curve based on the seepage theory model.

[0058] The seepage theory model can be a mathematical model constructed based on seepage mechanics theory to describe the fluid seepage law in a circular closed reservoir. The theoretically standardized characteristic curve can be understood as a double logarithmic curve calculated based on the seepage theory model to reflect the theoretical seepage characteristics of a closed reservoir.

[0059] Specifically, a seepage theory model for a circular closed reservoir is constructed, and a theoretically normalized characteristic curve is plotted based on this model. For example, based on modern reservoir engineering and seepage mechanics theory, the seepage control equations for a circular closed reservoir can be constructed, and the theoretical model is completed by combining the inner and outer boundaries and initial conditions. The dimensionless pressure solution is obtained through model solving, and then the theoretically normalized production-related parameters are calculated. The theoretically normalized characteristic curve is then plotted in a double logarithmic coordinate system. For example,... Figure 3 As shown, clicking the button at the bottom of the software interface will automatically start calculating and plotting the theoretical standardized production integral and the derivative curve of the standardized production integral of a circular closed reservoir.

[0060] S140. Determine the fitting parameters for the target reservoir based on the measured standardized characteristic curve and the theoretical standardized characteristic curve.

[0061] The target reservoir fitting parameters can be obtained through curve fitting inversion and are used to characterize the reservoir's seepage and geometric features. The genetic algorithm can be understood as a global optimization algorithm simulating biological evolution, used to iteratively solve for the parameters to be optimized. The preset threshold can be a critical value for determining whether the curve fitting meets the required accuracy.

[0062] Specifically, the target reservoir fitting parameters are determined based on measured and theoretical standardized characteristic curves. For example, the measured and theoretical standardized characteristic curves of the same production well can be placed in the same logarithmic coordinate system. With the goal of minimizing curve fitting error, a genetic algorithm is used to iteratively solve for parameters such as reservoir radius and permeability. When the fitting accuracy of the two curves reaches a preset threshold, the parameters of the current iteration are output as the target reservoir fitting parameters. For example,... Figure 4 As shown, click "Double Logarithmic Curve Fitting" at the bottom of the software interface. The software will start the calculation of the pressure superposition of the interference well and quickly draw a preliminary fitting effect diagram of the measured data and theoretical data. After that, the software will use a genetic algorithm to repeatedly perform optimization automatic search fitting until satisfactory accuracy is achieved.

[0063] Based on the above technical solution, the target reservoir fitting parameters are determined based on the measured standardized characteristic curve and the theoretical standardized characteristic curve, including: placing the measured standardized characteristic curve and the theoretical standardized characteristic curve corresponding to the same production well in the same double logarithmic coordinate system; iteratively solving the parameters to be optimized based on the genetic algorithm; when the fitting accuracy of the measured standardized characteristic curve and the theoretical standardized characteristic curve reaches a preset threshold, the parameters to be optimized obtained in the current iteration are output and used as the target reservoir fitting parameters.

[0064] Among them, the parameters to be optimized include reservoir radius, reservoir permeability, skin coefficient, and wellbore storage coefficient.

[0065] Specifically, the measured and theoretical standardized characteristic curves corresponding to a single well can be imported into the same double logarithmic coordinate system to establish an optimization function with the goal of minimizing the sum of squared deviations of the two curves. A genetic algorithm is used to encode, cross, mutate, and select the parameters to be optimized, and the parameter values ​​are continuously iterated and optimized. When the fitting accuracy reaches a preset threshold, the iteration is terminated and the current parameters to be optimized are output as the fitting parameters for the target reservoir corresponding to that well.

[0066] For example, in the same log-log coordinate system, the standardized production integral and the curves relating the derivative of the standardized production integral to the standardized time are plotted simultaneously for both measured and theoretical data. During the iterative fitting process, a genetic algorithm is applied as the optimal approximation algorithm to continuously improve the parameters and enhance the fitting accuracy between the measured and theoretical data. Here, the key fitting parameters for the genetic algorithm are reservoir radius, reservoir permeability, skin factor, and wellbore storage factor.

[0067] The technical solution of this invention achieves accurate inversion of reservoir parameters corresponding to each well by single-well curve pairing fitting and genetic algorithm iterative optimization. The fitting process is highly automated, effectively reducing human operation errors and ensuring the reliability of single-well fitting parameters.

[0068] S150. Determine the dynamic geological reserves corresponding to the target closed reservoir based on the fitting parameters of the target reservoir.

[0069] Among them, dynamic geological reserves can be the actual geological reserves of the reservoir obtained by inversion calculation based on reservoir production dynamic data. Well-controlled dynamic geological reserves are the dynamic geological reserves within the control range of a single well, calculated based on the fitting parameters of a single well.

[0070] Specifically, the dynamic geological reserves corresponding to the target closed reservoir are determined based on the fitted parameters of the target reservoir. For example, the well-controlled dynamic geological reserves of the corresponding single well can be calculated using the volumetric method formula based on the reservoir radius parameters obtained from the fitting and the basic reservoir parameters. All production wells in the reservoir are traversed to complete the calculation of the well-controlled dynamic geological reserves of each well. The well-controlled dynamic geological reserves of all single wells are summed to obtain the total dynamic geological reserves of the target closed reservoir.

[0071] Based on the above technical solution, the dynamic geological reserves corresponding to the target closed reservoir are determined according to the fitting parameters of the target reservoir, including: calculating the well-controlled dynamic geological reserves of the corresponding single well using the volumetric method based on the reservoir radius in the fitting parameters of the target reservoir; traversing all production wells in the target closed reservoir to complete the calculation of the well-controlled dynamic geological reserves of all single wells; and summing up the well-controlled dynamic geological reserves of all single wells to obtain the total dynamic geological reserves of the target closed reservoir.

[0072] Specifically, the reservoir radius obtained from fitting a single well can be substituted into the volumetric method calculation formula, and combined with basic parameters such as oil layer thickness, porosity, and oil saturation, the well-controlled dynamic geological reserves of the single well can be calculated. The well-controlled reserves of all production wells in the reservoir can be calculated using the same process. The well-controlled reserves of all single wells can be summed to obtain the total dynamic geological reserves of the target closed reservoir.

[0073] For example, after obtaining the radius parameter of a circular reservoir, the dynamic geological reserves can be calculated by substituting the latest radius parameter into the volumetric method formula. If the reservoir has multiple production wells, the above steps can be repeated for each production well to calculate the well-controlled dynamic geological reserves corresponding to each well. The sum of the well-controlled dynamic geological reserve calculation results for all individual wells gives the dynamic geological reserves of the entire circular closed reservoir.

[0074] The technical solution of this invention involves acquiring the basic reservoir parameters of a target closed reservoir and the production dynamic data of the production wells within the target closed reservoir; calculating standardized production-related parameters based on the production dynamic data, and plotting measured standardized characteristic curves based on these parameters; constructing a seepage theory model for a circular closed reservoir, and plotting theoretical standardized characteristic curves based on the seepage theory model; determining the target reservoir fitting parameters based on the measured and theoretical standardized characteristic curves; and determining the dynamic geological reserves corresponding to the target closed reservoir based on the target reservoir fitting parameters. By calculating the standardized production integral and its derivative curve from the actual test data, and then theoretically plotting the standardized production integral and its derivative curves for the same time period, the radius parameter of the closed circular reservoir when the actual data and theoretical data have a high degree of fit is obtained from the above curves. The dynamic geological reserves are then calculated based on the radius parameter of the closed circular reservoir, thereby achieving intelligent and automatic analysis and improving the scientific rigor and efficiency of the analysis work.

[0075] In one possible implementation of the present invention Figure 5 This is a flowchart illustrating a method for determining the reserves of a closed oil reservoir produced by multiple wells, as provided in an embodiment of the present invention. The embodiment further describes a technical solution for constructing a seepage theory model of a circular closed oil reservoir and plotting a theoretically standardized characteristic curve based on the seepage theory model. Figure 5 As shown, the method includes:

[0076] S510. Establish the seepage control equation for a circular closed reservoir and set the basic conditions corresponding to the seepage control equation.

[0077] The fundamental conditions include internal boundary conditions, closed external boundary conditions, and initial pressure conditions. The flow governing equation is a partial differential equation used to describe the seepage behavior of fluids in a porous medium within a circular, closed reservoir. Internal boundary conditions can describe the seepage characteristics near the wellbore, defining the flow rate and pressure variations at the wellbore. Closed external boundary conditions can describe the absence of fluid seepage at the outer boundary of a closed reservoir. Initial pressure conditions can be understood as conditions describing the formation pressure distribution at the initial stage of reservoir development.

[0078] Specifically, the seepage control equation for a circular closed reservoir is established, and the corresponding basic conditions are set. For example, the radial seepage control equation for a circular closed reservoir can be established based on the theory of seepage mechanics. The production boundary conditions are set in combination with the wellbore production characteristics, the closed outer boundary conditions are set according to the closed and impermeable characteristics of the reservoir, and the initial pressure conditions are set in combination with the initial pressure state of the reservoir, thus completing the setting of the boundary conditions for the seepage equation.

[0079] S520. Based on the seepage control equation and basic conditions, the bottom-hole flow pressure solution of the Laplace space is obtained by solving the equations simultaneously.

[0080] The bottom-hole flow pressure solution in Laplace space can be obtained by transforming the real-space seepage equation into Laplace space using the Laplace transform, and then solving the analytical solution for the bottom-hole pressure. Potential superposition theory is a reservoir engineering theory for calculating bottom-hole pressure under multi-well interference; it is used to superimpose the pressure drop of the interfering wells to achieve bottom-hole pressure correction under multi-well production. Dimensionless inter-well distance is a dimensionless distance parameter converted from the actual distance between wells, used to calculate the additional pressure drop of the interfering well. The additional pressure drop is the extra pressure drop generated at the bottom of the target well by the production of the interfering well.

[0081] Specifically, the bottom-hole flow pressure solution in Laplace space is obtained by simultaneously solving the seepage control equation and the basic conditions. For example, the seepage control equation and the basic conditions can be transformed into a real space partial differential equation and then solved simultaneously to obtain the bottom-hole flow pressure solution of a single well in Laplace space. When there are multiple production wells in the reservoir, the dimensionless distance between the interfering well and the target well is calculated, and the additional pressure drop generated by the interfering well is calculated based on the potential superposition theory to correct the interference in the bottom-hole flow pressure solution of the single well.

[0082] Based on the above technical solution, after obtaining the bottom-hole flow pressure solution of the Laplace space by simultaneously solving the seepage control equation and basic conditions, the solution further includes: determining the dimensionless well-to-well distance between the interfering well and the target research well, with the target research well as the reference, when there are at least two production wells in the target closed reservoir; calculating the additional pressure drop generated by the interfering well at the bottom of the target research well based on the potential superposition theory; and correcting the interference of the bottom-hole flow pressure solution of the Laplace space based on the additional pressure drop.

[0083] In this context, the target study well can be a single well within a multi-well producing closed reservoir, serving as the core object for bottomhole pressure calculation and curve fitting analysis. Interfering wells can be understood as other synchronously producing wells within the target closed reservoir, whose production activities interfere with the bottomhole pressure of the target study well. Dimensionless well-to-well distance is a parameter obtained by dimensionlessly processing the actual well distance between the target study well and the interfering wells using reservoir characteristic parameters. Potential superposition theory can be a seepage mechanics theory used to calculate the total bottomhole pressure drop during multi-well production. Additional pressure drop can be understood as the extra pressure drop formed at the bottom of the target study well due to pressure loss generated by the interfering well's production. Interference correction can be the process of superimposing the additional pressure drop onto the single-well bottomhole flow pressure solution to correct for the interference effects of multiple wells.

[0084] Specifically, when there are multiple production wells in the target closed reservoir, the target study well can be selected first, the other interfering wells can be identified, the actual distance between the wells can be measured and converted into dimensionless distance between the wells; based on the potential superposition theory, the production data of the interfering wells and the dimensionless distance between the wells can be combined to calculate the additional pressure drop generated by the interfering wells at the bottom of the target study well; the additional pressure drop can be superimposed on the single-well Laplace space bottom-hole flow pressure solution to complete the multi-well interference correction.

[0085] The technical solution of this invention quantifies the influence of well spacing by dimensionless well-to-well distance, calculates the additional pressure drop caused by multi-well interference by combining potential superposition theory, and corrects the interference of the bottom hole pressure solution of a single well. This allows the theoretical model to accurately fit the actual scenario of oilfields with multiple wells producing simultaneously, solving the core problem that existing technologies cannot handle the dynamic reserve calculation of closed oil reservoirs with multiple wells producing simultaneously, and improving the fitting accuracy between theoretical curves and measured data.

[0086] S530. Numerical Laplace inversion is performed on the bottom-hole flow pressure solution in the Laplace space to determine the dimensionless pressure solution.

[0087] Numerical Laplace inversion is a numerical calculation method that converts analytical solutions in Laplace space into numerical solutions in real space. This scheme adopts the Stefest numerical inversion method. Dimensionless pressure solutions can be understood as dimensionless numerical pressure solutions in real space that characterize reservoir pressure changes.

[0088] Specifically, the dimensionless pressure solution is determined by numerical Laplace inversion of the bottom-hole flow pressure solution in Laplace space. For example, the Stefest numerical Laplace inversion algorithm can be used to invert the bottom-hole flow pressure solution in Laplace space, converting the analytical solution in Laplace space into dimensionless pressure data in real space. By calculating the dimensionless pressure corresponding to different dimensionless times, a complete sequence of dimensionless pressure solutions is obtained.

[0089] S540. Plot the theoretically normalized characteristic curve in a double logarithmic coordinate system based on the dimensionless pressure solution.

[0090] Among them, the theoretical standardized characteristic curves include the curve showing the relationship between the theoretical standardized output integral and the standardized time, and the curve showing the relationship between the derivative of the theoretical standardized output integral and the standardized time.

[0091] Specifically, based on the dimensionless pressure solution sequence, the corresponding data of theoretical standardized output integral, standardized output integral derivative and standardized time can be calculated; with standardized time as the horizontal axis and theoretical standardized output integral and standardized output integral derivative as the vertical axis, the corresponding curve can be plotted in a double logarithmic coordinate system to form the theoretical standardized characteristic curve.

[0092] For example, plot the theoretical standardized production integral and its derivative curves for a circular closed reservoir. The basic seepage equation is:

[0093] The seepage equation at the inner boundary is: ;

[0094] The seepage equation at the outer boundary is: ;

[0095] The initial seepage equation is: ;

[0096] In the above formula, Represents the dimensionless wellbore radius; Represents dimensionless time; Represents the radius of a dimensionless circular reservoir; This represents dimensionless pressure. Combining the above formulas, we can further derive: ; ; Where I1 and K1 are first-order Bessel functions, and I0 and K0 are zero-order Bessel functions.

[0097] This involves determining the bottomhole flow pressure solution of a single production well in a closed reservoir within Laplace space. Using the Stefest numerical Laplace inversion method, the dimensionless pressure solution in real space can be obtained. Based on this dimensionless pressure solution, the standardized production integral and its derivative versus standardized time curves for a circular closed reservoir are plotted in a double logarithmic coordinate system. The potential superposition theory is applied to the theoretical formula to address the interference problem caused by simultaneous production from multiple wells. Assume well 1 is the object of study, well 2 is the interfering well, and the distance between well 1 and well 2 is... Therefore, when calculating the theoretical solution for the bottomhole flowing pressure of well 1, the additional pressure drop caused by the disturbance from well 2 needs to be considered, i.e.: .

[0098] The technical solution of this invention involves acquiring the basic reservoir parameters of a target closed reservoir and the production dynamic data of the production wells within the target closed reservoir; calculating standardized production-related parameters based on the production dynamic data, and plotting measured standardized characteristic curves based on these parameters; constructing a seepage theory model for a circular closed reservoir, and plotting theoretical standardized characteristic curves based on the seepage theory model; determining the target reservoir fitting parameters based on the measured and theoretical standardized characteristic curves; and determining the dynamic geological reserves corresponding to the target closed reservoir based on the target reservoir fitting parameters. By calculating the standardized production integral and its derivative curve from the actual test data, and then theoretically plotting the standardized production integral and its derivative curves for the same time period, the radius parameter of the closed circular reservoir when the actual data and theoretical data have a high degree of fit is obtained from the above curves. The dynamic geological reserves are then calculated based on the radius parameter of the closed circular reservoir, thereby achieving intelligent and automatic analysis and improving the scientific rigor and efficiency of the analysis work.

[0099] Figure 6 This is a schematic diagram of a device for determining the reserves of a closed oil reservoir produced by multi-well production, provided as an embodiment of the present invention. Figure 6 As shown, the device includes: a data acquisition module 610, a measured standardized characteristic curve plotting module 620, a theoretical standardized characteristic curve plotting module 630, a reservoir fitting parameter determination module 640, and a dynamic geological reserve calculation module 650.

[0100] The data acquisition module 610 is used to acquire the basic reservoir parameters of the target closed reservoir, as well as the production dynamic data of the production wells within the target closed reservoir;

[0101] The measured standardized characteristic curve plotting module 620 is used to calculate standardized output-related parameters based on production dynamic data and plot the measured standardized characteristic curve based on the standardized output-related parameters.

[0102] The theoretically standardized characteristic curve plotting module 630 is used to construct a seepage theory model of a circular closed reservoir and plot theoretically standardized characteristic curves based on the seepage theory model.

[0103] The reservoir fitting parameter determination module 640 is used to determine the target reservoir fitting parameters based on the measured standardized characteristic curve and the theoretical standardized characteristic curve.

[0104] The dynamic geological reserves calculation module 650 is used to determine the dynamic geological reserves corresponding to the target closed reservoir based on the fitting parameters of the target reservoir.

[0105] Based on the above technical solution, the measured standardized characteristic curve plotting module is used to calculate the standardized production-related parameters of each production well in the target closed reservoir based on production dynamic data. The standardized production-related parameters include standardized time, standardized production, standardized production integral, and standardized production integral derivative. Based on the standardized production-related parameters, the measured standardized characteristic curve is plotted in a double logarithmic coordinate system. The measured standardized characteristic curve includes the curves showing the correspondence between the standardized production integral and the standardized time, and the curves showing the correspondence between the standardized production integral derivative and the standardized time.

[0106] Based on the above technical solution, the measured standardized characteristic curve plotting module is used to calculate the standardized time based on the cumulative production and daily production of a single well; to calculate the standardized production based on the daily production of a single well, the difference between the initial pressure of the reservoir and the bottom-hole flowing pressure; to calculate the standardized production integral based on the daily production and cumulative production of a single well; and to calculate the derivative of the standardized production integral based on the derivative of the standardized production integral with respect to standardized time, the daily production and the cumulative production of a single well.

[0107] Based on the above technical solution, a theoretically standardized characteristic curve plotting module is used to establish the seepage control equation for a circular closed reservoir and set the corresponding basic conditions for the seepage control equation. These basic conditions include the production boundary conditions, the closed outer boundary conditions, and the initial pressure conditions. The module then solves the simultaneous equations based on the seepage control equation and the basic conditions to obtain the bottom-hole flow pressure solution in the Laplace space. Numerical Laplace inversion is performed on the bottom-hole flow pressure solution in the Laplace space to determine the dimensionless pressure solution. Based on the dimensionless pressure solution, theoretically standardized characteristic curves are plotted in a double logarithmic coordinate system. These curves include the curves showing the relationship between the theoretically standardized production integral and the standardized time, and the curves showing the relationship between the derivative of the theoretically standardized production integral and the standardized time.

[0108] Based on the above technical solutions, a theoretically standardized characteristic curve plotting module is used to determine the dimensionless well-to-well distance between the interfering well and the target research well, with the target research well as the benchmark, when there are at least two production wells in the target closed reservoir; calculate the additional pressure drop generated by the interfering well at the bottom of the target research well based on the potential superposition theory; and perform interference correction on the bottom flow pressure solution of the Laplace space based on the additional pressure drop.

[0109] Based on the above technical solution, the reservoir fitting parameter determination module is used to place the measured standardized characteristic curve and the theoretical standardized characteristic curve corresponding to the same production well in the same double logarithmic coordinate system; iteratively solves the parameters to be optimized based on a genetic algorithm, wherein the parameters to be optimized include reservoir radius, reservoir permeability, skin coefficient, and wellbore storage coefficient; when the fitting accuracy of the measured standardized characteristic curve and the theoretical standardized characteristic curve reaches a preset threshold, the parameters to be optimized obtained in the current iteration are output and used as the target reservoir fitting parameters.

[0110] Based on the above technical solution, the dynamic geological reserves calculation module is used to calculate the well-controlled dynamic geological reserves of the corresponding single well using the volumetric method based on the reservoir radius in the target reservoir fitting parameters; it traverses all production wells in the target closed reservoir to complete the calculation of the well-controlled dynamic geological reserves of all single wells; and it sums up the well-controlled dynamic geological reserves of all single wells to obtain the total dynamic geological reserves of the target closed reservoir.

[0111] The technical solution of this invention involves acquiring the basic reservoir parameters of a target closed reservoir and the production dynamic data of the production wells within the target closed reservoir; calculating standardized production-related parameters based on the production dynamic data, and plotting measured standardized characteristic curves based on these parameters; constructing a seepage theory model for a circular closed reservoir, and plotting theoretical standardized characteristic curves based on the seepage theory model; determining the target reservoir fitting parameters based on the measured and theoretical standardized characteristic curves; and determining the dynamic geological reserves corresponding to the target closed reservoir based on the target reservoir fitting parameters. By calculating the standardized production integral and its derivative curve from the actual test data, and then theoretically plotting the standardized production integral and its derivative curves for the same time period, the radius parameter of the closed circular reservoir when the actual data and theoretical data have a high degree of fit is obtained from the above curves. The dynamic geological reserves are then calculated based on the radius parameter of the closed circular reservoir, thereby achieving intelligent and automatic analysis and improving the scientific rigor and efficiency of the analysis work.

[0112] The closed oil reservoir reserve determination device for multi-well production provided in this embodiment of the invention can execute the closed oil reservoir reserve determination method for multi-well production provided in any embodiment of the invention, and has the corresponding functional modules and beneficial effects of the method.

[0113] Figure 7 A schematic diagram of an electronic device 10, which can be used to implement embodiments of the present invention, is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices (e.g., helmets, glasses, watches, etc.), and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.

[0114] like Figure 7 As shown, the electronic device 10 includes at least one processor 11 and a memory, such as a read-only memory (ROM) 12 or a random access memory (RAM) 13, communicatively connected to the at least one processor 11. The memory stores computer programs executable by the at least one processor. The processor 11 can perform various appropriate actions and processes based on the computer program stored in the ROM 12 or loaded from storage unit 18 into the RAM 13. The RAM 13 can also store various programs and data required for the operation of the electronic device 10. The processor 11, ROM 12, and RAM 13 are interconnected via a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0115] Multiple components in electronic device 10 are connected to I / O interface 15, including: input unit 16, such as keyboard, mouse, etc.; output unit 17, such as various types of displays, speakers, etc.; storage unit 18, such as disk, optical disk, etc.; and communication unit 19, such as network card, modem, wireless transceiver, etc. Communication unit 19 allows electronic device 10 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0116] Processor 11 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of processor 11 include, but are not limited to, central processing unit (CPU), graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, digital signal processors (DSPs), and any suitable processor, controller, microcontroller, etc. Processor 11 performs the various methods and processes described above, such as methods for determining the reserves of closed reservoirs in multi-well production.

[0117] In some embodiments, the method for determining the reserves of closed reservoirs produced by multiple wells can be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 18. In some embodiments, part or all of the computer program can be loaded and / or installed on electronic device 10 via ROM 12 and / or communication unit 19. When the computer program is loaded into RAM 13 and executed by processor 11, one or more steps of the method for determining the reserves of closed reservoirs produced by multiple wells described above can be performed. Alternatively, in other embodiments, processor 11 can be configured to perform the method for determining the reserves of closed reservoirs produced by multiple wells by any other suitable means (e.g., by means of firmware).

[0118] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), payload-programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transmitting data and instructions to the storage system, the at least one input device, and the at least one output device.

[0119] Computer programs used to implement the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the processor, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be performed. The computer programs may be executed entirely on a machine, partially on a machine, or as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0120] In the context of this invention, a computer-readable storage medium can be a tangible medium that may contain or store a computer program for use by or in conjunction with an instruction execution system, apparatus, or device. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination thereof. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof.

[0121] To provide interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user provides input to the electronic device. Other types of devices can also be used to provide interaction with the user; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including sound input, voice input, or tactile input).

[0122] The systems and technologies described herein can be implemented in computing systems that include backend components (e.g., as data servers), or middleware components (e.g., application servers), or frontend components (e.g., user computers with graphical user interfaces or web browsers through which users can interact with implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium (e.g., communication networks). Examples of communication networks include local area networks (LANs), wide area networks (WANs), blockchain networks, and the Internet.

[0123] A computing system can include clients and servers. Clients and servers are generally located far apart and typically interact through communication networks. The client-server relationship is created by computer programs running on the respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or cloud host, which is a hosting product within the cloud computing service system to address the shortcomings of traditional physical hosts and VPS services, such as high management difficulty and weak business scalability.

[0124] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0125] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for determining the reserves of a closed oil reservoir produced by multiple wells, characterized in that, include: Obtain the reservoir basic parameters of the target closed reservoir, as well as the production dynamic data of the production wells within the target closed reservoir; Based on the production dynamic data, standardized output-related parameters are calculated, and measured standardized characteristic curves are plotted according to the standardized output-related parameters. A seepage theory model for a circular closed reservoir is constructed, and a theoretically standardized characteristic curve is plotted based on the seepage theory model. The target reservoir fitting parameters are determined based on the measured standardized characteristic curve and the theoretical standardized characteristic curve. The dynamic geological reserves corresponding to the target closed reservoir are determined based on the fitting parameters of the target reservoir.

2. The method according to claim 1, characterized in that, The process of calculating standardized output-related parameters based on the production dynamic data and plotting measured standardized characteristic curves based on the standardized output-related parameters includes: Based on the production dynamic data, the standardized production-related parameters of each production well in the target closed reservoir are calculated, wherein the standardized production-related parameters include standardized time, standardized production, standardized production integral, and standardized production integral derivative. Based on the standardized output-related parameters, the measured standardized characteristic curves are plotted in a double logarithmic coordinate system. The measured standardized characteristic curves include the curves showing the relationship between the standardized output integral and the standardized time, and the curves showing the relationship between the derivative of the standardized output integral and the standardized time.

3. The method according to claim 2, characterized in that, The calculation of standardized production-related parameters for each production well within the target closed reservoir based on the production dynamic data includes: The standardized time is calculated based on the cumulative production and daily production of a single well. The standardized production rate is calculated based on the daily production rate of a single well, the difference between the initial reservoir pressure and the bottom-hole flowing pressure; The standardized production integral is calculated based on the daily production and cumulative production of a single well. The derivative of the standardized production integral is calculated based on the derivative of the standardized production integral with respect to standardized time, the daily production of a single well, and the cumulative production of a single well.

4. The method according to claim 1, characterized in that, The construction of a seepage theory model for a circular closed reservoir, and the plotting of a theoretically normalized characteristic curve based on the seepage theory model, includes: Establish the seepage control equation for a circular closed reservoir and set the basic conditions corresponding to the seepage control equation, wherein the basic conditions include the internal boundary conditions, the closed external boundary conditions, and the initial pressure conditions. The bottom-hole flow pressure solution of the Laplace space is obtained by simultaneously solving the seepage control equation and the basic conditions. Numerical Laplace inversion is performed on the bottom-hole flow pressure solution of the Laplace space to determine the dimensionless pressure solution; The theoretically standardized characteristic curve is plotted in a double logarithmic coordinate system based on the dimensionless pressure solution. The theoretically standardized characteristic curve includes the curve showing the relationship between the theoretically standardized product integral and the standardized time, and the curve showing the relationship between the derivative of the theoretically standardized product integral and the standardized time.

5. The method according to claim 4, characterized in that, After obtaining the bottom-hole flow pressure solution in the Laplace space by simultaneously solving the seepage control equation and the basic conditions, the solution further includes: When there are at least two production wells in the target closed reservoir, the dimensionless well-to-well distance between the interfering well and the target research well is determined based on the target research well. The additional pressure drop generated by the interfering well at the bottom of the target well is calculated based on the potential superposition theory. The bottom-hole flow pressure solution of the Lagrange space is perturbed and corrected based on the additional pressure drop.

6. The method according to claim 1, characterized in that, The determination of target reservoir fitting parameters based on the measured standardized characteristic curve and the theoretical standardized characteristic curve includes: The measured standardized characteristic curves and theoretical standardized characteristic curves corresponding to the same production well are placed in the same double logarithmic coordinate system; The genetic algorithm is used to iteratively solve the parameters to be optimized, which include reservoir radius, reservoir permeability, skin coefficient, and wellbore storage coefficient. If the fitting accuracy between the measured standardized characteristic curve and the theoretical standardized characteristic curve reaches a preset threshold, the parameters to be optimized obtained in the current iteration are output and used as the fitting parameters for the target reservoir.

7. The method according to claim 1, characterized in that, The step of determining the dynamic geological reserves corresponding to the target closed reservoir based on the target reservoir fitting parameters includes: Based on the reservoir radius in the target reservoir fitting parameters, the well-controlled dynamic geological reserves of the corresponding single well are calculated by the volumetric method. Traverse all production wells within the target closed reservoir and complete the well-controlled dynamic geological reserves calculation for all individual wells; The total dynamic geological reserves of the target closed reservoir are obtained by summing up the well-controlled dynamic geological reserves of all individual wells.

8. A device for determining the reserves of a closed oil reservoir produced by multiple wells, characterized in that, include: The data acquisition module is used to acquire the basic reservoir parameters of the target closed reservoir, as well as the production dynamic data of the production wells within the target closed reservoir; The measured standardized characteristic curve plotting module is used to calculate standardized output-related parameters based on the production dynamic data, and plot the measured standardized characteristic curve according to the standardized output-related parameters. The theoretically standardized characteristic curve plotting module is used to construct a seepage theory model for a circular closed reservoir and plot theoretically standardized characteristic curves based on the seepage theory model. The reservoir fitting parameter determination module is used to determine the target reservoir fitting parameters based on the measured standardized characteristic curve and the theoretical standardized characteristic curve. The dynamic geological reserves calculation module is used to determine the dynamic geological reserves corresponding to the target closed reservoir based on the fitting parameters of the target reservoir.

9. An electronic device, characterized in that, The electronic device includes: At least one processor; and A memory communicatively connected to the at least one processor; wherein, The memory stores a computer program that can be executed by the at least one processor, the computer program being executed by the at least one processor to enable the at least one processor to perform the method for determining the reserves of a closed reservoir produced by a multi-well production as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that, when executed by a processor, implement the method for determining the reserves of a closed oil reservoir produced by a multi-well process as described in any one of claims 1-7.

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