Interwell interference discrimination and optimization method for water drive reservoir based on combined well pattern deployment

Abstract

The application discloses a water drive reservoir well interference discrimination and optimization method based on combined well pattern deployment, which comprises the following steps: horizontal well replacement ratio conversion; calculating directional, small layer and single well development indexes under the condition that the horizontal well is not deployed, simulating oilfield development changes; establishing a horizontal well deployment mode in the original percolation area, calculating directional, small layer and single well development indexes under the condition that the horizontal well is deployed outside the original percolation area; establishing a horizontal well deployment mode outside the original percolation area, calculating directional, small layer and single well development indexes under the condition that the horizontal well is deployed outside the original percolation area; establishing a net interference value calculation method to reflect the interference of the horizontal well deployment on the original directional well pattern; and optimizing well deployment according to the interference of the horizontal well deployment on the original directional well pattern. The application establishes a directional well and horizontal well combined exploitation interference mathematical model, quantitatively represents the development dynamic of single wells, small layers and directions in real time, and realizes directional well pattern deployment horizontal well related index calculation.

Description

Technical Field

[0001] The present invention belongs to the technical field of oilfield development, and in particular relates to a method for distinguishing and optimizing the interference between wells in a water-drive oil reservoir based on a combined well network deployment. Background Art

[0002] At present, offshore oilfield development mostly involves deploying directional wells first to exploit the oil for a period of time, and then conducting horizontal wells to tap the remaining oil in specific layers. However, the deployment of horizontal wells will cause certain interference to the original directional wells.

[0003] Existing interference research focuses on five areas: indoor physical simulation experiments, reservoir numerical simulation, reservoir engineering dynamic analysis, computer algorithm model training, and mathematical model establishment. However, the extent of interference with the production patterns of the original directional well group after deploying horizontal wells remains unclear, and the quantification of this interference is insufficient. Consequently, there is a lack of effective guidance for efficiently tapping the remaining oil potential of directional well groups with infilled horizontal wells.

[0004] Therefore, the present invention provides a method for identifying and optimizing the interference between wells in water-drive oil reservoirs based on the deployment of a joint well network. It innovatively considers the two modes of deploying horizontal wells, and realizes the calculation of relevant development indicators of the directional well group after the deployment of horizontal wells. On the one hand, it clarifies the interference mechanism of the joint exploitation of directional wells and horizontal wells, and on the other hand, it quantitatively characterizes the degree of interference between the two, thus solving the problems existing in other methods. Summary of the Invention

[0005] The problem to be solved by the present invention is to provide a method for distinguishing and optimizing the inter-well interference of water-drive oil reservoirs based on the deployment of a joint well network. The method makes full use of actual data such as dynamic and static data of the oil field, based on the principle of seepage mechanics, and considers the splitting algorithm, substitution ratio, isosaturation movement equation, etc. to perform inter-well interference analysis after the deployment of horizontal wells in different modes, thereby real-time and quantitatively characterizing the development dynamics of single wells, small layers and directions, reflecting the interference process between directional wells and horizontal wells, and providing guidance for optimizing the deployment of horizontal wells.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for distinguishing and optimizing the interference between wells in water-flooding reservoirs based on the deployment of a joint well pattern, which is characterized by comprising the following steps:

[0007] S1: Collect basic static geological, dynamic development and engineering data of the reservoir and convert the horizontal well replacement ratio. S1 includes the following steps:

[0008] S11: The substitution ratio R is used to represent the ratio of the drainage area of ​​the directional well to that of the horizontal well;

[0009] S12: Convert the drainage area between directional wells and horizontal wells;

[0010] S13: performing iterative calculation of the substitution ratio R;

[0011] S2: Based on reservoir engineering methods, time series calculations are used to calculate the direction, small layer, and single well development indicators when the horizontal well is not deployed, simulating the changes in oilfield development at each moment;

[0012] S3: Establishing a deployment pattern of horizontal wells in the original seepage area, performing weighted average of the relative permeability of each part of the seepage area of ​​the horizontal well based on the arc, and calculating the direction, small layer, and single well development indicators of the horizontal wells when deployed in the original seepage area. S3 includes the following steps:

[0013] S31: dividing the seepage area after the horizontal wells are deployed, and deploying the horizontal well H1 between the fan-shaped seepage area of ​​well O1 and the fan-shaped seepage area of ​​well O2;

[0014] S32: For the well layout pattern in the original seepage area, by dividing the seepage area of ​​the equivalent circle of the horizontal well drainage area, the development dynamics of the original seepage area overlapped by each part immediately before the horizontal well is put into production are expressed as the initial development dynamics of each part of the seepage area of ​​the equivalent circle of the horizontal well drainage area;

[0015] S33: perform phase permeability calculation;

[0016] S4: establishing a deployment mode of horizontal wells outside the original seepage area, performing weighted average of the relative permeability of each part of the seepage area of ​​the horizontal well based on the area and arc, and calculating the direction, small layer, and single well development indicators of the horizontal wells when deployed outside the original seepage area. S4 includes the following steps:

[0017] S41: dividing the seepage area after the horizontal wells are deployed, and deploying the horizontal well H2 outside the fan-shaped seepage area of ​​the O1 well and the fan-shaped seepage area of ​​the O2 well;

[0018] S42: For the well pattern outside the original seepage area, the seepage area of ​​the horizontal well is divided. The overlapping part with the original seepage area before the horizontal well is put into production is expressed by the development dynamics of the original seepage area immediately before production. For the non-overlapping area, its water saturation and relative permeability are both original and expressed by irreducible water saturation.

[0019] S43: perform phase permeability calculation;

[0020] S5: Based on the direction, sub-layer, and single-well development indicators calculated in S2-S4 modes, a net interference value calculation method is established to quantitatively reflect the interference of horizontal well deployment on the original directional well pattern;

[0021] S6: Optimize well location deployment based on the interference of simulated horizontal well deployment on the original directional well pattern.

[0022] Furthermore, the S2 includes the following steps:

[0023] S21: Calculate the water well splitting coefficient using formation coefficient, location coefficient and well spacing as splitting calculation parameters. The calculation formula is:

[0024]

[0025] Where: is the average formation coefficient in the connected direction, in μm 2 m;α ik is the connectivity direction position coefficient; D ik is the well spacing in the connecting direction, in m;

[0026] S22: Split the oil wells according to the formation coefficient, location coefficient, relative permeability, injection coefficient and well spacing, and calculate the oil well splitting coefficient. The calculation formulas for the oil production splitting condition value and the water production splitting condition value are:

[0027]

[0028] Where: K ro is the relative permeability of the oil phase; K rw is the relative permeability of water phase; B ki is the water injection coefficient;

[0029] S23: Calculate the liquid production of a single well based on the injection-production ratio of the well group and the splitting coefficient of each effective well;

[0030] S24: Calculate the liquid production, oil production, water production and water content of a single layer based on the oil production splitting coefficient and water production splitting coefficient of the small layer;

[0031] S25: The liquid production, oil production, water production and water content in each direction are obtained according to the directional oil production splitting coefficient and the water production splitting coefficient.

[0032] Furthermore, the S21 includes the following steps:

[0033] S211: Calculate the average formation coefficient. The calculation formula is:

[0034]

[0035] Where: K i is the effective permeability of the injection well, in μm 2 ;H i is the water injection thickness, in m; K k is the effective permeability of the oil well, in μm 2 ;H k is the production thickness, in m;

[0036] S212: Calculate the position coefficient. The calculation formula is:

[0037]

[0038] S213: Calculate the distance between oil and water wells in the connection direction. The specific calculation formula is:

[0039]

[0040] D ik ′=lnD ik

[0041] Where: x i is the horizontal coordinate of the injection well, in m; i is the vertical coordinate of the injection well, in m; x k is the horizontal coordinate of the oil well, in m; k is the vertical coordinate of the oil well, in m; D ik ′ is the logarithmic well spacing.

[0042] Furthermore, the S22 includes the following steps:

[0043] S221: Calculate the water injection coefficient. The calculation formula is:

[0044]

[0045] Where: W ki The water injection volume in the direction of the splitting of the connecting direction, in m 3 ;

[0046] S222: Calculate oil saturation and relative permeability using the water saturation and relative permeability relationship curve;

[0047] S223: Calculate the water cut and its derivative corresponding to different water saturations based on the relative permeability data to obtain the change in water cut at different times.

[0048] Furthermore, the S5 includes the following steps:

[0049] S51: Calculate using a net interference value calculation method;

[0050] S52: Calculate using the interference degree calculation method;

[0051] S53: Classify the net interference value.

[0052] Furthermore, in S53, when the net interference value is greater than 1, the oil production interference degree is greater than the liquid production interference degree, and the water content decreases; when the net interference value is equal to 1, the oil production interference degree is equal to the liquid production interference degree, and the water content remains unchanged; when the net interference value is less than 1, the oil production interference degree is less than the liquid production interference degree, and the water content increases.

[0053] Furthermore, the S6 includes the following steps:

[0054] S61: For areas where well pattern infill is being planned, by designing different locations for horizontal wells, the net interference value after the horizontal wells are opened is calculated using a computer language based on the established method, and the maximum value scheme is selected as the horizontal well layout scheme;

[0055] S62: For areas where well pattern densification has been completed, design a directional well opening and closing scheme around the same layer of horizontal wells, calculate the net interference value, and determine whether the directional well should be opened based on the maximum value scheme.

[0056] The advantages and positive effects of the present invention are:

[0057] 1. The present invention uses data analysis methods to establish a quantitative method for distinguishing the interference mechanism and degree of the original directional well pattern after the deployment of horizontal wells, thereby realizing the prediction of the optimal deployment position of horizontal wells and improving oilfield efficiency.

[0058] 2. The present invention combines a variety of reservoir engineering methods with data analysis methods to achieve automated comprehensive determination of the interference degree of the combined well layout of directional wells and horizontal wells.

[0059] 3. The present invention can program the research results into software, integrate and modularize the reservoir engineering methods in various steps into a computerized manner, visualize the data analysis, and call various functional modules through the main interface, making the entire process clear and understandable. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 It is a schematic diagram of the overall process of an embodiment of the present invention.

[0061] Figure 2 4 is a flowchart of iterative calculation of the substitution ratio R according to an embodiment of the present invention.

[0062] Figure 3 It is a schematic diagram of deploying horizontal wells in the original seepage area according to an embodiment of the present invention.

[0063] Figure 4 The fan-shaped seepage area S in the embodiment of the present invention 扇dWe Schematic diagram.

[0064] Figure 5 Schematic diagram of deploying horizontal wells outside the original seepage area according to an embodiment of the present invention.

[0065] Figure 6 The fan-shaped seepage area S in the embodiment of the present invention 扇fWg Schematic diagram.

[0066] Figure 7 This is a well location distribution diagram of the D17 well group before deploying new wells in one embodiment of the present invention.

[0067] Figure 8This is a well location distribution diagram after the deployment of new wells in the D17 well group according to an embodiment of the present invention.

[0068] Figure 9 It is the calculation result of the interference degree and net interference value before and after the adjustment of the injection-production relationship of the D17 well group in one embodiment of the present invention. DETAILED DESCRIPTION

[0069] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0070] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0071] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0072] The embodiments of the present invention are further described below with reference to the accompanying drawings:

[0073] like Figure 1 As shown in FIG, a method for identifying and optimizing the inter-well interference of water drive reservoirs based on joint well pattern deployment includes the following steps.

[0074] S1: Collect basic static geological, dynamic development and engineering data of the reservoir and convert the horizontal well replacement ratio. Figure 2 As shown, S1 includes the following steps.

[0075] S11: The substitution ratio R is used to represent the ratio of the drainage area of ​​directional wells to that of horizontal wells.

[0076] In an oil reservoir, when the production of a horizontal well is equal to the sum of the production of R directional wells, R is the replacement ratio. For a directional well, its drainage area can be regarded as a circle. If the drainage radius of a single well is r e , then the single well drainage area S is:

[0077]

[0078] For the area production index A U , which is equal to the ratio of the oil recovery index U to the drainage area:

[0079]

[0080] Assume that two well pattern systems I and J are deployed in the same oil reservoir, where system I is a horizontal well production pattern and system J is a directional well production pattern. The well spacing, number of wells, and single well drainage radius (r ei , r ej ) are different, but the area production index (A Ui , A Uj ) are the same, that is:

[0081]

[0082] Replace the wells of system J with the wells of system I:

[0083]

[0084] S12: Conversion of drainage area between directional wells and horizontal wells.

[0085] For horizontal wells, the drainage area S H for:

[0086]

[0087] The horizontal well drainage area S H It can also be equivalent to the effective oil leakage radius r eh The area of ​​the circle:

[0088]

[0089] So we have:

[0090]

[0091] For the oil production index of horizontal wells and directional wells, there are:

[0092]

[0093] Right now

[0094]

[0095] After conversion, we can get

[0096]

[0097] and

[0098]

[0099] r e Convert to Available

[0100]

[0101] Based on the research on horizontal wells, Joshi proposed that the main semi-axis of the horizontal well drainage ellipse and the effective wellbore radius of the horizontal well are expressed as follows:

[0102]

[0103] in:

[0104] Where: R is the substitution ratio, dimensionless; S is the drainage area of ​​a single directional well, unit is m 2 ;S H is the drainage area of ​​a single horizontal well, in m 2 ; r e is the directional well drainage radius, in m; r eh is the effective drainage radius of the horizontal well, in m; U H is the horizontal well production index, unit is m / (d·MPa);

[0105] U v is the directional well production index, unit is m / (d·MPa); q H is the oil production rate of the horizontal well, in m 3 / d;

[0106] q v is the oil production rate of the directional well, in m 3 / d;Δp H is the horizontal well production pressure difference, in MPa; Δp v is the production pressure difference of the directional well, in MPa; r w is the radius of the directional wellbore, in meters; r wv ' is the effective wellbore radius of the horizontal well, in m; a is the main semi-axis of the horizontal well drainage circle, in m; L is the length of the horizontal section, in m; h is the oil layer thickness, in m; K h is the horizontal permeability, in mD; K vis the vertical permeability, in mD; β is the reservoir heterogeneity coefficient, dimensionless.

[0107] S13: Iterative calculation of the substitution ratio R.

[0108] First, the reservoir static parameters and the horizontal section length of the horizontal well are determined. Given the initial value of the replacement ratio R = 1.0, the effective wellbore radius r of the horizontal well with the equivalent circular drainage area obtained by the two calculation methods is obtained by substituting it into equations (14) and (16). wv1 ′ and the effective wellbore radius r of the horizontal well with elliptical drainage area wv2 ′. Through iterative calculation, when the given R can satisfy r wv ′=r wv2 ′, that is, C=|r wv ′-r wv2 ′|≤ε (infinitely small), which is the final replacement ratio; if C≤ε is not satisfied, R=1.0+0.01, and continue the iterative calculation until C≤ε is satisfied.

[0109] S2: Based on reservoir engineering methods, a time series calculation is performed to simulate oilfield development changes at each moment, without adjusting the injection-production relationship. Specifically, S2 includes the following steps:

[0110] S21: Calculation of water well splitting coefficient,

[0111] Taking formation coefficient, location coefficient and well spacing as splitting calculation parameters, the calculation formula is:

[0112]

[0113] Where: is the average formation coefficient, in μm 2 m;α ik is the position coefficient; D ik is the well spacing, in m.

[0114] The calculation process of each parameter is as follows:

[0115] S211: Calculate the average formation coefficient,

[0116] For the formation coefficient of water wells and oil wells, the product of the effective permeability in the direction of oil-water well connection and the sandstone thickness is mainly calculated. The specific calculation formula is:

[0117]

[0118] Where: K i is the effective permeability of the injection well, in μm 2 ;H i is the water injection thickness, in m; Kk is the effective permeability of the oil well, in μm 2 ;H k It is the production thickness, in m.

[0119] S212: Calculate the position coefficient,

[0120] The position coefficient of a certain direction of a certain layer of a certain well is equal to the square root of the product of the azimuth angle in that direction and the number of effective oil wells around the well, divided by 360.

[0121] The specific calculation formula is:

[0122]

[0123] Where: n is the number of effective oil wells around the water well, unit is mouth; θ is the azimuth, unit is degree.

[0124] S213: Well spacing calculation,

[0125] Calculate the distance between oil and water wells in the connection direction. The specific calculation formula is:

[0126]

[0127] D ik ′=lnD ik (19)

[0128] Where: x i is the horizontal coordinate of the injection well, in m; i is the vertical coordinate of the injection well, in m; x k is the horizontal coordinate of the oil well, in m; k is the vertical coordinate of the oil well, in m; D ik ′ is the logarithmic well spacing.

[0129] S22: Calculation of oil well splitting coefficient,

[0130] According to the formation coefficient, location coefficient, relative permeability, water injection coefficient and well spacing, the calculation formulas for the oil production splitting condition value and the water production splitting condition value are as follows:

[0131]

[0132] Where: K ro is the relative permeability of the oil phase; K rw is the relative permeability of water phase; B ki is the water injection coefficient.

[0133] Among them, the parameters are calculated as follows:

[0134] S221: Calculation of water injection coefficient,

[0135] The directional water production and oil production of each layer of the oil well are related to the water injection volume split from the connected water well to the oil well. The directional water injection coefficient is calculated as follows:

[0136]

[0137] Where: W ki The amount of water injected in the splitting direction, in m 3 .

[0138] S222: Oil saturation and relative permeability calculation,

[0139] The calculation of oil saturation and relative permeability is obtained through the relationship curve between water saturation and relative permeability. The seepage area is fan-shaped, and the radius of the fan is set to d, the arc is θ, and the arc is θ. Then:

[0140]

[0141] Where: S 扇 is the seepage area, in m 2 ; r0 is the starting position of the oil-water two-phase region, unit is m; r is any position in the oil-water two-phase region, unit is m.

[0142] The equation for the movement of the isosaturation surface is:

[0143]

[0144] Where: S is the area of ​​the circular seepage region, unit is m 2 ;f w ′ is the derivative of water content with respect to water saturation; h is the oil layer thickness, in m; φ is the porosity; W(t) is the cumulative injection volume, in m 3 .

[0145] However, the actual seepage area is a fan-shaped area, so we can get:

[0146]

[0147] Where: r is any position of the two-phase region in the connecting direction, unit is m; r0 is the radius of the injection well, unit is m; φ is the porosity in the connecting direction; Q is the injection volume in the connecting direction, unit is m 3 / d; t is the development time, the unit is d.

[0148] Transforming formula (25), we can get:

[0149]

[0150] Where: d is the distance between the effective well and the injection well, in meters; t0 is the water breakthrough time, in days.

[0151] Based on the relative permeability data, the water cut and its derivative corresponding to different water saturations are calculated to obtain the changes in water cut at different times.

[0152] S23: Calculation of direction, sub-layer, and single well development indicators.

[0153] The sum of the oil production splitting coefficient and the water production splitting coefficient is the liquid production splitting coefficient. The overall calculation method is to calculate the splitting condition value and splitting coefficient from direction to sub-layer and then to individual well, and then calculate the liquid production, oil production, water production, and water cut from individual well to sub-layer and then direction. First, calculate the liquid production of each well based on the well group injection-production ratio and the splitting coefficient of each effective well. Then, calculate the liquid production, oil production, water production, and water cut of each layer based on the oil production splitting coefficient and water production splitting coefficient of the sub-layer. Finally, the liquid production, oil production, water production, and water cut of each direction are obtained based on the oil production splitting coefficient and water production splitting coefficient of the direction.

[0154] S3: Establish a deployment pattern for horizontal wells in the original seepage area, perform weighted average of the relative permeability of each part of the seepage area of ​​the horizontal well based on the arc, and calculate the direction, small layer, and single well development indicators of the horizontal well when deployed outside the original seepage area. Specifically, S3 includes the following steps:

[0155] S31: Compared with S2, the difference in the calculation method is mainly reflected in the difference in the phase permeability value. First, the seepage area after the deployment of the horizontal well is divided.

[0156] like Figure 3 As shown, in the fan-shaped seepage area S of well O1 扇aWb S with fan-shaped seepage area of ​​O2 well 扇bWc A horizontal well H1 is deployed between the two, and the horizontal well is regarded as a directional well with a substitution ratio of R, then its fan-shaped seepage area is SfandWe.

[0157] For the well layout pattern in the original seepage area, by dividing the seepage area of ​​the equivalent circle of the horizontal well drainage area, the development dynamics of the original seepage area overlapped by each part immediately before the horizontal well is put into production are expressed as the initial development dynamics of each part of the seepage area of ​​the equivalent circle of the horizontal well drainage area. Figure 4 As shown, the fan S 扇dWe Divided into S 扇dWH1 and S 扇H1We Two parts, including:

[0158] 1. Sector S 扇dWH1 In the sector S 扇fWb Within the seepage area, it belongs to the original fan-shaped seepage area S of well O1. 扇aWb , so, sector S 扇dWH1 The regional water content, water saturation, and relative permeability of oil and water phases are consistent with the development performance of Well O1.

[0159] 2. Sector S 扇H1We In the sector S 扇bWg Within the seepage area, it belongs to the original O2 well fan-shaped seepage area S 扇bWc , so, sector S 扇H1We The regional water content, water saturation and oil-water phase permeability are consistent with the development performance of O2 well.

[0160] S32: Phase permeability calculation,

[0161] From the isosaturation surface movement equation, we know that well H1 is uniformly displaced within the seepage area. 扇dWH1 and fan-shaped S 扇H1We Within the regional range, the fluid supply per unit area within the seepage area of ​​well H1 is the same, so at a certain moment, the fan S 扇dWH1 and fan-shaped S 扇H1We The ratio of the total liquid supply is equal to the ratio of the fan area,

[0162]

[0163] For the sector S 扇dWH1 and fan-shaped S 扇H1We , the ratio of their areas is equal to the ratio of their radians,

[0164]

[0165] The relative permeability of the two areas is weighted with respect to the arc, and the seepage area S is calculated. 扇dWe The average phase permeability is:

[0166]

[0167] Where: d H is the distance between the horizontal well and the central water well, in m; r0 is the radius of the injection well, in m; θ1 is the arc of area 1; θ2 is the arc of area 2; K ro1 , K rw1 , K ro2 , K rw2 The oil and water phase permeability in regions 1 and 2 respectively; The average permeabilities of oil phase and water phase in area 1 and area 2 respectively.

[0168] S4: Establish a deployment model for horizontal wells outside the original seepage area, perform a weighted average of the relative permeability of each seepage area of ​​the horizontal well based on area and arc, and calculate the direction, sub-layer, and single-well development indicators for the horizontal wells deployed outside the original seepage area. Specifically, S4 includes the following steps.

[0169] S41: Compared with S2, the difference in the calculation method is mainly reflected in the difference in the phase permeability value. First, the seepage area after the deployment of the horizontal well is divided.

[0170] like Figure 5 As shown, in the fan-shaped seepage area S of well O1 扇aWb S with fan-shaped seepage area of ​​O2 well 扇bWc The horizontal well H2 is deployed externally. If the horizontal well is regarded as a directional well with a substitution ratio of R, then its fan-shaped seepage area is S 扇fWg .

[0171] For the well layout outside the original seepage area, the seepage area of ​​the horizontal well is divided, and the overlapping part with the original seepage area before the horizontal well is put into production is expressed by the development dynamics of the original seepage area before production; for the non-overlapping area, its water saturation and relative permeability are both original and expressed by irreducible water saturation. Figure 6 As shown, the fan S 扇fWg Divided into S 扇dWb 、S 扇bWe 、S 环fdbH2 and S 环H2beg Four parts, including:

[0172] 1. Sector S 扇dWb Belongs to the original O1 well fan-shaped seepage area S 扇aWb , so, sector S 扇dWb The regional water content, water saturation, and relative permeability of oil and water phases are consistent with the development performance of Well O1.

[0173] 2. Sector S 扇bWe Belongs to the original O2 well fan-shaped seepage area S 扇bWc , so, sector S 扇bWe The regional water content, water saturation and oil-water phase permeability are consistent with the development performance of O2 well.

[0174] 3. Ring S 环fdbH2 For undeveloped areas, the water saturation is irreducible water saturation.

[0175] 4. Ring S 环H2beg For undeveloped areas, their water saturation is also irreducible water saturation.

[0176] S42: Phase permeability calculation,

[0177] From formula (26), we can get the ring S 环fdbH2 The first-order derivative of regional moisture content is:

[0178]

[0179] Where: d His the distance between the horizontal well and the central well, in m; d1 is the radius of the seepage area 1 sector, in m; Q1 is S 扇FwH2 The injection volume of the region, in m 3 / d.

[0180] Similarly, from formula (26), we can get the ring S 环H2beg The first-order derivative of regional moisture content is:

[0181]

[0182] Where: d2 is the radius of the seepage area 2 sector, in meters; Q2 is S 扇H2wg The injection volume of the region, in m 3 / d.

[0183] For sector S 扇fWH2 , which contains sector S 扇dWb and ring S 环fdbH2 The two parts, the fluid supply per unit area within the seepage area of ​​well H2 is the same, so at a certain moment, the fan S 扇dWb and ring S 环fdbH2 The ratio of the total liquid supply is equal to the ratio of the sector area to the annular area,

[0184]

[0185] Sector S 扇dWb and ring S 环fdbH2 The relative permeability of these two areas is weighted by area, and the seepage area S is calculated. 扇fWH2 The average phase permeability is:

[0186]

[0187]

[0188] For sector S 扇H2Wg , which contains sector S 扇bWe and ring S 环H2beg The two parts, the fluid supply per unit area within the seepage area of ​​well H2 is the same, so at a certain moment, the fan S 扇bWe and ring S 环H2beg The ratio of the total liquid supply is equal to the ratio of the sector area to the annular area,

[0189]

[0190] Sector S 扇bWe and ring S 环H2beg The relative permeability of these two areas is weighted by area, and the seepage area S is calculated. 扇H2Wg The average phase permeability is:

[0191]

[0192] S is obtained by area weighted calculation 扇fWH2 The average relative permeability and S 扇H2Wg After the average phase permeability of the two areas is calculated, the seepage area S is calculated by weighting the average phase permeability of the two areas with respect to the arc. 扇fWg The average phase permeability is:

[0193]

[0194] Where: d H is the distance between the horizontal well and the central water well, in m; d1 is the radius of the sector of seepage area 1, in m; d2 is the radius of the sector of seepage area 2, in m; r0 is the radius of the injection well bore, in m; θ1 is the radian of area 1; θ2 is the radian of area 2.

[0195] S5: Based on the direction, sub-layer, and single-well development indicators calculated in each of S2-S4 modes, a net interference value calculation method is established to quantitatively reflect the interference of horizontal well deployment on the original directional well pattern. Specifically, S5 includes the following steps.

[0196] S51: Net interference value calculation method. In order to compare the interference degree between oil production and liquid production, the net interference value is used to represent it. Net interference value = oil production interference degree / liquid production interference degree. The larger the net interference value, the better the development effect.

[0197] S52: Interference degree calculation method, which is the quantitative value of the interference degree of the oil wells and well groups in the original well area after the horizontal well is added. It is specifically expressed as the ratio of the three differences before and after the horizontal well is put into production to the value three months before production.

[0198] S53: Net interference value classification, specifically,

[0199] 1. Net interference value > 1: Oil production interference degree > liquid production interference degree, water content decreases.

[0200] 2. Net interference value = 1: Oil production interference degree = liquid production interference degree, water content remains unchanged.

[0201] 3. Net interference value <1: Oil production interference degree < liquid production interference degree, water content increases.

[0202] S6: Optimize well location deployment based on the interference of simulated horizontal well deployment on the original directional well pattern. Specifically, S6 includes the following steps.

[0203] S61: For areas where well densification is being planned, by designing different locations of horizontal wells, the net interference value after the horizontal wells are opened is calculated using computer language based on the established method, and the maximum value scheme is selected as the horizontal well layout scheme.

[0204] S62: For areas where well pattern densification has been completed, design a directional well opening and closing scheme around the same layer of horizontal wells, calculate the net interference value, and determine whether the directional well should be opened based on the maximum value scheme.

[0205] The present invention is specifically described below by taking the D17 well group of the Bohai L oilfield as an example:

[0206] S1: Based on the static parameters of the reservoir and the horizontal section length of the horizontal well, the horizontal well replacement ratio is iteratively calculated. The calculation formulas are shown in Equations (12)-(14). The calculation parameters and replacement ratio calculation results are shown in Table 1.

[0207] Table 1 Calculation parameters and results

[0208]

[0209] S2: Calculate the direction, small layer, and single well development indicators when horizontal wells are not deployed. Collect and organize the basic static geological, dynamic development and monitoring data of the D17 well group in the L oil field. The well location distribution map is as follows: Figure 7 As shown in Figure 2, taking the L50 layer of the D17 well group as an example, the splitting condition values ​​and splitting coefficients of the oil wells in each direction of each small layer connected to the D17 central water well are calculated without adjustment. The calculation formulas are shown in Equations (15)-(26). The results of the splitting coefficients of the central water wells in each direction of the L50 layer of the D17 well group are shown in Table 2.

[0210] Table 2 Splitting coefficients of the central water wells in each connection direction in the L50 layer of the D17 well group

[0211]

[0212] The results of the splitting coefficient of the L50 layer oil wells in the D17 well group are shown in Table 3.

[0213] Table 3 Splitting coefficient of L50 oil wells in D17 well group

[0214]

[0215] S3: Establish the deployment mode of horizontal wells in the original seepage area, perform weighted average of the relative permeability of each part of the horizontal well seepage area based on the arc, and calculate the direction, small layer, and single well development indicators of the horizontal wells deployed outside the original seepage area. After the V61H well is deployed, outside the original seepage area, such as Figure 8 As shown, S4 can be directly used to calculate the direction, small layer, and single well development indicators when the horizontal well is deployed outside the original seepage area.

[0216] S4: Establish a deployment mode for horizontal wells outside the original seepage area, and perform weighted average of the relative permeability of each part of the seepage area of ​​the horizontal well based on the area and arc. The calculation formulas are shown in Equations (31)-(40). After the horizontal well V61H is deployed in the D17 well group, the effective thickness of the reservoir in the V61H well is 5.2m, and the average permeability is 1584×10 -3 μm 2 , calculate the splitting condition values ​​and splitting coefficients of the oil wells in each direction of each small layer connected to the D17 central water well under the condition of adjustment at the same time. The results of the splitting coefficients of the central water wells in each connecting direction of the L50 layer of the D17 well group are shown in Table 4.

[0217] Table 4 Splitting coefficients of the central water wells in each connection direction of the L50 layer of the D17 well group after the injection-production relationship adjustment

[0218]

[0219] The results of the splitting coefficient of the L50 layer oil wells in the D17 well group are shown in Table 5.

[0220] Table 5 Splitting coefficient of L50 layer oil wells in D17 well group after injection-production relationship adjustment

[0221]

[0222] S5: A net interference value calculation method is established to quantitatively reflect the interference of horizontal well deployment on the original directional well pattern. The calculation results are shown in Table 6.

[0223] Table 6 Calculation of net interference value before and after adjustment of injection-production relationship of D17 well group

[0224]

[0225] S6: Optimize well location deployment based on the interference of simulated horizontal well deployment on the original directional well pattern. Figure 9 As shown in the figure, the deployment of the V61H well improved the development results for the L50 layer of the D17 well group and the entire D17 well group. This also affected the development results of the four directional wells perforated in the L50 layer (wells D11ST1, D16ST1, D18ST1, and D23ST1). Among them, the change in fluid production in well D16ST1 was much greater than the change in oil production, and the water cut increased rapidly. This allowed the L50 layer of well D16ST1 to be closed for development in subsequent development.

[0226] The advantages and positive effects of the present invention are:

[0227] 1. The present invention uses data analysis methods to establish a quantitative method for distinguishing the interference mechanism and degree of the original directional well pattern after the deployment of horizontal wells, thereby realizing the prediction of the optimal deployment position of horizontal wells and improving oilfield efficiency.

[0228] 2. The present invention combines a variety of reservoir engineering methods with data analysis methods to achieve automated comprehensive determination of the interference degree of the combined well layout of directional wells and horizontal wells.

[0229] 3. The present invention can program the research results into software, integrate and modularize the reservoir engineering methods in various steps into a computerized manner, visualize the data analysis, and call various functional modules through the main interface, making the entire process clear and understandable.

[0230] The above is a detailed description of an embodiment of the present invention. However, the content described is only a preferred embodiment of the present invention and should not be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A method for identifying and optimizing inter-well interference in water-flooded oil reservoirs based on joint well pattern deployment, characterized by: The following steps are included: S1: Collect basic static geological, dynamic development and engineering data of the reservoir and convert the horizontal well replacement ratio. S1 includes the following steps: S11: The substitution ratio R is used to represent the ratio of the drainage area of ​​the directional well to that of the horizontal well; S12: Convert the drainage area between directional wells and horizontal wells; S13: performing iterative calculation of the substitution ratio R; S2: Based on reservoir engineering methods, time series calculations are used to calculate the direction, small layer, and single well development indicators when the horizontal well is not deployed, simulating the changes in oilfield development at each moment; S3: Establishing a deployment pattern of horizontal wells in the original seepage area, performing weighted average of the relative permeability of each part of the seepage area of ​​the horizontal well based on the arc, and calculating the direction, small layer, and single well development indicators of the horizontal wells when deployed in the original seepage area. S3 includes the following steps: S31: dividing the seepage area after the horizontal wells are deployed, and deploying the horizontal well H1 between the fan-shaped seepage area of ​​well O1 and the fan-shaped seepage area of ​​well O2; S32: For the well layout pattern in the original seepage area, by dividing the seepage area of ​​the equivalent circle of the horizontal well drainage area, the development dynamics of the original seepage area overlapped by each part immediately before the horizontal well is put into production are expressed as the initial development dynamics of each part of the seepage area of ​​the equivalent circle of the horizontal well drainage area; S33: perform phase permeability calculation; S4: establishing a deployment mode of horizontal wells outside the original seepage area, performing weighted average of the relative permeability of each part of the seepage area of ​​the horizontal well based on the area and arc, and calculating the direction, small layer, and single well development indicators of the horizontal wells when deployed outside the original seepage area. S4 includes the following steps: S41: dividing the seepage area after the horizontal wells are deployed, and deploying the horizontal well H2 outside the fan-shaped seepage area of ​​the O1 well and the fan-shaped seepage area of ​​the O2 well; S42: For the well pattern outside the original seepage area, the seepage area of ​​the horizontal well is divided. The overlapping part with the original seepage area before the horizontal well is put into production is expressed by the development dynamics of the original seepage area immediately before production. For the non-overlapping area, its water saturation and relative permeability are both original and expressed by irreducible water saturation. S43: perform phase permeability calculation; S5: Based on the direction, sub-layer, and single-well development indicators calculated in S2-S4 modes, a net interference value calculation method is established to quantitatively reflect the interference of horizontal well deployment on the original directional well pattern; S6: Optimize well location deployment based on the interference of simulated horizontal well deployment on the original directional well pattern.

2. The method for identifying and optimizing inter-well interference in water flooding reservoirs based on joint well pattern deployment according to claim 1, characterized in that: Said S2 comprises the following steps, S21: Calculate the water well splitting coefficient using formation coefficient, location coefficient and well spacing as splitting calculation parameters. The calculation formula is: Where: is the average formation coefficient in the connected direction, in μm 2 m;α ik is the connectivity direction position coefficient; D ik is the well spacing in the connecting direction, in m; S22: Split the oil wells according to the formation coefficient, location coefficient, relative permeability, injection coefficient and well spacing, and calculate the oil well splitting coefficient. The calculation formulas for the oil production splitting condition value and the water production splitting condition value are: Where: K ro is the relative permeability of the oil phase; K rw is the relative permeability of water phase; B ki is the water injection coefficient; S23: Calculate the liquid production of a single well based on the injection-production ratio of the well group and the splitting coefficient of each effective well; S24: Calculate the liquid production, oil production, water production and water content of a single layer based on the oil production splitting coefficient and water production splitting coefficient of the small layer; S25: The liquid production, oil production, water production and water content in each direction are obtained according to the directional oil production splitting coefficient and the water production splitting coefficient.

3. The method for identifying and optimizing inter-well interference in water flooding reservoirs based on joint well pattern deployment according to claim 2, characterized in that: Said S21 comprises the following steps: S211: Calculate the average formation coefficient. The calculation formula is: Where: K i is the effective permeability of the injection well, in μm 2 ; H i is the water injection thickness, in m; K k is the effective permeability of the oil well, in μm 2 ; H k is the production thickness, in m; S212: Calculate the position coefficient. The calculation formula is: Where: α is the location coefficient; n is the number of effective oil wells around the water well, unit is mouth; θ is the azimuth, unit is degree; S213: Calculate the distance between oil and water wells in the connection direction. The specific calculation formula is: D ik ′=lnD ik Where: x i is the horizontal coordinate of the injection well, in m; i is the vertical coordinate of the injection well, in m; x k is the horizontal coordinate of the oil well, in m; k is the vertical coordinate of the oil well, in m; D ik ′ is the logarithmic well spacing.

4. The method for identifying and optimizing the inter-well interference in a water flooding reservoir based on a combined well pattern deployment according to claim 2 or 3, characterized in that: The S22 includes the following steps: S221: Calculate the water injection coefficient. The calculation formula is: Where: W ki The water injection volume in the direction of the splitting of the connecting direction, in m 3 ; S222: Calculate oil saturation and relative permeability using the water saturation and relative permeability relationship curve; S223: Calculate the water cut and its derivative corresponding to different water saturations based on the relative permeability data to obtain the change in water cut at different times.

5. The method for identifying and optimizing the inter-well interference in water flooding reservoirs based on joint well pattern deployment according to claim 1 or 2, characterized in that: Said S5 comprises the following steps, S51: Calculate using a net interference value calculation method; S52: Calculate using the interference degree calculation method; S53: Classify the net interference value.

6. The method for identifying and optimizing inter-well interference in water flooding reservoirs based on joint well pattern deployment according to claim 5, characterized in that: In S53, when the net interference value is greater than 1, the oil production interference degree is greater than the liquid production interference degree, and the water content decreases; when the net interference value is equal to 1, the oil production interference degree is equal to the liquid production interference degree, and the water content remains unchanged; when the net interference value is less than 1, the oil production interference degree is less than the liquid production interference degree, and the water content increases.

7. The method for identifying and optimizing inter-well interference in water flooding reservoirs based on joint well pattern deployment according to claim 1 or 2, characterized in that: Said S6 comprises the following steps, S61: For areas where well pattern infill is being planned, by designing different locations for horizontal wells, the net interference value after the horizontal wells are opened is calculated using a computer language based on the established method, and the maximum value scheme is selected as the horizontal well layout scheme; S62: For areas where well pattern densification has been completed, design a directional well opening and closing scheme around the same layer of horizontal wells, calculate the net interference value, and determine whether the directional well should be opened based on the maximum value scheme.

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