Static evaluation method, device and equipment for actively utilizing the effect of spatial stress field

Abstract

This text relates to the field of oil and gas field development engineering, and particularly to a static evaluation method, device and equipment for the active utilization effect of a spatial stress field. The method includes calculating the angle between the fracture direction of each fracture in the three-dimensional well pattern space and the maximum principal stress direction of the original in-situ stress field of the three-dimensional well pattern space; calculating a fracture network complexity coefficient according to the angle and the number of fractures in the three-dimensional well pattern space; and quantitatively evaluating the active utilization effect of the spatial stress field of the three-dimensional well pattern space according to the fracture network complexity coefficient. Through the embodiments of this text, it is realized to quantitatively evaluate the active utilization effect of the spatial stress field according to the number of existing fractures in the three-dimensional well pattern space and the fracture direction of each fracture, thereby improving the evaluation accuracy.

Description

Technical Field

[0001] This article relates to the field of oil and gas field development engineering, and particularly to a static evaluation method, device and equipment for the active utilization effect of the spatial stress field. Background Art

[0002] Tight oil and gas reservoirs generally have the characteristics of low porosity and low permeability. During the development process, large-scale hydraulic fracturing technology is required to create a large-scale artificial fracture network, thereby increasing the matrix conductivity and achieving the purpose of improving resource utilization rate and recovery rate, and ultimately realizing efficient development. During the hydraulic fracturing process, a large amount of fracturing fluid and proppant need to be injected into the rock formation in a short time, thereby changing the stress state of the rock formation and causing rock fractures, and finally forming a connected fracture network structure. At the same time, the large amount of injected fracturing fluid and proppant will generate induced stress around the fractures. When synchronous fracturing or zipper fracturing is carried out in multiple wells, the induced stresses generated by each fracture will be superimposed on each other to form a complex spatial stress. However, well interference is not necessarily negative for development. Under the condition of three-dimensional development, by arranging a three-dimensional well pattern and staggered fractures, the well interference is "changed from passive to active", and the well interference-induced stress field is used to create complex fractures, thereby improving the degree of inter-well utilization and recovery rate.

[0003] In the existing evaluation methods for the active utilization effect of the spatial stress field of three-dimensional well patterns, it is difficult to quantitatively evaluate the active utilization effect of the spatial stress field of three-dimensional well patterns, resulting in the problem that the spatial induced stress field cannot be fully utilized to create complex fractures, low inter-well utilization degree and low recovery rate.

[0004] There is an urgent need for a static evaluation method for the active utilization effect of the spatial stress field to solve the problems that it is difficult to quantitatively evaluate the active utilization effect of the spatial stress field of three-dimensional well patterns and the evaluation accuracy is low in the evaluation methods for the active utilization effect of the spatial stress field of three-dimensional well patterns. Summary of the Invention

[0005] To solve the problems that it is difficult to quantitatively evaluate the active utilization effect of the spatial stress field of three-dimensional well patterns and the evaluation accuracy is low in the existing evaluation methods for the active utilization effect of the spatial stress field of three-dimensional well patterns, the embodiments of this article provide a static evaluation method, device and equipment for the active utilization effect of the spatial stress field, realizing the quantitative evaluation of the active utilization effect of the spatial stress field and improving the evaluation accuracy.

[0006] To solve the above technical problems, the specific technical solutions of this article are as follows:

[0007] On the one hand, the embodiments of this article provide a static evaluation method for the active utilization effect of the spatial stress field, including,

[0008] Calculating the included angle between the fracture direction of each fracture in the three-dimensional well pattern space and the maximum principal stress direction of the original in-situ stress field of the three-dimensional well pattern space;

[0009] Calculate the fracture network complexity coefficient according to the included angle and the number of fractures in the three-dimensional well pattern space;

[0010] Quantitatively evaluate the active utilization effect of the stress field in the three-dimensional well pattern space according to the fracture network complexity coefficient.

[0011] Furthermore, the method for calculating the fracture direction of each fracture includes,

[0012] Calculate the fracture direction of the fracture according to the fracture path and the stress field in the space of the three-dimensional well pattern; or,

[0013] Calculate the fracture direction of the fracture according to the fracture initiation position and the fracture tip position of the fracture.

[0014] Furthermore, calculating the fracture direction of the fracture according to the fracture path and the stress field in the space of the three-dimensional well pattern further includes,

[0015] When the fracture is a tortuous fracture, calculate the horizontal maximum principal stress direction at each point on the fracture path according to the stress state in the space of the three-dimensional well pattern at each point on the fracture path, and take the average value of the horizontal maximum principal stress directions of each point on the fracture path as the fracture direction of the fracture;

[0016] When the fracture is a straight fracture, calculate the horizontal maximum principal stress direction at the fracture tip position according to the stress state in the space of the three-dimensional well pattern at the fracture tip position, and take the horizontal maximum principal stress direction at the fracture tip position as the fracture direction of the fracture.

[0017] Furthermore, the formula for calculating the horizontal maximum principal stress direction is,

[0018]

[0019] where, θ uni represents the horizontal maximum principal stress direction at a certain point on the fracture path, τ xy,uni represents the shear stress in the x0y plane of the stress state in the space of the three-dimensional well pattern at a certain point on the fracture path, σ xx,uni represents the stress component in the x direction of the stress state in the space of the three-dimensional well pattern at a certain point on the fracture path, σ yy,uni represents the stress component in the y direction of the stress state in the space of the three-dimensional well pattern at a certain point on the fracture path, and x, y represent the coordinates of a certain point on the fracture path in the space of the three-dimensional well pattern.

[0020] Furthermore, calculating the fracture direction of the fracture according to the fracture initiation position and the fracture tip position of the fracture further includes,

[0021] In the three-dimensional well pattern space, calculate the direction of the crack tip position relative to the crack initiation position;

[0022] Take the direction of the crack tip position relative to the crack initiation position as the crack direction of the crack.

[0023] Furthermore, the formula for calculating the fracture network complexity coefficient according to the included angle and the number of fractures in the three-dimensional well pattern space is,

[0024]

[0025] where θ′ represents the fracture network complexity coefficient, represents the included angle between the fracture direction of the fractures on the fracture path of the i-th fracture and the maximum principal stress direction of the original in-situ stress field of the space, and n represents the number of fractures in the space.

[0026] Furthermore, quantitatively evaluating the active utilization effect of the stress field in the three-dimensional well pattern space according to the fracture network complexity coefficient further includes,

[0027] Evaluating the active utilization effect of the space stress field according to the fracture network complexity coefficient and a preset fracture network complexity coefficient threshold.

[0028] On the other hand, the embodiments of the present invention also provide a static evaluation device for the active utilization effect of the space stress field, including,

[0029] A crack included angle calculation unit for calculating the included angle between the crack direction of each crack in the three-dimensional well pattern space and the maximum principal stress direction of the original in-situ stress field of the three-dimensional well pattern space;

[0030] A fracture network complexity coefficient calculation unit for calculating the fracture network complexity coefficient according to the included angle and the number of fractures in the three-dimensional well pattern space;

[0031] A quantitative evaluation unit for the active utilization effect of the space stress field, for quantitatively evaluating the active utilization effect of the stress field in the three-dimensional well pattern space according to the fracture network complexity coefficient.

[0032] On the other hand, the embodiments of the present invention also provide a computer device, including a memory, a processor, and a computer program stored on the memory. When the processor executes the computer program, the above method is implemented.

[0033] Finally, the embodiments of the present invention also provide a computer storage medium, on which a computer program is stored. When the computer program is run by the processor of the computer device, the above method is executed.

[0034] Using the embodiments of the present invention, first calculate the included angle between the fracture direction of each fracture in the three-dimensional well pattern space and the maximum principal stress direction of the original in-situ stress field, then calculate the fracture network complexity coefficient according to the calculated included angle and the number of fractures in the three-dimensional well pattern space, and finally quantitatively evaluate the active utilization effect of the stress field in the three-dimensional well pattern space according to the calculated fracture network complexity coefficient, realizing the quantitative evaluation of the active utilization effect of the spatial stress field according to the number of existing fractures and the fracture direction of each fracture in the three-dimensional well pattern space, thereby improving the evaluation accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts.

[0036] Figure 1 The figure shows a schematic diagram of an implementation system of a static evaluation method for the active utilization effect of a spatial stress field according to an embodiment of the present invention;

[0037] Figure 2 The figure shows a flowchart of a static evaluation method for the active utilization effect of a spatial stress field according to an embodiment of the present invention;

[0038] Figure 3 The figure shows the process of calculating the fracture direction of the fracture according to the fracture path and the spatial stress field of the three-dimensional well pattern;

[0039] Figure 4 The figure shows the process of calculating the fracture direction of the fracture according to the fracture initiation position and the fracture tip position of the fracture;

[0040] Figure 5 The figure shows a schematic diagram of the structure of a static evaluation device for the active utilization effect of a spatial stress field according to an embodiment of the present invention;

[0041] Figure 6 The figure shows a schematic flowchart of a static evaluation method for the active utilization effect of a spatial stress field according to an embodiment of the present invention;

[0042] Figure 7 The figure shows a schematic diagram of the structure of a computer device according to an embodiment of the present invention.

[0043]

Description of the Reference Numerals

[0044] 101, horizontal well;

[0045] 102, fracture;

[0046] 501, fracture included angle calculation unit;

[0047] 502, Fracture network complexity coefficient calculation unit;

[0048] 503, Quantitative evaluation unit for the active utilization effect of the spatial stress field;

[0049] 702, Computer device;

[0050] 704, Processing device;

[0051] 706, Storage resource;

[0052] 708, Driving mechanism;

[0053] 710, Input / output module;

[0054] 712, Input device;

[0055] 714, Output device;

[0056] 716, Presentation device;

[0057] 718, Graphical user interface;

[0058] 720, Network interface;

[0059] 722, Communication link;

[0060] 724, Communication bus. Detailed implementation manners

[0061] Next, the technical solutions in the embodiments of this article will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of this article. Obviously, the described embodiments are only a part of the embodiments of this article, rather than all the embodiments. Based on the embodiments in this article, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of this article.

[0062] It should be noted that the terms "first", "second", etc. in the specification and claims of this article and the above-mentioned accompanying drawings are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of this article described here can be implemented in an order different from those illustrated or described here. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, device, product, or equipment that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or are inherent to these processes, methods, products, or equipment.

[0063] As Figure 1The figure shows a schematic diagram of an implementation system for a static evaluation method of the active utilization effect of a spatial stress field in an embodiment of this article, including: a horizontal well 101 and a fracture 102. As Figure 1 shown, L is the well spacing between two horizontal wells 101 on the same horizontal plane, a is the half fracture length of the fracture 102, and b is the half fracture height of the fracture 102. Since tight oil and gas reservoirs generally have the characteristics of low porosity and low permeability, during the development process, large-scale hydraulic fracturing technology needs to be used to create large-scale fractures 102 on the horizontal well 101, thereby increasing the matrix conductivity and achieving the purpose of improving resource utilization rate and recovery rate, and finally realizing efficient development. During the hydraulic fracturing process, a large amount of fracturing fluid and proppant need to be injected into the rock formation in a short time, thereby changing the stress state of the rock formation and causing rock fracture, and finally forming a connected fracture network structure in the space of the three-dimensional well pattern. At the same time, the large amount of injected fracturing fluid and proppant will generate induced stress around the fracture. When synchronous fracturing or zipper fracturing is carried out on multiple horizontal wells 101, the induced stresses generated by each fracture 102 will be superimposed on each other, forming a complex spatial stress field.

[0064] In order to evaluate the active utilization effect of the complex spatial stress field, the embodiment of this article provides a static evaluation method for the active utilization effect of the spatial stress field, which can quantitatively evaluate the active utilization effect of the spatial stress field. Figure 2 The figure shows a flow chart of an evaluation method for the active utilization effect of a three-dimensional well pattern spatial stress field provided by the embodiment of this article. The evaluation process of the active utilization effect of the three-dimensional well pattern spatial stress field is described in this figure, but based on routine or non-creative labor, it may include more or fewer operation steps. The order of steps listed in the embodiment is only one way among the execution orders of numerous steps, and does not represent the only execution order. When the actual system or device product is executed, it can be executed in the method order shown in the embodiment or the figure, or executed in parallel. Specifically, as Figure 2 shown, the method may include:

[0065] Step 201: Calculate the included angle between the fracture direction of each fracture in the three-dimensional well pattern space and the maximum principal stress direction of the original in-situ stress field of the three-dimensional well pattern space;

[0066] Step 202: Calculate the fracture network complexity coefficient according to the included angle and the number of fractures in the three-dimensional well pattern space;

[0067] Step 203: Quantitatively evaluate the active utilization effect of the three-dimensional well pattern spatial stress field according to the fracture network complexity coefficient.

[0068] Through the method of the embodiments of this article, first calculate the angle between the fracture direction of each fracture in the three-dimensional well pattern space and the maximum principal stress of the original in-situ stress field, then calculate the fracture network complexity coefficient according to the calculated angle and the number of fractures in the three-dimensional well pattern space, and finally quantitatively evaluate the active utilization effect of the stress field in the three-dimensional well pattern space according to the calculated fracture network complexity coefficient, realizing the quantitative evaluation of the active utilization effect of the spatial stress field according to the number of existing fractures and the fracture direction of each fracture in the three-dimensional well pattern space, thereby improving the evaluation accuracy.

[0069] In the embodiments of this article, based on the three-dimensional geophysical exploration data of the three-dimensional well pattern obtained on site, the numerical inversion method can be used to obtain the spatial stress field, or other methods in the prior art can be used, such as establishing a three-dimensional geological mechanics model using industrial software and obtaining the spatial stress field through numerical solution methods, etc. There is no limitation in the embodiments of this specification. Preferably, in the embodiments of this article, the spatial stress field of the three-dimensional well pattern space can be calculated by formula (1).

[0070]

[0071] In formula (1), σ uni is the said spatial stress field, σ xx,uni is the stress component of the said spatial stress field in the x direction of the said space, σ yy,uni is the stress component of the said spatial stress field in the y direction of the said space, σ zz,uni is the stress component of the said spatial stress field in the z direction of the said space, τ xy,uni is the shear stress of the said spatial stress field in the x0y plane, τ xz,uni is the shear stress of the said spatial stress field in the x0z plane, τ yz,uni is the shear stress of the said spatial stress field in the y0z plane, i represents the i-th fracture in the said space, n represents the number of fractures in the said space, σ zz is the stress component of the induced stress field of the fracture in the z direction of the said space, σ xx is the stress component of the induced stress field of the fracture in the x direction of the said space, σ yy is the stress component of the induced stress field of the fracture in the y direction of the said space, τ xy is the shear stress of the induced stress field of the fracture in the x0y plane, τ yz is the shear stress of the induced stress field of the fracture in the y0z plane, τ xz is the shear stress of the induced stress field of the fracture in the x0z plane, σ xF is the stress component of the said original in-situ stress field in the x direction of the said space, σ yF is the stress component of the said original in-situ stress field in the y direction of the said space, σ zFis the stress component of the original in-situ stress field in the z direction of the space, where x, y, and z are the coordinates of a certain point in the space. Among them, the induced stress state of each point can be measured by measuring instruments, which is not limited in the embodiments of this specification.

[0072] In the embodiments of this article, the maximum principal stress direction of the original in-situ stress field in the three-dimensional well pattern space can be determined by geophysical exploration, logging, fracturing construction, and borehole wall breakage direction of the target layer.

[0073] The principle of the present invention lies in:

[0074] For the evaluation of the active utilization effect of the stress field, its basic starting point is the quantitative evaluation of the active utilization effect of the stress field. Actively utilize the induced stress field to assist in generating a complex fracture network. The core is to cleverly arrange the spatial positions of each main fracture, so that the tensile stress areas are staggered from each other, expand the area of the low horizontal stress difference area, and at the same time make the fractures be interfered by the induced stress of adjacent fractures at the tips, reducing the horizontal stress difference, so that the fractures no longer extend forward to the wellbore of the adjacent well to cause shear deformation, but generate a complex fracture network under the action of the low horizontal stress difference. Therefore, the evaluation of the active utilization effect of the stress field can start from the angle of how much the induced stress of the adjacent well and adjacent fracture affects the secondary fracture and deflects it from the maximum principal stress direction of the original in-situ stress field.

[0075] Statistically calculate the average value of the angles between all fracture planes and the maximum principal stress direction of the original in-situ stress field, which is the fracture network complexity coefficient described in the embodiments of this article. In fact, it is the average value of the directions of all fractures and the maximum principal stress direction of the original in-situ stress field, that is, the characterization of the degree of deviation from the maximum horizontal principal stress, which can characterize the complexity of the fracture network. If the induced stress is utilized sufficiently, a stress difference reduction area is formed at the tip of the main fracture, forming a complex fracture network, then an angle will be generated between the fracture direction and the main fracture direction of the original in-situ stress field. The larger the angle, the more severe the deflection, the better the fracture formation effect, and the better the active utilization effect of the stress field. On the contrary, if all the fractures extend along the maximum horizontal principal stress direction of the original in-situ stress field, it indicates that the effect of using the spatial induced stress to make the generated fractures complex is not good, that is, the active utilization effect of the spatial stress field is not good. Therefore, the fracture network complexity coefficient calculated by the method described in the embodiments of this article can be used to evaluate the active utilization effect of the spatial stress field.

[0076] In addition, in some other embodiments of this article, when differentiating main fractures and secondary fractures in the fracture network space of a three-dimensional well pattern, different weight values can be assigned to the angles between the fracture directions of the main fractures and secondary fractures and the maximum principal stress direction of the original in-situ stress field. Then, according to the angle between the fracture direction of the main fracture or secondary fracture and the maximum principal stress direction of the original in-situ stress field, the weight value of the angle, and the number of the fractures, the fracture network complexity coefficient is calculated. The weight value can be allocated according to the importance of the main fracture or secondary fracture in increasing oil and gas production. For example, the more important the main fracture or secondary fracture is in increasing oil and gas production, the higher the weight of the main fracture or secondary fracture. Through the above method, the calculation of the fracture network complexity coefficient according to the importance of fractures in increasing oil and gas production is realized, thereby further improving the accuracy of evaluating the active utilization effect of the spatial stress field.

[0077] The fracture direction of a fracture can be represented as the propagation direction of the fracture. According to an embodiment of this article, the method for calculating the fracture direction of each fracture includes

[0078] calculating the fracture direction of the fracture according to the fracture path and the spatial stress field of the three-dimensional well pattern; or,

[0079] calculating the fracture direction of the fracture according to the fracture initiation position and the fracture tip position of the fracture.

[0080] In the embodiments of this article, the active utilization of the spatial stress field means that fractures in the space form a complex fracture network structure. The more complex the fracture network structure is, the greater the angle between the propagation directions of each fracture in the space should be. The spatial stress field also includes the superposition of the spatial induced stress of each fracture in the space on each point in the space and the original in-situ stress. The fracture path represents the position of each point on the fracture in the three-dimensional well pattern space. Or rather, the path composed of each point on the fracture is the fracture path. Therefore, the propagation direction of the fracture will be affected by the spatial stress field, that is, the propagation direction of the fracture can be calculated according to the fracture path and the spatial stress field.

[0081] In addition, the evaluation method for the active utilization effect of the spatial stress field of the three-dimensional well pattern described in the embodiments of this specification is evaluated based on the existing fractures in the three-dimensional well pattern space. Further, the fractures described in the embodiments of this specification may include primary fractures and secondary fractures, that is, the fracture termination position of the primary fracture is the fracture initiation position of the secondary fracture under the primary fracture (that is, the crack tip of the primary fracture forms a secondary fracture, and the primary fracture has formed a fracture). In addition, multiple secondary fractures may be formed at the tip of the primary fracture. Therefore, each fracture in the three-dimensional well pattern space includes the fracture initiation position and the crack tip position (or fracture termination position) of the fracture. The fracture propagation direction can be calculated based on the fracture initiation position and the crack tip position. Optionally, the direction of the line connecting the fracture initiation position and the crack tip position in the three-dimensional well pattern space can be used as the fracture propagation direction.

[0082] In the embodiments herein, the fracture path of each fracture in the three-dimensional well pattern space during the propagation process will be affected by the spatial stress field formed by the superposition of the spatial induced stress and the original in-situ stress of each other fracture at each point in the space. Therefore, the fracture morphology may be a straight fracture or a tortuous fracture (that is, the fracture propagates along a curved path).

[0083] In view of the above situation, according to an embodiment of this article, in order to further improve the accuracy of evaluating the active utilization effect of the spatial stress field, as Figure 3 shown, calculating the fracture direction of the fracture according to the fracture path and the spatial stress field of the three-dimensional well pattern further includes,

[0084] Step 301: When the fracture is a tortuous fracture, calculate the horizontal maximum principal stress direction at each point on the fracture path according to the spatial stress state of the spatial stress field of the three-dimensional well pattern at each point on the fracture path, and take the average value of the horizontal maximum principal stress directions of each point on the fracture path as the fracture direction of the fracture;

[0085] Step 302: When the fracture is a straight fracture, calculate the horizontal maximum principal stress direction at the crack tip position of the fracture according to the spatial stress state of the spatial stress field of the three-dimensional well pattern at the crack tip position of the fracture, and take the horizontal maximum principal stress direction at the crack tip position of the fracture as the fracture direction of the fracture.

[0086] When the crack is a tortuous crack, it indicates that the crack direction during the crack propagation is greatly affected by the spatial stress state at each point on the crack path in the spatial stress field. The horizontal maximum principal stress directions at each point on the crack path vary significantly, resulting in the crack propagating in a tortuous shape. Therefore, the horizontal maximum principal stress direction at each point on the crack path can be calculated separately according to the spatial stress state at each point on the crack path in the spatial stress field, and the average value of the horizontal maximum principal stress directions at each point on the crack path is taken, and the obtained average value is used as the crack direction of the crack.

[0087] When the crack is a straight crack, it indicates that the crack direction during the crack propagation is less affected by the spatial stress state at each point on the crack path in the spatial stress field. The horizontal maximum principal stress directions at each point on the crack path do not vary much, so the crack propagates in a straight line shape. Therefore, only the horizontal maximum principal stress direction at the crack tip position of the crack needs to be calculated according to the spatial stress state at the crack tip position of the crack in the spatial stress field, and the obtained horizontal maximum principal stress direction at the crack tip position is used as the crack direction of the crack.

[0088] According to an embodiment of the present invention, the formula for calculating the horizontal maximum principal stress direction is shown in formula (2),

[0089]

[0090] where θ uni represents the horizontal maximum principal stress direction at a certain point on the crack path, τ xy,uni represents the shear stress in the x0y plane of the spatial stress state at a certain point on the crack path in the three-dimensional well pattern space, σ xx,uni represents the stress component in the x direction of the spatial stress state at a certain point on the crack path in the three-dimensional well pattern space, σ yy,uni represents the stress component in the y direction of the spatial stress state at a certain point on the crack path in the three-dimensional well pattern space, and x, y represent the coordinates of a certain point on the crack path in the three-dimensional well pattern space.

[0091] According to an embodiment of the present invention, as Figure 4 shown, calculating the crack direction of the crack according to the crack initiation position and the crack tip position of the crack further includes,

[0092] Step 401: In the three-dimensional well pattern space, calculate the direction of the crack tip position relative to the crack initiation position;

[0093] Step 402: Use the direction of the crack tip position relative to the crack initiation position as the crack direction of the crack.

[0094] In the embodiments of the present disclosure, the direction of the crack tip position of the crack relative to the crack initiation position in the three-dimensional well pattern space can be calculated, and this direction can be used as the crack direction of the crack.

[0095] According to an embodiment of the present disclosure, the formula for calculating the fracture network complexity coefficient in step 202 based on the included angle and the number of fractures in the three-dimensional well pattern space is formula (3),

[0096]

[0097] where θ′ represents the fracture network complexity coefficient, represents the included angle between the fracture direction of the fractures on the fracture path of the i-th fracture and the maximum principal stress direction of the original in-situ stress field of the space, and n represents the number of fractures in the space.

[0098] In the embodiments of the present disclosure, after calculating the included angles between the fracture directions of the fractures in the three-dimensional well pattern space and the maximum principal stress direction of the original in-situ stress field of the three-dimensional well pattern space, the included angles are summed up, and the average value of the included angles is calculated according to the number of fractures. This average value is the fracture network complexity coefficient described in the embodiments of the present disclosure.

[0099] If a complex fracture network structure is formed among the fractures in the three-dimensional well pattern space, the fracture directions of the fractures are different, and the included angles between the fracture directions of the fractures and the maximum principal stress direction of the original in-situ stress field are also different, that is, each fracture extends in a different direction. Therefore, the larger the average value of the included angles obtained by summing up the included angles and calculating according to the number of fractures, the greater the degree of outward divergence of each fracture in the three-dimensional well pattern space. In addition, the propagation directions of the fractures are affected by the spatial stress state at each point on the respective fracture paths of the spatial stress field of the three-dimensional well pattern. Therefore, the fracture network complexity coefficient calculated according to the above steps can represent the active utilization effect of the spatial stress field of the three-dimensional well pattern.

[0100] According to an embodiment of the present disclosure, step 203 for quantitatively evaluating the active utilization effect of the spatial stress field of the three-dimensional well pattern based on the fracture network complexity coefficient further includes,

[0101] Evaluating the active utilization effect of the spatial stress field according to the fracture network complexity coefficient and a preset fracture network complexity coefficient threshold.

[0102] In the embodiments of the present invention, the preset threshold value of the fracture network complexity coefficient can be determined according to the fracturing condition and production efficiency of a single well in the three-dimensional well pattern. Optionally, first, according to the economic production index, determine the ultimate recoverable reserve of a single well in the three-dimensional well pattern space. Calculate the spatial stress field of adjacent wells by obtaining the fracturing conditions of adjacent wells in the three-dimensional well pattern, and calculate the fracture network complexity coefficient θ′ according to the spatial stress field. Finally, determine the threshold value of the fracture network complexity coefficient based on the fracture network complexity coefficient θ′ and the ultimate recoverable reserve of a single well.

[0103] In the embodiments of the present invention, since the fracture network complexity coefficient θ′ can represent the active utilization effect of the spatial stress field of the three-dimensional well pattern, the larger the fracture network complexity coefficient θ′, the more complex the fracture network structure formed by fractures in the three-dimensional well pattern space, that is, the better the active utilization effect of the spatial stress field of the three-dimensional well pattern. Therefore, the calculated fracture network complexity coefficient θ′ can be compared with the preset threshold value of the fracture network complexity coefficient. When the calculated fracture network complexity coefficient θ′ is greater than or equal to the preset threshold value of the fracture network complexity coefficient, it indicates that the active utilization effect of the spatial stress field of the three-dimensional well pattern reaches the predetermined requirement. If the calculated fracture network complexity coefficient θ′ is less than the preset threshold value of the fracture network complexity coefficient, it indicates that the active utilization effect of the spatial stress field of the three-dimensional well pattern does not reach the predetermined requirement, realizing the quantitative evaluation of the active utilization effect of the spatial stress field according to the number of existing fractures and the fracture directions of each fracture in the three-dimensional well pattern space.

[0104] Based on the same inventive concept, the embodiments of the present specification also provide a static evaluation device for the active utilization effect of the spatial stress field, as Figure 5 shown, including a fracture angle calculation unit 501, a fracture network complexity coefficient calculation unit 502, and a quantitative evaluation unit 503 for the active utilization effect of the spatial stress field:

[0105] The fracture angle calculation unit 501 is used to calculate the angle between the fracture direction of each fracture in the three-dimensional well pattern space and the maximum principal stress direction of the original in-situ stress field of the three-dimensional well pattern space;

[0106] The fracture network complexity coefficient calculation unit 502 is used to calculate the fracture network complexity coefficient according to the angle and the number of fractures in the three-dimensional well pattern space;

[0107] The quantitative evaluation unit 503 for the active utilization effect of the spatial stress field is used to quantitatively evaluate the active utilization effect of the spatial stress field of the three-dimensional well pattern according to the fracture network complexity coefficient.

[0108] The beneficial effects obtained by the above device are the same as those obtained by the above method, and the embodiments of the present specification will not be elaborated.

[0109] As Figure 6The figure shows a schematic flowchart of the static evaluation method for the active utilization effect of the spatial stress field in the embodiments of this article. The steps for evaluating the active utilization effect of the spatial stress field of the three-dimensional well pattern are described in this figure. It should be noted that the steps and sequences described in this figure are not the only steps and sequences for evaluating the active utilization effect of the spatial stress field of the three-dimensional well pattern in the embodiments of this article. Those skilled in the art can obtain other steps and sequences for evaluating the active utilization effect of the spatial stress field of the three-dimensional well pattern according to the content described in this figure, and the embodiments of this specification do not make any restrictions.

[0110] Specifically, the steps for evaluating the active utilization effect of the spatial stress field of the three-dimensional well pattern include:

[0111] Step 601: Obtain the target well pattern for which the active utilization effect of the stress field is to be evaluated;

[0112] In this step, first, obtain the target well pattern for which the active utilization effect of the stress field is to be evaluated. The target well pattern can be a three-dimensional well pattern with formed fractures. The target well pattern includes multiple fractures, and each fracture can be divided into primary fractures or secondary fractures. The fracture termination position (i.e., the fracture tip position) of the primary fracture is the fracture initiation position (i.e., a secondary fracture is formed at the fracture tip of the primary fracture, and the primary fracture has been formed) of the secondary fracture under the primary fracture. In addition, multiple secondary fractures can be formed at the tip of the primary fracture. In the target well pattern, a complex fracture network structure is formed by multiple fractures.

[0113] In addition, the fracture path of each fracture in the space of the target well pattern will be affected by the spatial stress field formed by the superposition of the spatial induced stress and the original in-situ stress of each other fracture at each point in the space. Therefore, the fracture morphology may be a straight fracture or a tortuous fracture. Then, execute Step 602 to determine whether the fracture is a tortuous fracture.

[0114] It should be noted that the fracture propagation direction can also be calculated based on the fracture initiation position and the tip position. Calculate the direction of the fracture tip position relative to the fracture initiation position in the target well pattern as the fracture direction of the fracture, and then execute Step 605.

[0115] Step 602: Determine whether the fracture is a tortuous fracture;

[0116] In this step, determine the fracture morphology of each fracture respectively. If it is a tortuous fracture, it means that the fracture direction during the fracture propagation is greatly affected by the spatial stress state at each point on the fracture path, and the horizontal maximum principal stress directions at each point on the fracture path vary greatly, resulting in the fracture propagating in a tortuous form. Then, execute Step 603 to calculate the fracture direction of the tortuous fracture;

[0117] If it is a straight crack, it means that the crack direction during the crack propagation is less affected by the spatial stress state at each point on the crack path in the spatial stress field. The horizontal maximum principal stress directions at each point on the crack path are not very different. Therefore, the crack propagates in a straight line shape, and step 604 is executed to calculate the crack direction of the straight crack.

[0118] Step 603: Calculate the horizontal maximum principal stress at each point on the crack path according to the spatial stress state at each point on the crack path in the spatial stress field of the target well pattern, and take the average value of the horizontal maximum principal stress directions at each point on the crack as the crack direction of the crack.

[0119] In this step, when the crack is a tortuous crack, according to the spatial stress state at each point on the crack path in the spatial stress field, use formula (2) in this specification to calculate the horizontal maximum principal stress direction at each point on the crack path respectively, and take the average value of the horizontal maximum principal stress directions at each point on the crack path as the crack direction of the crack.

[0120] Step 604: Calculate the horizontal maximum principal stress direction at the crack tip position of the crack according to the spatial stress state at the crack tip position of the crack in the spatial stress field of the target well pattern, and take the horizontal maximum principal stress direction at the crack tip position of the crack as the crack direction of the crack.

[0121] In this step, when the crack is a straight crack, according to the spatial stress state at the crack tip position of the crack, use formula (2) in this specification to calculate the horizontal maximum principal stress direction at the crack tip position of the crack, and take the obtained horizontal maximum principal stress direction at the crack tip position as the crack direction of the crack.

[0122] It should be noted that the spatial stress field described in step 603 or step 604 can be obtained by using the numerical inversion method based on the three-dimensional geophysical exploration data of the three-dimensional well pattern obtained on site, or other methods in the prior art can also be used, such as establishing a three-dimensional geological mechanics model using industrial software and obtaining the spatial stress field by means of numerical solution and other methods. Preferably, the spatial stress field described in step 603 or step 604 is calculated by formula (1) in this specification, which will not be elaborated here.

[0123] Step 605: Calculate the included angle between the crack direction of each crack and the maximum principal stress direction of the original in-situ stress field.

[0124] In this step, the direction of the maximum principal stress of the original in-situ stress field of the target well pattern is determined. If a complex fracture network structure is formed among the fractures in the three-dimensional well pattern space, the fracture directions of the fractures are different, and the angles between the fracture directions of the fractures and the direction of the maximum principal stress of the original in-situ stress field are also different, that is, each fracture extends in a different direction. Therefore, the angles between the fracture directions of each fracture and the direction of the maximum principal stress of the original in-situ stress field are calculated respectively, so that in step 606, the fracture network complexity coefficient can be calculated according to the above angles of each fracture and the number of fractures.

[0125] Step 606: Calculate the fracture network complexity coefficient according to the angle and the number of fractures in the target well pattern space;

[0126] In this step, as shown in formula (3) of this specification, after step 605 calculates the angles between the fracture directions of each fracture in the three-dimensional well pattern space and the direction of the maximum principal stress of the original in-situ stress field of the three-dimensional well pattern space, the angles are summed up, and the average value of the angles is calculated according to the number of fractures. This average value is the fracture network complexity coefficient described in the embodiments of this article. The greater the average value of the angles obtained after summing up the angles and calculating according to the number of fractures, the greater the degree of outward divergence of each fracture in the three-dimensional well pattern space. In addition, the propagation direction of each fracture is affected by the spatial stress state at each point on the respective fracture path of the spatial stress field of the three-dimensional well pattern. Therefore, the fracture network complexity coefficient calculated according to the above steps can represent the active utilization effect of the spatial stress field of the three-dimensional well pattern space.

[0127] Step 607: Evaluate the active utilization effect of the spatial stress field of the target well pattern according to the fracture network complexity coefficient and the preset fracture network complexity coefficient threshold.

[0128] In this step, the preset fracture network complexity coefficient threshold can be determined according to the fracturing conditions and production efficiency of single wells in the three-dimensional well pattern, etc. Optionally, first, according to the economic production index, determine the ultimate recoverable reserves of a single well in the three-dimensional well pattern space, calculate the spatial stress field of adjacent wells by obtaining the fracturing conditions of adjacent wells in the three-dimensional well pattern, calculate the fracture network complexity coefficient according to the spatial stress field, and finally determine the fracture network complexity coefficient threshold according to the fracture network complexity coefficient and the ultimate recoverable reserves of a single well. Compare the fracture network complexity coefficient calculated through the above steps 601 to 606 with the preset fracture network complexity coefficient threshold. When the calculated fracture network complexity coefficient is greater than or equal to the preset fracture network complexity coefficient threshold, it means that the active utilization effect of the spatial stress field of the three-dimensional well pattern space meets the predetermined requirements. If the calculated fracture network complexity coefficient is less than the preset fracture network complexity coefficient threshold, it means that the active utilization effect of the spatial stress field of the three-dimensional well pattern space does not meet the predetermined requirements, realizing the quantitative evaluation of the active utilization effect of the spatial stress field according to the number of existing fractures and the fracture directions of each fracture in the three-dimensional well pattern space.

[0129] As shown Figure 7 in the structural schematic diagram of the computer device according to the embodiment of the present invention, the evaluation device for the active utilization effect of the three-dimensional well pattern space stress field in the present invention may be the computer device in this embodiment, and execute the method of the present invention above. The computer device 702 may include one or more processing devices 704, such as one or more central processing units (CPUs), and each processing unit may implement one or more hardware threads. The computer device 702 may also include any storage resource 706 for storing any kind of information such as code, settings, data, etc. Non-limitingly, for example, the storage resource 706 may include any one or a combination of the following: any type of RAM, any type of ROM, flash memory devices, hard disks, optical discs, etc. More generally, any storage resource may store information using any technology. Further, any storage resource may provide volatile or non-volatile retention of information. Further, any storage resource may represent a fixed or removable component of the computer device 702. In one case, when the processing device 704 executes the associated instructions stored in any storage resource or combination of storage resources, the computer device 702 may perform any operation of the associated instructions. The computer device 702 also includes one or more drive mechanisms 708 for interacting with any storage resource, such as a hard disk drive mechanism, an optical disc drive mechanism, etc.

[0130] The computer device 702 may also include an input / output module 710 (I / O) for receiving various inputs (via the input device 712) and for providing various outputs (via the output device 714). A specific output mechanism may include a presentation device 716 and an associated graphical user interface (GUI) 718. In other embodiments, the input / output module 710 (I / O), the input device 712, and the output device 714 may not be included, and it may only be a computer device in the network. The computer device 702 may also include one or more network interfaces 720 for exchanging data with other devices via one or more communication links 722. One or more communication buses 724 couple the components described above together.

[0131] The communication link 722 may be implemented in any way, for example, through a local area network, a wide area network (e.g., the Internet), a point-to-point connection, etc., or any combination thereof. The communication link 722 may include any combination of hardwired links, wireless links, routers, gateway functions, name servers, etc. governed by any protocol or combination of protocols.

[0132] Corresponding to Figures 2 to 4 、 Figure 6For the method in [description], embodiments of the present invention also provide a computer-readable storage medium, on which a computer program is stored. When the computer program is run by a processor, it executes the steps of the above-mentioned method.

[0133] Embodiments of the present invention also provide a computer-readable instruction. When the processor executes the instruction, the program therein causes the processor to execute as Figures 2 to 4 、 Figure 6 the method shown.

[0134] It should be understood that in various embodiments of the present invention, the magnitudes of the sequence numbers of the above processes do not imply the order of execution. The order of execution of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.

[0135] It should also be understood that in the embodiments of the present invention, the term "and / or" is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in the present invention generally represents an "or" relationship between the associated objects before and after.

[0136] Those of ordinary skill in the art can realize that the units and algorithm steps of the examples described in combination with the embodiments disclosed in the present invention can be implemented by electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of each example have been generally described according to their functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0137] Those skilled in the art can clearly understand that for the convenience and conciseness of description, the specific working processes of the systems, devices, and units described above can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0138] In several embodiments provided in this document, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For instance, the division of the units is only a logical function division. In actual implementation, there can be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Additionally, the displayed or discussed couplings or direct couplings or communication connections to each other can be indirect couplings or communication connections through some interfaces, devices, or units, and can also be electrical, mechanical, or other forms of connection.

[0139] The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the objectives of the embodiments of this document.

[0140] In addition, in each embodiment of this document, the functional units can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

[0141] If the above-mentioned integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the essence of the technical solution in this document, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in each embodiment of this document. The aforementioned storage medium includes: USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs, etc., which can store program codes.

[0142] Specific embodiments are used in this document to elaborate on the principles and implementation manners of this document. The descriptions of the above embodiments are only used to help understand the methods and their core ideas in this document; at the same time, for those of ordinary skill in the art, according to the ideas in this document, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to this document.

Claims

1. A static evaluation method for the active utilization effect of a spatial stress field, characterized in that The method includes calculating the angle between the fracture direction of each fracture in the three-dimensional well pattern space and the maximum principal stress direction of the original in-situ stress field of the three-dimensional well pattern space; calculating the fracture network complexity coefficient according to the angle and the number of fractures in the three-dimensional well pattern space; quantitatively evaluating the active utilization effect of the stress field in the three-dimensional well pattern space according to the fracture network complexity coefficient; The formula for calculating the fracture network complexity coefficient according to the angle and the number of fractures in the three-dimensional well pattern space is: where θ′ represents the complexity coefficient of the fracture network, represents the included angle between the fracture direction on the fracture path of the i-th fracture and the maximum principal stress direction of the original in-situ stress field of the space, and n represents the number of fractures in the space.

2. The static evaluation method for the active utilization effect of the spatial stress field according to claim 1, characterized in that The method for calculating the fracture direction of each fracture includes calculating the fracture direction of the fracture according to the fracture path and the spatial stress field of the three-dimensional well pattern; or calculating the fracture direction of the fracture according to the fracture initiation position and the fracture tip position of the fracture.

3. The static evaluation method for the active utilization effect of the spatial stress field according to claim 2, wherein, Calculating the fracture direction of the fracture according to the fracture path and the spatial stress field of the three-dimensional well pattern further includes when the fracture is a tortuous fracture, calculating the horizontal maximum principal stress direction at each point on the fracture path according to the spatial stress state of the three-dimensional well pattern at each point on the fracture path, and taking the average value of the horizontal maximum principal stress directions at each point on the fracture path as the fracture direction of the fracture; when the fracture is a straight fracture, calculating the horizontal maximum principal stress direction at the fracture tip position of the fracture according to the spatial stress state of the three-dimensional well pattern at the fracture tip position of the fracture, and taking the horizontal maximum principal stress direction at the fracture tip position of the fracture as the fracture direction of the fracture.

4. The static evaluation method for the active utilization effect of the spatial stress field according to claim 3, characterized in that, The formula for calculating the horizontal maximum principal stress direction is: Among them, θ uni represents the horizontal maximum principal stress direction at a certain point on the crack path, τ xy,uni represents the shear stress in the x0y plane of the spatial stress state at a certain point on the crack path in the spatial pattern of vertical wells, σ xx,uni represents the stress component in the x direction of the spatial stress state at a certain point on the crack path in the spatial pattern of vertical wells, σ yy,uni represents the stress component in the y direction of the spatial stress state at a certain point on the crack path in the spatial pattern of vertical wells, and x, y represent the coordinates of a certain point on the crack path in the spatial pattern of vertical wells.

5. The static evaluation method for the active utilization effect of the spatial stress field according to claim 2, wherein Calculating the fracture direction of the fracture according to the fracture initiation position and the fracture tip position of the fracture further includes calculating the direction of the fracture tip position relative to the fracture initiation position in the three-dimensional well pattern space; taking the direction of the fracture tip position relative to the fracture initiation position as the fracture direction of the fracture.

6. The static evaluation method for the active utilization effect of the spatial stress field according to claim 1, characterized in that, Quantitatively evaluating the active utilization effect of the stress field in the three-dimensional well pattern space according to the fracture network complexity coefficient further includes evaluating the active utilization effect of the spatial stress field according to the fracture network complexity coefficient and a preset fracture network complexity coefficient threshold value.

7. A static evaluation device for the active utilization effect of a spatial stress field, characterized in that, including a fracture angle calculation unit for calculating the angle between the fracture direction of each fracture in the three-dimensional well pattern space and the maximum principal stress direction of the original in-situ stress field of the three-dimensional well pattern space; a fracture network complexity coefficient calculation unit for calculating the fracture network complexity coefficient according to the angle and the number of fractures in the three-dimensional well pattern space; a spatial stress field active utilization effect quantitative evaluation unit for quantitatively evaluating the active utilization effect of the stress field in the three-dimensional well pattern space according to the fracture network complexity coefficient; The formula for calculating the fracture network complexity coefficient according to the angle and the number of fractures in the three-dimensional well pattern space is: Wherein, θ′ represents the complexity coefficient of the fracture network, represents the included angle between the fracture direction on the fracture path of the i-th fracture and the maximum principal stress direction of the original in-situ stress field of the space, and n represents the number of fractures in the space.

8. A computer device, comprising a memory, a processor, and a computer program stored on the memory, characterized in that, When the computer program is run by the processor, it executes the instructions of the method according to any one of claims 1 to 6.

9. A computer storage medium, on which a computer program is stored, characterized in that, When the computer program is run by the processor of a computer device, it executes the instructions of the method according to any one of claims 1 to 6.

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