Oil reservoir injection-production connectivity identification method and device, processor and storage medium

Abstract

The invention provides an oil reservoir injection-production connectivity recognition method and device and a storage medium, and belongs to the technical field of oilfield development. According to the method, well points in an oil reservoir are connected according to the maximum communication distance to generate an oil reservoir communication unit system, and the initial communication conductivity and the initial communication volume of inter-well communication units are calculated; constructing a flow network model through the component model to predict the theoretical production of the oil reservoir, and adjusting the initial connectivity conductivity and the initial connectivity volume in combination with a target fitting function to obtain an effective connectivity conductivity and an effective connectivity volume; and finally, calculating a flow splitting coefficient of the oil reservoir communication unit system through a path tracking algorithm to obtain a connectivity identification result so as to accurately characterize and identify the distribution and scale of the gas channeling channel of the water-gas alternating drive oil reservoir.

Description

Technical Field

[0001] The present invention relates to the technical field of oilfield development, and particularly to a method for identifying injection-production connectivity of a reservoir, a device for identifying injection-production connectivity of a reservoir, a machine-readable storage medium, and a processor. Background Art

[0002] Gas injection development is an effective means to improve the development effect of a reservoir. Compared with water injection and gas injection, it can quickly increase the reservoir pressure and supplement the formation energy. In addition, many gases can greatly reduce the viscosity and interfacial tension of crude oil through mechanisms such as dissolution and extraction, expand and increase the volume, and greatly improve the oil recovery rate. However, the heterogeneity of some oilfields is relatively strong, resulting in prominent gas channeling problems during on-site implementation. After gas channeling occurs in some oil wells, the gas-oil ratio rises rapidly and the oil production drops sharply, leading to the shut-in or even abandonment of oil wells, seriously restricting the large-scale popularization and application of gas drive technology. Therefore, there is an urgent need to propose an efficient and reliable technical system to accurately characterize and identify the distribution and scale of gas channeling channels, and improve the oil recovery rate and development economic benefits of the reservoir. Summary of the Invention

[0003] The purpose of the embodiments of the present invention is to provide a method, device, and storage medium for identifying injection-production connectivity of a reservoir to solve the problem that the existing technology cannot accurately characterize and identify the distribution and scale of gas channeling channels.

[0004] To achieve the above purpose, the first aspect of the present invention provides a method for identifying injection-production connectivity of a reservoir, the method comprising:

[0005] Connecting well points in the reservoir according to the maximum connection distance to generate a reservoir connection unit system, and the well points in the reservoir connection unit system are connected by connection units;

[0006] Calculating the connection conductivity of the connection unit as the initial connection conductivity, and calculating the pore volume of the connection unit as the initial connection volume;

[0007] Constructing a flow network model by performing time integration and control volume integration on a component model, and predicting the theoretical production of the reservoir based on the flow network model;

[0008] Invoking a target fitting function to iteratively fit the actual production of the reservoir and the theoretical production of the reservoir, adjusting the initial connection conductivity and the initial connection volume until the target fitting function reaches an iteration stop condition, stopping the iterative fitting, and taking the current connection conductivity and the current connection volume as the effective connection conductivity and the effective connection volume;

[0009] Based on the effective connection conductivity and the effective connection volume, calculating the flow splitting coefficient of the reservoir connection unit system by combining a path tracking algorithm as the connectivity identification result.

[0010] Optionally, the specific calculation formula for the initial connectivity conductivity is as follows:

[0011]

[0012] In the formula, T ij represents the initial connectivity conductivity between well point i and well point j, K ij represents the average permeability value of the connectivity unit between well point i and well point j, A ij represents the average cross-sectional area of the connectivity unit between well point i and well point j, h ij represents the average porosity value of the connectivity unit between well point i and well point j, μ o represents the viscosity of crude oil, L ij represents the distance between well point i and well point j, and α is the unit conversion coefficient;

[0013] The specific calculation formula for the initial connectivity volume is as follows:

[0014]

[0015] In the formula, V p represents the pore volume of the connectivity unit, V pij represents the initial connectivity volume between well point i and well point j, that is, the pore volume of the connectivity unit between well point i and well point j, L ij represents the distance between well point i and well point j, φ ij represents the average thickness value of the connectivity unit between well point i and well point j, h ij represents the average porosity value of the connectivity unit between well point i and well point j, V F represents the total pore volume of the inter-well connectivity unit, L al represents the distance between well point a and well point l, φ al represents the average thickness value of the connectivity unit between well point a and well point l, h al represents the average porosity value of the connectivity unit between well point a and well point l, N w represents the total number of wells connected to well point i, including the number of injection wells and production wells in the oilfield.

[0016] Optionally, the prediction of the theoretical oil production of the reservoir based on the flow network model includes:

[0017] Calculating the total production index of the well points and calculating the injection-production volume according to the total production index;

[0018] Calculating the underground flow distribution of the well points through the injection-production volume and inputting the underground flow distribution of the well points into the flow network model to obtain the theoretical oil production of the reservoir of the well points.

[0019] Optionally, the calculation of the total production index of the well points includes:

[0020] When it is a vertical well, the mobility at the well points at both ends of the connected unit is calculated by the upstream weight method to obtain the mobility within the connected unit;

[0021] Based on the mobility within the connected unit, the total productivity index of each well point is calculated through the vertical well point productivity index calculation formula;

[0022] The vertical well point productivity index calculation formula is:

[0023]

[0024] In the formula, J i represents the total productivity index of well point i, n represents the nth time step, k represents the kth layer connected unit of the vertical well, J ijk represents the productivity index of the connected unit between well point i and well point j in the kth layer, N l represents the total number of layers of the connected unit of the vertical well, N w represents the total number of wells connected to well point i, including the number of injection wells and production wells in the oilfield;

[0025] Among them,

[0026]

[0027] In the formula, J ijk represents the productivity index of the connected unit between well point i and well point j in the kth layer, λ ik represents the mobility of the connected unit of well point i in the kth layer, λ ijk represents the mobility of the connected unit between well point i and well point j in the kth layer, L ijk represents the length of the connected unit between well point i and well point j in the kth layer, r ik represents the wellbore radius of the connected unit of well point i in the kth layer, s ik represents the skin factor of the connected unit of well point i in the kth layer, n represents the nth time step, and n - 1 represents the (n - 1)th time step;

[0028] Among them,

[0029]

[0030] In the formula, λ jk represents the mobility of the connected unit of well point j in the kth layer, K ijk represents the average permeability of the connected unit between well point i and well point j in the kth layer, S wik represents the water saturation of the connected unit of well point i in the kth layer, k ro represents the relative permeability of the oil phase, k rw represents the relative permeability of the water phase, μ ok represents the crude oil viscosity of the kth layer connected unit, μ wk represents the water viscosity of the kth layer connected unit.

[0031] Optionally, calculating the total production index of the well points includes:

[0032] When it is a horizontal well, calculate the total production index of each well point through the horizontal well point production index calculation formula;

[0033] The horizontal well point production index calculation formula is:

[0034]

[0035] In the formula, J h represents the total production index of well point h, n represents the nth time step, m represents the mth layer connection unit of the horizontal well, J jm represents the production index of the connection unit of well point j in the mth layer, N sh represents the total number of connection units of the horizontal well in the mth layer, N w represents the total number of wells connected to well point h, including the number of injection wells and production wells in the oil field;

[0036] Among them,

[0037]

[0038] In the formula, J jm represents the production index of the connection unit of well point j in the mth layer, λ jm represents the mobility of the connection unit of well point j in the mth layer, λ jm represents the mobility of the connection unit of well point j in the mth layer, L jm represents the length of the connection unit of well point j in the mth layer, r jm represents the wellbore radius of the connection unit of well point j in the mth layer, s jm represents the skin factor of the connection unit of well point j in the mth layer, n represents the nth time step, and n - 1 represents the (n - 1)th time step;

[0039] Among them,

[0040]

[0041] In the formula, λ jk represents the mobility of the connection unit of well point j in the mth layer, K jm represents the average permeability of the connection unit of well point j in the mth layer, S wjm represents the water saturation of the connection unit of well point j in the mth layer, k ro represents the relative permeability of the oil phase, k rw represents the relative permeability of the water phase, μ om represents the crude oil viscosity of the mth layer connection unit, μ wm represents the water viscosity of the mth layer connection unit.

[0042] Optionally, the target fitting function is specifically:

[0043]

[0044] In the formula, M represents the model parameters, that is, the initial connected conductivity and the initial connected volume of each connected unit in the flow network model, g(M) represents the theoretical oil production of the reservoir predicted by the flow network model, d obs represents the actual oil production of the reservoir, C d is the dynamic covariance matrix;

[0045] The iteration stop conditions include:

[0046] M low ≤ M ≤ M up

[0047]

[0048] In the formula, M low represents the vector composed of the lower limits of the model parameters, M up represents the vector composed of the upper limits of the model parameters, represents the pore volume of the connected unit between well point i and well point j in the k-th layer under the initial state, V R represents the total pore volume of the reservoir, N w represents the total number of wells connected to well point i, including the number of injection wells and production wells in the oil field; or,

[0049]

[0050] In the formula, V c represents the control volume of well point i, c lowi represents the lower boundary coefficient of the control variable of well point i, c upi represents the upper boundary coefficient of the control variable of well point i, N w represents the total number of wells connected to well point i, including the number of injection wells and production wells in the oil field.

[0051] Optionally, calculating the flow splitting coefficient of the reservoir connected unit system based on the effective connected conductivity and the effective connected volume and combining with the path tracing algorithm includes:

[0052] When adjacent well points in the reservoir connected unit system are connected by a single connected unit, calculate the splitting coefficient of the single connected unit based on the effective connected conductivity and the effective connected volume as the unit splitting coefficient;

[0053] When adjacent well points in the reservoir connected unit system are not connected by a single connected unit, after calculating the splitting coefficient of the single connected unit between the adjacent well points, sum the splitting coefficients of all the connected units between the adjacent well points to obtain the unit splitting coefficient;

[0054] Multiply the splitting coefficients of each unit to obtain the flow splitting coefficient of the reservoir connected unit system.

[0055] The second aspect of the present invention provides a device for identifying reservoir injection-production connectivity, and the device includes:

[0056] A connected unit system construction module, configured to connect well points in the reservoir according to the maximum connected distance to generate a reservoir connected unit system, and the well points in the reservoir connected unit system are connected by connected units;

[0057] An initial connectivity parameter calculation module, configured to calculate the connectivity conductivity of the connected unit as the initial connectivity conductivity, and calculate the pore volume of the connected unit as the initial connected volume;

[0058] A flow network model construction module, configured to construct a flow network model by performing time integration and control volume integration on the component model, and predict the theoretical production of the reservoir based on the flow network model;

[0059] A target fitting function processing module, configured to call the target fitting function to perform iterative fitting on the actual production and the theoretical production of the reservoir, adjust the initial connectivity conductivity and the initial connected volume until the target fitting function reaches the iteration stop condition, stop the iterative fitting, and use the current connectivity conductivity and the current connected volume as the effective connectivity conductivity and the effective connected volume;

[0060] A connectivity identification result acquisition module, configured to calculate the flow splitting coefficient of the reservoir connected unit system as the connectivity identification result based on the effective connectivity conductivity and the effective connected volume in combination with the path tracing algorithm.

[0061] The third aspect of the present invention provides a processor configured to execute the above-mentioned reservoir injection-production connectivity identification method.

[0062] The fourth aspect of the present invention provides a machine-readable storage medium, on which instructions are stored, and when the instructions are executed by a processor, the processor is configured to execute the above-mentioned reservoir injection-production connectivity identification method.

[0063] The present application provides a method, apparatus, and storage medium for identifying the injection-production connectivity of a reservoir. The method generates a reservoir connectivity unit system by connecting well points in the reservoir according to the maximum connectivity distance, and calculates the initial connectivity conductivity and initial connectivity volume of the connectivity unit; constructs a flow network model through a component model to predict the theoretical production of the reservoir, and adjusts the initial connectivity conductivity and initial connectivity volume in combination with a target fitting function to obtain the effective connectivity conductivity and effective connectivity volume. Finally, the flow splitting coefficient of the reservoir connectivity unit system is calculated through a path tracing algorithm to obtain the connectivity identification result, so as to accurately characterize and identify the distribution and scale of gas channeling in a water-alternating-gas injection reservoir.

[0064] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] The drawings are used to provide a further understanding of the embodiments of the present invention, and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the embodiments of the present invention, but do not constitute a limitation to the embodiments of the present invention. In the drawings:

[0066] Figure 1 is a flowchart of a method for identifying the injection-production connectivity of a reservoir provided by an embodiment of the present invention;

[0067] Figure 2 is a schematic diagram of a connectivity unit provided by an embodiment of the present invention;

[0068] Figure 3 is a specific flowchart of step S30 provided by an embodiment of the present invention;

[0069] Figure 4 is a schematic diagram of path tracing and splitting coefficient calculation provided by an embodiment of the present invention;

[0070] Figure 5 (a)- Figure 5 (c) are the fitting results of reservoir block indicators provided by an embodiment of the present invention;

[0071] Figure 6 (a)- Figure 6 (c) are the fitting results of some single wells provided by an embodiment of the present invention;

[0072] Figure 7 is a distribution diagram of splitting coefficients provided by an embodiment of the present invention;

[0073] Figure 8 is a structural block diagram of an apparatus for identifying the injection-production connectivity of a reservoir provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0074] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not intended to limit the present invention.

[0075] Figure 1 It is a flowchart of a method for identifying the injection-production connectivity of an oil reservoir provided by an embodiment of the present invention. As Figure 1 shown, an embodiment of the present invention provides a method for identifying the injection-production connectivity of an oil reservoir, and the method includes:

[0076] S10: Connect the well points in the oil reservoir according to the maximum connection distance to generate an oil reservoir connection unit system, and the well points in the oil reservoir connection unit system are connected by connection units. The schematic diagram of the connection unit in this embodiment is as Figure 2 shown.

[0077] S20: Calculate the connection conductivity of the connection unit as the initial connection conductivity, and calculate the pore volume of the connection unit as the initial connection volume.

[0078] In this embodiment, the specific calculation formula of the initial connection conductivity is:

[0079]

[0080] In the formula, T ij represents the initial connection conductivity between well point i and well point j, K ij represents the average permeability value of the connection unit between well point i and well point j, A ij represents the average cross-sectional area of the connection unit between well point i and well point j, h ij represents the average porosity value of the connection unit between well point i and well point j, μ o represents the crude oil viscosity, L ij represents the distance between well point i and well point j, and α is a unit conversion coefficient with a value of 0.0864.

[0081] The specific calculation formula of the initial connection volume is:

[0082]

[0083] In the formula, V p represents the pore volume of the connection unit, V pij represents the initial connection volume between well point i and well point j, that is, the pore volume of the connection unit between well point i and well point j, L ij represents the distance between well point i and well point j, φ ij represents the average thickness value of the connection unit between well point i and well point j, h ij represents the average porosity value of the connection unit between well point i and well point j, V F represents the total pore volume of the connection unit between wells, Lal represents the distance between well point a and well point l, φ al represents the average thickness value of the connected unit between well point a and well point l, h al represents the average porosity value of the connected unit between well point a and well point l, N w represents the total number of wells connected to well point i, including the number of injection wells and production wells in the oilfield.

[0084] In this embodiment, V pij ≈L ij h ij A ij φ ij , therefore,

[0085] S30: Construct a flow network model by performing time integration and control volume integration on the component model, and predict the theoretical oil reservoir production based on the flow network model.

[0086] In this embodiment, the component model includes the mass conservation equation of oil and gas components and the mass conservation equation of water components;

[0087] Among them, the mass conservation equation of oil and gas components is specifically:

[0088]

[0089] Among them,

[0090] In the formula, ρ o represents the crude oil density, ρ g represents the gas density, S o represents the oil saturation, S g represents the gas saturation, v o represents the oil phase seepage velocity, v g represents the gas phase seepage velocity, x m represents the molar fraction of crude oil components, y m represents the molar fraction of gas components, z m represents the total fluid component molar fraction, q m represents the crude oil component flow rate, K represents the absolute permeability of the oil reservoir, k ro represents the relative permeability of the oil phase, k rg represents the relative permeability of the gas phase, p o represents the partial pressure of the oil phase, p g represents the partial pressure of the gas phase, μ o represents the crude oil viscosity, μ g represents the gas viscosity;

[0091] The mass conservation equation of water components is:

[0092]

[0093] Among them,

[0094] In the formula, ρ w represents the density of water, S w represents the water saturation, v w represents the seepage velocity of the water-bearing phase, q w represents the flow rate of the water component, k rw represents the relative permeability of the water phase, p w represents the partial pressure of the water phase, μ w represents the water viscosity, and t represents time.

[0095] Furthermore, as Figure 3 shown, in step S30 of this embodiment, predicting the theoretical production of the reservoir based on the flow network model specifically includes the following steps:

[0096] S31: Calculate the total production index of the well points and calculate the injection-production volume according to the total production index.

[0097] Specifically, when it is a vertical well, the mobility at both well points of the connected unit is calculated by the upstream weight method to obtain the mobility within the connected unit;

[0098] Based on the mobility within the connected unit, calculate the total production index of each well point through the vertical well point production index calculation formula;

[0099] The vertical well point production index calculation formula is:

[0100]

[0101] In the formula, J i represents the total production index of well point i, n represents the nth time step, k represents the kth layer connected unit of the vertical well, J ijk represents the production index of the connected unit between well point i and well point j in the kth layer, N l represents the total number of connected units of the vertical well, N w represents the total number of wells connected to well point i, including the number of injection wells and production wells in the oil field;

[0102] Among them,

[0103]

[0104] In the formula, J ijk represents the production index of the connected unit between well point i and well point j in the kth layer, λ ik represents the mobility of the connected unit of well point i in the kth layer, λ ijk represents the mobility of the connected unit between well point i and well point j in the kth layer, L ijkDenotes the length of the connected unit between well points i and j in the k-th layer, r ik Denotes the wellbore radius of the connected unit of well point i in the k-th layer, s ik Denotes the skin factor of the connected unit of well point i in the k-th layer, n represents the n-th time step, and n - 1 represents the (n - 1)-th time step;

[0105] Among them,

[0106]

[0107] In the formula, λ jk Denotes the mobility of the connected unit of well point j in the k-th layer, K ijk Denotes the average permeability of the connected unit between well points i and j in the k-th layer, S wik Denotes the water saturation of the connected unit of well point i in the k-th layer, k ro Denotes the relative permeability of the oil phase, k rw Denotes the relative permeability of the water phase, μ ok Denotes the crude oil viscosity of the connected unit in the k-th layer, μ wk Denotes the water viscosity of the connected unit in the k-th layer.

[0108] Currently, since many oilfields have entered the late stage of water flooding development, and horizontal wells are mostly used in some blocks, horizontal well development is an important way to increase the production of single wells, delay the coning of bottom water or gas cap gas, and improve the development effect and recovery rate. Therefore, when it is a horizontal well, the total production index of each well point is calculated through the horizontal well point production index calculation formula;

[0109] The horizontal well point production index calculation formula is:

[0110]

[0111] In the formula, J h Denotes the total production index of well point h, n represents the n-th time step, m represents the m-th layer connected unit of the horizontal well, J jm Denotes the production index of the connected unit of well point j in the m-th layer, N sh Denotes the total number of connected units of the horizontal well in the m-th layer, N w Denotes the total number of wells connected to well point h, including the number of injection wells and production wells in the oilfield;

[0112] Among them,

[0113]

[0114] In the formula, J jm Denotes the production index of the connected unit of well point j in the m-th layer, λ jm Denotes the mobility of the connected unit of well point j in the m-th layer, λ jmDenote the mobility of the connected unit of well point j in the m-th layer, L jm Denote the length of the connected unit of well point j in the m-th layer, r jm Denote the wellbore radius of the connected unit of well point j in the m-th layer, s jm Denote the skin factor of the connected unit of well point j in the m-th layer, n represents the n-th time step, and n - 1 represents the (n - 1)-th time step;

[0115] Among them,

[0116]

[0117] In the formula, λ jk Denote the mobility of the connected unit of well point j in the m-th layer, K jm Denote the average permeability of the connected unit of well point j in the m-th layer, S wjm Denote the water saturation of the connected unit of well point j in the m-th layer, k ro Denote the relative permeability of the oil phase, k rw Denote the relative permeability of the water phase, μo m Denote the crude oil viscosity of the connected unit in the m-th layer, μ wm Denote the water viscosity of the connected unit in the m-th layer.

[0118] After calculating the total production index of the well point, calculate the injection-production volume according to the injection-production volume calculation formula. Among them, the injection-production volume calculation formula is specifically:

[0119]

[0120] In the formula, WLPR m Denote the liquid production volume of the connected unit in the m-th layer, n represents the n-th time step, J h Denote the total production index of well point h, J m Denote the production index of the connected unit in the m-th layer, WLPR h Denote the total liquid production volume of well point h.

[0121] S32: Calculate the underground flow rate distribution of the well point through the injection-production volume, and input the underground flow rate distribution of the well point into the flow network model to obtain the theoretical oil reservoir production of the well point.

[0122] Among them, the underground flow rate distribution calculation formula is specifically:

[0123]

[0124] In the formula, q m Denote the crude oil component flow rate, n represents the n-th time step, Q jm Denote the underground flow rate distribution of the connected unit of well point j in the m-th layer, T jm Denote the conductivity of the connected unit of well point j in the m-th layer, pj Denotes the pressure of well point j, p h Denotes the pressure of well point h.

[0125] The above injection-production volume calculation formula and underground flow distribution calculation formula are applicable to horizontal wells and vertical wells.

[0126] After obtaining the underground flow distribution, substitute the underground flow distribution into the mass conservation equations of oil and gas components and the mass conservation equation of water components in the flow network model for calculation to obtain the pressure and saturation of the connected unit. Obtain the relative permeability according to the saturation and relative permeability curve of the connected unit, and then calculate the theoretical oil reservoir production of the well point according to the pressure and relative permeability of the connected unit.

[0127] Specifically, integrate the left side of the mass conservation equation of oil and gas components over the control volume and the right side over time. To simplify the formula, first remove the point source / sink term:

[0128]

[0129] Take the implicit format and add the source-sink term to get:

[0130]

[0131] In the formula, λ o,ij Denotes the oil-phase mobility of the connected unit between well point i and well point j, λ g,ij Denotes the gas-phase mobility of the connected unit between well point i and well point j, λ w,ij Denotes the water-phase mobility of the connected unit between well point i and well point j, G ij Denotes the shape factor of the connected unit between well point i and well point j.

[0132] Integrate both sides of the mass conservation equation of water components over time and the control volume. To simplify the formula, first remove the point source / sink term:

[0133]

[0134] Discretize and take the implicit format and add the source-sink term to get:

[0135]

[0136] For the relative permeability term, use the upstream weight value, and for the function of pressure, use the arithmetic mean value:

[0137]

[0138] In the formula, k ro,upstream Denotes the upstream weight value of the relative permeability of crude oil, k rg,upstream Denotes the upstream weight value of the relative permeability of gas.

[0139] S40: Call the target fitting function to iteratively fit the actual oil reservoir production and the theoretical oil reservoir production, adjust the initial connectivity conductivity and the initial connectivity volume until the target fitting function reaches the iteration stop condition, stop the iterative fitting, and use the current connectivity conductivity and the current connectivity volume as the effective connectivity conductivity and the effective connectivity volume.

[0140] Specifically, the target fitting function is:

[0141]

[0142] In the formula, M represents the model parameters, that is, the initial connectivity conductivity and the initial connectivity volume of each connected unit in the flow network model, g(M) represents the theoretical oil reservoir production predicted by the flow network model, d obs represents the actual oil reservoir production, C d is the dynamic covariance matrix;

[0143] The iteration stop conditions include:

[0144] M low ≤M≤M up

[0145]

[0146] In the formula, M low represents the vector composed of the lower limits of the model parameters, M up represents the vector composed of the upper limits of the model parameters, represents the pore volume of the connected unit between well point i and well point j in the kth layer under the initial state, V R represents the total pore volume of the oil reservoir, N w represents the total number of wells connected to well point i, including the number of injection wells and production wells in the oil field; or,

[0147]

[0148] In the formula, V c represents the control volume of well point i, c lowi represents the lower boundary coefficient of the control variable of well point i, c upi represents the upper boundary coefficient of the control variable of well point i, N w represents the total number of wells connected to well point i, including the number of injection wells and production wells in the oil field. In actual operation, the uncertainty of the control variables in dynamic analysis is large, and the adjustable constraint range can be enlarged. For example, the upper and lower boundary coefficients are set to 0.9 and 1.1 respectively.

[0149] In summary, the target fitting function can be expressed as:

[0150]

[0151]

[0152] st

[0153] M low ≤M≤M up

[0154]

[0155]

[0156] In the formula, V R represents the total pore volume of the reservoir represents the pore volume of the connected unit between well point i and well point j in the initial state represents the conductivity of the connected unit between well point i and well point j in the initial state

[0157] S50: Based on the effective connected conductivity and the effective connected volume, combined with the path tracing algorithm, calculate the flow splitting coefficient of the reservoir connected unit system as the connectivity identification result

[0158] Among them, the effective connected conductivity refers to the connected conductivity obtained by adjusting the initial connected conductivity through the target fitting function; the effective connected volume refers to the connected volume obtained by adjusting the initial connected volume through the target fitting function

[0159] Specifically, when the adjacent well points in the reservoir connected unit system are connected by a single connected unit, calculate the splitting coefficient of the single connected unit based on the effective connected conductivity and the effective connected volume as the unit splitting coefficient; when the adjacent well points in the reservoir connected unit system are not connected by a single connected unit, after calculating the splitting coefficient of the single connected unit between the adjacent well points, sum the splitting coefficients of all the connected units between the adjacent well points to obtain the unit splitting coefficient; multiply the unit splitting coefficients to obtain the flow splitting coefficient of the reservoir connected unit system

[0160] Furthermore, the calculation process of the splitting coefficient of a single connected unit is specifically as follows

[0161] Assume that at the nth time step, the adjacent well points i and j are connected by a single connected unit, then the unit splitting coefficient between the adjacent well points i and j is

[0162]

[0163] In the formula represents the number of well points connected to well point i represents the flow rate of the connected unit between well point i and well point k represents the flow rate of the connected unit between well point i and well point j Denotes the effective connected conductivity between well points i and j. Denotes the effective connected conductivity between well points i and k. Denotes the average pressure of the control volume of well point i at time n. Denotes the average pressure of the control volume of well point j at time n. Denotes the average pressure of the control volume of well point k at time n.

[0164] As Figure 4 shown, for well points that are not directly connected by a single connection unit, there may be multiple connection paths composed of multiple connection units. Taking nodes 1 and 4 as an example, assuming that the node pressure values gradually decrease along the arrow direction, the splitting coefficient of path 1-2-3-4 is defined as the product of the splitting coefficients of each simple path on this path (i.e., 1-2, 2-3, 3-4), that is:

[0165]

[0166] In the formula, The superscript 1 represents the serial number of this path among all paths between nodes 1 and 4.

[0167] The total splitting coefficient between two well points, that is, the unit splitting coefficient, is equal to the sum of the splitting coefficients of all paths between the two well points.

[0168] Three types of constraint conditions, namely equality constraints, inequality constraints, and boundary constraints, are established for the reservoir. Among them, the equality constraint can constrain the total liquid production volume or the total gas / water injection volume in each time period of the oilfield to be a fixed value; the inequality constraint can constrain the total injection-production volume in each time period of the oilfield to be not less than a certain value; the boundary constraint can constrain the range of gas / water injection volume or the range of production well output. This control problem is to optimally find u to maximize J under the condition of satisfying the constraint conditions.

[0169] Equality constraint: e i (u, y, m) = 0, i = 1, 2, …, n e

[0170] Inequality constraint: C j (u, y, m) ≤ 0, j = 1, 2, …, n c

[0171] Boundary constraint: k = 1, 2, …, N u

[0172] In the formula, e i (u, y, m) represents the equality constraint function, c j (u, y, m) represents the inequality constraint function, u k represents the constraint variable, represents the lower limit of the constrained variable represents the upper limit of the constrained variable, \(u\) represents the injection-production control variable, \(y\) represents the state variable, \(m\) represents the geological model parameter variable, and \(J\) represents the optimization objective function

[0173] Taking a certain oil reservoir in the Middle East as an example, this oil reservoir contains three special geological features and well types, namely horizontal wells, gas caps, and water bodies. Consider its equivalent treatment: ① The horizontal well is equivalently characterized by three well points; ② The gas cap and water body are equivalently characterized by a numerical gas cap / water body Figure 5 (a)- Figure 5 (c) shows the fitting results of the block indicators. The fitting rate of the cumulative oil production in the block is 91.6%, and the fitting rate of the cumulative gas production in the block is 83.2%. It can be seen that the cumulative oil production and cumulative gas production in the block obtained by the inversion of the connectivity model match the actual field values to a high degree. The curves of the cumulative oil production and cumulative gas production in the later production stage are basically the same, indicating that the model after fitting can reflect the actual production situation of the block and can be further used as the basic model for the development adjustment and optimization of this oilfield

[0174] Figure 6 (a)- Figure 6 (c) shows the fitting results of some single wells. It can be seen that the matching degrees of the daily oil production, daily gas production, and water cut of the horizontal wells and vertical wells after fitting are very high, and they are highly consistent with the actual production situation

[0175] Based on the connected units, the flow paths between each well point and the corresponding splitting coefficients are obtained through the path tracing method. After fitting, the obtained connected conductivity and connected volume are superimposed, and the three well points of the horizontal well are converted into a single well point (there is no obvious interlayer between each small layer). The values of the connected conductivity and connected volume after fitting correspond to the actual situation of the oil reservoir and reflect the true formation parameter information. The distribution map of the calculated splitting coefficients is as Figure 7 shown

[0176] It can be known from the fitting results that the results obtained by using the above oil reservoir injection-production connectivity identification method are highly accurate, effectively improving the identification accuracy

[0177] Figure 8 is a block diagram of an oil reservoir injection-production connectivity identification device provided by an embodiment of the present invention. As Figure 8 shown, the embodiment of the present invention provides an oil reservoir injection-production connectivity identification device, which includes a connected unit system construction module 10, an initial connected parameter calculation module 20, a flow network model construction module 30, a target fitting function processing module 40, and a connectivity identification result acquisition module 50

[0178] The connected unit system construction module 10 is used to connect the well points in the oil reservoir according to the maximum connected distance to generate an oil reservoir connected unit system, and the well points in the oil reservoir connected unit system are connected by connected units

[0179] An initial connectivity parameter calculation module 20 is configured to calculate the connectivity conductivity of the connected unit as the initial connectivity conductivity and calculate the pore volume of the connected unit as the initial connected volume.

[0180] A flow network model construction module 30 is configured to construct a flow network model by performing time integration and control volume integration on a component model, and predict the theoretical oil reservoir production based on the flow network model.

[0181] A target fitting function processing module 40 is configured to call a target fitting function to iteratively fit the actual oil reservoir production and the theoretical oil reservoir production, adjust the initial connectivity conductivity and the initial connected volume until the target fitting function reaches an iteration stop condition, stop the iterative fitting, and use the current connectivity conductivity and the current connected volume as the effective connectivity conductivity and the effective connected volume.

[0182] A connectivity identification result acquisition module 50 is configured to calculate the flow split coefficient of the oil reservoir connected unit system as the connectivity identification result based on the effective connectivity conductivity and the effective connected volume in combination with a path tracing algorithm.

[0183] An embodiment of the present invention further provides a machine-readable storage medium, on which computer program instructions are stored, and when the computer program instructions are executed by a processor, the above-mentioned method for identifying oil reservoir injection-production connectivity is implemented.

[0184] An embodiment of the present invention further provides a machine-readable storage medium, on which instructions are stored, and when the instructions are executed by an electronic governor, the processor can be configured to execute the above-mentioned method for identifying oil reservoir injection-production connectivity.

[0185] Those skilled in the art can understand that all or part of the steps in the methods of the above embodiments can be completed by instructing relevant hardware through a program, and the program is stored in a storage medium, including several instructions for causing a single-chip microcomputer, a chip or a processor to execute all or part of the steps of the methods described in various embodiments of the present invention. The foregoing storage medium includes: various media such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disc that can store program codes.

[0186] The optional embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the scope of the technical concept of the embodiments of the present invention, various simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all fall within the protection scope of the embodiments of the present invention. In addition, it should be noted that in the above specific embodiments, the various specific technical features described can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the embodiments of the present invention will not separately describe various possible combination methods.

[0187] In addition, any combination can be made between various different embodiments of the present invention, as long as it does not violate the idea of the embodiments of the present invention, and it should also be regarded as the content disclosed by the embodiments of the present invention.

Claims

1. A method for identifying the injection-production connectivity of an oil reservoir, characterized in that, the method includes: Connecting the well points in the oil reservoir according to the maximum connectivity distance to generate an oil reservoir connectivity unit system, and the well points in the oil reservoir connectivity unit system are connected by connectivity units; Calculating the connectivity conductivity of the connectivity unit as the initial connectivity conductivity, and calculating the pore volume of the connectivity unit as the initial connectivity volume; Constructing a flow network model by performing time integration and control volume integration on the component model, and predicting the theoretical production of the oil reservoir based on the flow network model; Invoking the target fitting function to perform iterative fitting on the actual production of the oil reservoir and the theoretical production of the oil reservoir, adjusting the initial connectivity conductivity and the initial connectivity volume until the target fitting function reaches the iterative stop condition, stopping the iterative fitting, and taking the current connectivity conductivity and the current connectivity volume as the effective connectivity conductivity and the effective connectivity volume; Based on the effective connectivity conductivity and the effective connectivity volume, combining with the path tracing algorithm to calculate the flow split coefficient of the oil reservoir connectivity unit system as the connectivity identification result.

2. The method for identifying the injection-production connectivity of an oil reservoir according to claim 1, characterized in that, The specific calculation formula for the initial connectivity conductivity is: where, T ij represents the initial connectivity conductivity between well points i and j, K ij represents the average permeability value of the connectivity unit between well points i and j, A ij represents the average cross-sectional area of the connectivity unit between well points i and j, h ij represents the average porosity value of the connectivity unit between well points i and j, μ o represents the viscosity of crude oil, L ij represents the distance between well points i and j, and α is the unit conversion coefficient; The specific calculation formula for the initial connectivity volume is: Where, V p represents the pore volume of the connected unit, V pij represents the initial connected volume between well point i and well point j, that is, the pore volume of the connected unit between well point i and well point j, L ij represents the distance between well point i and well point j, φ ij represents the average thickness value of the connected unit between well point i and well point j, h ij represents the average porosity value of the connected unit between well point i and well point j, V F represents the total pore volume of the inter-well connected unit, L al represents the distance between well point a and well point l, φ al represents the average thickness value of the connected unit between well point a and well point l, h al represents the average porosity value of the connected unit between well point a and well point l, N w represents the total number of wells connected to well point i, including the number of injection wells and production wells in the oilfield.

3. The method for identifying the injection-production connectivity of an oil reservoir according to claim 1, characterized in that, Predicting the theoretical production of the oil reservoir based on the flow network model includes: Calculating the total production index of the well points, and calculating the injection-production volume according to the total production index; Calculating the underground flow distribution of the well points through the injection-production volume, and inputting the underground flow distribution of the well points into the flow network model to obtain the theoretical production of the oil reservoir of the well points.

4. The method for identifying the injection-production connectivity of an oil reservoir according to claim 3, characterized in that, Calculating the total production index of the well points includes: When it is a vertical well, calculating the mobility at both ends of the well points in the connectivity unit by the upstream weight method to obtain the mobility in the connectivity unit; Based on the mobility in the connectivity unit, calculating the total production index of each well point by the vertical well point production index calculation formula; The vertical well point production index calculation formula is: Where J i represents the total production index of well point i, n represents the nth time step, k represents the kth layer connection unit of the vertical well, and J ijk represents the production index of the connection unit between well points i and j in the kth layer, and N l Indicates the total number of layers of the connected unit of the vertical well, N w Indicates the total number of wells connected to well point i, including the number of injection wells and production wells in the oilfield; Where, Where, J ijk represents the productivity index of the connection unit between well point i and well point j in the k-th layer, λ ik represents the mobility of the connection unit of well point i in the k-th layer, λ ijk represents the mobility of the connection unit between well point i and well point j in the k-th layer, L ijk represents the length of the connection unit between well point i and well point j in the k-th layer, r ik represents the wellbore radius of the connection unit of well point i in the k-th layer, s ik represents the skin factor of the connection unit of well point i in the k-th layer, n represents the n-th time step, and n - 1 represents the (n - 1)-th time step; Where, Where, λ jk represents the mobility of the connected unit of well point j in the k-th layer, L ijk represents the average permeability of the connected unit between well point i and well point j in the k-th layer, S wik represents the water saturation of the connected unit of well point i in the k-th layer, k ro represents the relative permeability of the oil phase, l rw represents the relative permeability of the water phase, μ ok represents the viscosity of the crude oil in the connected unit of the k-th layer, μ wk represents the viscosity of the water in the connected unit of the k-th layer.

5. The method for identifying the injection-production connectivity of an oil reservoir according to claim 3, characterized in that, Calculating the total production index of the well points includes: When it is a horizontal well, calculating the total production index of each well point by the horizontal well point production index calculation formula; The horizontal well point production index calculation formula is: Where, J h represents the total production index of well point h, n represents the nth time step, m represents the mth layer connection unit of the horizontal well, and J jm represents the production index of the connection unit of well point j in the mth layer, and N sh represents the total number of connection units of the horizontal well in the mth layer, and N w represents the total number of wells connected to well point h, including the number of injection wells and production wells in the oilfield; Where, In the formula, J jm represents the productivity index of the connected unit of well point j in the m-th layer, λ jm represents the mobility of the connected unit of well point j in the m-th layer, λ jm represents the mobility of the connected unit of well point j in the m-th layer, L jm represents the length of the connected unit of well point j in the m-th layer, r jm represents the wellbore radius of the connected unit of well point j in the m-th layer, s jm represents the skin factor of the connected unit of well point j in the m-th layer, n represents the n-th time step, and n - 1 represents the (n - 1)-th time step; Where, where λ jk represents the mobility of the connected unit of well point j in the m-th layer, K jm represents the average permeability of the connected unit of well point j in the m-th layer, S wjm represents the water saturation of the connected unit of well point j in the m-th layer, k ro represents the relative permeability of the oil phase, k rw represents the relative permeability of the water phase, μ om represents the viscosity of the crude oil in the connected unit of the m-th layer, μ wm represents the viscosity of the water in the connected unit of the m-th layer.

6. The method for identifying the injection-production connectivity of an oil reservoir according to claim 1, characterized in that, The target fitting function is specifically: In the formula, M represents the model parameters, that is, the initial connected conductivity and the initial connected volume of each connected unit in the flow network model, g(M) represents the theoretical oil reservoir production predicted by the flow network model, d obs represents the actual oil reservoir production, C d is the dynamic covariance matrix; The iterative stop condition includes: M low ≤M≤M up where, M low denotes the vector composed of the lower limits of the model parameters, and M up denotes the vector composed of the upper limits of the model parameters, denotes the pore volume of the connected unit between well point i and well point j in the k-th layer under the initial state, and V R denotes the total pore volume of the reservoir, and N w denotes the total number of wells connected to well point i, including the number of injection wells and production wells in the oilfield; or, Where, V c represents the control volume of well point i, c lowi represents the lower boundary coefficient of the control variable of well point i, c upi represents the upper boundary coefficient of the control variable of well point i, N w represents the total number of wells connected to well point i, including the number of injection wells and production wells in the oilfield.

7. The method for identifying the injection-production connectivity of an oil reservoir according to claim 1, characterized in that, Calculating the flow split coefficient of the oil reservoir connectivity unit system based on the effective connectivity conductivity and the effective connectivity volume, combining with the path tracing algorithm, includes: When the adjacent well points in the oil reservoir connectivity unit system are connected by a single connectivity unit, calculating the split coefficient of the single connectivity unit based on the effective connectivity conductivity and the effective connectivity volume as the unit split coefficient; When adjacent well points in the reservoir connection unit system are not connected by a single connection unit, after calculating the splitting coefficient of the single connection unit between the adjacent well points, the splitting coefficients of all connection units between the adjacent well points are summed to obtain the unit splitting coefficient; Multiply the unit splitting coefficients to obtain the flow splitting coefficient of the reservoir connection unit system.

8. An apparatus for identifying the injection-production connectivity of a reservoir, Characterized in that, The apparatus includes: A connection unit system construction module, configured to connect well points in the reservoir according to the maximum connection distance to generate a reservoir connection unit system, and the well points in the reservoir connection unit system are connected by connection units; An initial connection parameter calculation module, configured to calculate the connection conductivity of the connection unit as the initial connection conductivity, and calculate the pore volume of the connection unit as the initial connection volume; A flow network model construction module, configured to construct a flow network model by performing time integration and control volume integration on a component model, and predict the theoretical production of the reservoir based on the flow network model; A target fitting function processing module, configured to call a target fitting function to perform iterative fitting on the actual production and the theoretical production of the reservoir, and adjust the initial connection conductivity and the initial connection volume until the target fitting function reaches the iterative stop condition, stop the iterative fitting, and use the current connection conductivity and the current connection volume as the effective connection conductivity and the effective connection volume; A connectivity identification result acquisition module, configured to calculate the flow splitting coefficient of the reservoir connection unit system as the connectivity identification result based on the effective connection conductivity and the effective connection volume, in combination with a path tracing algorithm.

9. A processor, Characterized in that, It is configured to execute the method for identifying the injection-production connectivity of a reservoir according to any one of claims 1 to 7.

10. A machine-readable storage medium, on which instructions are stored, Characterized in that, When the instructions are executed by a processor, the processor is configured to execute the method for identifying the injection-production connectivity of a reservoir according to any one of claims 1 to 7.

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