A convenient method for identifying horizontal well water flooding types using dynamic data

Abstract

The present invention provides a convenient method for identifying the type of water drive in horizontal wells by using dynamic data. The convenient method for identifying the type of water drive in horizontal wells by using dynamic data includes: step 1, analyzing the characteristics of the water content curve of a single well to determine the water drive stage; step 2, preparing basic data; step 3, establishing a horizontal well sweep coefficient calculation model, and using dynamic data to obtain the horizontal well sweep coefficient by a graphical method; step 4, establishing a sweep type identification standard, and judging the sweep type according to the horizontal well sweep coefficient. The convenient method for identifying the type of water drive in horizontal wells by using dynamic data can use dynamic data to conveniently and quickly identify the sweep degree and sweep type of water drive in horizontal wells, establish a sweep coefficient calculation model, determine the sweep type identification standard, and guide the formulation of potential tapping strategies for horizontal wells. The method is convenient, fast, and generally applicable, and provides a basis for on-site technicians to accurately formulate potential tapping strategies.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas field development, and in particular to a convenient method for identifying horizontal well water drive sweep types by using dynamic data. Background Art

[0002] In oilfield development, horizontal wells are widely used due to their advantages such as increased oil leakage area, small production pressure difference, and effective control of edge and bottom water or cone advancement of injected water. At present, they have become an important technical means for oilfields to increase oil production speed and increase recoverable reserves. As the development of the oilfield proceeds, horizontal wells will gradually see water and even enter the high water-cut oil production period, with a significant increase in water production and a rapid decrease in oil production. Studies have shown that even if the reservoir enters the high water-cut period, there is still a large amount of residual oil retained underground, which has the potential for continued exploitation. The water drive sweep coefficient is an important factor affecting the recovery rate of water-flooded oilfields. The calculation of the sweep coefficient of horizontal wells and the accurate identification of the sweep type of the horizontal section are important parameters for evaluating the effect of water drive development, and are also an important basis for formulating fine potential tapping strategies for horizontal wells.

[0003] At present, the identification of sweep type mainly adopts indoor experiments and numerical simulation methods to calculate the sweep coefficient of water flooding according to specific conditions such as fluid properties and well pattern. The influence of reservoir dynamic conditions is not considered, and it is not universally applicable. The workload is large, the time is long, and the field application is inconvenient. Moreover, the research object is mainly vertical wells, and there is no report on the calculation of sweep coefficient and sweep type identification of horizontal wells.

[0004] In the Chinese patent application with application number: CN201010154493.6, a method for optimizing the horizontal well plane network is involved, which includes the following steps: 1) using conventional technical means to explore the distribution of underground oil reservoirs; 2) based on the distribution of underground oil reservoirs, determining the horizontal well network in a plane row; 3) based on the distribution of underground oil reservoirs, determining the horizontal well network in a plane staggered; 4) based on the determined horizontal well network in a plane row and the horizontal well network in a plane staggered, comparing and determining the optimal plane well network and its well network parameters: ① given the dimensionless length of the horizontal section lD and the well network unit area S, while other parameters remain unchanged, changing the well row spacing ratio F, and calculating the average single well dimensionless 1) Dimensional production QD, the relationship curve between dimensionless production and well-row spacing ratio can be obtained, and the optimal well-row spacing ratio Fop can be obtained from the curve; 2) Keep the well network unit area S unchanged, change the dimensionless horizontal section length lD, and change the well-row spacing ratio F while keeping other parameters unchanged, calculate the average single-well dimensionless production QD of the well network, and the optimal well-row spacing ratio Fop under different horizontal section dimensionless lengths can be obtained; 3) Determine the optimal well spacing and row spacing of the well network based on the well network unit area S and the optimal well-row spacing ratio Fop; Under the optimal well-row spacing, optimize the horizontal section length based on the dimensionless horizontal section length lD and the dimensionless production relationship curve; 5) Arrange wells according to the optimized horizontal section length

[0005] In the Chinese patent application with application number: CN201811129798.4, a method and device for predicting the oil production of a horizontal well are involved, which relates to the field of oil production. The method includes: after determining the horizontal length of the rectangular part in the driving range of the horizontal well to be predicted, the pressure difference between the driving range boundary and the horizontal well, the oil leakage radius, the wellbore radius of the horizontal well, the distance between the horizontal well and the lower boundary of the driving range, the permeability of the oil layer where the horizontal well is located, the viscosity of the oil layer, the volume coefficient of the oil layer and the thickness of the oil layer, the first oil production corresponding to the rectangular part in the rectangular range and the second oil production corresponding to the two end parts can be determined; then after determining the sweep coefficient of the oil layer, the third oil production corresponding to the horizontal well can be determined according to the first oil production of the rectangular part, the second oil production of the two end parts and the sweep coefficient of the oil layer.

[0006] In the Chinese patent application with application number: CN201310080017.8, a method for interpreting a well test of a heavy oil thermal recovery horizontal well is involved, which includes: according to the underground fluid and thermal field distribution characteristics of the heavy oil horizontal well, a time-varying line source composite well test model is adopted; a line source function is constructed according to the time-varying line source composite well test model; a plate source function is selected according to the boundary conditions of the heavy oil horizontal well; the line source function and the plate source function are superimposed to obtain a source function of the heavy oil thermal recovery horizontal well; from the source function of the heavy oil thermal recovery horizontal well, a Laplace space solution of a bottom hole pressure function without a well reservoir is obtained; from the Laplace space solution of the bottom hole pressure function without a well reservoir, a real space solution of the bottom hole pressure function with a well reservoir is obtained.

[0007] The above existing technologies are greatly different from the present invention and fail to solve the technical problem we want to solve. Therefore, we have invented a new and convenient method for identifying the type of horizontal well water flooding using dynamic data. Summary of the invention

[0008] The purpose of the present invention is to provide a convenient method for identifying the type of horizontal well water flooding by applying dynamic data, which is convenient, fast and generally applicable and provides a basis for on-site technicians to accurately formulate potential tapping strategies.

[0009] The purpose of the present invention can be achieved by the following technical measures: a convenient method for identifying the type of horizontal well water flooding using dynamic data, the convenient method for identifying the type of horizontal well water flooding using dynamic data includes:

[0010] Step 1: Analyze the characteristics of the water cut curve of a single well and determine the water flooding sweep stage;

[0011] Step 2: Prepare basic data;

[0012] Step 3, establish a horizontal well sweep coefficient calculation model, and use dynamic data to obtain the horizontal well sweep coefficient using a graphical method;

[0013] Step 4: Establish a sweep type identification standard and determine the sweep type based on the horizontal well sweep coefficient.

[0014] The purpose of the present invention can also be achieved by the following technical measures:

[0015] In step 1, the horizontal well water flooding sweep process is staged. In the first stage, the water flooding sweep range of the reservoir continues to expand, and in the second stage, the water flooding sweep range is basically fixed, that is, the stable stage. The sweep coefficient in this stage can be used to evaluate the horizontal well water flooding effect and then guide the formulation of control countermeasures.

[0016] In step 1, the water flooding sweep stage is determined according to the water content change characteristics of a single horizontal well. The heterogeneity of the permeability of the horizontal well affects the rising characteristics of the water content. The heterogeneity of the permeability will cause the water content to rise in a step-by-step manner. In order to more sensitively and quantitatively measure the change in water content, the water content derivative is introduced. Amplify the signal, where fw is the moisture content and t is a time parameter consistent with the time unit for calculating fw, which can be years, months or days.

[0017] In step 1, when a horizontal well encounters n permeable zones, its water cut derivative curve will have n humps. After the water cut derivative has the nth hump, the water cut rises steadily, indicating that the sweep range of the horizontal well water drive is basically fixed, that is, the sweep enters a stable stage, and the sweep coefficient can be calculated.

[0018] In step 2, the controlled reserves and underground pore volume of a single horizontal well are calculated based on the injection-production well spacing, thickness, horizontal section length, and single-reservoir coefficient of the horizontal well; the relative permeability data table of the area is collected and sorted; the dynamic data such as water content and injection volume at different times are also collected and sorted.

[0019] In step 3, firstly, the parameter B is calculated from the relative permeability curve of the block; secondly, the controlled reserves of the horizontal well and the underground pore volume are calculated; then, the cumulative water injection volume of the dynamic data is used to calculate the multiple of the injected pore volume of the reservoir; then, the water content of the single well of the dynamic data is used to calculate fw(1-fw)B, where fw is the water content; finally, fw(1-fw)B is used as the ordinate, and A relationship curve is drawn on the horizontal axis, where IPV is the multiple of the injected pore volume of the reservoir, and the slope of the curve is the sweep coefficient.

[0020] In step 3, the model of horizontal well sweep coefficient is related to the single well water content and pore volume injection multiple, and the model is established through the following process:

[0021] For non-piston displacement, ignoring gravity and capillary forces, the water content of the reservoir is:

[0022]

[0023] Where: fw is the moisture content; k r is the relative permeability, μ is the fluid viscosity, mPa·s; w is the water phase subscript, o is the oil phase subscript;

[0024] In an oil reservoir, water content is a function of water saturation. Therefore, the partial differential of water saturation in equation (1) yields

[0025]

[0026] Where: S w is water saturation; assuming that the oil-water permeability relationship conforms to In the formula, C and B are constants, and formula (2) can be changed to:

[0027]

[0028] Substituting formula (1) into formula (3), we can obtain the partial derivative of water content with respect to water saturation:

[0029]

[0030] According to Welge oil displacement theory, there is a relationship at the outlet of one-dimensional displacement

[0031]

[0032] Where, IPV is the reservoir injection pore volume multiple;

[0033] According to the definition of sweep degree and injection pore volume multiple, we can get:

[0034]

[0035] Where, IPV′ is the injection pore volume multiple based on the reservoir volume swept by water injection;

[0036] According to the water flooding process analyzed above, it is assumed that the water flooding range of the reservoir still meets the formula (5), that is:

[0037]

[0038] Then in actual reservoir displacement, there is a relationship:

[0039]

[0040] Swe is the average water saturation at the outlet of the one-dimensional water-to-oil displacement;

[0041] Combining equations (4) and (8) we can obtain the horizontal well water flooding sweep coefficient calculation model:

[0042]

[0043] The parameter on the left side of formula (9) is the outlet water content, and the corresponding reservoir is the water content of the production well. The parameter on the right side of the formula is the injection pore volume multiple. The constant B can be obtained from the oil-water relative permeability relationship.

[0044] In step 4, according to the heterogeneous characteristics of the permeability of the block, a conceptual model for horizontal well mining is designed, and the water drive process is simulated using numerical simulation methods. The sweep coefficients of models with different permeability heterogeneity characteristics are calculated, the sweep characteristics are analyzed, and the sweep coefficients are divided into three intervals as a criterion for sweep type identification.

[0045] In step 4, among the three intervals divided as the sweep type identification standard, type I is overall sweep, with a sweep coefficient of 0.8 to 1.0 and a very good sweep effect; type II is local sweep, with a sweep coefficient of 0.3 to 0.8 and a medium sweep effect; type III is point-line sweep, with a sweep coefficient of 0 to 0.3 and a very poor sweep effect; for each single well, according to the water drive sweep coefficient calculated in step 3 and the above identification standard, the sweep type of each horizontal well is judged to provide a basis for the formulation of horizontal well control strategies.

[0046] The invention belongs to the technical field of oilfield development. It is a dynamic method for quickly calculating the sweep coefficient of horizontal well water drive and identifying the sweep type. The method applies actual reservoir parameters and production data of horizontal wells, and is based on the material balance principle of reservoir engineering, Welge water-to-oil theory, and the seepage law of horizontal wells to establish a sweep coefficient calculation model, determine the sweep type identification standard, evaluate the water drive effect of horizontal wells, and provide a basis for formulating water control and oil stabilization control countermeasures such as acidification and plugging removal of horizontal wells, reasonable parameter adjustment of oil and water wells, and water plugging and profile adjustment. The method is suitable for horizontal wells in the middle and high water content period of water drive development of heterogeneous types of different permeabilities. The method has wide applicability, zero investment, short time consumption, and is economical and effective. It not only has theoretical significance, but also proposes a new research idea for oil fields to accurately and quickly calculate the sweep coefficient of horizontal wells and evaluate the water drive effect. It can also meet the quick demand of identifying the development effect of horizontal wells at any time and timely regulating on site, and has important practical significance for mine production practice. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A flowchart of a specific embodiment of the convenient method for identifying horizontal well water flooding types using dynamic data of the present invention;

[0048] Figure 2 It is a water content derivative curve diagram for judging the water flooding sweep stage in the specific embodiment 1 of the present invention;

[0049] Figure 3 This is a graph of water drive sweep coefficient calculated by the graphical method in specific embodiment 1 of the present invention.

[0050] Figure 4It is a water content derivative curve diagram for judging the water flooding sweep stage in specific embodiment 2 of the present invention;

[0051] Figure 5 This is a graph of water flooding sweep coefficient calculated by the graphical method in specific embodiment 2 of the present invention.

[0052] Figure 6 It is a water content derivative curve diagram for judging the water flooding sweep stage in specific embodiment 3 of the present invention;

[0053] Figure 7 This is a graph of water drive sweep coefficient calculated by the graphical method in specific embodiment 3 of the present invention. DETAILED DESCRIPTION

[0054] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0055] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations and / or combinations thereof.

[0056] like Figure 1 As shown, Figure 1 The present invention is a flow chart of a convenient method for identifying horizontal well water flooding sweep types using dynamic data.

[0057] In step 101, the water content curve characteristics are analyzed to determine the water flooding sweep stage.

[0058] Current research suggests that the horizontal well water flooding process is staged. In the first stage, the water flooding sweep range of the reservoir continues to expand, and in the second stage, the water flooding sweep range is basically fixed, that is, the stable stage. The sweep coefficient of this stage can be used to evaluate the horizontal well water flooding effect and then guide the formulation of control strategies.

[0059] The water flooding sweep stage can be determined based on the water content change characteristics of a single horizontal well. The heterogeneity of the permeability of a horizontal well affects the rising characteristics of the water content. The heterogeneity of the permeability will cause a step-by-step increase in the water content. In order to more sensitively and quantitatively measure the change in water content, the water content derivative is introduced. Amplify the signal. When a horizontal well encounters n permeable bands, its water cut derivative curve will have n humps. When the water cut derivative has the nth hump, the water cut rises steadily, indicating that the horizontal well water drive sweep range is basically fixed, that is, the sweep enters the second stage, and the sweep coefficient can be calculated.

[0060] In step 102: prepare basic data

[0061] According to the injection-production spacing, thickness, horizontal section length, and single-reservoir coefficient of the horizontal well, the controlled reserves and underground pore volume of the single horizontal well are calculated; the relative permeability data table of the area is collected and sorted; the dynamic data such as water content and injection volume at different times are also collected and sorted.

[0062] In step 103: Based on Welge's oil recovery theory, a model is established that can use dynamic data to calculate the sweep coefficient of horizontal wells. The sweep coefficient can be directly calculated according to the model. However, in the actual production process, dynamic data such as liquid production and water content will fluctuate to a certain extent, and the calculation results will also change irregularly, which is not conducive to the judgment of the water drive sweep condition of the reservoir. Therefore, in order to eliminate the impact caused by data fluctuations, this paper uses a graphical method to calculate the water drive sweep coefficient based on the horizontal well water drive sweep coefficient calculation model. First, the parameter B is calculated from the phase permeability curve of this block; secondly, the controlled reserves and underground pore volume of the horizontal well are calculated; then, the cumulative water injection volume of the dynamic data is used to calculate the multiples of the injected pore volume of the reservoir; then, the water content of a single well is calculated using the dynamic data; finally, fw(1-fw)B is used as the vertical coordinate, and the vertical coordinate is used as the vertical coordinate. Draw a relationship curve for the horizontal axis, and the slope of the curve is the sweep coefficient.

[0063] The model of horizontal well sweep coefficient is related to the water content and pore volume injection multiple of a single well. The model is established through the following process:

[0064] For non-piston displacement, ignoring gravity and capillary forces, the water content of the reservoir is:

[0065]

[0066] Where: f w is the moisture content; k r is the relative permeability, μ is the fluid viscosity, mPa·s; w is the water phase subscript, and o is the oil phase subscript.

[0067] In an oil reservoir, water content is a function of water saturation. Therefore, the partial differential of water saturation in equation (1) yields

[0068]

[0069] Where: S w is the water saturation. Assume that the oil-water relative permeability relationship conforms to (where C and B are constants), then formula (2) can be changed to:

[0070]

[0071] Substituting formula (1) into formula (3), we can obtain the partial derivative of water content with respect to water saturation:

[0072]

[0073] According to Welge oil displacement theory, there is a relationship at the outlet of one-dimensional displacement

[0074]

[0075] Where IPV is the injected pore volume multiple of the reservoir.

[0076] According to the definition of sweep degree and injection pore volume multiple, we can get:

[0077]

[0078] Where IPV′ is the injected pore volume multiple based on the volume of the reservoir affected by water injection.

[0079] According to the water flooding process analyzed above, it is assumed that the water flooding range of the reservoir still meets the formula (5), that is:

[0080] Then in actual reservoir displacement, there is a relationship:

[0081]

[0082] Combining equations (4) and (8) can obtain the horizontal well water flooding sweep coefficient calculation model:

[0083]

[0084] The parameter on the left side of formula (9) is the outlet water content, and the corresponding reservoir is the water content of the production well. The parameter on the right side of the formula is the injection pore volume multiple. The constant B can be obtained from the oil-water relative permeability relationship.

[0085] Step 104: Establish a standard for identifying the type of impact to determine the impact type of the horizontal well.

[0086] According to the heterogeneous characteristics of the permeability of the block, a conceptual model for horizontal well mining is designed, and the numerical simulation method is used to simulate the water drive process. The sweep coefficients of different permeability heterogeneous characteristic models are calculated, the sweep characteristics are analyzed, and the sweep coefficients are divided into three intervals as sweep type identification standards. Class I is overall sweep, with a sweep coefficient of 0.8-1.0 and a very good sweep effect; Class II is local sweep, with a sweep coefficient of 0.3-0.8 and a medium sweep effect; Class III is point-line sweep, with a sweep coefficient of 0-0.3 and a very poor sweep effect. For each single well, according to the water drive sweep coefficient calculated in step 3 and the above identification standards, the sweep type of each horizontal well is judged, providing a basis for the formulation of horizontal well control countermeasures.

[0087] Embodiment 1:

[0088] In a specific embodiment 1 of the present invention, the reservoir of a block in a certain offshore oilfield in Shengli is the meandering river deposit in the upper section of the Guan River. It was put into development in 2003 with a mixed well network of directional wells + horizontal wells. A total of 62 wells were drilled, including 23 horizontal wells. The heterogeneity characteristics of the horizontal wells are divided into three types: homogeneous, two-stage and multi-stage. The current water content is between 30% and 90%. This block is used as an example for explanation.

[0089] In step 1, analyze the characteristics of the water content curve and determine the water flooding sweep stage

[0090] Draw the relationship curve between the water content and time of the 6HP horizontal well in this block, and calculate the inverse of the water content The permeability heterogeneity type of the horizontal section of the horizontal well is homogeneous, and its water content derivative has a peak, such as Figure 2 As shown in the figure, it means that the water drive sweep range has entered a basically fixed stage and the sweep coefficient can be calculated using dynamic data.

[0091] In step 2: Use the model to calculate the sweep coefficient using a graphical method

[0092] According to static data, the controlled reserves of horizontal well 6HP are calculated to be 1.41 million tons, and the underground pore volume is 2.319 million cubic meters; the parameter B is calculated to be 17.2 based on the phase permeability curve data of this area; according to the dynamic data of mining, the controlled reserves of horizontal well 6HP are calculated to be 1.41 million tons, and the underground pore volume is 2.319 million cubic meters; the controlled reserves of horizontal well 6HP are calculated to be Values ​​and draw relationship curves, such as Figure 3 As shown, the slope of the curve is 0.93, that is, the 6HP sweep coefficient of the horizontal well is 0.93.

[0093] Table 1 Phase permeability curve data table of this area

[0094]

[0095]

[0096] In step 3: Determine the impact type based on the identification criteria

[0097] In step 2, the horizontal well 6HP sweep coefficient is calculated to be 0.93. According to the horizontal well water drive sweep type identification standard, the horizontal well 43HP sweep type is Class I overall sweep type. This sweep type has balanced water drive. The main control measures are to increase fluid and increase water injection multiples, thereby improving oil washing efficiency.

[0098] Embodiment 2:

[0099] In a specific embodiment 2 of the present invention, the reservoir of a block in a certain oil field on the Shengli Sea is the meandering river deposit in the upper section of the Guan River. It was put into development in 2003 with a mixed well network of directional wells + horizontal wells. A total of 62 wells were drilled, including 23 horizontal wells. The heterogeneity characteristics of the horizontal wells are divided into three types: homogeneous, two-stage and multi-stage. The current water content is between 30% and 90%. This block is used as an example for explanation.

[0100] In step 1, analyze the characteristics of the water content curve and determine the water flooding sweep stage

[0101] Draw the relationship curve between water content and time of 43HP horizontal well in this block, and calculate the inverse of water content The horizontal section permeability heterogeneity type of this horizontal well is two-stage type, and its water content derivative has two steps, such as Figure 4 As shown in the figure, it means that the water drive sweep range has entered a basically fixed stage and the sweep coefficient can be calculated using dynamic data.

[0102] In step 2: Use the model to calculate the sweep coefficient using a graphical method

[0103] According to static data, the controlled reserves of horizontal well 4HP are calculated to be 510,000 tons and the underground pore volume is 928,000 cubic meters. The parameter B is calculated to be 17.2 based on the phase permeability curve data of this area. Values ​​and draw relationship curves, such as Figure 5 As shown, the slope of the curve is taken as 0.65, that is, the 43HP sweep coefficient of the horizontal well is 0.65.

[0104] Table 1 Phase permeability curve data table of this area

[0105]

[0106]

[0107] In step 3: Determine the impact type based on the identification criteria

[0108] In step 2, the horizontal well 43HP sweep coefficient is calculated to be 0.65. According to the horizontal well water drive sweep type identification standard, the horizontal well 43HP sweep type is Class II local sweep type. The main control strategy for this sweep type is to adjust the well pattern and water injection structure to expand the sweep, while increasing the fluid to improve the oil washing efficiency.

[0109] Embodiment 3:

[0110] In a specific embodiment 3 of the present invention, the reservoir of a block in a certain offshore oilfield in Shengli is the meandering river deposit in the upper section of the Guan River. It was put into development in 2003 with a mixed well network of directional wells + horizontal wells. A total of 62 wells were drilled, including 23 horizontal wells. The heterogeneity characteristics of the horizontal wells are divided into three types: homogeneous, two-stage and multi-stage. The current water content is between 30% and 90%. This block is used as an example for explanation.

[0111] In step 1, analyze the characteristics of the water content curve and determine the water flooding sweep stage

[0112] Draw the relationship curve between the water content and time of the horizontal well 34HP in this block, and calculate the inverse of the water content The horizontal section permeability heterogeneity of this horizontal well is multi-segment type, with three high and low permeability zones, and its water content derivative has three steps, such as Figure 6 As shown in the figure, it means that the water drive sweep range has entered a basically fixed stage and the sweep coefficient can be calculated using dynamic data.

[0113] In step 2: Use the model to calculate the sweep coefficient using a graphical method

[0114] According to static data, the controlled reserves of horizontal well 4HP are calculated to be 630,000 tons and the underground pore volume is 1.025 million cubic meters;

[0115] In step 2: Use the model to calculate the sweep coefficient using a graphical method

[0116] According to static data, the controlled reserves of horizontal well 4HP are calculated to be 710,000 tons, and the underground pore volume is 1.174 million cubic meters; the parameter B is calculated to be 17.2 based on the phase permeability curve data of this area; according to the dynamic data of mining, the controlled reserves of horizontal well 4HP are calculated to be 710,000 tons, and the underground pore volume is 1.174 million cubic meters; the controlled reserves of horizontal well 4HP Values ​​and draw relationship curves, such as Figure 7 As shown, the slope of the curve is 0.23, that is, the 34HP sweep coefficient of the horizontal well is 0.23.

[0117] Table 1 Phase permeability curve data table of this area

[0118]

[0119]

[0120] In step 3: Determine the impact type based on the identification criteria

[0121] In step 2, the horizontal well 34HP sweep coefficient is calculated to be 0.23. According to the horizontal well water drive sweep type identification standard, the horizontal well 34HP sweep type is Class III point-line sweep type. The main control strategy for this sweep type is to plug water and adjust the profile to change the flow field and expand the sweep range.

[0122] The method of the present invention was used to determine the water drive sweep stage of the 22 horizontal wells in the block, and the sweep coefficients of the 15 wells that have entered the stable sweep stage were calculated to quickly identify the sweep type. For horizontal wells with different sweep types, technical countermeasures for classified management and potential tapping were proposed. For type I overall sweep, the liquid was increased and the speed was increased to improve the oil washing efficiency; for type II local sweep, the well network or water injection structure was adjusted to expand the sweep range; for type III point and line sweep, the high permeability zone was blocked, the flow field direction was changed, and the sweep was expanded. The on-site implementation effect was significant, with the daily oil increase in the block increasing by 155 tons and the water cut increase rate slowing down by 2.3%.

[0123] Table 2 Water flooding sweep type identification results

[0124]

[0125] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions recorded in the aforementioned embodiments or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0126] Except for the technical features described in the specification, all other technical features are known technologies to those skilled in the art.

Claims

1. A convenient method for identifying horizontal well water flooding sweep types using dynamic data, characterized in that: The convenient method for identifying the type of horizontal well water flooding using dynamic data includes: Step 1: Analyze the characteristics of the water cut curve of a single well and determine the water flooding sweep stage; Step 2: Prepare basic data; Step 3, establish a horizontal well sweep coefficient calculation model, and use dynamic data to obtain the horizontal well sweep coefficient using a graphical method; Step 4: Establish a sweep type identification standard and determine the sweep type based on the horizontal well sweep coefficient; In step 1, the horizontal well water flooding process is staged. In the first stage, the water flooding sweep range of the reservoir continues to expand, and in the second stage, the water flooding sweep range is basically fixed, that is, the stable stage. The sweep coefficient in this stage can be used to evaluate the horizontal well water flooding effect and then guide the formulation of control countermeasures. In step 1, the water flooding sweep stage is determined according to the water content change characteristics of a single horizontal well. The heterogeneity of the permeability of the horizontal well affects the rising characteristics of the water content. The heterogeneity of the permeability will cause the water content to rise in a step-by-step manner. In order to more sensitively and quantitatively measure the change in water content, the water content derivative is introduced. Amplify the signal, where fw is the water content, and t is a time parameter consistent with the time unit for calculating fw, and its unit is year, month or day; In step 2, according to the horizontal well injection and production well spacing, thickness, horizontal section length, and single-reservoir coefficient, the horizontal well single-well controlled reserves and underground pore volume are calculated; the block phase permeability data table is collected and sorted out; the dynamic data such as water content and injection volume at different times; In step 3, firstly, the parameter B is calculated from the relative permeability curve of the block; secondly, the controlled reserves of the horizontal well and the underground pore volume are calculated; then, the cumulative water injection volume of the dynamic data is used to calculate the multiple of the injected pore volume of the reservoir; then, the water content of the single well of the dynamic data is used to calculate fw(1-fw)B, where fw is the water content; finally, fw(1-fw)B is used as the ordinate, and A relationship curve is drawn on the horizontal axis, where IPV is the multiple of the injected pore volume of the reservoir, and the slope of the curve is the sweep coefficient; In step 3, the model of horizontal well sweep coefficient is related to the single well water content and pore volume injection multiple, and the model is established through the following process: For non-piston displacement, ignoring gravity and capillary forces, the water content of the reservoir is: Where: f w is the moisture content; k r is the relative permeability, μ is the fluid viscosity, mPa·s; w is the water phase subscript, o is the oil phase subscript; In an oil reservoir, water content is a function of water saturation. Therefore, the partial differential of water saturation in equation (1) yields Where: S w is water saturation; assuming that the oil-water relative permeability relationship conforms to k ro / k rw =Ce -BSw , where C and B are constants, then formula (2) can be changed to: Substituting formula (1) into formula (3), we can obtain the partial derivative of water content with respect to water saturation: According to Welge's oil displacement theory, there is a relationship at the outlet of one-dimensional displacement Where, IPV is the reservoir injection pore volume multiple; According to the definition of sweep degree and injection pore volume multiple, we can get: Where, IPV′ is the injection pore volume multiple based on the reservoir volume swept by water injection; According to the water flooding process analyzed above, it is assumed that the water flooding range of the reservoir still meets the formula (5), that is: Then in actual reservoir displacement, there is a relationship: Swe is the average water saturation at the outlet of the one-dimensional water-to-oil displacement; Combining equations (4) and (8) we can obtain the horizontal well water flooding sweep coefficient calculation model: The parameter on the left side of formula (9) is the outlet water content, and the corresponding reservoir is the water content of the production well. The parameter on the right side of the formula is the injection pore volume multiple. The constant B can be obtained from the oil-water relative permeability relationship.

2. The convenient method for identifying horizontal well water flooding types using dynamic data according to claim 1 is characterized in that: In step 1, when a horizontal well encounters n permeable bands, its water cut derivative curve will have n humps. After the water cut derivative has the nth hump, the water cut rises steadily, indicating that the sweep range of the horizontal well water drive is basically fixed, that is, the sweep enters the second stage, and the sweep coefficient can be calculated.

3. The convenient method for identifying horizontal well water flooding types using dynamic data according to claim 1 is characterized in that: In step 4, according to the heterogeneous characteristics of the permeability of the block, a conceptual model for horizontal well mining is designed, and the water drive process is simulated using numerical simulation methods. The sweep coefficients of models with different permeability heterogeneity characteristics are calculated, the sweep characteristics are analyzed, and the sweep coefficients are divided into three intervals as a criterion for sweep type identification.

4. The convenient method for identifying horizontal well water flooding types using dynamic data according to claim 1 is characterized in that: In step 4, among the three intervals divided as the sweep type identification standard, type I is overall sweep, with a sweep coefficient of 0.8 to 1.0 and a very good sweep effect; type II is local sweep, with a sweep coefficient of 0.3 to 0.8 and a medium sweep effect; type III is point-line sweep, with a sweep coefficient of 0 to 0.3 and a very poor sweep effect; for each single well, according to the water drive sweep coefficient calculated in step 3 and the above identification standard, the sweep type of each horizontal well is judged to provide a basis for the formulation of horizontal well control strategies.

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