Method and device for optimizing fracture parameters of fractured horizontal well

Abstract

The invention discloses a method and a device for optimizing fracture parameters of a fractured horizontal well. The method comprises the following steps: determining a dimensionless proppant index according to main control parameters influencing the productivity index of a horizontal well to be fractured; based on the first dimensionless optimization chart of the horizontal well to be fractured, the predetermined productivity index of the horizontal well to be fractured and the dimensionless proppant index, the optimal number of fractures of the horizontal well to be fractured is determined; according to the determined optimal fracture number of the horizontal well to be fractured and preset well control physical property parameters of the horizontal well to be fractured, optimal fracture control physical property parameter indexes of the horizontal well to be fractured are determined; and determining the optimal dimensionless fracture conductivity of the horizontal well to be fractured based on the second dimensionless optimization chart of the horizontal well to be fractured, a predetermined dimensionless proppant index and the optimal fracture control physical property parameter index of the horizontal well to be fractured. The optimal crack parameter combination can be quickly and accurately determined under the condition that a large amount of experimental simulation is not carried out, and the working efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and natural gas development, and in particular to a method and device for optimizing crack parameters of a fractured horizontal well. Background Art

[0002] Horizontal well drilling and staged fracturing are the primary technologies for developing unconventional oil and gas reservoirs. During fracturing, hydraulic pressure fractures the rock, creating multiple horizontal and vertical fractures along the wellbore. A certain amount of proppant, such as quartz sand and ceramsite, is then moved into the fractures to prevent the rock from reclosing. Each fracture has a specific height, length, and conductivity. By designing different fracture parameter combinations, such as combining four parameters—number of fractures, width, length, and conductivity—it is possible to control the contact area between fractures and the formation, the interference between fractures, the sealing effect of formation boundaries, and the relationship between fractures and formation inflow and outflow, thereby achieving different horizontal well productivity indices.

[0003] Given a given well control volume and proppant volume, when an optimal combination of fracture parameters within a horizontal well is achieved, four seepage relationships—fracture-formation contact area, formation boundary sealing, mutual interference between fractures, and inflow and outflow dynamics between fractures and formations—are balanced. The horizontal well productivity index reaches its maximum value. A higher horizontal well productivity index indicates higher production capacity and better actual production results. Summary of the Invention

[0004] Existing technologies often design different fracture parameter combinations using methods such as enumeration, orthogonal experiments, and optimization algorithms. The optimal fracture parameter combination is determined by comparing the productivity indicators of fractured horizontal wells under different fracture parameter combinations. However, the fracturing parameters that affect horizontal well productivity are numerous and not independent. Enumeration and other techniques can generate an excessively large number of fracture parameter combinations. The optimal combination obtained from these enumerated fracture parameter combinations may not fully cover all parameters that affect horizontal well productivity. Designing fracture parameter combinations using intelligent optimization algorithms such as genetic algorithms results in a dramatic increase in the search space as the number of fractures increases. In short, existing fracture parameter optimization methods require processing large amounts of data, resulting in slow and inefficient optimization processes. Furthermore, the optimized fracture parameter combinations cannot meet the requirements for optimizing productivity indicators.

[0005] In view of the above problems, the present invention is proposed to provide a method and device for optimizing fracture parameters of a fractured horizontal well that overcomes the above problems or at least partially solves the above problems.

[0006] In a first aspect, an embodiment of the present invention provides a method for optimizing fracture parameters of a fractured horizontal well, comprising:

[0007] Determine the dimensionless proppant index based on the main control parameters that affect the productivity index of the horizontal well to be fractured;

[0008] Determining an optimal number of fractures in the horizontal well to be fractured based on a first dimensionless optimization map of the horizontal well to be fractured, a predetermined productivity index of the horizontal well to be fractured, and the dimensionless proppant index; the first dimensionless optimization map including a correspondence between the number of fractures, the productivity index of the horizontal well to be fractured, and the dimensionless proppant index;

[0009] Determining optimal fracture control physical property parameter indicators for the horizontal well to be fractured based on the determined optimal number of fractures for the horizontal well to be fractured and the preset well control physical property parameters for the horizontal well to be fractured;

[0010] The optimal dimensionless fracture conductivity of the horizontal well to be fractured is determined based on a second dimensionless optimization map of the horizontal well to be fractured, a predetermined dimensionless proppant index, and an optimal fracture control physical property parameter index of the horizontal well to be fractured; the second dimensionless optimization map includes a correspondence between the fracture control physical property parameter index, the optimal dimensionless fracture conductivity, and the dimensionless proppant index.

[0011] In some optional embodiments, the dimensionless proppant index is determined based on the main control parameters that affect the productivity index of the horizontal well to be fractured, including:

[0012] Obtain fracture permeability and reservoir permeability from geological interpretation data of the horizontal well to be fractured;

[0013] Obtaining the well-controlled volume of the horizontal well to be fractured based on the geological interpretation data and well test interpretation data of the horizontal well to be fractured;

[0014] A dimensionless proppant index is determined according to the fracture permeability, reservoir permeability, well control volume, and a preset proppant volume pumped into the fracture.

[0015] In some optional embodiments, the dimensionless proppant index N is determined by the following formula: prop :

[0016]

[0017] Among them, k f is the fracture permeability, k m is the reservoir permeability, V res is the preset volume of proppant pumped into the fracture, V prop is the well-controlled volume of the horizontal well to be fractured.

[0018] In some optional embodiments, determining the optimal fracture control physical property parameter index of the horizontal well to be fractured based on the determined optimal number of fractures of the horizontal well to be fractured and the preset well control physical property parameters of the horizontal well to be fractured includes:

[0019] Determining the optimal fracture control area aspect ratio of the horizontal well to be fractured based on the determined optimal number of fractures in the horizontal well to be fractured and the preset well control area aspect ratio of the horizontal well to be fractured;

[0020] The length and width of the optimal seam control area λ opt The ratio is determined by the following formula: opt =Λn fprop , where Λ is the aspect ratio of the well control area of ​​the preset horizontal well to be fractured, n fprop is the optimal number of fractures in the horizontal well to be fractured.

[0021] In some optional embodiments, the above method further includes:

[0022] The optimal fracture length and the optimal fracture conductivity of the horizontal well to be fractured are determined based on the determined optimal fracture number and the optimal dimensionless fracture conductivity of the horizontal well to be fractured.

[0023] In some optional embodiments, determining the optimal fracture length and optimal fracture conductivity of the horizontal well to be fractured based on the determined optimal number of fractures and the optimal dimensionless fracture conductivity of the horizontal well to be fractured includes:

[0024] Obtain fracture permeability and reservoir permeability from geological interpretation data of the horizontal well to be fractured;

[0025] Obtain the well-controlled volume and effective reservoir thickness of the horizontal well to be fractured based on the geological interpretation data and well test interpretation data of the horizontal well to be fractured;

[0026] The optimal fracture length and optimal fracture conductivity of the horizontal well to be fractured are determined based on the optimal number of fractures, optimal dimensionless fracture conductivity, fracture permeability, reservoir permeability, well-controlled volume and effective reservoir thickness of the horizontal well to be fractured.

[0027] In some optional embodiments, the optimal fracture length L of the horizontal well to be fractured is fopt Determined by the following formula:

[0028]

[0029] Among them, C fDopt is the optimal dimensionless fracture conductivity of the horizontal well to be fractured, n fprop is the optimal number of fractures in the horizontal well to be fractured, and h is the effective reservoir thickness of the horizontal well to be fractured;

[0030] Optimal fracture conductivity F copt By the following formula:

[0031]

[0032] Among them, C fDopt is the optimal dimensionless fracture conductivity of the horizontal well to be fractured, n fprop is the optimal number of fractures in the horizontal well to be fractured, and h is the effective reservoir thickness of the horizontal well to be fractured.

[0033] In some optional embodiments, the above method further includes:

[0034] The determined optimal number of fractures and optimal fracture-controlling physical property parameter ratio of the horizontal well to be fractured are used in the fracturing operation of the horizontal well to be fractured, so as to form multiple evenly distributed fractures along the wellbore of the horizontal well to be fractured.

[0035] In a second aspect, an embodiment of the present invention provides a device for optimizing fracture parameters of a hydraulically fractured horizontal well, comprising:

[0036] The dimensionless proppant index determination module is used to determine the dimensionless proppant index according to the main control parameters that affect the productivity index of the horizontal well to be fractured.

[0037] The module for determining the number of fractures is used to determine the optimal number of fractures in the horizontal well to be fractured based on a first dimensionless optimization map of the horizontal well to be fractured, a predetermined productivity index and a dimensionless proppant index of the horizontal well to be fractured; the first dimensionless optimization map includes a correspondence between the number of fractures, the productivity index of the horizontal well to be fractured and the dimensionless proppant index.

[0038] The fracture control physical property parameter index determination module is used to determine the optimal fracture control physical property parameter index of the horizontal well to be fractured based on the determined optimal number of fractures of the horizontal well to be fractured and the preset well control physical property parameters of the horizontal well to be fractured.

[0039] A fracture conductivity determination module is configured to determine the optimal dimensionless fracture conductivity of the horizontal well to be fractured based on a second dimensionless optimization map for the horizontal well to be fractured, a predetermined dimensionless proppant index, and an optimal fracture-control physical property parameter index for the horizontal well to be fractured; the second dimensionless optimization map includes a correspondence between the fracture-control physical property parameter index, the optimal dimensionless fracture conductivity, and the dimensionless proppant index.

[0040] An embodiment of the present invention further provides a computer storage medium storing computer executable instructions. When the computer executable instructions are executed by a processor, a method for optimizing fracture parameters of a fractured horizontal well is implemented.

[0041] An embodiment of the present invention further provides a computer device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements a method for optimizing fracture parameters of a horizontal well under fracture when executing the program.

[0042] The beneficial effects of the above technical solutions provided by the embodiments of the present invention include at least:

[0043] This method determines a dimensionless proppant index based on a main control parameter that affects the productivity index of a horizontal well to be fractured. There are many parameters that affect the productivity index of a horizontal well to be fractured, and the main control parameter has a great influence on the productivity index of the horizontal well to be fractured, thereby reducing the scope and number of fracture parameter enumerations. Based on a first dimensionless optimization map of the horizontal well to be fractured, a predetermined productivity index of the horizontal well to be fractured, and the dimensionless proppant index, the optimal number of fractures in the horizontal well to be fractured is determined. The first dimensionless optimization map includes a correspondence between the number of fractures, the productivity index of the horizontal well to be fractured, and the dimensionless proppant index. By utilizing the correspondence of the first dimensionless map, the optimal number of fractures can be quickly determined without the need for a large number of scheme simulations and parameter enumerations, and without the problem of an increase in the search space due to an increase in the number of fractures, thereby saving working time and improving working efficiency.

[0044] Based on the determined optimal number of fractures and the preset well control physical property parameters of the horizontal well to be fractured, the optimal fracture control physical property parameter index of the horizontal well to be fractured is determined; based on the second dimensionless optimization plate of the horizontal well to be fractured, the predetermined dimensionless proppant index and the optimal fracture control physical property parameter index of the horizontal well to be fractured, the optimal dimensionless fracture conductivity of the horizontal well to be fractured is determined; the second dimensionless optimization plate includes the corresponding relationship between the fracture control physical property parameter index, the optimal dimensionless fracture conductivity and the dimensionless proppant index. Through the optimization method of the present invention, based on the relationship between each dimensionless optimization plate, the fracture parameter optimization process of the fractured horizontal well is designed, which can quickly and efficiently obtain the maximum horizontal well productivity index. Without the help of a large number of scheme simulations, the optimal fracture parameter combination of the fractured horizontal well under any geological engineering background can be determined, which greatly improves the work efficiency of the fractured horizontal well design.

[0045] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purposes and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings.

[0046] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0048] Figure 1This is a flow chart of the method for optimizing fracture parameters of a horizontal well under fracture in Example 1 of the present invention;

[0049] Figure 2 Schematic diagram of the first dimensionless optimization plate in Example 1 of the present invention;

[0050] Figure 3 Schematic diagram of the second dimensionless optimization plate in Example 1 of the present invention;

[0051] Figure 4 This is a schematic structural diagram of a device for optimizing fracture parameters of a horizontal well under hydraulic fracturing according to a first embodiment of the present invention;

[0052] Figure 5 This is an example diagram of fracture distribution in a horizontal well in Example 2 of the present invention; DETAILED DESCRIPTION

[0053] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0054] When the fracture parameters in a horizontal well reach a certain optimal combination, four seepage relationships, including the contact area between the fracture and the formation, the influence of the formation boundary closure, the mutual interference between the fractures, and the inflow and outflow dynamics between the fracture and the formation, can be balanced, and the horizontal well productivity index reaches its maximum value. Existing methods for designing fracture parameter combinations have the disadvantages of complex design processes, numerous parameters affecting the horizontal well productivity index, and the need for a large number of experimental simulations. The fracture parameter combinations optimized using existing methods cannot meet the needs of optimizing productivity indicators and have low work efficiency.

[0055] In order to solve the problems in the prior art of large amount of processed data, slow optimization process speed and low optimization efficiency, an embodiment of the present invention provides a method for optimizing fracture parameters of a fractured horizontal well.

[0056] Example 1

[0057] The first embodiment of the present invention provides a method for optimizing fracture parameters of a horizontal well fracture, the process of which is as follows: Figure 1 As shown, the following steps are included:

[0058] Step S101: determining a dimensionless proppant index according to a main control parameter affecting the productivity index of a horizontal well to be fractured.

[0059] Step S102: determining the optimal number of fractures in the horizontal well to be fractured based on the first dimensionless optimization chart of the horizontal well to be fractured, the predetermined productivity index of the horizontal well to be fractured, and the dimensionless proppant index.

[0060] Step S103: determining optimal fracture control physical property parameter indicators of the horizontal well to be fractured according to the determined optimal number of fractures of the horizontal well to be fractured and the preset well control physical property parameters of the horizontal well to be fractured.

[0061] Step S104: determining the optimal dimensionless fracture conductivity of the horizontal well to be fractured based on the second dimensionless optimization chart of the horizontal well to be fractured, the predetermined dimensionless proppant index and the optimal fracture control physical property parameter index of the horizontal well to be fractured.

[0062] In an optional embodiment, for a horizontal well, the productivity index may include a single fracture productivity index (J DSF ) and horizontal well productivity index (J DMF ), single fracture productivity index (J DSF ) refers to the productivity index corresponding to each fracture; horizontal well productivity index (J DMF ) refers to the sum of the productivity indices of multiple fractures in a horizontal well. The main control parameters affecting the productivity index of a fractured horizontal well can be derived from the geological interpretation data and well test interpretation data of the horizontal well to be fractured. The main control parameters affecting the productivity index of a fractured horizontal well may include, but are not limited to, at least one of: fracture permeability, reservoir permeability, well control volume, proppant volume, number of fractures, fracture height, fracture length, fracture conductivity, and fracture width. Among them:

[0063] Number of cracks (n f ), mainly refers to the number of fractures distributed laterally along the wellbore formed after fracturing, which is an integer;

[0064] Crack height (h f ) and crack length (L f ), mainly refers to the width and length of the fracture formed by proppant support;

[0065] Fracture conductivity (F c ), refers to the product of crack permeability and crack width (k f ×w f );

[0066] Formation permeability (k m ), refers to the formation permeability within the well-controlled volume;

[0067] Proppant volume (V prop ), refers to the volume of proppant pumped into the fracture, which can be set during fracturing design;

[0068] Well control volume (V res), obtained from geological interpretation or well test interpretation, refers to the reservoir volume effectively produced by the horizontal well, that is, the reservoir width (Y e )×reservoir length(X e )×reservoir thickness (h).

[0069] In the above step S101, different main control parameters can be selected to determine the dimensionless proppant index based on the main control parameters that affect the productivity index of the horizontal well to be fractured. A preferred determination method includes: obtaining the fracture permeability and reservoir permeability from the geological interpretation data of the horizontal well to be fractured; obtaining the well control volume of the horizontal well to be fractured based on the geological interpretation data and well test interpretation data of the horizontal well to be fractured; and determining the dimensionless proppant index based on the fracture permeability, reservoir permeability, well control volume and the preset proppant volume pumped into the fracture.

[0070] The reservoir permeability in step S101 refers to the reservoir permeability within the well control volume, and the well control volume refers to the volume effectively mobilized by the horizontal well to be fractured. In addition, in this preferred determination method, to determine the dimensionless proppant index, it is necessary to screen out the fracture permeability, reservoir permeability, well control volume, and the preset proppant volume pumped into the fracture from the main control parameters as the basis for data calculation in the optimization process. If it is necessary to determine other basic data in the optimization process, other main control parameters can be selected based on the calculation formula corresponding to the data or the calculation method such as the correlation between the data. For example, in this embodiment, the dimensionless proppant index N is calculated according to the following formula prop :

[0071]

[0072] Among them, k f is the fracture permeability, k m is the preset reservoir permeability, V res is the preset volume of proppant pumped into the fracture, V prop is the well-controlled volume of the horizontal well to be fractured.

[0073] In some optional embodiments, a first dimensionless optimization chart of the horizontal well to be fractured can be pre-established. The first dimensionless optimization chart can be used to conveniently determine the optimal number of fractures by combining the productivity index and the dimensionless proppant index. The first dimensionless optimization chart in step S102 includes the corresponding relationship between the number of fractures, the productivity index of the horizontal well to be fractured, and the dimensionless proppant index. Figure 2 As shown, Figure 2 The first dimensionless optimization plate in reflects different dimensionless proppant index N prop Number of lower cracks n f and the productivity index J of the horizontal well to be fractured DMF The corresponding relationship between Figure 2The derivative of the horizontal well productivity index marked on the right vertical axis is to facilitate the determination of the optimal number of fractures. When the derivative of the horizontal well productivity index in the first dimensionless optimization plate is zero, the horizontal well productivity index reaches its maximum value. At this time, the number of fractures corresponding to the horizontal axis is the optimal number of fractures n. fprop ,Right now Figure 2 The horizontal coordinates of the three dots in the image correspond to the number of cracks. Figure 2 The curves formed by the three solid lines from top to bottom are the dimensionless proppant index N prop The curves corresponding to the horizontal well productivity index for values ​​of 1000, 50, and 5 are shown. The three dashed lines represent the derivatives of the horizontal well productivity index for different dimensionless proppants. By determining the dimensionless proppant index and then using the first dimensionless optimization chart, the optimal number of fractures can be quickly determined during actual construction, resulting in the optimal parameter data for the fracture parameter combination. When fracturing the horizontal well using this optimal data, the horizontal well productivity index is maximized.

[0074] In some optional embodiments, in step S103, the optimal fracture control physical property parameter index of the horizontal well to be fractured can be determined based on the optimal number of fractures and the selected well control physical property parameters. The well control physical property parameters used to determine the optimal fracture control physical property parameter index can be selected according to the needs. For example, the well control area aspect ratio can be selected, and the corresponding optimal fracture control physical property parameter index can be the optimal fracture control area aspect ratio. Of course, other well control physical property parameters can also be selected to calculate the corresponding optimal fracture control physical property parameter index. In the embodiment of the present invention, a preferred solution for determining the optimal fracture control physical property parameter index of the horizontal well to be fractured may include:

[0075] Determining the optimal fracture control area aspect ratio of the horizontal well to be fractured based on the determined optimal number of fractures in the horizontal well to be fractured and the preset well control area aspect ratio of the horizontal well to be fractured;

[0076] Optimal seam control area length and width λ opt The ratio is determined by the following formula: opt =Λn fprop , where Λ is the aspect ratio of the well control area of ​​the preset horizontal well to be fractured, n fprop is the optimal number of fractures in the horizontal well to be fractured.

[0077] Based on the optimal number of fractures and the preset well control area aspect ratio, the optimal fracture control area aspect ratio of each fracture can be obtained. Once the optimal fracture control area aspect ratio is determined, each fracture in the horizontal well can be fractured according to this ratio, so that the final horizontal well productivity index is maximized. The parameters involved in the design process provided in this embodiment are the main control parameters that affect the productivity of the horizontal well. The number of parameters is small. Compared with the existing enumeration method for optimizing parameters, there is no need to enumerate many parameter combinations and then select the optimal parameter combination for fracturing. The enumeration method requires listing a variety of different parameter combinations, which increases the workload on the one hand and may not cover all fracture parameter combinations on the other hand. This will make the obtained parameter combination data inaccurate and unable to maximize the horizontal well productivity index in actual production, resulting in a waste of resources. The fracture parameter optimization method provided in this embodiment can calculate the optimal parameter data according to actual conditions under preset conditions, reducing the workload while improving work efficiency. The data obtained is also more accurate and can be applied to actual production.

[0078] In some optional embodiments, a second dimensionless optimization chart can be pre-established in step S104. Based on the second dimensionless optimization chart, the dimensionless proppant index and the optimal fracture control physical property parameter index can be combined to conveniently determine the optimal dimensionless fracture conductivity of the horizontal well to be fractured. Optionally, the second dimensionless optimization chart includes the corresponding relationship between the fracture control physical property parameter index, the optimal dimensionless fracture conductivity and the dimensionless proppant index. The second dimensionless optimization chart can be found in Figure 3 As shown, Figure 3 The second dimensionless optimization plate in the figure reflects the different dimensionless proppant index N prop The physical property parameters of the fracture control and the optimal dimensionless fracture conductivity C fDopt The corresponding relationship between them, the horizontal axis seam control area aspect ratio λ is the seam control physical parameter index, Figure 3 The three curves in the figure are the dimensionless proppant index N from top to bottom. prop The curves corresponding to the values ​​of 1000, 50, and 5 are shown. When determining the optimal dimensionless fracture conductivity, based on the second dimensionless optimization chart, on the curve corresponding to the preset dimensionless proppant index, the optimal fracture-control physical property parameter, i.e., the optimal fracture-control area aspect ratio, obtained in step S103, can be used to determine the optimal dimensionless fracture conductivity under the corresponding dimensionless proppant index and optimal fracture-control area aspect ratio. Fracture conductivity refers to the ability of a proppant-filled fracture to pass fluid under the influence of reservoir in-situ stress. Fracture conductivity is generally expressed as the product of fracture width and fracture permeability.

[0079] The fracture parameter combination consisting of the optimal number of fractures, the optimal fracture-controlling physical property index, and the optimal dimensionless fracture conductivity obtained by the fracture parameter optimization method of an embodiment of the present invention can maximize the productivity index of the horizontal well to be fractured. This method can determine the optimal fracture parameter combination for a fractured horizontal well under any geological engineering background without resorting to a large number of simulation scenarios, greatly improving the efficiency of fracturing design.

[0080] The specific implementation process of optimizing various crack parameters is described below through specific embodiments:

[0081] For example, the fracture permeability k is obtained from the geological interpretation data of the horizontal well to be fractured. f =10 4 mD, reservoir permeability k m =0.1mD, obtain the well control volume V of the horizontal well to be fractured prop =2500m 3 , preset proppant volume V pumped into the fracture res =10 7 m 3 The preset aspect ratio of the well control area of ​​the horizontal well to be fractured is Λ=1.5.

[0082] According to the crack permeability k f , reservoir permeability k m , horizontal well control volume V prop and the preset proppant volume V pumped into the fracture res , the dimensionless proppant volume is determined by the following formula:

[0083] After determining the dimensionless proppant index, Figure 2 The first dimensionless optimization chart shown in FIG, can determine the horizontal well productivity index and the number of fractures on the curve with a dimensionless proppant index of 50, because when the derivative of the horizontal well productivity index is 0, the horizontal well productivity index reaches the highest, and the corresponding number of fractures is 40 at this time, which is the optimal number of fractures. Figure 2 The first dimensionless optimization diagram shown shows that when the dimensionless proppant index is 50, the optimal number of fractures is 40. Under such conditions, the horizontal well productivity index can reach its maximum value.

[0084] According to the determined maximum number of fractures and the preset well control area length ratio of the horizontal well to be fractured, the optimal fracture control area length-to-width ratio is determined by the following formula: opt =Λn fopt =1.5×40=70.

[0085] After determining the optimal length-to-width ratio of the seam control area, based on Figure 3The second dimensionless optimization chart and the predetermined dimensionless proppant index are used to determine the optimal dimensionless fracture conductivity of the horizontal well to be fractured. Figure 3 On the curve with a dimensionless support-squeezing index of 50, it can be determined that when the optimal fracture-controlled area aspect ratio is 70, the corresponding optimal dimensionless fracture conductivity is 1. Through the above optimization process, it can be determined that the fracture parameter combination of 40 fractures, a fracture-controlled area aspect ratio of 70, and a dimensionless fracture conductivity of 1 maximizes the productivity index of the horizontal well to be fractured. This method, by combining data with the dimensionless optimization chart, can quickly determine the optimal solution for each parameter. The method provided in this embodiment is efficient and accurate, and can be applied in practical applications.

[0086] In another optional embodiment, the above-mentioned method for optimizing fracture parameters of a hydraulically fractured horizontal well may further include the following steps:

[0087] The optimal fracture length and the optimal fracture conductivity of the horizontal well to be fractured are determined based on the determined optimal fracture number and the optimal dimensionless fracture conductivity of the horizontal well to be fractured.

[0088] In the above steps, the optimal fracture length and the optimal fracture conductivity of the horizontal well to be fractured are determined based on the determined optimal number of fractures and the optimal dimensionless fracture conductivity of the horizontal well to be fractured, including:

[0089] Obtain fracture permeability and reservoir permeability from geological interpretation data of the horizontal well to be fractured;

[0090] Obtain the well-controlled volume and effective reservoir thickness of the horizontal well to be fractured based on the geological interpretation data and well test interpretation data of the horizontal well to be fractured;

[0091] The optimal fracture length and optimal fracture conductivity of the horizontal well to be fractured are determined based on the optimal number of fractures, optimal dimensionless fracture conductivity, fracture permeability, reservoir permeability, well-controlled volume and effective reservoir thickness of the horizontal well to be fractured.

[0092] The optimal fracture length L of the horizontal well to be fractured fopt Determined by the following formula:

[0093]

[0094] Among them, C fDopt is the optimal dimensionless fracture conductivity of the horizontal well to be fractured, n fprop is the optimal number of fractures in the horizontal well to be fractured, and h is the effective reservoir thickness of the horizontal well to be fractured;

[0095] Optimal fracture conductivity F copt By the following formula:

[0096]

[0097] Among them, C fDopt is the optimal dimensionless fracture conductivity of the horizontal well to be fractured, n fprop is the optimal number of fractures in the horizontal well to be fractured, and h is the effective dynamic reservoir thickness of the horizontal well to be fractured.

[0098] After optimizing the number of fractures and the optimal dimensionless conductivity, the fracture length of the well to be fractured can be determined based on the optimal number of fractures, the optimal dimensionless fracture conductivity, fracture permeability, reservoir permeability, well-controlled volume and effective reservoir thickness. When the fracture conductivity reaches a maximum, the productivity index of the fracture of the horizontal well will be maximized.

[0099] For example, when the optimal number of fractures is 40, the optimal dimensionless fracture conductivity is 1, and the fracture permeability k f =10 4 mD, reservoir permeability k m =0.1mD, obtain the well control volume V of the horizontal well to be fractured prop =2500m 3 Under the condition of , according to the field exploration, the effective reservoir thickness of the horizontal well is 10m. At this time, the optimal fracture length can be obtained according to the following formula: The optimal fracture conductivity is obtained according to the following formula: The conductivity of a fracture is usually expressed by the product of the fracture width and the fracture permeability. If the optimal fracture conductivity has been determined, the fracture width can also be indirectly determined, providing data support for subsequent fracturing work.

[0100] In this embodiment, when executing steps S101-S104, the fracture parameter combination of the number of fractures, the aspect ratio of the fracture-controlled area, and the dimensionless fracture conductivity is optimized. When executing steps S101-S105, the number of fractures, the aspect ratio of the fracture-controlled area, the dimensionless fracture conductivity, the fracture length, and the fracture conductivity can also be optimized. When the parameter data in the fracture parameter combination reaches an optimal solution, the horizontal well productivity index obtained by fracturing the horizontal well according to the optimal fracture parameter solution can be maximized. In this case, resources are not wasted and the fracturing efficiency is improved. Of course, the fracture parameter combination is not limited to the parameter combination in this embodiment. According to actual construction needs, a suitable fracture parameter combination should be selected for horizontal well fracturing.

[0101] In the above method, when optimizing the fracture parameters such as the optimal number of fractures and the optimal fracture-controlled physical property parameter ratio of the horizontal well to be fractured, the distribution of multiple fractures in a fractured horizontal well and the layout of the reservoir can be pre-defined. For example, it can be assumed that the fractures are evenly distributed along the wellbore, the fractures are symmetrically distributed about the horizontal wellbore, the parameters of each fracture are the same, and the fracture height is equal to the formation thickness, etc. It can also be assumed that the horizontal well production capacity comes entirely from the contribution of the fractures, and the contribution of the horizontal wellbore is ignored. The fracture-controlled volume occupied by each fracture is the reservoir width (y e )×reservoir length(x e )×reservoir height (h). The relationship between the well-controlled area width and the fracture-controlled area width is: On this basis, the fracture parameters are optimized to obtain the optimal horizontal well fracture layout.

[0102] Based on the same inventive concept, the embodiment of the present invention also provides a device for optimizing fracture parameters of a horizontal well fracture, which can be set in a device capable of processing computer instructions. The structure of the device is as follows: Figure 4 Shown, including:

[0103] The dimensionless proppant index determination module 11 is used to determine the dimensionless proppant index according to the main control parameters that affect the productivity index of the horizontal well to be fractured.

[0104] The fracture number determination module 12 is used to determine the optimal number of fractures in the horizontal well to be fractured based on the first dimensionless optimization map of the horizontal well to be fractured, the predetermined productivity index and dimensionless proppant index of the horizontal well to be fractured; the first dimensionless optimization map includes the corresponding relationship between the number of fractures, the productivity index of the horizontal well to be fractured and the dimensionless proppant index.

[0105] The fracture control physical property parameter index determination module 13 is used to determine the optimal fracture control physical property parameter index of the horizontal well to be fractured according to the determined optimal number of fractures of the horizontal well to be fractured and the preset well control physical property parameters of the horizontal well to be fractured.

[0106] The fracture conductivity determination module 14 is configured to determine the optimal dimensionless fracture conductivity of the horizontal well to be fractured based on a second dimensionless optimization map of the horizontal well to be fractured, a predetermined dimensionless proppant index, and an optimal fracture control physical property parameter index of the horizontal well to be fractured; the second dimensionless optimization map includes a correspondence between the fracture control physical property parameter index, the optimal dimensionless fracture conductivity, and the dimensionless proppant index.

[0107] In another optional embodiment, the above-mentioned device may also include: a fracture length and conductivity determination module, which is specifically used to determine the optimal fracture length and optimal fracture conductivity of the horizontal well to be fractured based on the optimal number of fractures of the horizontal well to be fractured determined by the fracture number determination module 12 and the optimal dimensionless fracture conductivity of the horizontal well to be fractured determined by the fracture control physical property parameter index determination module 13.

[0108] Regarding the device for optimizing fracture parameters of horizontal wells in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated on here.

[0109] The method and apparatus of this embodiment can use master control parameters as the data calculation basis for the optimization process, quickly and accurately determining the optimal solution for each parameter in the fracture parameter combination without requiring extensive experimental simulation. Only when the parameters in the fracture parameter combination reach the optimal solution can the productivity index of the fractured horizontal well be maximized. This method can determine the optimal fracture parameter combination for a fractured horizontal well under any geological engineering background, significantly improving the efficiency of fractured horizontal well design.

[0110] Example 2

[0111] Embodiment 2 of the present invention provides a horizontal well fracturing method based on embodiment 1, including:

[0112] The optimal number of fractures and the optimal fracture-controlling physical property parameter ratio of the horizontal well to be fractured determined in Example 1 are used in the fracturing operation of the horizontal well to be fractured, so as to form multiple evenly distributed fractures along the wellbore of the horizontal well to be fractured.

[0113] When fracturing a horizontal well, it can be fractured into Figure 5 The distribution of cracks, Figure 5 The plane expansion diagram of the fracture distribution of the horizontal well, in which X e Y is the length of the reservoir effectively produced by the horizontal well, e is the width of the reservoir effectively produced by the horizontal well, x e is the reservoir length occupied by each fracture, y e is the reservoir width occupied by each fracture, L f is the length of the crack, n f is the number of cracks. Figure 5 It can be seen that the effective reservoir of the horizontal well is evenly divided into several parts, each fracture occupies one part, and the fractured fractures are evenly distributed along the wellbore.

[0114] Unless otherwise specifically stated, terms such as process, calculate, compute, determine, display, and the like may refer to the actions and / or processes of one or more processing or computing systems, or similar devices, that manipulate and convert data represented as physical (e.g., electronic) quantities within registers or memories of a processing system into other data similarly represented as physical quantities within the memories, registers, or other such information storage, transmission, or display devices of the processing system. Information and signals may be represented using any of a variety of different techniques and methods. For example, data, instructions, commands, information, signals, bits, symbols, and chips referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, light fields or particles, or any combination thereof.

[0115] It should be understood that the specific order or hierarchy of steps in the disclosed processes is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process can be rearranged without departing from the scope of the present disclosure. The accompanying method claims present elements of the various steps in an exemplary order and are not intended to be limited to the specific order or hierarchy described.

[0116] In the foregoing detailed description, various features are grouped together in a single embodiment to simplify the disclosure. This method of disclosure should not be interpreted as reflecting an intention that embodiments of the claimed subject matter require more features than are expressly recited in each claim. On the contrary, as reflected in the appended claims, the invention comprises less than all the features of any individual disclosed embodiment. The appended claims are therefore hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the invention.

[0117] Those skilled in the art will also appreciate that the various illustrative logic blocks, modules, circuits, and algorithmic steps described in conjunction with the embodiments herein may be implemented as electronic hardware, computer software, or a combination thereof. In order to clearly illustrate the interchangeability between hardware and software, the various illustrative components, blocks, modules, circuits, and steps described above are generally described around their functions. Whether such functions are implemented as hardware or software depends on the specific application and the design constraints imposed on the entire system. A skilled person may implement the described functions in an adaptable manner for each specific application, but such implementation decisions should not be interpreted as departing from the scope of protection of this disclosure.

[0118] The steps of the methods or algorithms described in conjunction with the embodiments herein may be directly embodied as hardware, software modules executed by a processor, or a combination thereof. The software module may be located in a RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, register, hard disk, removable disk, CD-ROM, or any other form of storage medium well known in the art. An exemplary storage medium is connected to the processor so that the processor can read information from the storage medium and write information to the storage medium. Of course, the storage medium may also be an integral part of the processor. The processor and storage medium may be located in an ASIC. The ASIC may be located in a user terminal. Of course, the processor and storage medium may also be present in a user terminal as discrete components.

[0119] For software implementation, the techniques described in this application can be implemented using modules (e.g., procedures, functions, etc.) that perform the functions described in this application. These software codes can be stored in a memory unit and executed by a processor. The memory unit can be implemented within the processor or external to the processor. In the latter case, it is communicatively coupled to the processor via various means, which are well known in the art.

[0120] The foregoing description includes examples of one or more embodiments. Of course, it is not possible to describe all possible combinations of components or methods for the purposes of describing the above embodiments, but one of ordinary skill in the art will recognize that the various embodiments may be further combined and arranged. Therefore, the embodiments described herein are intended to encompass all such changes, modifications and variations that fall within the scope of the appended claims. Furthermore, to the extent the term "comprising" is used in the specification or claims, the term is intended to be encompassed in a manner similar to the term "including," as explained in terms of "including," used as a transitional word in the claims. Furthermore, any use of the term "or" in the specification of the claims is intended to mean a "non-exclusive or."

Claims

1. A method for optimizing fracture parameters of a horizontal well, characterized in that: include: Determine the dimensionless proppant index based on the main control parameters that affect the productivity index of the horizontal well to be fractured; Determining an optimal number of fractures in the horizontal well to be fractured based on a first dimensionless optimization map of the horizontal well to be fractured, a predetermined productivity index of the horizontal well to be fractured, and the dimensionless proppant index; wherein the first dimensionless optimization map includes a correspondence between the number of fractures, the productivity index of the horizontal well to be fractured, and the dimensionless proppant index; Determining optimal fracture control physical property parameter indicators for the horizontal well to be fractured based on the determined optimal number of fractures for the horizontal well to be fractured and the preset well control physical property parameters for the horizontal well to be fractured; The optimal dimensionless fracture conductivity of the horizontal well to be fractured is determined based on a second dimensionless optimization map of the horizontal well to be fractured, a predetermined dimensionless proppant index, and an optimal fracture control physical property parameter index of the horizontal well to be fractured; the second dimensionless optimization map includes a correspondence between the fracture control physical property parameter index, the optimal dimensionless fracture conductivity, and the dimensionless proppant index.

2. The method according to claim 1, wherein The dimensionless proppant index is determined based on the main control parameters that affect the productivity index of the horizontal well to be fractured, including: Obtain fracture permeability and reservoir permeability from geological interpretation data of the horizontal well to be fractured; Obtaining the well-controlled volume of the horizontal well to be fractured based on the geological interpretation data and well test interpretation data of the horizontal well to be fractured; A dimensionless proppant index is determined according to the fracture permeability, reservoir permeability, well control volume, and a preset proppant volume pumped into the fracture.

3. The method according to claim 2, wherein The dimensionless proppant index N is determined by the following formula prop : Among them, k f is the fracture permeability, k m is the reservoir permeability, V res is the preset volume of proppant pumped into the fracture, V prop is the well-controlled volume of the horizontal well to be fractured.

4. The method according to claim 1, wherein The method of determining the optimal fracture control physical property parameter index of the horizontal well to be fractured based on the determined optimal number of fractures of the horizontal well to be fractured and the preset well control physical property parameters of the horizontal well to be fractured includes: Determining the optimal fracture control area aspect ratio of the horizontal well to be fractured based on the determined optimal number of fractures in the horizontal well to be fractured and the preset well control area aspect ratio of the horizontal well to be fractured; The length and width of the optimal seam control area λ opt The ratio is determined by the following formula: opt =Λn fprop , where Λ is the aspect ratio of the well control area of ​​the preset horizontal well to be fractured, n fprop is the optimal number of fractures in the horizontal well to be fractured.

5. The method according to claim 1, wherein Also includes: The optimal fracture length and the optimal fracture conductivity of the horizontal well to be fractured are determined based on the determined optimal fracture number and the optimal dimensionless fracture conductivity of the horizontal well to be fractured.

6. The method according to claim 5, wherein The step of determining the optimal fracture length and the optimal fracture conductivity of the horizontal well to be fractured based on the determined optimal fracture number and the optimal dimensionless fracture conductivity of the horizontal well to be fractured comprises: Obtain fracture permeability and reservoir permeability from geological interpretation data of the horizontal well to be fractured; Obtain the well-controlled volume and effective reservoir thickness of the horizontal well to be fractured based on the geological interpretation data and well test interpretation data of the horizontal well to be fractured; The optimal fracture length and optimal fracture conductivity of the horizontal well to be fractured are determined based on the optimal number of fractures, optimal dimensionless fracture conductivity, fracture permeability, reservoir permeability, well-controlled volume and effective reservoir thickness of the horizontal well to be fractured.

7. The method according to claim 5, wherein The optimal fracture length L of the horizontal well to be fractured fopt Determined by the following formula: Among them, C fDopt is the optimal dimensionless fracture conductivity of the horizontal well to be fractured, n fprop is the optimal number of fractures in the horizontal well to be fractured, and h is the effective reservoir thickness of the horizontal well to be fractured; The optimal fracture conductivity F copt By the following formula: Among them, C fDopt is the optimal dimensionless fracture conductivity of the horizontal well to be fractured, n fprop is the optimal number of fractures in the horizontal well to be fractured, and h is the effective reservoir thickness of the horizontal well to be fractured.

8. The method according to claim 1, wherein Also includes: The determined optimal number of fractures and optimal fracture-controlling physical property parameter ratio of the horizontal well to be fractured are used in the fracturing operation of the horizontal well to be fractured, so as to form multiple evenly distributed fractures along the wellbore of the horizontal well to be fractured.

9. A device for optimizing fracture parameters of a horizontal well, characterized in that: include: A dimensionless proppant index determination module, used to determine the dimensionless proppant index based on the main control parameters that affect the productivity index of the horizontal well to be fractured; a fracture number determination module, configured to determine an optimal number of fractures in a horizontal well to be fractured based on a first dimensionless optimization map of the horizontal well to be fractured, a predetermined productivity index and a dimensionless proppant index of the horizontal well to be fractured, wherein the first dimensionless optimization map includes a correspondence between the number of fractures, the productivity index of the horizontal well to be fractured, and the dimensionless proppant index; A fracture control physical property parameter index determination module is used to determine the optimal fracture control physical property parameter index of the horizontal well to be fractured based on the determined optimal number of fractures of the horizontal well to be fractured and the preset well control physical property parameters of the horizontal well to be fractured; A fracture conductivity determination module is configured to determine the optimal dimensionless fracture conductivity of the horizontal well to be fractured based on a second dimensionless optimization map for the horizontal well to be fractured, a predetermined dimensionless proppant index, and an optimal fracture-control physical property parameter index for the horizontal well to be fractured; the second dimensionless optimization map includes a correspondence between the fracture-control physical property parameter index, the optimal dimensionless fracture conductivity, and the dimensionless proppant index.

10. A computer storage medium, characterized in that The computer storage medium stores computer executable instructions, and when the computer executable instructions are executed by the processor, the method for optimizing fracture parameters of a fractured horizontal well according to any one of claims 1 to 8 is implemented.

11. A computer device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method for optimizing fracture parameters of a fractured horizontal well according to any one of claims 1 to 8 is implemented.

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