An unconventional volumetric fracturing design method

Abstract

The application provides an unconventional volume fracturing design method, relates to the technical field of petroleum and natural gas, and comprises the following steps: determining the segment length of each perforated well segment of a target well by referring to the perforated well segment data of a reference well; calculating the planar distance between the reference well and each perforated well segment of the target well; calculating the cluster number of each perforated well segment of the target well based on a design cluster spacing and the segment length; calculating the perforation position of each perforated well segment of the target well according to the perforated well segment data, the cluster number and the design cluster spacing; taking the artificial fracture length as a target, simulating and optimizing construction parameters, combining the planar distance, and determining the limit value of the construction parameters of each perforated well segment of the target well; and taking the segment length, the perforation position and the limit value of the construction parameters as the unconventional volume fracturing design result of the target well. The application adopts the staggered sweet spot + multi-cluster perforation + moderate strength process, and realizes the optimal design of related construction parameters (fracturing fluid consumption and construction displacement).

Description

Technical Field

[0001] This invention relates to the field of oil and gas technology, and is applied to the reservoir stimulation optimization design of renewal wells or parallel replacement wells. Specifically, it relates to an unconventional volumetric fracturing design method. Background Technology

[0002] Tight gas within unconventional natural gas is a crucial area for natural gas development. Its untapped reserves hold significant potential, making it a key area for large-scale production.

[0003] The pore throat diameter of ordinary tight reservoirs is measured in micrometers, which is 1 / 5000th the thickness of a human hair. Reservoir stimulation is required to achieve economical production capacity. Volumetric fracturing technology uses high-pressure fluid to break up the formation and continuously injects fluid to expand it into fractures. Then, proppant is injected to form artificial fractures with high flow capacity, ultimately creating a "highway" for underground oil and gas flow, thereby greatly increasing oil and gas production.

[0004] With the application of volumetric fracturing technology, the control level of a single well has been greatly improved, with axial control reaching about 90% and the horizontal length extended to between 150-200m. However, in the early stages, the well spacing was relatively large, at 300-400m, and the technology was not volumetric fracturing. Therefore, the remaining reserve area between two wells was relatively large, and replacement wells or parallel replacement wells were usually used for supplementary production. This often resulted in cross-flow of old wells after fracturing, and the post-fracturing effect was not ideal.

[0005] Current volumetric fracturing technology focuses on increasing fracture density and improving the stimulated volume, employing techniques such as high flow rates, high fluid intensity, high proppant intensity, and dense fracture distribution. However, when these techniques are used in replacement wells or parallel replacement wells, they suffer from stress lows caused by long-term production in adjacent wells. Under high flow rates, artificial fractures can lead to multi-point flow, affecting the normal production of adjacent wells. Under high fluid volumes, single-layer conical entry is significant, easily resulting in unidirectional stimulation and poor stimulation effects. Furthermore, high-volume flowback after fracturing adjacent wells is difficult, severely damaging low-permeability tight reservoirs.

[0006] Given the various drawbacks of existing conventional volumetric fracturing technologies, there is an urgent need to develop an unconventional volumetric fracturing process to meet the needs of regeneration wells or parallel replacement wells, and to overcome the challenges of multi-point flow, unidirectional fracturing, and backflow damage.

[0007] To address the problems of existing technologies, this invention provides an unconventional volumetric fracturing design method. Summary of the Invention

[0008] To address the problems of existing technologies, this invention provides an unconventional volumetric fracturing design method, which includes the following steps:

[0009] By referencing the perforated section data of the reference well, the length of each perforated section in the target well is determined.

[0010] Calculate the planar distances between each perforated section of the reference well and the target well;

[0011] Based on the designed cluster spacing and the segment length, the number of clusters in each perforated segment of the target well is calculated;

[0012] Based on the data of the perforated well sections, the number of clusters, and the designed cluster spacing, the perforation location of each perforated well section of the target well is calculated;

[0013] Using the length of the artificial fracture as the target, the construction parameters are simulated and optimized. Combined with the plane distance, the limit values ​​of the construction parameters for each perforated section of the target well are determined.

[0014] The section length, the perforation location, and the limit values ​​of the construction parameters are used as the unconventional volumetric fracturing design results for the target well.

[0015] According to one embodiment of the present invention, the length of each perforated section of the target well is determined by the following expression:

[0016]

[0017] In the formula, i represents the serial number of the perforation location of the reference well, which is dimensionless; j represents the serial number of each perforation section of the target well, which is dimensionless; p i Indicates the perforation location of the i-th segment of the reference well, m; p i+1 Indicates the perforation position of the (i+1)th segment of the reference well, m; p i+2 Indicates the perforation location of the (i+2)th segment of the reference well, m; L j Let A represent the length of the j-th segment of the target well, in m; and let A represent the segment boundary value.

[0018] According to one embodiment of the present invention, the method includes the following steps: calculating the planar distance between each perforated section of the reference well and the target well by using the parallel spacing of the drilling trajectory in the drilling and completion report.

[0019] According to one embodiment of the present invention, the number of clusters in each perforated section of the target well is calculated using the following expression:

[0020]

[0021] In the formula, INT represents the design cluster spacing in meters; j represents the serial number of each perforated section of the target well, which is dimensionless; L j Let m represent the length of the j-th segment of the target well; k represents the length of the j-th segment. j represents the number of clusters in the j-th segment of the target well, which is dimensionless; ROUNDDOWN represents the rounding function, which truncates the decimal and rounds down to the nearest integer.

[0022] According to one embodiment of the present invention, the perforation location of each perforated section of the target well is calculated using the following expression:

[0023] T j,n =p i -n*INT(n=1,2,3,...,k j )

[0024] In the formula, i represents the serial number of the reference well perforation location, which is dimensionless; p i Indicates the perforation location of the i-th segment of the reference well, m; k j The number of clusters in the j-th segment of the target well is dimensionless; n represents the number of clusters within the j-th segment. j The serial number is dimensionless; INT represents the design cluster spacing, in meters; T j,n The value m represents the perforation location of the j-th segment of the target well.

[0025] According to an embodiment of the present invention, the construction parameters are simulated and optimized through the following steps: using a fracturing fracture propagation simulation method, based on the reservoir physical parameters, rock mechanical parameters, wellbore parameters, and fluid rheological parameters of the target layer, the artificial fracture length under different construction parameter conditions is simulated to obtain artificial fracture length data.

[0026] According to one embodiment of the present invention, the limit values ​​of the construction parameters for each perforated section of the target well are determined by the following steps:

[0027] Based on the artificial crack length data, a curve showing the relationship between the artificial crack length and the construction parameters is plotted with the construction parameters as the horizontal axis and the artificial crack length as the vertical axis.

[0028] Draw the perpendicular line of the plane distance corresponding to each perforated section to the vertical axis in sequence;

[0029] The intersection of the vertical line and the relationship curve is taken as the limit value of the construction parameters for each perforated section.

[0030] According to one embodiment of the present invention, the construction parameters include, but are not limited to: liquid usage and construction discharge rate.

[0031] According to another aspect of the invention, a storage medium is also provided, which includes a series of instructions for performing the method steps described above.

[0032] According to another aspect of the invention, an unconventional volumetric fracturing design system is also provided, performing the method as described in any of the preceding claims, the system comprising:

[0033] The section length determination module is used to determine the section length of each perforated section in the target well by using the perforated section data of the reference well.

[0034] The planar distance module is used to calculate the planar distance between each perforated section of the reference well and the target well;

[0035] The cluster number determination module is used to calculate the number of clusters in each perforated section of the target well based on the designed cluster spacing and the section length;

[0036] The perforation location module is used to calculate the perforation location of each perforated section of the target well based on the perforated section data, the number of clusters, and the designed cluster spacing.

[0037] The limit value module is used to simulate and optimize construction parameters with the artificial fracture length as the target, and combined with the plane distance, to determine the limit values ​​of construction parameters for each perforated section of the target well.

[0038] The design results module is used to take the section length, the perforation location, and the limit values ​​of the construction parameters as the unconventional volumetric fracturing design results of the target well.

[0039] This invention provides an unconventional volumetric fracturing design method, which has the following advantages compared with existing technologies: This invention employs a staggered sweet spot + multi-cluster perforation + moderate strength process, and optimizes the design of relevant construction parameters (fracturing fluid volume and discharge rate). It avoids selecting sweet spots by staggering the perforated sections of the reference well; simultaneously, it optimizes the difference in reference well section length, using sections exceeding the segmentation boundary value (e.g., 50m) as the boundary for segmentation and implementing multi-cluster perforation according to the existing cluster spacing; furthermore, based on the difference in planar position between the reference well and the target well, it uses the fracture length as a control point to optimize the fluid volume and discharge rate, thereby achieving moderate modification and balancing the construction of artificial fractures with the independence of the reference well fractures.

[0040] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims and drawings. Attached Figure Description

[0041] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0042] Figure 1 A flowchart illustrating the steps of an unconventional volumetric fracturing design method according to an embodiment of the present invention is shown.

[0043] Figure 2 The graph shows the relationship between the fracture length under different fluid volume conditions according to an embodiment of the present invention.

[0044] Figure 3 The graph shows the relationship between the fracture length under different construction displacement conditions according to an embodiment of the present invention.

[0045] In the accompanying drawings, the same parts use the same reference numerals. Also, the drawings are not drawn to scale. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0047] Current volumetric fracturing technology focuses on increasing fracture density and improving the stimulated volume, employing techniques such as high flow rates, high fluid intensity, high proppant intensity, and dense fracture distribution. However, when these techniques are used in replacement wells or parallel replacement wells, they suffer from stress lows caused by long-term production in adjacent wells. Under high flow rates, artificial fractures can lead to multi-point flow, affecting the normal production of adjacent wells. Under high fluid volumes, single-layer conical entry is significant, easily resulting in unidirectional stimulation and poor stimulation effects. Furthermore, high-volume flowback after fracturing adjacent wells is difficult, severely damaging low-permeability tight reservoirs.

[0048] Given the various drawbacks of existing conventional volumetric fracturing technologies, there is an urgent need to develop an unconventional volumetric fracturing process to meet the needs of regeneration wells or parallel replacement wells, and to overcome the challenges of multi-point flow, unidirectional fracturing, and backflow damage.

[0049] To address the aforementioned shortcomings of existing technologies, this invention employs a staggered sweet spot, multi-cluster perforation, and moderate strength process, and optimizes the design of relevant construction parameters (fracturing fluid usage and discharge rate). The purpose of this invention is to provide an unconventional volumetric fracturing design method, offering technical support for the optimized design of reservoir stimulation in renewal wells or parallel replacement wells. This invention is applicable not only to the optimized design of reservoir stimulation in renewal wells but also to the optimized design of reservoir stimulation in parallel replacement wells.

[0050] Figure 1 A flowchart illustrating the steps of an unconventional volumetric fracturing design method according to an embodiment of the present invention is shown.

[0051] like Figure 1 As shown, in step S1, the length of each perforated section of the target well is determined using the perforated section data of the reference well. Specifically, the reference well is an old well, and the target well is a replacement well or a parallel replacement well. Further, an old well refers to a well that already existed before the reservoir stimulation optimization design or construction.

[0052] In one embodiment, in step S1, artificial bottom hole data of the reference well and location data of the perforated section p are collected. i The length of each perforated section of the target well is determined by the following expression (1):

[0053]

[0054] In the formula, i represents the serial number of the perforation location of the reference well, which is dimensionless; j represents the serial number of each perforation section of the target well, which is dimensionless; p i Indicates the perforation location of the i-th segment of the reference well, m; p i+1 Indicates the perforation position of the (i+1)th segment of the reference well, m; p i+2 Indicates the perforation location of the (i+2)th segment of the reference well, m; L j Let A represent the length of the j-th segment of the target well, in m; and let A represent the segment boundary value.

[0055] Specifically, artificial wellbore data can be obtained by consulting the drilling and completion report. i=0 indicates that this well section is an artificial wellbore number. Furthermore, the segment boundary value is set at 50m.

[0056] This invention can avoid the perforated section of the reference well and select the sweet spot of the target well by using expression (1); at the same time, it optimizes the difference in the length of the reference well section and uses the section exceeding the segment boundary value (e.g., 50m) as the boundary segment, which can achieve the unconventional volumetric fracturing design result of the target well with the "misaligned sweet spot" as the goal.

[0057] like Figure 1 As shown, in step S2, the planar distance between each perforated section of the reference well and the target well is calculated.

[0058] In one embodiment, in step S2, the planar distance (e.g., the minimum planar distance within each perforated section) between the reference well and the target well is calculated using the parallel spacing of the drilling trajectories in the drilling and completion report. Specifically, the planar distance S between the reference well and the updated well is collected. i Where, the planar distance S i The spacing is determined by the parallel spacing of the drilling trajectory in the drilling and completion report, where i represents the serial number of the reference well perforation location, which is dimensionless; S i The distance between the reference well and the target well in segment i is expressed in meters.

[0059] like Figure 1 As shown, in step S3, the number of clusters in each perforated section of the target well is calculated based on the designed cluster spacing and section length.

[0060] In one embodiment, in step S2, based on the designed cluster spacing INT, the length L of the j-th segment of the target well is determined. j The number of clusters k for each perforated section of the target well is calculated using the following expression (2). j :

[0061]

[0062] In the formula, INT represents the design cluster spacing in meters; j represents the serial number of each perforated section of the target well, which is dimensionless; L j Let m represent the length of the j-th segment of the target well; k represents the length of the j-th segment. j represents the number of clusters in the j-th segment of the target well, which is dimensionless; ROUNDDOWN represents the rounding function, which truncates the decimal and rounds down to the nearest integer.

[0063] Furthermore, the cluster spacing INT is designed as an empirical value, which can be 13m.

[0064] like Figure 1 As shown, in step S4, the perforation location of each perforated section of the target well is calculated based on the data of the perforated well section, the number of clusters, and the designed cluster spacing.

[0065] In one embodiment, in step S4, based on the reference well perforation position p i The number of clusters k in the j-th segment of the target well j The cluster spacing INT is designed, and the perforation position T of each perforated section of the target well is calculated by the following expression (3). j,n :

[0066] T j,n =p i -n*INT(n=1,2,3,...,k j (3)

[0067] In the formula, i represents the serial number of the reference well perforation location, which is dimensionless; p i Indicates the perforation location of the i-th segment of the reference well, m; k j The number of clusters in the j-th segment of the target well is dimensionless; n represents the number of clusters within the j-th segment. j The serial number is dimensionless; INT represents the design cluster spacing, in meters; T j,n The value m represents the perforation location of the j-th segment of the target well.

[0068] This invention optimizes the difference in reference well section length, using the section exceeding the segmentation boundary value (e.g., 50m) as the boundary for segmentation, and achieves multi-cluster perforation (perforation position T) according to the existing cluster spacing (e.g., the designed cluster spacing). j,n It can achieve unconventional volumetric fracturing design results for target wells with "multi-cluster perforation" as the objective.

[0069] like Figure 1 As shown, in step S5, with the artificial fracture length as the target, the construction parameters are simulated and optimized. Combined with the planar distance, the limit values ​​of the construction parameters for each perforated section of the target well are determined. Specifically, the construction parameters include, but are not limited to: fluid volume V. injec Construction displacement D frac .

[0070] In one embodiment, in step S5, the construction parameters are simulated and optimized through the following steps: using a fracturing fracture propagation simulation method, based on the reservoir physical parameters, rock mechanical parameters, wellbore parameters, and fluid rheological parameters of the target layer, the artificial fracture length under different construction parameter conditions is simulated to obtain artificial fracture length data.

[0071] Specifically, fracturing fracture propagation simulation methods include using fracturing fracture propagation simulation software. Furthermore, fracturing fracture propagation simulation software such as Fracpro PT, Meyer, and Stimplan can be used.

[0072] In one embodiment, in step S5, fracturing fracture propagation simulation software is used to input reservoir physical parameters, rock mechanical parameters, wellbore parameters, and fluid rheological parameters of the target layer, simulating different (fracturing fluid) volumes V. injec Different construction displacements D frac The length F of the artificial crack under the given conditions.

[0073] In one embodiment, the artificial crack length F is related to the liquid volume V. injec Construction displacement D frac The two satisfy the functional relationship (4):

[0074] F = f(V) injec D frac (4)

[0075] In the formula: F is the simulated artificial crack length, in meters; V injec The fracturing fluid dosage is m 3 ;D frac For fracturing operation displacement, m 3 / min.

[0076] In one embodiment, in step S5, the limit values ​​of construction parameters for each perforated section of the target well are determined through the following steps: based on artificial fracture length data, the construction parameters are used as the abscissa and the artificial fracture length is used as the ordinate (e.g., Figure 2 and Figure 3 Plot the relationship curve between the length of the artificial crack and the construction parameters (as shown on the coordinate axes). Figure 2 line b in Figure 3 (e) in the middle; draw the perpendicular lines of the plane distance corresponding to each perforated section to the vertical axis (e.g., line e); Figure 2 line a in Figure 3 (line d in the middle); the intersection of the perpendicular line and the relation curve (e.g., the line ... Figure 2 Intersection point c in Figure 3The intersection point f) is taken as the limit value of the construction parameters for each perforated well section. Furthermore, the limit value of the construction parameters can be regarded as the optimal value of the construction parameters for unconventional volumetric fracturing.

[0077] Specifically, the relationship between the artificial fracture length F and the fracturing fluid volume V can be plotted using the functional relationship (4). injec Construction displacement D frac The relationship curve. Through the planar distance S in step S2. i With fracturing fluid dosage V injec Construction displacement D frac The intersection point represents the limit value. The intersection point is traversed by a planar distance S. i The point where the perpendicular line to the vertical axis intersects the relationship curve is determined.

[0078] This invention is based on the planar position (planar distance S) between the reference well and the target well. i The difference was analyzed by using the crack length F as the control point to optimize the liquid dosage V. injec With construction displacement D frac This allows for appropriate modification, balancing the construction of artificial fractures with the independence of reference well fractures, and achieving "appropriate strength" (using fluid volume V). injec With construction displacement D frac The unconventional volumetric fracturing design results for the target well (with the limit value as the objective).

[0079] like Figure 1 As shown, in step S6, the section length, perforation location, and construction parameter limit values ​​are used as the unconventional volumetric fracturing design results for the target well.

[0080] In one embodiment, based on steps S1 to S5, an unconventional volumetric fracturing design result of "misaligned sweet spot + multiple perforations + moderate strength" is finally formed. In this design result, the length L of the misaligned sweet spot segment is... j The position T of the multi-cluster perforation is calculated and determined in step S1. j,n In steps S3 and S4, the volume of liquid V is determined. injec Construction displacement D frac The limit value is determined in steps S2 and S5.

[0081] This invention first identifies the perforated section data of the reference well and determines the perforated section length of the target well. Then, it calculates the minimum planar distance between each section of the reference well and the target well. Within the section length range, it selects the perforation position of the target well according to the designed cluster spacing to achieve staggered perforation. Then, it uses fracture propagation software with fracture length as the target to simulate and optimize the fluid consumption and construction displacement parameters. Finally, by combining the optimized process parameters, it forms an unconventional volumetric fracturing design result of "staggered sweet spot + multi-cluster perforation + moderate strength".

[0082] This invention employs a staggered sweet spot + multi-cluster perforation + moderate strength process, and optimizes the design of relevant construction parameters (fracturing fluid usage and construction flow rate). It avoids selecting sweet spots in perforated sections of reference wells by staggering the selection of sweet spots; simultaneously, it optimizes the difference in reference well section length, using sections exceeding the segmentation boundary (e.g., 50m) as the boundary for segmentation and implementing multi-cluster perforation according to the existing cluster spacing; furthermore, based on the difference in planar position between the reference well and the target well, it uses fracture length as the control point to optimize fluid usage and construction flow rate, thereby achieving moderate modification while ensuring the construction of artificial fractures and the independence of the reference well fractures.

[0083] The unconventional volumetric fracturing design method provided by this invention can also be used in conjunction with a computer-readable storage medium. The storage medium stores a computer program, which is executed to run the unconventional volumetric fracturing design method. The computer program is capable of executing computer instructions, which include computer program code. The computer program code can be in the form of source code, object code, executable file, or some intermediate form.

[0084] Computer-readable storage media can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc.

[0085] It should be noted that the contents of computer-readable storage media may be appropriately added to or subtracted from the contents according to the requirements of legislation and patent practice in a jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable storage media may not include electrical carrier signals and telecommunication signals.

[0086] According to another aspect of the present invention, an unconventional volumetric fracturing design system is also provided, which executes an unconventional volumetric fracturing design method. The system includes: a segment length determination module, a planar distance module, a cluster number determination module, a perforation location module, a limit value module, and a design result module.

[0087] The segment length determination module is used to determine the segment length of each perforated segment in the target well using data from the perforated segments of the reference well; the planar distance module is used to calculate the planar distance between each perforated segment of the reference well and the target well; the cluster number determination module is used to calculate the number of clusters in each perforated segment of the target well based on the designed cluster spacing and segment length; the perforation location module is used to calculate the perforation location of each perforated segment of the target well based on the data from the perforated segments, the number of clusters, and the designed cluster spacing; the limit value module is used to simulate and optimize the construction parameters with the artificial fracture length as the target, and combined with the planar distance, to determine the limit values ​​of the construction parameters for each perforated segment of the target well; the design result module is used to use the segment length, perforation location, and limit values ​​of the construction parameters as the unconventional volumetric fracturing design result for the target well.

[0088] In one embodiment, the implementation of the present invention is described in detail with reference to examples, taking a tight sandstone renewal well X in the Sichuan Basin as an example.

[0089] Step S1: Collect artificial bottom hole data and perforated section location data from the old well (reference well). i As shown in Table 1, the perforation section length L of the updated well (target well) is calculated using formula (1). j As shown in Table 2.

[0090] Table 1 Perforation parameters of old wells

[0091] <![CDATA[artificial bottom hole p0]]> 3120 <![CDATA[Perforation position p5]]> 2845 <![CDATA[Perforation location p1]]> 3056 <![CDATA[Perforation position p6]]> 2782 <![CDATA[Perforation position p2]]> 2970 <![CDATA[Perforation position p7]]> 2703 <![CDATA[Perforation position p3]]> 2946 <![CDATA[Perforation position p8]]> 2641 <![CDATA[Perforation position p4]]> 2913 <![CDATA[Perforation position p9]]> 2569

[0092] Table 2 Updated well perforation interval length

[0093]

[0094]

[0095] Step S2: Collect the planar distance S between the old well and the new well. i As shown in Table 3.

[0096] Table 3. Horizontal Distance Between Old Wells and New Well Sections

[0097] <![CDATA[Distance S1]]> 143 <![CDATA[Distance S5]]> 248 <![CDATA[Distance S2]]> 132 <![CDATA[Distance S6]]> 109 <![CDATA[Distance S3]]> 125 <![CDATA[Distance S7]]> 198 <![CDATA[Distance S4]]> 161 <![CDATA[Distance S8]]> 86

[0098] Step S3: Based on the designed cluster spacing INT, update the length L of the j-th segment of the well. j The cluster number k of the j-th segment of the updated well is calculated according to formula (2). j The results are shown in Table 4.

[0099] Table 4 Number of clusters in different sections of the updated well

[0100] <![CDATA[Number of clusters k1]]> 4 <![CDATA[Number of clusters k5]]> 4 <![CDATA[Number of clusters k2]]> 6 <![CDATA[Number of clusters k6]]> 6 <![CDATA[Number of clusters k3]]> 4 <![CDATA[Number of clusters k7]]> 4 <![CDATA[Number of clusters k4]]> 5 <![CDATA[Number of clusters k8]]> 5

[0101] Step S4: Based on the location p of the old well perforationi Update the cluster number k of the j-th segment of the well. j The cluster spacing INT is designed, and the perforation position T of the updated well is calculated according to formula (3). j,n The results are shown in Table 5.

[0102] Table 5. Perforation locations in different sections of the updated well.

[0103]

[0104] Step S5: Using fracturing fracture propagation simulation software, input the reservoir physical properties, rock mechanical parameters, wellbore parameters, and fluid rheological parameters of the target layer, as shown in Table 6.

[0105] Table 6. Basic Input Parameters for Acid Fracturing Crack Propagation Simulation

[0106]

[0107]

[0108] Simulate different liquid volumes V injec Different construction displacements D frac Artificial crack length F under certain conditions, F and V injec D frac The two satisfy the functional relationship (4). The planar distance S in step S2 is used to determine this. i Determine the optimal fracturing fluid dosage V injec Construction displacement D frac .

[0109] The relationship between the fracturing fracture length F and the fracturing fluid volume V can be plotted using the functional relationship (4). injec Fracturing operation displacement D frac Relationship curves (such as) Figure 2 line b in Figure 3 Line e) in step S2 passes through the planar distance S. i With fracturing fluid dosage V injec Construction displacement D frac The intersection point represents the limit value. The intersection point is traversed by a planar distance S. i On the vertical axis (e.g.) Figure 2 line a in Figure 3 The point where line d in the middle intersects the curve (e.g., the point where line d in the middle inter Figure 2 Intersection point c in Figure 3 The intersection point f) is determined. For example... Figure 2 , Figure 3 As shown, taking S4 as an example, the amount of fracturing fluid V used in the fourth stage of the updated well is... injec The limit value is 1100m 3 Fracturing operation displacement D frac 13m3 / min.

[0110] Step S6, based on steps S1 to S5, ultimately yields an unconventional volumetric fracturing design result of "misaligned sweet spot + multiple perforations + moderate intensity". This design first calculates the length of the misaligned sweet spot, then determines the location of the multiple perforations, and finally optimizes the fluid usage and perforation limits to ensure no hydraulic channeling. The entire process calculation is divided into 8 segments and 38 clusters. Taking S4 as an example, the maximum fluid usage for the fourth segment of the updated well is set at 1100 m³ / s. 3 Construction displacement 13m 3 / min.

[0111] The method provided by this invention has been applied in more than 10 wells in tight sandstone gas reservoirs, achieving good results. Compared with the conventional volumetric fracturing process used in the previous stages of this gas reservoir without this method, the probability of hydraulic channeling has been reduced by 82% and the average test production has increased by 12.5% ​​after adopting the method provided by this invention.

[0112] In summary, this invention provides an unconventional volumetric fracturing design method, which has the following advantages compared with existing technologies: This invention adopts a staggered sweet spot + multi-cluster perforation + moderate strength process, and optimizes the design of relevant construction parameters (fracturing fluid volume, construction flow rate). It avoids selecting sweet spots by staggering the perforated sections of the reference well; simultaneously, it optimizes the difference in reference well section length, using a segmentation boundary value (e.g., 50m) as the boundary segmentation and implementing multi-cluster perforation according to the existing cluster spacing; furthermore, based on the difference in planar position between the reference well and the target well, it uses the fracture length as a control point to optimize the fluid volume and construction flow rate, thereby achieving moderate modification and balancing the construction of artificial fractures with the independence of the reference well fractures.

[0113] It should be understood that the embodiments disclosed herein are not limited to the specific structures, processing steps, or materials disclosed herein, but should be extended to equivalent substitutions of these features as understood by those skilled in the art. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0114] In the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0115] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0116] Certain terms are used throughout this application to refer to specific system components. As those skilled in the art will recognize, the same components may often be referred to by different names, and therefore this application is not intended to distinguish those components that differ only in name and not in function. In this application, the terms “comprise,” “include,” and “have” are used in an open-ended manner and should therefore be interpreted as meaning “including, but not limited to…”. Furthermore, the terms “substantially,” “materially,” or “approximately” as used herein refer to industry-accepted tolerances for the corresponding terms. The term “coupling,” as may be used herein, includes direct coupling and indirect coupling via additional components, elements, circuits, or modules, wherein, for indirect coupling, the intermediate component, element, circuit, or module does not alter the information of the signal but may adjust its current level, voltage level, and / or power level. Inferred coupling (e.g., one element is inferredly coupled to another element) includes direct and indirect coupling between two elements in the same manner as “coupling.”

[0117] The phrase "an embodiment" or "an embodiment" used in this specification means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Therefore, the phrase "an embodiment" or "an embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0118] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

[0119] While the embodiments disclosed in this invention are as described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and variations in form and detail of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection for this invention shall still be determined by the scope defined in the appended claims.

Claims

1. An unconventional volumetric fracturing design method, characterized in that, The method includes the following steps: By referencing the perforated section data of the reference well, the length of each perforated section in the target well is determined. Calculate the planar distances between each perforated section of the reference well and the target well; Based on the designed cluster spacing and the segment length, the number of clusters in each perforated segment of the target well is calculated; Based on the data of the perforated well sections, the number of clusters, and the designed cluster spacing, the perforation location of each perforated well section of the target well is calculated; Using the length of the artificial fracture as the target, the construction parameters are simulated and optimized. Combined with the plane distance, the limit values ​​of the construction parameters for each perforated section of the target well are determined. The section length, the perforation location, and the limit values ​​of the construction parameters are used as the unconventional volumetric fracturing design results for the target well.

2. The unconventional volumetric fracturing design method as described in claim 1, characterized in that, The length of each perforated section of the target well is determined by the following expression: In the formula, i represents the serial number of the perforation location of the reference well, which is dimensionless; j represents the serial number of each perforation section of the target well, which is dimensionless; p i Indicates the perforation location of the i-th segment of the reference well, m; p i+1 Indicates the perforation position of the (i+1)th segment of the reference well, m; p i+2 Indicates the perforation location of the (i+2)th segment of the reference well, m; L j Let A represent the length of the j-th segment of the target well, in m; and let A represent the segment boundary value.

3. An unconventional volumetric fracturing design method as described in claim 1 or 2, characterized in that, The method includes the following steps: calculating the planar distance between each perforated section of the reference well and the target well by using the parallel spacing of the drilling trajectory in the drilling and completion report.

4. An unconventional volumetric fracturing design method as described in any one of claims 1-3, characterized in that, The number of clusters in each perforated section of the target well is calculated using the following expression: In the formula, INT represents the design cluster spacing in meters; j represents the serial number of each perforated section of the target well, which is dimensionless; L j Let m represent the length of the j-th segment of the target well; k represents the length of the j-th segment. j represents the number of clusters in the j-th segment of the target well, which is dimensionless; ROUNDDOWN represents the rounding function, which truncates the decimal and rounds down to the nearest integer.

5. An unconventional volumetric fracturing design method as described in any one of claims 1-4, characterized in that, The perforation location of each perforated section of the target well is calculated using the following expression: T j,n =p i -n*INT(n=1,2,3,...,k j ) In the formula, i represents the serial number of the reference well perforation location, which is dimensionless; p i Indicates the perforation location of the i-th segment of the reference well, m; k j The number of clusters in the j-th segment of the target well is dimensionless; n represents the number of clusters within the j-th segment. j The serial number is dimensionless; INT represents the design cluster spacing, in meters; T j,n The value m represents the perforation location of the j-th segment of the target well.

6. An unconventional volumetric fracturing design method as described in any one of claims 1-5, characterized in that, The construction parameters are simulated and optimized through the following steps: using the fracturing fracture propagation simulation method, based on the reservoir physical parameters, rock mechanical parameters, wellbore parameters, and fluid rheological parameters of the target layer, the artificial fracture length under different construction parameter conditions is simulated and the artificial fracture length data is obtained.

7. The unconventional volumetric fracturing design method as described in claim 6, characterized in that, The following steps are used to determine the limit values ​​of the construction parameters for each perforated section of the target well: Based on the artificial crack length data, a curve showing the relationship between the artificial crack length and the construction parameters is plotted with the construction parameters as the horizontal axis and the artificial crack length as the vertical axis. Draw the perpendicular line of the plane distance corresponding to each perforated section to the vertical axis in sequence; The intersection of the vertical line and the relationship curve is taken as the limit value of the construction parameters for each perforated section.

8. An unconventional volumetric fracturing design method as described in any one of claims 1-7, characterized in that, The construction parameters include, but are not limited to: liquid usage and construction discharge rate.

9. A storage medium, characterized in that, It includes a series of instructions for performing the method steps as described in any one of claims 1-8.

10. An unconventional volumetric fracturing design system, characterized in that, The system, which performs the method as described in any one of claims 1-8, comprises: The section length determination module is used to determine the section length of each perforated section in the target well by using the perforated section data of the reference well. The planar distance module is used to calculate the planar distance between each perforated section of the reference well and the target well; The cluster number determination module is used to calculate the number of clusters in each perforated section of the target well based on the designed cluster spacing and the section length; The perforation location module is used to calculate the perforation location of each perforated section of the target well based on the perforated section data, the number of clusters, and the designed cluster spacing. The limit value module is used to simulate and optimize the construction parameters with the artificial fracture length as the target, and combined with the plane distance, to determine the limit values ​​of the construction parameters for each perforated section of the target well. The design results module is used to take the section length, the perforation location, and the limit values ​​of the construction parameters as the unconventional volumetric fracturing design results of the target well.

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