Analysis method of horizontal well testing for multi-stage fracturing of shale gas

Abstract

The present application discloses an analysis method for shale gas multi-stage fracturing horizontal well testing, which belongs to the technical field of shale gas development. The method includes: establishing a numerical well testing model of the target well control area, the numerical well testing model includes multiple fracturing parameters; based on the permeability of each unit area in the numerical well testing model, a plurality of different types of control areas are divided in the numerical well testing model; based on the control area type between each two adjacent fractures in the numerical well testing model, the connectivity relationship between each two adjacent fractures is determined to obtain an adjusted numerical well testing model; sensitivity analysis is performed on the adjusted numerical well testing model to obtain sensitivity analysis results; the sensitivity analysis results are compared and analyzed with the measured data corresponding to the target well control area to determine the fracturing parameters that need to be adjusted in the target well control area. The method provided in the present application can accurately determine the parameters that need to be adjusted in the actual well area, and then clarify the measures and directions for improving the production of the well area.

Description

Technical Field

[0001] The present application relates to the technical field of shale gas development, and in particular to an analysis method for shale gas multi-stage fracturing horizontal well testing. Background Art

[0002] China's shale gas is widely distributed in marine shales and has broad prospects for exploration and development. For shale gas with large resources, shale gas is often mined through fracturing and production enhancement technology. In the implementation of fracturing and production enhancement technology, the cluster spacing or segment spacing generated in the fracturing and production enhancement process is calculated by a preset formula, which is used as the actual cluster spacing or segment spacing. According to the actual cluster spacing or segment spacing, corresponding fracturing measures are taken to improve the fracturing effect of the water well. Alternatively, the fracture length can be calculated by various parameters in the fracturing and production enhancement process, which is used as the actual fracture length, and corresponding fracturing measures are taken according to the actual fracture length to optimize the fracturing and production enhancement process. Among them, shale gas refers to unconventional natural gas attached to reservoir rock systems dominated by organic-rich shale. It is a continuously generated biochemical gas, thermogenic gas or a mixture of the two. It can exist in natural fractures and pores in a free state, exist in kerogen and clay particle surfaces in an adsorbed state, and a very small amount is stored in kerogen and asphaltene in a dissolved state.

[0003] In the process of implementing this application, the inventors found that the related technology has at least the following problems:

[0004] Since the cluster spacing, segment spacing and fracture length in the above process are calculated by calculation formulas, when the above parameters change, it is impossible to determine the reasons that affect the changes in these parameters, and thus it is impossible to know whether the adopted fracturing transformation measures can increase the production of the well area. Summary of the invention

[0005] The present application provides an analysis method for shale gas multi-stage fracturing horizontal well testing, the method comprising:

[0006] Establishing a numerical well test model of the target well control area, wherein the numerical well test model includes a plurality of fracturing parameters, wherein the plurality of fracturing parameters include the permeability corresponding to each unit area in the target well control area and the parameters of each fracture in the target well control area;

[0007] Based on the permeability of each unit area in the numerical well test model, a plurality of different types of control areas are divided in the numerical well test model;

[0008] Based on the control area type between every two adjacent fractures in the numerical well testing model, determining the connectivity relationship between every two adjacent fractures to obtain an adjusted numerical well testing model;

[0009] Performing sensitivity analysis on the adjusted numerical well testing model to obtain sensitivity analysis results;

[0010] The sensitivity analysis result is compared with the measured data corresponding to the target well to determine the fracturing parameters that need to be adjusted for the target well.

[0011] Optionally, the control zone type includes: one or more of a primary fracture control zone, a secondary fracture control zone, a matrix control zone and a stagnant flow control zone.

[0012] Optionally, based on the permeability of each unit area in the numerical well test model, a plurality of different types of control areas are divided in the numerical well test model, including:

[0013] Determine the area where the permeability is within the first numerical range as the main fracture control area;

[0014] Determine the area where the permeability is within the second numerical range as the secondary fracture control area;

[0015] Determine the region where the permeability is within the third numerical range as the matrix control region;

[0016] Determine the region where the permeability is within a fourth numerical range as the stagnant flow control region;

[0017] Among them, the permeability of the main fracture control zone, the permeability of the secondary fracture control zone, the permeability of the matrix control zone and the permeability of the stagnant flow control zone become smaller in sequence.

[0018] Optionally, the method further includes:

[0019] If the non-flow control area exists in the control region between two adjacent fractures, determining that the connection relationship between the two adjacent fractures is disconnected;

[0020] Optionally, the method further includes:

[0021] If the matrix control region exists in the control area between two adjacent fractures, it is determined that the connection relationship between the two adjacent fractures is disconnected.

[0022] It should be noted that in the embodiment of the present application, if the connection relationship between two adjacent cracks is not connected, the distribution distance between the two cracks is too large, the fracturing strength is insufficient, and the fracturing strength can be appropriately increased and the crack spacing can be reduced. The amount of improvement measures is determined by experiments and the above-mentioned methods, or there is an unfracturable barrier between the cracks, and the geological analysis results are required to determine whether there are faults, natural cracks, or geological reasons such as changes in ground stress, and formulate corresponding measures to avoid the occurrence of similar situations.

[0023] Optionally, in an embodiment of the present application, if the control region between two adjacent cracks only has a main crack control region, the connectivity relationship between the two adjacent cracks is determined to be connectivity.

[0024] In the embodiment of the present application, if the area between two adjacent fractures is entirely controlled by the main fracture, the distribution distance between the two adjacent fractures is too small, and the fracturing is excessive. Some measures can be appropriately taken to increase the fracture distance.

[0025] Optionally, if a primary fracture control region and a secondary fracture control region exist in the control region between two adjacent fractures, the connectivity relationship between the two adjacent fractures is determined to be connectivity.

[0026] In an embodiment of the present application, if there are only a primary crack control area and a secondary crack control area between the control regions between two adjacent cracks, the distribution spacing between the two adjacent cracks is optimal, and there is no need to adjust the spacing between the cracks.

[0027] Optionally, performing sensitivity analysis on the adjusted numerical well testing model to obtain sensitivity analysis results includes:

[0028] Obtaining a first characteristic curve corresponding to each fracturing parameter of the adjusted numerical well testing model;

[0029] A sensitivity analysis result is obtained by performing a sensitivity analysis on the first characteristic curve.

[0030] Optionally, determining the fracturing parameters that need to be adjusted for the target well according to the sensitivity analysis result and the measured data corresponding to the target well includes:

[0031] Based on the measured data of the target well, obtaining a second characteristic curve corresponding to various fracturing parameters in the target well;

[0032] Based on the sensitivity analysis result and the second characteristic curve, the fracturing parameters that need to be adjusted in the target well control area are determined.

[0033] Optionally, the fracturing parameters include: one or more of the area of ​​the unit region corresponding to the permeability, the number of fractures, the length of the fractures and reservoir parameters.

[0034] The beneficial effects of the technical solution provided by the embodiment of the present application are:

[0035] The method provided in the embodiment of the present application can establish a numerical well test model of the target well control area, perform sensitivity analysis on the numerical well test model, and obtain sensitivity analysis results. Since the numerical well test model can reflect the fracturing characteristics of the target well control area, the sensitivity analysis results obtained according to the numerical well test model can accurately describe the fracturing changes in the target well control area. By analyzing the measured data of the target well control area according to the sensitivity analysis results, the parameters that affect the production of the target well control area can be accurately obtained, thereby clarifying the measures and directions for increasing the production of the well area. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0037] Figure 1 It is a flow chart of an analysis method for shale gas multi-stage fracturing horizontal well testing provided in an embodiment of the present application;

[0038] Figure 2 It is a schematic diagram of an analysis method for shale gas multi-stage fracturing horizontal well testing provided in an embodiment of the present application;

[0039] Figure 3 It is a schematic diagram of an analysis method for shale gas multi-stage fracturing horizontal well testing provided in an embodiment of the present application. DETAILED DESCRIPTION

[0040] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0041] Figure 1 Flow chart of a method for analyzing shale gas multi-stage fracturing horizontal well testing provided in the embodiment of the present application. Figure 1 , the embodiment comprises:

[0042] Step 101: Establish a numerical well test model of the target well control area.

[0043] Among them, the numerical well testing model includes multiple fracturing parameters, and the multiple fracturing parameters include the permeability corresponding to each unit area in the target well control area and the parameters of each crack in the target well control area, for example, the area of ​​the unit area corresponding to the permeability, the number of cracks, the length of the cracks and one or more of the reservoir parameters, wherein the reservoir parameters include one or more of the thickness, gas / water saturation, porosity, formation pressure and temperature of each reservoir.

[0044] In implementation, at least one fracturing parameter included in the target well control area is collected to establish a numerical well test model.

[0045] For example, a numerical well testing model is established through numerical well testing software and the collected fracturing parameters, such as: through pansystem software or saphir software, a numerical well testing model is established, and the required parameters may be as follows: the horizontal section length of the target well control area is 1500m, there are 20 fractures (i.e., fracturing level 20), the length of each fracture is 10m, the length of the unit area is 10m, the width is 10m, the permeability corresponding to each unit area, the length of the well control range is 1700m, the width is 400m, the porosity is 0.5, the reservoir thickness is 25m and other parameters, and the final model is as follows: Figure 2 As shown, 1 represents the fracture, 2 represents the segment spacing, 3 represents the horizontal segment length of the target well control area, and 4 represents the fracture half length.

[0046] Step 102: Based on the permeability of each unit area in the numerical well test model, a plurality of different types of control areas are divided in the numerical well test model.

[0047] Among them, permeability refers to the ability of rock to allow fluid to pass through under a certain pressure difference.

[0048] In implementation, there are multiple unit areas in the numerical well test model, each unit area corresponds to a permeability, and the permeability represents the average permeability corresponding to the unit area. According to the permeability corresponding to each unit area, multiple different types of control areas are divided in the numerical well test model.

[0049] The control area includes at least one unit area, and the types of the control area include: one or more of a primary fracture control area, a secondary fracture control area, a matrix control area, and a non-flow control area.

[0050] Optionally, an area with a permeability within a first numerical range is determined as a primary fracture control area; an area with a permeability within a second numerical range is determined as a secondary fracture control area; an area with a permeability within a third numerical range is determined as a matrix control area; and an area with a permeability within a fourth numerical range is determined as a stagnant flow control area; wherein the permeability of the primary fracture control area, the permeability of the secondary fracture control area, the permeability of the matrix control area, and the permeability of the stagnant flow control area decrease in sequence.

[0051] In implementation, the area with a permeability within (0.001mD, 0.01mD) is determined as the primary fracture control area, the area with a permeability within (0.0001mD, 0.001mD) is determined as the secondary fracture control area, the area with a permeability within (0.00001mD, 0.0001mD) is determined as the matrix control area, and the area with a permeability of 0mD is determined as the no-flow control area.

[0052] It should be noted that the abilities of the primary fracture control zone, the secondary fracture control zone, the matrix control zone and the non-flow control zone to allow fluid to pass through gradually weaken, among which the primary fracture control zone has the largest ability to allow fluid to pass through, and the non-flow control zone has the smallest ability to allow fluid to pass through. In the embodiments of the present application, it is considered that the non-flow control zone does not allow fluid to pass through.

[0053] Step 103: Based on the control area type between every two adjacent fractures in the numerical well testing model, the numerical well testing model is adjusted to obtain an adjusted numerical well testing model.

[0054] Among them, according to the type of control area between every two adjacent fractures in the numerical well test model, the connectivity relationship between every two adjacent fractures is determined, and then whether there is a correlation relationship between every two adjacent fractures is determined. When the connectivity relationship between every two adjacent fractures is connected, it is determined that there is no isolation zone between the two adjacent fractures, that is, the two adjacent fractures are related. When the connectivity relationship between every two adjacent fractures is disconnected, it is determined that there is an isolation zone between the two adjacent fractures, and the two adjacent fractures are unrelated. The isolation zone includes a non-flow control zone and a matrix control zone.

[0055] Optionally, if the control region between two adjacent fractures only has a primary fracture control region, the connectivity relationship between the two adjacent fractures is determined to be connectivity. If the control region between two adjacent fractures only has a primary fracture control region and a secondary fracture control region, the connectivity relationship between the two adjacent fractures is determined to be connectivity.

[0056] Among them, when the connectivity relationship between two adjacent cracks is connected, the control area between the two adjacent cracks includes either a main crack control area or a secondary crack control area; or there is a main crack control area and a secondary crack control area; or there is a secondary crack control area; or there is a main crack control area.

[0057] Alternatively, if there is a no-flow control zone in the control region between two adjacent fractures, the connectivity relationship between the two adjacent fractures is determined to be disconnected; if there is a matrix control zone in the control region between two adjacent fractures, the connectivity relationship between the two adjacent fractures is determined to be disconnected.

[0058] It should be noted that the main fracture control area will not be adjacent to the matrix control area and the stagnant flow control area, and if there is a matrix control area or a stagnant flow control area, there must be a main fracture control area and a secondary fracture control area.

[0059] The connection relationship between the above four control areas is that the primary fracture control area can only be adjacent to the secondary fracture control area, the secondary fracture control area can only be adjacent to the primary fracture control area or the matrix control area, and the matrix control area can only be adjacent to the secondary fracture control area or the stagnant flow control area. According to the adjacent relationship between the above control areas, the adjacent relationship of the control areas in the numerical well test model is adjusted to obtain the adjusted numerical well test model.

[0060] In implementation, when the area between two adjacent fractures is entirely controlled by the main fracture, the area between the two adjacent fractures is entirely a high permeability area, and the permeability between the two adjacent fractures is the permeability of the main fracture control area; when there is a main fracture control area and a secondary fracture control area between two adjacent fractures, the secondary fracture control area is adjacent to the main fracture control area, and the main fracture control areas of the two adjacent fractures are separated from each other by the secondary fracture control area; when there is a matrix control area between two fractures, and there is a gray isolation zone (i.e., a non-flowing area) between the fractures, the permeability between the two fractures is the permeability corresponding to the matrix control area.

[0061] In the software design process, the primary crack control area, secondary crack control area, matrix control area and non-flow control area can be represented by white, yellow, purple and gray respectively. After each control area is set, it is detected whether white is adjacent to other colors except yellow, and whether yellow is adjacent to gray. When white is adjacent to other colors except yellow, the color adjacent to white is replaced with yellow. When yellow is adjacent to gray, the color adjacent to yellow is replaced with white or purple.

[0062] Step 104: Perform sensitivity analysis on the adjusted numerical well testing model to obtain sensitivity analysis results.

[0063] Optionally, a first characteristic curve corresponding to each fracturing parameter of the adjusted numerical well testing model is obtained; and a sensitivity analysis result is obtained by performing a sensitivity analysis on the first characteristic curve.

[0064] Among them, the first characteristic curve is a double logarithmic curve of pressure and pressure derivative generated by numerical well test design and time, and the pressure is the bottom hole pressure corresponding to the pressure recovery time period, wherein the double logarithmic curve is in a logarithmic scale coordinate system for both coordinate axes. In the embodiment of the present application, the first characteristic curve includes two double logarithmic curves, one is a double logarithmic curve of pressure and time, and the other is a double logarithmic curve of the inverse of pressure and time.

[0065] In implementation, the numerical well testing software obtains the adjusted numerical well testing model according to the designed reservoir parameters and various fracturing parameters, simulates the actual production after actual fracturing, and the data of shut-in pressure recovery to obtain the corresponding first characteristic curve. By changing any one of the fracturing parameters multiple times and keeping the other fracturing parameters unchanged, the influence of the fracturing parameter on the change of the first characteristic curve is determined to obtain the sensitivity analysis results. The sensitivity analysis results include which part of the first characteristic curve is affected by each fracturing parameter to obtain the change relationship between the first characteristic curve and each parameter.

[0066] Step 105: Compare and analyze the sensitivity analysis results and the measured data corresponding to the target well to determine the fracturing parameters that need to be adjusted for the target well.

[0067] Optionally, based on the measured data of the target well, a corresponding second characteristic curve is obtained, and various fracturing parameters of the target well are analyzed and obtained; based on the sensitivity analysis results and the second characteristic curve, the fracturing parameters that need to be adjusted for the target well are determined.

[0068] It should be noted that what is essentially done here is to determine the first characteristic curve having the greatest similarity to the second characteristic curve, and in the sensitivity analysis result, obtain the fracturing parameters that affect the change of the first characteristic curve having the greatest similarity to the second characteristic curve.

[0069] Among them, the target well is dynamically monitored to obtain the double logarithmic relationship curve part of the pressure and time in the double logarithmic curve corresponding to the pressure recovery time period, the pressure is differentiated to obtain the double logarithmic relationship curve part of the pressure derivative and time in the double logarithmic curve, and the double logarithmic curve of pressure / pressure derivative and time obtained by superimposing the two parts is the second characteristic curve (the first characteristic curve and the second characteristic curve are composed in the same way, except that the first characteristic curve is a model designed based on the reservoir physical properties interpreted by well logging and the average fracturing parameters of the well area (number of fractures, horizontal section length, average fracture spacing, fracture half-length, vertical wellbore direction control distance, permeability), and is obtained by simulating production and shut-in pressure recovery; the second characteristic curve is obtained based on the measured pressure recovery data.

[0070] During implementation, the second characteristic curve is analyzed based on the first characteristic curve in the sensitivity analysis results and the changing relationship between various fracturing parameters and the first characteristic curve, and combined with the changing trend of the target well during actual use, the changes of various fracturing parameters in the measured data of the target well are obtained, and the causes of the changes are analyzed through the changes.

[0071] In some embodiments of the present application, according to the first characteristic curve in the sensitivity analysis result and the variation relationship between various fracturing parameters and the first characteristic curve, the second characteristic curve corresponding to the target well is analyzed to obtain the optimal cluster spacing.

[0072] In the embodiment of the present application, during the analysis of the second characteristic curve, the connectivity relationship between every two adjacent fractures in the target well can be obtained, and then the optimal cluster spacing corresponding to the target well can be determined according to the connectivity relationship between every two adjacent fractures in the target well. For example, when the connectivity relationship between the fracture corresponding to the target well and the adjacent fractures is that the main fracture is connected to the secondary fracture, the cluster spacing corresponding to the target well is the optimal cluster spacing. When the connectivity relationship between the fracture corresponding to the target well and the adjacent fractures is not connected or the connectivity relationship between the fractures is that all are main fractures or there is matrix connectivity, the cluster spacing corresponding to the target well is not the optimal cluster spacing.

[0073] When there is no connection between every two adjacent fractures in the target well, there is an isolation zone between every two fractures in the target well, that is, the spacing between the two fractures is too large. In this case, the target well can be repeatedly fractured or the fracturing intensity can be increased to reduce the cluster spacing between every two fractures, so that the previously unusable reserves between each level of fractures in the prior art can be effectively used in the actual production process.

[0074] Furthermore, when every two adjacent fractures in the target well are connected, the second characteristic curve is analyzed according to the first characteristic curve in the sensitivity analysis result and the variation relationship between each fracturing parameter and the first characteristic curve to obtain the permeability between every two adjacent fractures in the target well, and then the control area between every two adjacent fractures in the target well is determined according to the permeability between every two adjacent fractures in the target well. When every two adjacent fractures in the target well are connected by the main fracture control area, the distance between the two fractures is too small, and the transformation is too sufficient, resulting in unnecessary increase in construction costs. It is necessary to avoid this in new fracturing wells, or adopt measures that can increase the fracture spacing. When every two adjacent fractures in the target well are connected by the main fracture control area and the secondary fracture control area, or by the secondary fracture control area, the distribution spacing between the two adjacent fractures is optimal, and there is no need to adjust the spacing between the fractures.

[0075] The method for obtaining the permeability between every two adjacent fractures in the target well is to analyze the second characteristic curve corresponding to the permeability according to the first characteristic curve in the sensitivity analysis result and the variation relationship between each fracturing parameter and the first characteristic curve, obtain the permeability between every two fractures in the target well, and determine whether there is only an area with a permeability in the first numerical range between every two fractures corresponding to the target well. If there is only an area with a permeability in the first numerical range between the fractures corresponding to the target well, it is determined that the control area between every two fractures corresponding to the target well is only the main fracture control area.

[0076] It should be noted that in the numerical well test model, the first characteristic curve corresponding to the well with the main fracture control area between every two fractures and the influence of permeability on the first characteristic curve are obtained. The second characteristic curve is analyzed to obtain the permeability between every two fractures corresponding to the target well.

[0077] In some embodiments of the present application, according to the first characteristic curve in the sensitivity analysis result and the change relationship between each fracturing parameter and the first characteristic curve, the second characteristic curve corresponding to the segment spacing is analyzed to obtain the connectivity relationship between every two cracks corresponding to the target well. If the connectivity relationship between every two cracks corresponding to the target well is not connected, the input of proppant and fracturing fluid in the target well can be increased to increase the pressure in the target well, thereby making the connectivity relationship between every two cracks in the target well connected. If the connectivity relationship between every two cracks corresponding to the target well is connected, it is determined that the amount of proppant or fracturing fluid used in the target well is appropriate, and the pressure of the proppant or fracturing fluid used in the target well is not adjusted.

[0078] The embodiment of the present application can determine the cluster spacing, segment spacing, fracture half-length or permeability based on the sensitivity analysis results and the second characteristic curve, and then determine whether the fractures in the target well are connected. When the fractures in the target well are not connected, the cluster spacing, segment spacing, fracture half-length or permeability of the target well is adjusted to increase the production of the target well. At the same time, the second characteristic curve in the embodiment of the present application is obtained based on the measured data of the target well. Therefore, the method provided in the embodiment of the present application can accurately determine the cluster spacing, segment spacing, fracture half-length and permeability of the target well, thereby avoiding the problem that the prior art needs to obtain the cluster spacing, segment spacing, fracture half-length and permeability through a complex calculation process.

[0079] In some embodiments of the present application, the third characteristic curve corresponding to the first well and the fourth characteristic curve corresponding to the second well are analyzed by the sensitivity analysis result to determine the first fracture half-length corresponding to the first well and the second fracture half-length corresponding to the second well. If the sum of the first fracture half-length and the second fracture half-length is less than the reference lane spacing, it is determined that there is no influence between the first well and the second well. If the first fracture half-length and the second fracture half-length are greater than or equal to the reference lane spacing, it is determined that there is mutual influence between the first well and the second well.

[0080] Alternatively, the third characteristic curve corresponding to the first well and the fourth characteristic curve corresponding to the second well are analyzed through the sensitivity analysis result to determine the first well control range corresponding to the first well and the second well control range corresponding to the second well. If the sum of the width of the first well control range and the width of the second well control range is less than 2 times the reference lane spacing, it is determined that there is no influence between the first well and the second well. If the sum of the width of the first well control range and the width of the second well control range is greater than or equal to 2 times the reference lane spacing, it is determined that there is mutual influence between the first well and the second well.

[0081] The first well can be Figure 3 The first well in the first row of wells shown is well 1, and the second well may be Figure 3 The second well in the first row of wells is shown, namely, well 2, where the position of the second well corresponds to the position of the first well, that is, the second well is located to the right of the first well. The reference lane spacing is the lane spacing required in the actual production process, which is equal to the distance between the first well and the second well, such as Figure 3 The width of the first well control range is equal to twice the half length of the fracture, that is, the width of the well control range is equal to the fracture length.

[0082] In some embodiments of the present application, the target well's fracture half-length, well control range, permeability, and distribution of three control areas can be analyzed to determine the abnormal parameters of the target well's fracturing construction, wherein the three control areas include the primary fracture control area, the secondary fracture control area, and the matrix control area. The specific steps are: according to the measured data of the target well, a second characteristic curve is obtained, and according to the influence of the fracture half-length, well control range, fracture half-length, well control range, permeability, and three regional distribution on the first characteristic curve, the fracture half-length, well control range, permeability, and three regional distribution corresponding to the second characteristic curve are predicted, and then the abnormal parameters of the target well's fracturing construction are determined.

[0083] The target well is any well in the target well control area. The well control range refers to the range of fluid that can be controlled by a single well, so that the single well can obtain a larger production within the controllable range.

[0084] In the implementation, by performing sensitivity analysis on the first characteristic curve, the influence of the half-length of the fracture, the half-length of the well control range, the permeability, and the distribution of the three control areas on the first characteristic curve is determined, and then the sensitivity analysis results are obtained. According to the sensitivity analysis results, the second characteristic curve is analyzed to predict the half-length of the fracture, the well control range, the permeability, and the distribution of the three areas corresponding to the second characteristic curve. According to the half-length of the fracture, the well control range, the permeability, and the distribution of the three areas corresponding to the second characteristic curve, the abnormal parameters of the fracturing construction of the target well are determined.

[0085] In some embodiments of the present application, the production capacity values ​​of all wells in the target well control area are determined, and the well with the largest production capacity value and the well with the smallest production capacity value are determined among these wells, and are respectively used as the well with the highest production capacity and the well with the lowest production capacity; based on the production capacity values ​​of all wells in the target well control area, the average production capacity value of the target well control area is determined, and then the well with the production capacity value closest to the average production capacity value is determined and is used as the well with average production capacity; the various fracturing parameters of the well with the highest production capacity are compared with the various fracturing parameters of the well with average production capacity to obtain the fracturing parameters that increase the production capacity; the various fracturing parameters of the well with the lowest production capacity are compared with the various fracturing parameters of the well with average production capacity to obtain the fracturing parameters that reduce the production capacity.

[0086] The capacity value is used to indicate the size of the capacity, and the capacity value of each well can be determined based on the total gas volume produced by each well. For example, if the total gas volume produced by a well is 100 million cubic meters, the capacity value of the well is 100 million cubic meters.

[0087] In implementation, the productivity of all wells in the target well control area is determined, the productivity values ​​of all wells in the target well control area are obtained, and the gas wells with the best productivity, the gas wells with the worst productivity, and the wells with average productivity are determined among these wells. The various fracturing parameters of the well with the highest productivity are compared with the various fracturing parameters of the wells with average productivity to obtain the difference degree of each fracturing parameter, and the fracturing parameters with a difference degree greater than a preset threshold are used as fracturing parameters that can increase productivity; the various fracturing parameters of the well with the lowest productivity are compared with the various fracturing parameters of the wells with average productivity to obtain the difference degree of each fracturing parameter, and the fracturing parameters with a difference degree greater than a preset threshold are used as fracturing parameters that can reduce productivity. According to the fracturing parameters that increase productivity and the fracturing parameters that reduce productivity, the various fracturing parameters corresponding to the wells with poor productivity are improved.

[0088] Among them, the well with poor productivity may be a well whose productivity value is lower than the average productivity value.

[0089] In some embodiments of the present application, any well in the target well control area is selected as the target well, and the production pressure and well control volume of the target well under different production systems are determined. The obtained production pressures are arranged in order from large to small, and the well control volumes are arranged in the order of production pressure. In the above two arrangement orders, a well control volume greater than the next well control volume is determined, and the production pressure difference value corresponding to the well control volume is determined as the critical production pressure difference value.

[0090] Among them, when the production differential pressure value is less than the critical production differential pressure value, the production of the target well increases as the production differential pressure value increases. When the production differential pressure value is equal to the critical production differential pressure value, the production of the target well is the maximum. When the production differential pressure value is greater than the critical production differential pressure value, the production of the target well decreases as the production differential pressure value increases.

[0091] Among them, the well control volume is the product of the well control range and the height of the well, and the production pressure difference is the difference between the formation pressure and the bottom hole flowing pressure.

[0092] It should be noted that different production systems lead to different production pressure differences. Under a production system with a large production pressure difference, cracks in the target well will be closed, and events such as sand production that cause changes in the fracture network will occur, which will lead to a decrease in the well control volume of the target well, ultimately affecting the production of the target well. The embodiment of the present application detects various data of wells under different production systems to obtain the maximum production pressure difference, thereby preventing the production pressure difference from being too large and causing crack closure.

[0093] All the above optional technical solutions can be arbitrarily combined to form optional embodiments of the present application, which will not be described one by one here.

[0094] The above description is only an optional embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for analyzing shale gas multi-stage fracturing horizontal well testing, characterized in that: The method comprises: Establishing a numerical well test model of the target well control area, wherein the numerical well test model includes a plurality of fracturing parameters, wherein the plurality of fracturing parameters include the permeability corresponding to each unit area in the target well control area and the parameters of each fracture in the target well control area; Based on the permeability of each unit area in the numerical well test model, a plurality of different types of control areas are divided in the numerical well test model; Based on the control area type between every two adjacent fractures in the numerical well testing model, the numerical well testing model is adjusted to obtain an adjusted numerical well testing model; Performing sensitivity analysis on the adjusted numerical well testing model to obtain sensitivity analysis results; The sensitivity analysis result is compared with the measured data corresponding to the target well to determine the fracturing parameters that need to be adjusted for the target well.

2. The method according to claim 1, characterized in that The control zone types include: one or more of a primary fracture control zone, a secondary fracture control zone, a matrix control zone, and a stagnant flow control zone.

3. The method according to claim 2, characterized in that Based on the permeability of each unit area in the numerical well test model, a plurality of different types of control areas are divided in the numerical well test model, including: Determine the area where the permeability is within the first numerical range as the main fracture control area; Determine the area where the permeability is within the second numerical range as the secondary fracture control area; Determine the region where the permeability is within the third numerical range as the matrix control region; Determine the region where the permeability is within a fourth numerical range as the stagnant flow control region; Among them, the permeability of the main fracture control zone, the permeability of the secondary fracture control zone, the permeability of the matrix control zone and the permeability of the stagnant flow control zone become smaller in sequence.

4. The method according to claim 3, characterized in that The method further comprises: If the no-flow control zone exists in the control region between two adjacent fractures, it is determined that the connection relationship between the two adjacent fractures is not connected.

5. The method according to claim 4, characterized in that The method further comprises: If the matrix control region exists in the control area between two adjacent fractures, it is determined that the connection relationship between the two adjacent fractures is disconnected.

6. The method according to claim 5, characterized in that The method further comprises: If the control region between two adjacent fractures only includes the main fracture control region, it is determined that the connection relationship between the two adjacent fractures is connected.

7. The method according to claim 6, characterized in that The method further comprises: If the control region between two adjacent fractures includes the primary fracture control region and the secondary fracture control region, it is determined that the connection relationship between the two adjacent fractures is connected.

8. The method according to claim 1, characterized in that The step of performing sensitivity analysis on the adjusted numerical well testing model to obtain sensitivity analysis results includes: Obtaining a first characteristic curve corresponding to each fracturing parameter of the adjusted numerical well testing model; A sensitivity analysis result is obtained by performing a sensitivity analysis on the first characteristic curve.

9. The method according to claim 1, characterized in that: Determining the fracturing parameters that need to be adjusted for the target well according to the sensitivity analysis result and the measured data corresponding to the target well includes: Based on the measured data of the target well, obtaining a second characteristic curve corresponding to various fracturing parameters in the target well; Based on the sensitivity analysis result and the second characteristic curve, the fracturing parameters that need to be adjusted for the target well are determined.

10. The method according to claim 8, characterized in that The fracturing parameters include: one or more of the area of ​​the unit region corresponding to the permeability, the number of fractures, the length of the fractures and the reservoir parameters.

Images