A method and device for quantifying and analyzing inter-well connectivity

Abstract

The present application discloses a method and device for quantifying and analyzing inter-well connectivity, relating to the technical field of water flooding development, including: dividing the original model into layers to clarify the distribution information of injection wells and production wells. Using the geometric segmentation method to divide the reservoir into multiple grid units to ensure that the injection wells and production wells are located within the grid units. Using the division rules to delimit the control area for each well and determining the attribution of the grid units by comparing the Euclidean distances. Obtaining the conductivity between two adjacent grid units separated by the controlled dividing line. Using the production index and injection index to evaluate the production and injection capabilities of the wells respectively. Based on the finite volume method, constructing a mass conservation equation for the grid units and iteratively solving until convergence. Traversing the conductivity connectivity table to calculate the flow components, accumulating to obtain the total flow, and deriving the inter-well connectivity coefficient therefrom to achieve its quantitative evaluation. Solving the problem of how to optimize the injection-production well pattern design and improve the effect of water flooding development and the reservoir recovery factor.

Description

Technical Field

[0001] This application relates to the technical field of water flooding development, and particularly to a method and device for quantifying and analyzing inter-well connectivity. Background Art

[0002] A key challenge in reservoir development is to efficiently manage the fluid flow in the underground reservoir to achieve optimal crude oil recovery.

[0003] The existing technologies for obtaining the formation distribution information of the reservoir usually rely on geological exploration, logging data, and reservoir modeling techniques. These technologies provide a basic understanding of the reservoir structure, fluid properties, and distribution. However, when converting this information into the actual water flooding injection-production well pattern design, some challenges still exist. For example, there is a lack of sufficient fineness and dynamics in describing the inter-well connectivity. The existing technologies often can only provide static and simplified descriptions of the inter-well connectivity, and cannot accurately capture the actual fluid flow between wells. As a result, the optimization effect of the injection-production well pattern design is limited, which affects the water flooding development effect and the reservoir recovery rate.

[0004] Therefore, how to develop a more comprehensive and accurate method to analyze the inter-well connectivity to optimize the injection-production well pattern design and improve the water flooding development effect and the reservoir recovery rate has become an urgent problem to be solved. Summary of the Invention

[0005] In the embodiments of this application, by providing a method for quantifying and analyzing inter-well connectivity, the problem of how to develop a more comprehensive and accurate method to analyze the inter-well connectivity to optimize the injection-production well pattern design and improve the water flooding development effect and the reservoir recovery rate is solved.

[0006] In a first aspect, an embodiment of the present application provides a method for quantifying and analyzing inter-well connectivity, including: performing inter-layer division on an original reservoir model to obtain distribution information of injection wells and production wells in a lateral layer system; processing the distribution information of injection wells and production wells in the lateral layer system by using a geometric segmentation method to divide the reservoir into multiple interconnected grid units, such that the injection wells and production wells are both located within the grid units; using a division rule to divide the control area for each injection well and production well; wherein, the control area of a well is a polygonal area surrounded by the intersection points of the control dividing lines of six pairs of injection wells or production wells around it; traversing all grid units, and determining whether the grid unit belongs to the control area of an injection well or a production well by comparing the Euclidean distance between the center point of each grid unit and all injection wells and production wells; obtaining the conductivity between two adjacent grid units divided by a control dividing line, and using a conductivity connectivity table to record the conductivity between all two adjacent grid units divided by a control dividing line; using a production index to represent the production capacity of a production well under a first pressure difference, and using a water injection index to represent the water injection capacity of an injection well under a second pressure difference; for all two adjacent grid units divided by a control dividing line, constructing a mass conservation equation according to the finite volume method, and iteratively solving the pressure vector and the total fluid saturation until the convergence condition is satisfied; traversing the conductivity connectivity table, and for all two adjacent grid units divided by a control dividing line, calculating the flow component between the injection well and the production well, accumulating all flow components, and calculating the total flow of the fluid between the injection well and the production well; obtaining an expression of the inter-well connectivity coefficient from the total flow calculation formula, and calculating the inter-well connectivity coefficient according to the expression of the inter-well connectivity coefficient.

[0007] In a possible implementation manner, the division rule includes: for any pair of an injection well and a production well, calculating the coordinates of their midpoint and the slope of the connecting line, and calculating the slope of the perpendicular bisector; obtaining the equation of the perpendicular bisector according to the slope of the perpendicular bisector, and using the perpendicular bisector as the control dividing line; the calculation formula for the coordinates of the midpoint is: ; wherein, is the coordinate of the midpoint , is the coordinate of the production well , is the coordinate of the injection well ; the calculation formula for the slope of the connecting line is: ; wherein, is the slope of the connecting line; the calculation formula for the slope of the perpendicular bisector is: ; wherein, is the slope of the perpendicular bisector; the equation of the perpendicular bisector is: ; wherein, and are variables in the equation of the perpendicular bisector, is the abscissa of any point in the horizontal layer system, is the ordinate of any point in the horizontal layer system.

[0008] In a possible implementation, traversing all grid cells and determining whether a grid cell belongs to the control area of an injection well or a production well by comparing the Euclidean distances between the center point of each grid cell and all injection wells and production wells includes: if the Euclidean distance from the center point of a grid cell to a certain injection well is less than its Euclidean distances to all production wells, it is determined that the grid cell belongs to the control area of the injection well; if the Euclidean distance from the center point of a grid cell to a certain production well is less than its Euclidean distances to all injection wells, it is determined that the grid cell belongs to the control area of the production well.

[0009] In a possible implementation, obtaining the conductivity between two adjacent grid cells divided by the control dividing line includes: the calculation formula for the conductivity between two adjacent grid cells divided by the control dividing line is: , , ; where is the conductivity between two adjacent grid cells divided by the control dividing line, and are intermediate variables, is the permeability of grid cell , is the permeability of grid cell , is the area of grid cell , is the area of grid cell , is the distance from the center point of grid cell to the control dividing line, is the distance from the center point of grid cell to the control dividing line, is the unit normal vector of the control dividing line pointing to grid cell , is the unit normal vector of the control dividing line pointing to grid cell , is the unit direction vector of the control dividing line pointing from the center point to grid cell , is the unit direction vector of the control dividing line pointing from the center point to grid cell .

[0010] In a possible implementation, using the production index to represent the production capacity of an oil production well under a first pressure difference and using the water injection index to represent the water injection capacity of a water injection well under a second pressure difference includes: The first pressure difference is: ; where is the first pressure difference, is the reservoir pressure, is the bottom hole pressure; The second pressure difference is: ; where is the second pressure difference; The calculation formula for the production index or the water injection index is: ; where is the production index or the water injection index , is the unit conversion factor, is the effective angle around the wellbore, is the reservoir capacity, is the pressure equivalent radius of the grid cell, is the actual radius of the wellbore, is the skin effect factor, is the logarithmic term, representing the flow resistance from the grid cell to the wellbore.

[0011] In a possible implementation, for all adjacent two grid cells divided by the controlled dividing line, constructing a mass conservation equation according to the finite volume method and iteratively solving the pressure vector and the total fluid saturation until the convergence condition is satisfied, includes: The mass conservation equation is: ; where is the fluid residual, is the porosity of the grid cell , is the density of the fluid in the grid cell , is the saturation of the fluid in the grid cell , is the time step within the change amount, is the volume of the grid cell , is the mass flow rate flowing into the grid cell from the grid cell , is the set of grid cells adjacent to the grid cell , is the source-sink term; When the grid cell is an oil production well, the source-sink term is: ; where is the relative permeability of the fluid in the grid cell ​ is a fluid in the grid cell viscosity is the production index ; when the grid cell is an injection well, the source-sink term is: , is the injection index ; from the grid cell flows into the adjacent grid cell mass flow rate The expression is: ; where is the conductivity between two adjacent grid cells separated by the controlled dividing line is in the grid cell and the grid cell the average value of the mobility parameters between is a fluid density is a fluid relative permeability is a fluid viscosity represents the gravity term is the acceleration of gravity is the height difference between adjacent grid cells is the pressure difference between adjacent grid cells; ; where is the fluid compressibility is the fluid density corresponding to the reference pressure under is the pressure of the current grid cell is the reference pressure is the base of the natural logarithm; ; where is the mobility parameter of the fluid in the grid cell ; is the mobility parameter of the fluid in the grid cell ; The pressure vector includes the pressures of all grid cells, and the total fluid saturation includes the saturations of the fluids in all grid cells.

[0012] In a possible implementation, traversing the conductivity connectivity table, for all adjacent two grid cells separated by the controlled dividing line, calculating the flow component between the injection well and the production well, accumulating all flow components, and calculating the total flow of the fluid between the injection well and the production well, including: The calculation formula for the flow component is: ; where is the flow component between two adjacent grid cells between the injection well and the production well; The calculation formula for the total flow is: ; among them, is the total flow rate of the fluid between the water injection well and the oil production well, is the control area of the water injection well , is the control area of the oil production well , is the inter-well connectivity coefficient, is the average pressure within the control area of the water injection well , is the average pressure within the control area of the oil production well .

[0013] In a possible implementation, the expression of the inter-well connectivity coefficient is obtained from the calculation formula of the total flow rate, and the inter-well connectivity coefficient is calculated according to this expression of the inter-well connectivity coefficient, including: The expression of the inter-well connectivity coefficient is: ; among them, , , is the pressure of the grid cell , is the pressure of the grid cell , is the volume of the grid cell , is the volume of the grid cell , is the total volume of the control area of the water injection well , is the total volume of the control area of the oil production well .

[0014] Second aspect, embodiments of the present application provide an inter-well connectivity quantification and analysis device, including: an acquisition distribution information module, configured to perform interlayer division on an original reservoir model to obtain the distribution information of injection wells and production wells in a lateral layer system; a grid cell division module, configured to process the distribution information of injection wells and production wells in the lateral layer system by using a geometric segmentation method, divide the reservoir into a plurality of interconnected grid cells, and enable the injection wells and production wells to be located within the grid cells; a control area division module, configured to use a division rule to divide the control area for each injection well and production well; wherein, the control area of a well is a polygonal area surrounded by the intersection points of the control dividing lines of six pairs of injection wells or production wells around it; a determination module, configured to traverse all grid cells, and determine whether the grid cell belongs to the control area of an injection well or a production well by comparing the Euclidean distance between the center point of each grid cell and all injection wells and production wells; an acquisition conductivity module, configured to acquire the conductivity between two adjacent grid cells divided by the control dividing line, and record the conductivity between all two adjacent grid cells divided by the control dividing line by using a conductivity connection table; a representation module, configured to represent the production capacity of a production well under a first pressure difference by using a production index, and represent the water injection capacity of an injection well under a second pressure difference by using a water injection index; an iterative solution module, configured to construct a mass conservation equation for all two adjacent grid cells divided by the control dividing line according to the finite volume method, and iteratively solve the pressure vector and the total fluid saturation until the convergence condition is satisfied; a total flow calculation module, configured to traverse the conductivity connection table, calculate the flow component between an injection well and a production well for all two adjacent grid cells divided by the control dividing line, accumulate all flow components, and calculate the total flow of the fluid between the injection well and the production well; a well-to-well connectivity coefficient calculation module, configured to obtain an expression of the well-to-well connectivity coefficient from the total flow calculation formula, and calculate the well-to-well connectivity coefficient according to the expression of the well-to-well connectivity coefficient.

[0015] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects:

[0016] The embodiment of the present application provides a method for quantifying and analyzing well - to - well connectivity. By performing inter - layer division on the original reservoir model, the distribution information of injection wells and production wells in the lateral layer system can be obtained more accurately. Using the geometric segmentation method, the lateral layer system of the reservoir is divided into multiple interconnected grid units, ensuring that injection wells and production wells are both located within the grid units. By dividing the control area for each injection well and production well, the distribution of fluid flow in the reservoir can be understood more intuitively. In determining the attribution of grid units, a method of comparing the Euclidean distances between the center points of each grid unit and all injection wells and production wells is adopted. This method is both simple and effective, and can accurately classify grid units into the control areas of the corresponding injection wells or production wells. The present application also obtains the conductivity between two adjacent grid units separated by the control dividing line and records it using a conductivity connection table. This step is crucial for subsequent calculation of the flow components between injection wells and production wells. In constructing the mass conservation equation, the present application adopts the finite volume method and iteratively solves the pressure vector and total fluid saturation until the convergence condition is met. This method can more accurately simulate the dynamic change process of fluids in the reservoir. By traversing the conductivity connection table, calculating the flow components between all adjacent two grid units separated by the control dividing line between injection wells and production wells, and accumulating to obtain the total flow, the expression of the well - to - well connectivity coefficient is derived, and the well - to - well connectivity coefficient is calculated accordingly. This result is of great significance for evaluating the connectivity between wells and optimizing production strategies. It solves the problem of how to develop a more comprehensive and accurate method to analyze well - to - well connectivity to optimize the injection - production well pattern design and improve the effect of water flooding development and reservoir recovery factor. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for describing the embodiments of the present application or the prior art. Obviously, the following drawings are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0018] Figure 1 It is a flowchart of the method for quantifying and analyzing well - to - well connectivity provided by the embodiment of the present application;

[0019] Figure 2 It is a schematic diagram of the original reservoir model provided by the embodiment of the present application;

[0020] Figure 3 It is a schematic diagram of the divided control area provided by the embodiment of the present application;

[0021] Figure 4 It is a schematic diagram of the conductivity between two adjacent grid units separated by the control dividing line provided by the embodiment of the present application;

[0022] Figure 5 This is the calculation data graph of the inter-well connectivity coefficient provided by the embodiment of the present application;

[0023] Figure 6 This is the comparison result graph of reservoir productivity prediction between the method based on numerical simulation and the method based on material balance principle provided by the embodiment of the present application;

[0024] Figure 7 This is the schematic diagram of the inter-well connectivity quantification and analysis device provided by the embodiment of the present application;

[0025] Figure 8 This is the schematic diagram of the inter-well connectivity quantification and analysis server provided by the embodiment of the present application. Detailed implementation manners

[0026] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0027] The following explanations are made for some technologies involved in the embodiments of the present application to facilitate understanding. It should be considered that they are merely exemplary. Therefore, those of ordinary skill in the art should recognize that various changes and modifications can be made to the embodiments described here without departing from the scope and spirit of the present application. Similarly, for the sake of clarity and conciseness, the descriptions of some well-known functions and structures are omitted in the following.

[0028] The embodiment of the present application provides an inter-well connectivity quantification and analysis method, as Figure 1 shown, this method includes steps S101 to S109. Among them, Figure 1 This is only an execution order shown in the embodiment of the present application and does not represent the only execution order of an inter-well connectivity quantification and analysis method. Under the condition that the final result can be achieved, Figure 1 the steps shown can be executed in parallel or reversed.

[0029] S101: Perform interlayer division on the original reservoir model to obtain the distribution information of injection wells and production wells in the horizontal layer series.

[0030] Specifically, this application combines the layered information of the original reservoir model with the actual perforation conditions of injection-production wells. By carefully classifying the perforation grids of injection-production wells within each layer, a unique injection-production well network system for each layer is constructed. Specifically, this application first accurately extracts the structural characteristics of each layer based on the layered data of the original reservoir model, and simultaneously collects the detailed perforation data of injection-production wells. Subsequently, each geological layer (zone) is traversed to accurately locate the perforation positions of each well in each layer, and then the perforation grid distribution of these wells in different layers is determined. If there is a perforation grid of an injection-production well in a certain layer, it means that the well has injection-production functions in that layer, so it is officially included in the composition of the injection-production well network of that layer. This process ensures that the injection-production well network of each layer can be accurately depicted, realizing the all-round division of the injection-production well network from the top layer to the bottom layer and from the vertical direction to the horizontal direction of the reservoir. It should be noted that injection-production wells refer to injection wells and production wells, and the injection-production well network refers to multiple pairs of injection wells and production wells.

[0031] Figure 2 It is a schematic diagram of the original reservoir model provided by the embodiment of this application. Figure 2 In (a), after the interlayer division of the original reservoir model, the distribution of a pair of injection well and production well in a longitudinal layer series of a certain layer at the vertical well position is shown. Figure 2 In (b), after the interlayer division of the original reservoir model, the distribution of the injection well and production well obtained in a transverse layer series of a certain layer at the vertical well position is shown. Figure 2 It shows the formation structure in the reservoir and the spatial distribution of geological bodies, and can intuitively reflect the overall situation of reservoir geology. Figure 2 In it, the injection well is marked in blue, the production well is marked in red, and the arrow indicates the direction of fluid flow, vividly depicting the fluid exchange process between injection-production wells. The distribution of the injection well and production well in a transverse layer series of a certain layer at the vertical well position can refine the specific distribution of the injection-production well network in different layers.

[0032] S102: Use the geometric division method to process the distribution information of injection wells and production wells in the transverse layer series, divide the reservoir into multiple interconnected grid units, and make both injection wells and production wells located within the grid units.

[0033] S103: Use the division rule to divide the control area for each injection well and production well. Among them, the control area of a well is a polygonal area surrounded by the intersection points of the control dividing lines of six pairs of surrounding injection wells or production wells.

[0034] The division rule includes: for any pair of injection well and production well, calculate the coordinates of their midpoint and the slope of the connecting line, and calculate the slope of the perpendicular bisector. Obtain the equation of the perpendicular bisector according to the slope of the perpendicular bisector, and use the perpendicular bisector as the control dividing line.

[0035] The calculation formula for the coordinates of the midpoint is as follows: . Among them, is the coordinate of the midpoint , is the coordinate of the oil production well , is the coordinate of the injection well I.

[0036] The calculation formula for the slope of the connecting line is as follows: . Among them, is the slope of the connecting line.

[0037] The calculation formula for the slope of the perpendicular bisector is as follows: . Among them, is the slope of the perpendicular bisector.

[0038] The equation of the perpendicular bisector is as follows: . Among them, and are variables in the equation of the perpendicular bisector, is the abscissa of any point in the horizontal layer system, is the ordinate of any point in the horizontal layer system.

[0039] Furthermore, the division rule of the present application not only considers the distribution information of injection wells and oil production wells in the horizontal layer system, but also deeply combines the actual geological conditions of the oil reservoir to ensure the accuracy and practicability of the division.

[0040] Specifically, the obtained distribution information is analyzed in detail, and then according to an innovative space segmentation strategy, the oil reservoir area in the horizontal layer system is carefully divided into multiple interconnected control areas. The division of these control areas is not random, but strictly follows the geometric rules mentioned above. For each pair of injection wells and oil production wells, the coordinates of their midpoints and the slope of the connecting line are calculated, and then the slope of the perpendicular bisector is obtained. Using these geometric parameters, the equation of the perpendicular bisector is obtained, and the perpendicular bisector is used as the control dividing line. It should be noted that when dividing the control areas in the present application, special attention is paid to the adaptability of the shape of each control area to the actual geological conditions of the oil reservoir. This means that the boundaries of the control areas are not simple straight lines or regular polygons, but are finely adjusted according to the geological characteristics of the oil reservoir, the well location distribution, and the fluid flow characteristics. Such a design ensures that each control area can accurately reflect the complex situation inside the oil reservoir, and at the same time ensures that the connection relationship between the injection wells and the oil production wells can be captured and calculated.

[0041] Figure 3 This is a schematic diagram of the divided control areas provided by the embodiment of the present application. Figure 3 In (a) shows multiple divided control areas, Figure 3In (b), the control area of specific injection wells and production wells is enlarged. Figure 3 The square grid in (b) in this is the multiple interconnected grid cells into which the reservoir is divided in S102. Figure 3 Well I in this is an injection well, well J is a production well, and the other wells are marked in blue and red respectively, with blue marking injection wells and red marking production wells. After determining the control areas of each well, the connectivity relationship between the injection wells and production wells is established using the pressure field distribution information in the reservoir. Specifically, after injecting fluid into the injection wells and production wells, the diffusion path of the fluid in the reservoir and the pumping situation of the production wells are analyzed. Figure 3 In (b) in this, the pressure field distribution between the injection and production wells is shown, where the arrows clearly indicate the direction of fluid displacement. It should be noted that the fluid in this application is the aqueous phase and the oil phase.

[0042] S104: Traverse all grid cells and determine whether the grid cell belongs to the control area of an injection well or a production well by comparing the Euclidean distance from the center point of each grid cell to all injection wells and production wells.

[0043] Traverse all grid cells and determine whether the grid cell belongs to the control area of an injection well or a production well by comparing the Euclidean distance from the center point of each grid cell to all injection wells and production wells, including: if the Euclidean distance from the center point of the grid cell to a certain injection well is less than its Euclidean distance to all production wells, then it is determined that the grid cell belongs to the control area of this injection well. If the Euclidean distance from the center point of the grid cell to a certain production well is less than its Euclidean distance to all injection wells, then it is determined that the grid cell belongs to the control area of this production well.

[0044] The calculation formula for the Euclidean distance from the center point of the grid cell to the production well is: . Where is the Euclidean distance from the center point of the grid cell to the production well, is the coordinate of the center point of the grid cell.

[0045] The calculation formula for the Euclidean distance from the center point of the grid cell to the injection well is: . Where is the Euclidean distance from the center point of the grid cell to the injection well.

[0046] S105: Obtain the conductivity between two adjacent grid cells divided by the control dividing line, and record the conductivity between all two adjacent grid cells divided by the control dividing line using a conductivity connection table.

[0047] Obtain the conductivity between two adjacent grid cells divided by the controlled dividing line, including: The calculation formula for the conductivity between two adjacent grid cells divided by the controlled dividing line is: , , . Wherein, is the conductivity between two adjacent grid cells divided by the controlled dividing line, and are intermediate variables, is the permeability of grid cell , is the permeability of grid cell , is the area of grid cell , is the area of grid cell , is the distance from the center point of grid cell to the controlled dividing line, is the distance from the center point of grid cell to the controlled dividing line, is the unit normal vector of the controlled dividing line pointing to grid cell , is the unit normal vector of the controlled dividing line pointing to grid cell , is the unit direction vector of the center point of the controlled dividing line pointing to grid cell , is the unit direction vector of the center point of the controlled dividing line pointing to grid cell .

[0048] It should be noted that the conductivity connection table can be presented in the form of a matrix, and each element in the matrix represents the conductivity between two adjacent grid cells divided by the controlled dividing line.

[0049] Figure 4 This is a schematic diagram of the conductivity between two adjacent grid cells divided by the controlled dividing line provided by the embodiment of the present application. Figure 4 The interpretations of the relevant parameters in

[0050] S106: Use the production index to represent the production capacity of the oil production well under the first pressure difference, and use the injection index to represent the injection capacity of the injection well under the second pressure difference.

[0051] Use the production index to represent the production capacity of the oil production well under the first pressure difference, and use the injection index to represent the injection capacity of the injection well under the second pressure difference, including: The first pressure difference is: . Wherein, is the first pressure difference, is the reservoir pressure, is the bottom-hole pressure. The second pressure difference is: . Among them, is the second pressure difference.

[0052] The calculation formula for the productivity index or injection index is: . Among them, is the productivity index or the injection index , is the unit conversion factor, is the effective angle around the wellbore, is the reservoir capacity, is the pressure equivalent radius of the grid cell, is the actual radius of the wellbore, is the skin effect factor, is the logarithmic term, representing the flow resistance from the grid cell to the wellbore.

[0053] Specifically, in reservoir development and fluid management, accurately quantifying the production capacity of oil production wells and the injection capacity of injection wells is crucial. For this purpose, this application introduces the productivity index and the injection index these two key indicators. These two indices not only reflect the fluid handling capacity of the wellbore under a specific pressure difference but also imply the influence of reservoir geological characteristics and wellbore conditions on fluid flow. The first pressure difference is the main driving force for driving reservoir fluids to flow towards the wellbore. The second pressure difference is the key driving force for pushing fluids from the wellbore into the reservoir. It should be noted that the calculation formulas for the productivity index and the injection index are the same.

[0054] S107: For all adjacent two grid cells divided by the controlled dividing line, construct a mass conservation equation according to the finite volume method, and iteratively solve the pressure vector and the total fluid saturation until the convergence condition is met.

[0055] The mass conservation equation is: . Among them, is the fluid residual, is the porosity of the grid cell , is the density of the fluid in the grid cell , is the saturation of the fluid in the grid cell , is the time step within the change amount, is the volume of the grid cell , For the mass flow rate flowing into the grid cell from the grid cell , is the set of grid cells adjacent to the grid cell , and

[0056] is the source-sink term. Among them, is the relative permeability of the fluid in the grid cell , is the viscosity of the fluid in the grid cell , is the productivity index .

[0057] When the grid cell is a production well, the source-sink term is: , is the injection index .

[0058] The mass flow rate flowing from the grid cell into the adjacent grid cell is expressed as: . Among them, is the conductivity between two adjacent grid cells divided by the control boundary, is the average value of the mobility parameters between the grid cell and the grid cell , is the density of the fluid , is the relative permeability of the fluid , is the viscosity of the fluid , represents the gravity term, is the acceleration due to gravity, is the height difference between adjacent grid cells, is the pressure difference between adjacent grid cells.

[0059] . Among them, is the fluid compressibility, is the fluid density at the corresponding reference pressure , is the pressure of the current grid cell, is the reference pressure, is the base of the natural logarithm.

[0060] , where is the fluid mobility parameter in the grid cell , is the fluid mobility parameter in the grid cell .

[0061] The pressure vector includes the pressures of all grid cells, and the total fluid saturation includes the saturations of the fluids in all grid cells.

[0062] Furthermore, the pressure vector and the total fluid saturation are iteratively solved until the convergence condition is satisfied, including the following steps.

[0063] Before the iterative solution, a series of initial conditions need to be set, including the initial pressure field , the saturation of the initial fluid , and the time step and the convergence threshold . These conditions provide a starting point for the iterative process and a criterion for judging convergence.

[0064] According to the current pressure field (k represents the number of iterations), calculate the residual of the mass conservation equation. The residual includes the oil-phase residual and the water-phase residual , corresponding to each grid cell respectively. Within the time step , assuming that variables such as the density, viscosity, and grid porosity of the fluid remain unchanged, take the partial derivatives of the residual with respect to the variables to be solved, namely the pressure of the grid cell and the saturation of the fluid in the grid cell. These partial derivatives will be used to construct the Jacobian matrix .

[0065] Specifically, the calculation process of taking the partial derivatives with respect to the variables to be solved, namely the pressure of the grid cell and the saturation of the fluid in the grid cell, is as follows.

[0066] The partial derivative of the oil-phase residual with respect to the oil-phase saturation is: . It should be noted that the subscripts all represent the relevant parameters of the oil phase in the grid cell . is the density of the oil phase in the grid cell , is the viscosity of the oil phase in the grid cell , is the relative permeability of the oil phase , is the symbol of partial derivative, is the relative permeability of the oil phase in grid cell and grid cell , is the density of the oil phase, is the viscosity of the oil phase.

[0067] The oil phase residual with respect to the pressure of grid cell has the partial derivative as: .

[0068] The oil phase residual with respect to the pressure of adjacent grid cell has the partial derivative as: .

[0069] The water phase residual with respect to the water phase saturation has the partial derivative as: . It should be noted that the subscript all represents the relevant parameters of the water phase in grid cell , is the density of the water phase in grid cell , is the viscosity of the water phase in grid cell , is the relative permeability of the water phase , is the relative permeability of the water phase in grid cell and grid cell , is the density of the water phase, is the viscosity of the water phase.

[0070] The water phase residual with respect to the pressure of grid cell has the partial derivative as: .

[0071] The water phase residual with respect to the pressure of adjacent grid cell has the partial derivative as: .

[0072] Furthermore, using the previously calculated partial derivatives, the Jacobian matrix 。The Jacobian matrix is a square matrix whose number of rows and columns is equal to the number of variables to be solved. In this application, it includes the pressure of each grid cell and the saturation of the fluid in the grid cell. Constructing the Jacobian matrix Each term of it is: Among them, is the element corresponding to the th row and the th column in the Jacobian matrix, is the th element of the residual vector , is the th element of the variable to be solved . , is the pressure vector, is the total fluid saturation. , is the pressure of different grid cells, is the total number of grid cells, is the transpose operation, , is the saturation of the fluid in different grid cells. , , is the oil-phase residual vector, is the oil-phase residual of different grid cells, , is the water-phase residual vector, is the water-phase residual of different grid cells.

[0073] Solve the linear equations: Among them, . is the change in the variable to be solved, which refers to the difference between the th iteration and the th iteration, is the variable to be solved at the th iteration, is the variable to be solved at the th iteration.

[0074] Set a small positive number as the convergence threshold. When , the convergence condition is satisfied, and the solution is completed. Record the pressure of each grid cell, the saturation of the fluid in the grid cell, and the flow rate between any adjacent grid cells. If the convergence condition is not met, continue the iteration.

[0075] S108: Traverse the conductivity connectivity table. For all adjacent two grid cells separated by the controlled dividing line, calculate the flow rate component between the injection well and the production well, accumulate all the flow rate components, and calculate the total flow rate of the fluid between the injection well and the production well.

[0076] The calculation formula for the flow rate component is: . Where is the flow rate component between the adjacent two grid cells between the injection well and the production well.

[0077] The calculation formula for the total flow rate is: . Where is the total flow rate of the fluid between the injection well and the production well, is the control area of the injection well , is the production well , is the inter-well connectivity coefficient, is the average pressure within the control area of the injection well , is the production well ,

[0078] S109: Derive the expression of the inter-well connectivity coefficient from the calculation formula of the total flow rate, and calculate the inter-well connectivity coefficient according to this expression of the inter-well connectivity coefficient.

[0079] The expression of the inter-well connectivity coefficient is: ; where , , is the pressure of the grid cell , is the pressure of the grid cell , is the pressure of the grid cell , is the volume of the grid cell , is the total volume of the control area of the injection well , is the total volume of the control area of the production well .

[0080] Figure 5 This is the calculation data graph of the inter-well connectivity coefficient provided by the embodiment of the present application. As Figure 5 shown, the abscissa represents the well name, and the ordinate is the inter-well connectivity coefficient.

[0081] Figure 6 This is the comparison result graph of the reservoir production capacity prediction between the method based on numerical simulation and the method based on the material balance principle provided by the embodiment of the present application. AsFigure 6 As shown, the abscissa represents the prediction time, and the ordinate is the daily crude oil production of the production well. The red broken line in the figure represents the prediction result of numerical simulation, and the green broken line represents the prediction result of material balance. The method used in this application is based on the principle of material balance. From Figure 6 it can be seen that for Well W15-17, the broken line graphs of the method based on numerical simulation and the method based on the principle of material balance in this application are basically coincident, and the accuracy rate of predicted production is maintained at 80%, which proves the reliability of the well connectivity quantification method in this application.

[0082] The embodiment of this application also provides an apparatus 700 for well connectivity quantification and analysis, as Figure 7 shown. The apparatus includes: an acquisition distribution information module 701, a grid cell division module 702, a control area division module 703, a determination module 704, a conductivity acquisition module 705, a representation module 706, an iterative solution module 707, a total flow calculation module 708, and a well connectivity coefficient calculation module 709.

[0083] The acquisition distribution information module 701 is used to perform interlayer division on the original reservoir model to obtain the distribution information of injection wells and production wells in the horizontal layer series.

[0084] The grid cell division module 702 is used to process the distribution information of injection wells and production wells in the horizontal layer series by using the geometric segmentation method, divide the reservoir into multiple interconnected grid cells, and make the injection wells and production wells all located within the grid cells.

[0085] The control area division module 703 is used to use the division rules to divide the control area for each injection well and production well. Among them, the control area of a well is a polygonal area surrounded by the intersection points of the control dividing lines of six pairs of injection wells or production wells around it.

[0086] The determination module 704 is used to traverse all grid cells, and determine whether the grid cell belongs to the control area of the injection well or the control area of the production well by comparing the Euclidean distance between the center point of each grid cell and all injection wells and production wells.

[0087] The conductivity acquisition module 705 is used to acquire the conductivity between two adjacent grid cells divided by the control dividing line, and record the conductivity between all two adjacent grid cells divided by the control dividing line by using a conductivity connection table.

[0088] The representation module 706 is used to represent the production capacity of the production well under the first pressure difference by using the production index, and represent the injection capacity of the injection well under the second pressure difference by using the injection index.

[0089] The iterative solution module 707 is used to construct a mass conservation equation for two adjacent grid cells divided by the controlled dividing line according to the finite volume method, and iteratively solve the pressure vector and the total fluid saturation until the convergence condition is met.

[0090] The total flow rate calculation module 708 is used to traverse the conductivity connection table. For two adjacent grid cells divided by the controlled dividing line, calculate the flow rate component between the injection well and the production well, accumulate all the flow rate components, and calculate the total flow rate of the fluid between the injection well and the production well.

[0091] The inter-well connection coefficient calculation module 709 is used to obtain the expression of the inter-well connection coefficient from the total flow rate calculation formula, and calculate the inter-well connection coefficient according to the expression of the inter-well connection coefficient.

[0092] Some modules in the device described in this application can be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, classes, etc. that perform specific tasks or implement specific abstract data types. This application can also be practiced in a distributed computing environment, where tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules can be located in local and remote computer storage media including storage devices.

[0093] The devices or modules illustrated in the above application embodiments can be specifically implemented by computer chips or entities, or by products with certain functions. For the convenience of description, the above devices are described by dividing them into various modules according to their functions. When implementing the embodiments of this application, the functions of each module can be implemented in the same or multiple software and / or hardware. Of course, the module that implements a certain function can also be implemented by combining multiple sub-modules or sub-units.

[0094] The methods, devices or modules described in this application can be implemented in the form of computer-readable program code. The controller can be implemented in any suitable manner. For example, the controller can take the form of, for example, a microprocessor or a processor, and a computer-readable medium that stores computer-readable program code (such as software or firmware) executable by the (micro)processor, logic gates, switches, application specific integrated circuits (ASICs), programmable logic controllers, and embedded microcontrollers. Examples of the controller include, but are not limited to, the following microcontrollers: ARC 625D, Atmel AT91SAM, Microchip PIC18F26K20, and Silicone Labs C8051F320. The memory controller can also be implemented as part of the control logic of the memory. Those skilled in the art also know that in addition to implementing the controller in the form of pure computer-readable program code, the method steps can be logically programmed to enable the controller to be implemented in the form of logic gates, switches, application specific integrated circuits, programmable logic controllers, and embedded microcontrollers to achieve the same function. Therefore, such a controller can be considered a hardware component, and the devices included therein for implementing various functions can also be regarded as the structures within the hardware component. Or even, the devices for implementing various functions can be regarded as either software modules for implementing the method or the structures within the hardware component.

[0095] As Figure 8 As shown, an inter-well connectivity quantification and analysis server is further provided in an embodiment of this application, including a memory 801 and a processor 802; the memory 801 is used to store computer-executable instructions; the processor 802 is used to execute the computer-executable instructions to implement an inter-well connectivity quantification and analysis method described above in the embodiment of this application.

[0096] An embodiment of this application further provides a computer-readable storage medium. The computer-readable storage medium stores executable instructions, and when a computer executes the executable instructions, it can implement an inter-well connectivity quantification and analysis method described above in the embodiment of this application.

[0097] As can be seen from the description of the above embodiments, those skilled in the art can clearly understand that this application can be implemented by means of software plus necessary hardware. Based on such an understanding, the technical solution of this application, in essence, or the part that makes a contribution to the prior art, can be embodied in the form of a software product, or can also be embodied in the implementation process of data migration. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions for causing a computer device (which can be a personal computer, mobile terminal, server, or network device, etc.) to execute the method described in the embodiments of this application.

[0098] The various embodiments in this specification are described in a progressive manner. For the same or similar parts between the various embodiments, reference can be made to each other. The key point of each embodiment is to illustrate the differences from other embodiments. All or part of this application can be used in many general or special computer system environments or configurations.

[0099] The above embodiments are only used to illustrate the technical solutions of this application, rather than to limit this application; although this application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of this application.

Claims

1. A method for quantifying and analyzing inter-well connectivity, characterized in that, Including: Performing interlayer division on the original reservoir model to obtain the distribution information of injection wells and production wells in the lateral layer series; Processing the distribution information of injection wells and production wells in the lateral layer series by using the geometric segmentation method, dividing the reservoir into multiple interconnected grid units, and making both the injection wells and production wells located within the grid units; Using the division rule to divide the control area for each injection well and each production well; wherein, the control area of an injection well is a polygonal area surrounded by the control demarcation lines of it and six surrounding production wells; The division rule includes: for any pair of injection well and production well, calculating the coordinates of their midpoint and the slope of the connection line, and calculating the slope of the perpendicular bisector; obtaining the equation of the perpendicular bisector according to the slope of the perpendicular bisector, and taking the perpendicular bisector as the control demarcation line; Traversing all grid units, and determining whether the grid unit belongs to the control area of the injection well or the control area of the production well by comparing the Euclidean distance between the center point of each grid unit and all injection wells and production wells; Obtaining the conductivity between two adjacent grid units divided by the control demarcation line, and using the conductivity connection table to record the conductivity between all two adjacent grid units divided by the control demarcation line; Using the production index to represent the production capacity of the production well under the first pressure difference, and using the injection index to represent the injection capacity of the injection well under the second pressure difference; For all two adjacent grid units divided by the control demarcation line, constructing a mass conservation equation according to the finite volume method, and iteratively solving the pressure vector and the total fluid saturation until the convergence condition is met; Traversing the conductivity connection table, for all two adjacent grid units divided by the control demarcation line, calculating the flow component between the injection well and the production well, accumulating all flow components, and calculating the total flow of the fluid between the injection well and the production well; Deriving the expression of the inter-well connectivity coefficient from the total flow calculation formula, and calculating the inter-well connectivity coefficient according to the expression of the inter-well connectivity coefficient.

2. The method for quantifying and analyzing the inter-well connectivity according to claim 1, wherein The calculation formula for the coordinates of the midpoint is as follows: ; where is the coordinate of the midpoint , is the coordinate of the oil production well , is the coordinate of the water injection well . The calculation formula for the slope of the connection line is as follows: ; where is the slope of the connection line; The calculation formula for the slope of the perpendicular bisector is as follows: ; where is the slope of the perpendicular bisector; The equation of the perpendicular bisector is: ; where and are variables in the equation of the perpendicular bisector, is the abscissa of any point in the transverse layer system, is the ordinate of any point in the transverse layer system.

3. The method for quantifying and analyzing inter-well connectivity according to claim 2, wherein The traversing all grid units, and determining whether the grid unit belongs to the control area of the injection well or the control area of the production well by comparing the Euclidean distance between the center point of each grid unit and all injection wells and production wells, includes: If the Euclidean distance from the center point of the grid unit to a certain injection well is less than its Euclidean distance to all production wells, then it is determined that the grid unit belongs to the control area of this injection well; If the Euclidean distance from the center point of the grid unit to a certain production well is less than its Euclidean distance to all injection wells, then it is determined that the grid unit belongs to the control area of this production well.

4. The method for quantifying and analyzing the inter-well connectivity according to claim 1, wherein The obtaining the conductivity between two adjacent grid units divided by the control demarcation line, includes: The calculation formula for the conductivity between two adjacent grid cells divided by the control dividing line is as follows: , , ; where, is the conductivity between two adjacent grid cells divided by the control dividing line, and are intermediate variables, is the permeability of grid cell , is the permeability of grid cell , is the area of grid cell , is the area of grid cell , is the distance from the center point of grid cell to the control dividing line, is the distance from the center point of grid cell to the control dividing line, is the unit normal vector from the control dividing line to grid cell , is the unit normal vector from the control dividing line to grid cell , is the unit direction vector from the center point of the control dividing line to grid cell , is the unit direction vector from the center point of the control dividing line to grid cell .

5. The method for quantifying and analyzing inter-well connectivity according to claim 4, wherein The using the production index to represent the production capacity of the production well under the first pressure difference, and using the injection index to represent the injection capacity of the injection well under the second pressure difference, includes: The first pressure difference is: ; where is the first pressure difference, is the reservoir pressure, is the bottom-hole pressure; The second pressure difference is: ; where is the second pressure difference; The calculation formula for the production index or water injection index is as follows: ; where is the production index or the water injection index , is the unit conversion factor, is the effective angle around the wellbore, is the reservoir capacity, is the pressure equivalent radius of the grid cell, is the actual radius of the wellbore, is the skin effect factor, is the logarithmic term, representing the flow resistance from the grid cell to the wellbore.

6. The method for quantifying and analyzing the inter-well connectivity according to claim 5, wherein The for all two adjacent grid units divided by the control demarcation line, constructing a mass conservation equation according to the finite volume method, and iteratively solving the pressure vector and the total fluid saturation until the convergence condition is met, includes: The mass conservation equation is as follows: ; where is the fluid residual, is the porosity of the grid cell ; is the density of the fluid in the grid cell ; is the saturation of the fluid in the grid cell ; is the change within the time step ; is the volume of the grid cell ; is the mass flow rate flowing into the grid cell from the grid cell ; is the set of adjacent grid cells to the grid cell ; and is the source-sink term; When the grid cell is an oil production well, the source-sink term is: ; where is the relative permeability of fluid in the grid cell , is the viscosity of fluid in the grid cell , is the productivity index ; When the grid cell is a water injection well, the source-sink term is: , is the water injection index ; From the grid cell Flows into the adjacent grid cell The mass flow rate The expression for is: ; where Is the conductivity between two adjacent grid cells divided by the control boundary Is in the grid cell And the grid cell The average value of the mobility parameter between Is the fluid Density of Is the fluid Relative permeability of Is the fluid Viscosity of Represents the gravity term Is the acceleration due to gravity Is the height difference between adjacent grid cells Is the pressure difference between adjacent grid cells; ; wherein, is the fluid compressibility, is the fluid density corresponding to the reference pressure below, is the pressure of the current grid cell, is the reference pressure, is the base of the natural logarithm; ; wherein, is the fluid mobility parameter in the grid cell , is the fluid mobility parameter in the grid cell ; The pressure vector includes the pressures of all grid cells, and the total fluid saturation includes the saturations of the fluids in all grid cells.

7. The method for quantifying and analyzing inter-well connectivity according to claim 6, characterized in that, Traverse the conductivity connection table. For every two adjacent grid cells separated by the controlled dividing line, calculate the flow component between the injection well and the production well, accumulate all the flow components, and calculate the total flow of the fluid between the injection well and the production well, including: The calculation formula for the flow rate component is as follows: ; where is the flow rate component between two adjacent grid cells between the injection well and the production well; The calculation formula for the total flow rate is as follows: ; where is the total flow rate between the injection well and the production well, is the control area of the injection well , is the control area of the production well , is the inter-well connectivity coefficient, is the average pressure in the control area of the injection well , is the average pressure in the control area of the production well .

8. The method for quantifying and analyzing the inter-well connectivity according to claim 7, wherein Derive the expression of the inter-well connection coefficient from the calculation formula of the total flow, and calculate the inter-well connection coefficient according to the expression of the inter-well connection coefficient, including: The expression for the inter-well connectivity coefficient is as follows: ; where , , is the pressure of grid cell , is the pressure of grid cell , is the volume of grid cell , is the volume of grid cell , is the total volume of the control area of injection well , is the total volume of the control area of production well .

9. An inter-well connectivity quantification and analysis device, characterized in that including: The distribution information acquisition module is used to perform interlayer division on the original reservoir model to obtain the distribution information of the injection wells and production wells in the lateral layer series; The grid cell division module is used to process the distribution information of the injection wells and production wells in the lateral layer series by using the geometric segmentation method, divide the reservoir into multiple interconnected grid cells, and make both the injection wells and production wells located within the grid cells; The control area division module is used to use the division rules to divide the control area for each injection well and each production well; wherein, the control area of an injection well is a polygonal area surrounded by the controlled dividing lines of it and the six pairs of surrounding production wells; the division rules include: for any pair of injection well and production well, calculate the coordinates of their midpoint and the slope of the connecting line, and calculate the slope of the perpendicular bisector; obtain the equation of the perpendicular bisector according to the slope of the perpendicular bisector, and use the perpendicular bisector as the controlled dividing line; The determination module is used to traverse all grid cells, and determine whether the grid cell belongs to the control area of the injection well or the control area of the production well by comparing the Euclidean distances between the center point of each grid cell and all injection wells and production wells; The conductivity acquisition module is used to obtain the conductivity between two adjacent grid cells separated by the controlled dividing line, and record the conductivity between all two adjacent grid cells separated by the controlled dividing line by using the conductivity connection table; The representation module is used to represent the production capacity of the production well under the first pressure difference by using the productivity index, and represent the injection capacity of the injection well under the second pressure difference by using the injection index; The iterative solution module is used to build a mass conservation equation for every two adjacent grid cells separated by the controlled dividing line according to the finite volume method, and iteratively solve the pressure vector and the total fluid saturation until the convergence condition is met; The total flow calculation module is used to traverse the conductivity connection table, calculate the flow component between the injection well and the production well for every two adjacent grid cells separated by the controlled dividing line, accumulate all the flow components, and calculate the total flow of the fluid between the injection well and the production well; The inter-well connection coefficient calculation module is used to derive the expression of the inter-well connection coefficient from the calculation formula of the total flow, and calculate the inter-well connection coefficient according to the expression of the inter-well connection coefficient.

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