A method and apparatus for fracturing a horizontal well in a tight sand formation

Abstract

A method and device for determining fracturing segmentation of a horizontal well in compact sandstone, the method comprising: determining an initial fracturing segment number of the horizontal well by using logging data and well logging interpretation data; determining a plurality of maximum influencing factors of the horizontal well production and establishing an orthogonal experiment; determining a first influencing factor according to a result of the orthogonal experiment; and adjusting the initial fracturing segment number according to the first influencing factor and determining a final fracturing segment number of the horizontal well.

Description

Technical Field

[0001] This article relates to the field of tight sandstone reservoir fracturing technology, and in particular to a method and apparatus for identifying water-flooded layers in infill wells. Background Technology

[0002] Recent development practices in various regions of my country have demonstrated that fracturing horizontal wells are a key technology for the effective exploitation of unconventional gas reservoirs. Accurately and efficiently obtaining optimal fracture parameters and well network deployment can provide crucial assistance to oil and gas field decision-makers. In the fracturing development of horizontal wells in unconventional oil and gas reservoirs, fracturing optimization design is mainly carried out using methods such as manual scheme design combined with numerical simulation. However, this method cannot accurately obtain globally optimal parameters, and manual scheme design is time-consuming and labor-intensive.

[0003] Therefore, how to scientifically optimize the horizontal well fracturing segmentation method is an urgent problem to be solved. Summary of the Invention

[0004] This application provides a method and apparatus for fracturing and segmenting a horizontal well in tight sandstone. The application can determine the maximum influencing factor for fracturing and segmenting a horizontal well through orthogonal experiments, and design the number of fracturing segments for a horizontal well in tight sandstone based on the determined maximum influencing factor.

[0005] In a first aspect, this application provides a method for determining the fracturing stages in a tight sandstone horizontal well, the method comprising:

[0006] Determine the initial number of fracturing stages in a horizontal well using logging data and well logging interpretation data;

[0007] Identify the major factors influencing horizontal well production and establish orthogonal experiments;

[0008] The first influencing factor was determined based on the results of the orthogonal experiment.

[0009] The initial number of fracturing stages is adjusted based on the first influencing factor, and the final number of horizontal well fracturing stages is determined.

[0010] Optionally, the determination of multiple fracture influencing factors for horizontal well production and the establishment of orthogonal experiments include:

[0011] Numerical simulation analysis was used to determine the relationship between each influencing factor and production capacity.

[0012] Select multiple factors influencing cracks based on the relationship between influencing factors and production capacity;

[0013] An orthogonal experiment was established based on the selected factors affecting cracks.

[0014] Optionally, the factors affecting the crack include: crack half-length, crack conductivity, and number of cracks.

[0015] Optionally, determining the first influencing factor based on the orthogonal experimental results includes:

[0016] For each scheme in the orthogonal experiment, the yield increase multiple and extraction rate were calculated respectively;

[0017] Based on the production increase multiple and extraction degree corresponding to each scheme, calculate the production increase multiple range and extraction degree range corresponding to each influencing factor;

[0018] The first influencing factor is determined based on the range of the production increase multiple and the range of the extraction degree.

[0019] Optionally, determining the first influencing factor based on the range of the yield increase multiple and the range of the extraction degree includes:

[0020] The range values ​​of the yield increase multiples are sorted to determine the factor corresponding to the largest range value of the yield increase multiple;

[0021] The extraction degree range values ​​are sorted to determine the factor corresponding to the largest extraction degree range value;

[0022] If the factor corresponding to the largest range of the yield increase multiple is the same as the factor corresponding to the largest range of the extraction degree, then that factor shall be taken as the first influencing factor.

[0023] If the factor corresponding to the largest range of the yield increase multiple is different from the factor corresponding to the largest range of the extraction degree, then the factor corresponding to the largest range of the yield increase multiple shall be taken as the first influencing factor.

[0024] Optionally, the first influencing factor is the number of cracks.

[0025] Optionally, adjusting the initial number of fracturing stages based on the first influencing factor and determining the final number of horizontal well fracturing stages includes:

[0026] The single fracture yield for each number of initial fracturing stages is determined, and the yield corresponding to different number of stages is determined.

[0027] The final number of horizontal well fracturing stages is determined based on the production output corresponding to different stages.

[0028] Optionally, the formula for the single crack production is:

[0029]

[0030] In the above formula, P e For reservoir pressure, p f Q is the bottom hole flow pressure, μ is the fluid viscosity, and Q is the fluid viscosity. fFor single fracture production, H is reservoir thickness, R is supply radius, k is permeability, l is fracture half-length, d is the spacing between fractures, and N is the production rate. f This represents the number of fracturing stages.

[0031] Secondly, this application also provides an apparatus for determining the fracturing segments of a horizontal well in tight sandstone, the apparatus comprising: a memory and a processor; the memory is used to store a program for determining the fracturing segments of a horizontal well in tight sandstone, and the processor is used to read and execute the program for determining the fracturing segments of a horizontal well in tight sandstone, and to execute the method described in any of the above embodiments.

[0032] Thirdly, this application also provides a computer-readable storage medium storing a data processing program, which is executed by a processor as described in any of the above embodiments, using a method for determining fracturing segments in a tight sandstone horizontal well.

[0033] Compared with related technologies, this application provides a method and apparatus for identifying water-flooded layers in infill wells. The method includes: determining the initial number of fracturing stages in a horizontal well using logging data and well interpretation data; determining multiple maximum influencing factors on the horizontal well production and establishing an orthogonal experiment; determining a first influencing factor based on the orthogonal experiment results; adjusting the initial number of fracturing stages based on the first influencing factor; and determining the final number of fracturing stages in the horizontal well. This application can determine the maximum influencing factor on the fracturing stages of a horizontal well through orthogonal experiments, and determine the number of fracturing stages in a tight sandstone horizontal well based on this determined maximum influencing factor.

[0034] Other features and advantages of this application will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the application. Other advantages of this application can be realized and obtained by means of the solutions described in the description and the accompanying drawings. Attached Figure Description

[0035] The accompanying drawings are used to provide an understanding of the technical solutions of this application and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of this application and do not constitute a limitation on the technical solutions of this application.

[0036] Figure 1 This is a flowchart illustrating the method for determining fracturing segments in a tight sandstone horizontal well according to an embodiment of this application.

[0037] Figure 2 This is a schematic diagram of an apparatus for determining the fracturing stages of a horizontal well in tight sandstone, according to an embodiment of this application.

[0038] Figure 3 This is a schematic diagram illustrating the difference in production multiplier and recovery rate of a fractured horizontal well in an exemplary embodiment.

[0039] Figure 4 This is a schematic diagram illustrating the effect of the number of fracturing stages on the stable production time of a fracturing horizontal well in an exemplary embodiment.

[0040] Figure 5 This is a schematic diagram illustrating the impact of the number of fracturing stages on the cumulative production of a fracturing horizontal well in an exemplary embodiment.

[0041] Figure 6 This is a schematic diagram illustrating the effect of the number of fractures on the production multiplier and recovery rate of a fractured horizontal well in an exemplary embodiment. Detailed Implementation

[0042] This application describes several embodiments, but these descriptions are exemplary and not restrictive, and it will be apparent to those skilled in the art that many more embodiments and implementations are possible within the scope of the embodiments described herein. Although many possible combinations of features are shown in the drawings and discussed in the detailed description, many other combinations of the disclosed features are also possible. Unless specifically limited, any feature or element of any embodiment may be used in combination with, or may replace, any feature or element of any other embodiment.

[0043] This application includes and contemplates combinations of features and elements known to those skilled in the art. The embodiments, features, and elements disclosed in this application may also be combined with any conventional features or elements to form a unique inventive scheme as defined by the claims. Any feature or element of any embodiment may also be combined with features or elements from other inventive schemes to form another unique inventive scheme as defined by the claims. Therefore, it should be understood that any feature shown and / or discussed in this application may be implemented individually or in any suitable combination. Therefore, the embodiments are not limited except by the limitations imposed by the appended claims and their equivalents. Furthermore, various modifications and changes may be made within the scope of the appended claims.

[0044] Furthermore, in describing representative embodiments, the specification may have presented methods and / or processes as a specific sequence of steps. However, the method or process should not be limited to the specific order of steps described herein, to the extent that it does not depend on such a specific order. As will be understood by those skilled in the art, other sequences of steps are also possible. Therefore, the specific order of steps set forth in the specification should not be construed as a limitation of the claims. Moreover, the claims concerning the method and / or process should not be limited to the steps performed in the written order, and those skilled in the art will readily understand that these orders can be varied and still remain within the spirit and scope of the embodiments of this application.

[0045] This invention provides a method for determining the fracturing stages in a horizontal well in tight sandstone, such as... Figure 1 As shown, the method includes steps S100-S130:

[0046] S100: Determine the initial number of fracturing stages in a horizontal well using logging data and well logging interpretation data;

[0047] S110: Determine multiple factors affecting horizontal well production based on fractures and establish orthogonal experiments;

[0048] S120: Determine the first influencing factor based on the orthogonal experiment results;

[0049] S130: Adjust the initial number of fracturing stages based on the first influencing factor, and determine the final number of horizontal well fracturing stages.

[0050] In one exemplary embodiment, multiple crack influencing factors are selected from the influencing factors, and an orthogonal experiment is established, including:

[0051] The first step is to use numerical simulation analysis to analyze the relationship between each influencing factor and production capacity.

[0052] The numerical simulation analysis method used here can be implemented using existing methods, and there are no specific limitations on this. Through analysis, the relationship between each influencing factor and production capacity can be determined.

[0053] The second step is to select multiple factors affecting cracks from the relationship between influencing factors and production capacity.

[0054] Analysis can identify the main factors affecting production capacity caused by cracks. These factors include crack half-length, crack conductivity, and number of cracks.

[0055] The third step is to establish an orthogonal experiment based on the selected effects of various cracks.

[0056] In this step, an orthogonal experiment can be established using the crack half-length, crack conductivity, and number of cracks to determine the maximum crack influencing factor on production capacity.

[0057] In one exemplary embodiment, determining the first influencing factor based on the orthogonal experimental results includes:

[0058] The first step is to calculate the yield increase factor and extraction rate for each scheme in the orthogonal experiment.

[0059] The second step is to calculate the range of production increase multiples and the range of extraction degree for each influencing factor based on the production increase multiple and extraction degree of each scheme;

[0060] The third step is to determine the first influencing factor based on the range of production increase multiples and the range of extraction degree.

[0061] In one exemplary embodiment, determining the first influencing factor based on the range of the yield increase multiple and the range of extraction degree is as follows:

[0062] The range of yield increase multiples is sorted to determine the factor corresponding to the largest range of yield increase multiples;

[0063] The extraction rate range values ​​are sorted to determine the factor corresponding to the smallest extraction rate range;

[0064] If the factor corresponding to the largest range of the yield increase multiple is the same as the factor corresponding to the largest range of the extraction degree, then that factor shall be taken as the first influencing factor.

[0065] If the factor corresponding to the largest range of the yield increase multiple is different from the factor corresponding to the largest range of the extraction degree, then the factor corresponding to the largest range of the yield increase multiple shall be taken as the first influencing factor.

[0066] In one exemplary embodiment, adjusting the initial number of fracturing segments based on the maximum influencing factor and determining the final number of horizontal well fracturing segments includes:

[0067] The first step is to determine the single crack output for each segment number based on the initial number of segments, and to determine the output corresponding to different segment numbers.

[0068] The output of a single crack is:

[0069]

[0070] In the above formula, P e For reservoir pressure, p f Q is the bottom hole flow pressure, μ is the fluid viscosity, and Q is the fluid viscosity. f For a single fracture, H is the reservoir thickness, R is the supply radius (this value varies from region to region, but can be constant within the same block), k is the permeability, l is the fracture half-length, d is the spacing between fractures, and N is the production rate. f This represents the total number of fractures, which is also the number of fracturing segments.

[0071] The second step is to determine the final number of horizontal well fracturing stages based on the production output corresponding to different stages.

[0072] Secondly, this application also provides an apparatus for determining the fracturing stages in a tight sandstone horizontal well, such as... Figure 2As shown, the device includes a memory and a processor; the memory is used to store a program for determining the fracturing segments of a tight sandstone horizontal well, and the processor is used to read and execute the program for determining the fracturing segments of a tight sandstone horizontal well, and execute the method described in any of the above embodiments.

[0073] Thirdly, this application also provides a computer-readable storage medium storing a data processing program, which is executed by a processor as described in any of the above embodiments, using a method for determining fracturing segments in a tight sandstone horizontal well.

[0074] This application has the following technical advantages:

[0075] First, by organically combining orthogonal experiments and the production formula for a single fracture in a horizontal well with the fracturing segmentation of a horizontal well, the fracturing segmentation of a horizontal well can be scientifically determined.

[0076] Second, it is widely applicable to horizontal well development in tight sandstone reservoirs, providing strong support for increasing reservoir stimulation volume and horizontal well production. Moreover, it is more time-saving and labor-saving than fracturing optimization design using manual scheme design combined with numerical simulation and other methods.

[0077] Example 1

[0078] This example demonstrates an optimized design method for staged fracturing of horizontal wells in tight sandstone, as detailed below:

[0079] 1. Determining the section length

[0080] By comprehensively utilizing geological research results such as well logging and well logging interpretation, the fractured well sections are divided according to lithology, physical properties, and gas content;

[0081] 2. Selection of perforation clusters

[0082] The choice between single-stage single-cluster fracturing or single-stage multi-cluster fracturing is made based on the thickness and development of the reservoir and interlayers.

[0083] Generally, single-cluster fracturing is used for thick layers with large vertical spans or thin interbedded layers with strong heterogeneity; multi-cluster fracturing within a segment can be used for reservoirs with small to medium vertical spans and relatively homogeneous upper and lower strata.

[0084] 3. Selection of perforation direction

[0085] Depending on the development of the interbedded mudstone well section encountered during drilling, directional or spiral hole layout may be adopted.

[0086] 4. Perforation location

[0087] The perforation location should avoid the phase transition mudstone between the river channels, and high gas logging and low GR points should be selected as perforation points. At the same time, the location of casing couplings and poor cementing quality should be avoided. The perforation layout should be staggered with that of adjacent horizontal wells as much as possible.

[0088] 5. Bridge plug location: Select a well section with good cementing quality, while avoiding casing couplings;

[0089] 6. Prevent pressure channeling risk: Optimize the distance between the first and last fracturing points and adjacent wells based on the dynamic conditions and pressure status of adjacent wells.

[0090] 7. Segment Spacing Optimization: 6 fracturing stages, horizontal stress difference 10 MPa, elastic modulus 24 GPa, Poisson's ratio 0.24, fracture height 40 m, displacement 3.5 m³ / min, segment spacing s set to 40, 50, 60, and 70 m.

[0091] When the segment spacing is 40m, inter-crack interference is significant; when the segment spacing is greater than 50m, subsequent cracks propagate along the direction of the maximum horizontal principal stress and are less affected by the induced stress field. The horizontal induced stress decreases with increasing distance from the crack surface, and the induced stress difference first increases and then decreases with increasing distance from the crack surface, with a maximum value for the induced stress difference. When the induced stress difference is greater than the original horizontal stress difference, inter-crack interference is significant.

[0092] When the segment spacing is 40m, the subsequent cracks are near the location of the maximum induced stress difference, causing a reversal of the stress field and a deflection of the crack propagation path. Simultaneously, the subsequent cracks are subjected to significant induced stress compression, resulting in a smaller crack width. When the segment spacing is greater than 50m, the subsequent hydraulic fracturing cracks are farther from the already fractured surface, resulting in a smaller induced stress difference. The cracks still extend along the direction of maximum horizontal stress, leading to a larger crack width. Therefore, based on the results of physical simulation experiments, a segment spacing of 60m or more is recommended.

[0093] 8. Analysis of the impact of fracture half-length, conductivity, and number of fractures on horizontal well production.

[0094] Using the formula and orthogonal experimental design method, a simulation study was conducted. The three horizontal values ​​that have the greatest impact on the productivity of fractured horizontal wells were selected: fracture half-length, conductivity, and number of fractures. An orthogonal scheme was designed, and the most important factor affecting fractures—the number of fractures—was determined based on the orthogonal experiment.

[0095] 9. Optimization of the number of fracturing stages: Determine the number of stages based on the length of the horizontal stage.

[0096] Based on the maximum impact scheme determined in step 8, which is the number of fractures, i.e. the number of fracturing stages, numerical simulation is performed based on the initial number of fracturing stages. Combined with the fracture production calculation formula, the optimal number of fracturing stages is determined.

[0097] Example 1

[0098] This example selects the Shanxi Formation and He8 Member of the xx Block in the Ordos Basin as the research object, and the specific implementation process of the segmented fracturing optimization design method for tight sandstone horizontal wells is shown below:

[0099] Step 1: Preliminary division of fracturing well sections and determination of fracturing section length.

[0100] Based on the comprehensive utilization of geological research results such as well logging and well interpretation, the fractured well sections are initially divided according to lithology, physical properties, and gas content; the spacing between fractured sections in the xx block is generally 100-150m.

[0101] Step 2, Perforation Cluster Selection

[0102] The choice between single-stage single-cluster fracturing or single-stage multi-cluster fracturing depends on the thickness and development of the reservoir and interlayers.

[0103] For example, single-cluster fracturing is used for thick layers with large vertical spans or thin interbedded layers with strong heterogeneity; multi-cluster fracturing within a segment is used for reservoirs with small to medium vertical spans and relatively homogeneous upper and lower interlayers.

[0104] Step 3: Selection of perforation direction

[0105] Depending on the development of the interbedded mudstone sections encountered during drilling, either directional perforation or spiral perforation can be used. If the upper interbedded mudstone is well-developed, directional perforation should be directed downwards; if the lower interbedded mudstone is well-developed, directional perforation should be directed upwards. If neither the upper nor lower reservoirs have interbedded mudstone, spiral perforation should be selected.

[0106] Step 4, Perforation location

[0107] Select high gas logging and low GR points as perforation points, while avoiding locations with poor casing couplings and cementing quality; and design perforation patterns that are staggered with adjacent horizontal wells as much as possible.

[0108] Step 5, Bridge plug location

[0109] Choose well sections with good cementing quality and avoid casing couplings.

[0110] Step 6: Prevent pressure channeling risks

[0111] Optimize the distance between the first and last fracturing points and the adjacent wells based on the dynamic conditions and pressure status of the adjacent wells.

[0112] Step 7: Determine the optimal segment spacing

[0113] Model parameters: 6-stage hydraulic fracturing, horizontal stress difference 10 MPa, elastic modulus 24 GPa, Poisson's ratio 0.24, fracture height 40 m, displacement 3.5 m³ / h 3 / min, with the segment spacing s set to 40, 50, 60, or 70m.

[0114] Simulation results using the above model parameters show that when the segment spacing is 40m, inter-crack interference is significant; when the segment spacing is greater than 50m, subsequent cracks propagate along the direction of the maximum horizontal principal stress and are less affected by the induced stress field. Numerical simulation results show that the horizontal induced stress decreases with increasing distance from the crack surface, and the induced stress difference first increases and then decreases with increasing distance from the crack surface, exhibiting a maximum value. When the induced stress difference exceeds the original horizontal stress difference, inter-crack interference is significant.

[0115] When the segment spacing is 40m, the subsequent cracks are near the location of the maximum induced stress difference, causing a reversal of the stress field and a deflection of the crack propagation path. Simultaneously, the subsequent cracks are subjected to significant induced stress compression, resulting in a smaller crack width. When the segment spacing is greater than 50m, the subsequent fracturing cracks are farther from the already fractured surface, resulting in a smaller induced stress difference. The cracks still extend along the direction of maximum horizontal stress, leading to a larger crack width. Therefore, based on the experimental results, it is recommended that the segment spacing be shortened to the range of 50–60m.

[0116] Step 8: Analysis of the impact of fracture half-length, conductivity, and number of fractures on horizontal well production.

[0117] Numerical simulation studies were conducted using orthogonal experimental design with the aid of formulas. Three horizontal values ​​with the greatest impact on the productivity of fractured horizontal wells were selected, and an orthogonal scheme was designed. Numerical simulation software revealed that the three horizontal values ​​with the greatest impact on the productivity of fractured horizontal wells are fracture half-length, conductivity, and number of fractures.

[0118] The fracture half-lengths were set to 160, 180, 200, and 220 m, respectively; the conductivity was set to 10, 20, 30, and 40 μm, respectively. 2 • cm; the number of cracks was set to 5, 6, 7, and 8 respectively. An orthogonal design experiment was conducted using the parameter values ​​of the above three factors. The factor level design is shown in Table 1, the table of factor level values ​​for the orthogonal experiment.

[0119] Table 1

[0120]

[0121] Based on the factor level values ​​of the orthogonal experimental design, the orthogonal experimental table in Table 1 was selected for scheme design, simulation calculation and result analysis. The simulation calculation and results are shown in Table 2 Numerical Simulation Orthogonal Design Table and Results.

[0122] Table 2

[0123]

[0124]

[0125] The numerical simulation results in Table 2 show the production increase multiple and extraction rate for each scheme.

[0126] Using the formula, an orthogonal experimental design method was adopted to conduct simulation research. The three horizontal values ​​that have the greatest impact on the productivity of fractured horizontal wells were selected: fracture half-length, conductivity, and number of fractures. An orthogonal scheme was designed.

[0127] After designing the orthogonal scheme, orthogonal experiments can determine that the number of fractures has the greatest impact, followed by the fracture half-length, and then the conductivity.

[0128] Fracture half-length is the distance a fracture extends radially from the wellbore into the coal reservoir after reservoir fracturing. It generally refers to the length of a horizontal fracture.

[0129] The range reflects the degree of influence of a certain factor on the evaluation index. The larger the range, the greater the influence of that factor on the index.

[0130] Range Calculation Method: Taking the crack half-length as an example, the calculation method for the range of the yield increase multiple is as follows: First, determine the yield increase multiple value in the four schemes of the orthogonal experiment corresponding to a crack half-length of 160m; Second, calculate the average value of the yield increase multiple values ​​in the four schemes: (6.2+7.7+9.1+10.4) / 4=8.35; Third, calculate the average value of the yield increase multiple values ​​corresponding to crack half-lengths of 180, 200, and 220m respectively; Fourth, determine the maximum and minimum values ​​of the average value under each crack half-length, as shown in Table 3, the average value table of yield increase multiples; Fifth, calculate the range value based on the maximum and minimum values. The range value is the difference between the maximum and minimum values, i.e., range = maximum value - minimum value.

[0131] Taking the extraction degree of conductivity as an example, the conductivity is calculated to be 10μm. 2 The average extraction rate in the orthogonal experiment corresponding to ·cm is (45.3+46.7+48.6+50) / 4=47.65, and then the conductivity is calculated to be 20μm. 2 ·cm, 30μm 2 ·cm, 40μm 2 The average sampling degree in the orthogonal experiment corresponding to cm is shown in Table 4. Finally, the sampling degree range is obtained by subtracting the minimum value from the maximum value among all average values.

[0132] Table 3

[0133] Mean 1 8.350 8.700 8.500 Mean 2 10.300 10.225 9.875 Mean 3 11.050 11.075 10.875 Mean 4 11.950 11.650 12.400 Range 3.600 2.950 3.900

[0134] Table 4

[0135] Mean 1 46.925 47.650 46.300 Mean 2 47.275 47.700 47.375 Mean 3 48.125 47.850 48.425 Mean 4 48.750 47.875 48.975 Range 1.825 0.225 2.675

[0136] pass Figure 3The range chart of production increase factor and recovery rate of fractured horizontal wells shows that... Figure 3 Figure a shows the range of yield increase multiples. Figure 3 Figure b shows the production range. By comparing and analyzing these two results, and combining them with the range data in Tables 3 and 4, it can be determined that the factor that has the greatest impact on the production of tight gas reservoirs is the number of fractures, followed by the fracture half-length and fracture conductivity.

[0137] Therefore, in order to achieve higher gas well productivity after fracturing, the number and length of fractures should be increased without inter-fracture interference. The number of fractures has the most important effect on the recovery rate of tight gas reservoirs, followed by the fracture half-length. The conductivity of fractures has a very small impact on the degree of gas recovery.

[0138] Step 9: Determine the production rate and the final number of fracturing sections based on the length of the horizontal section and the number of fractures.

[0139] Assume a gas reservoir with thickness H and permeability k, and a horizontal well with a single fracture producing Q. f Given the reservoir pressure Pe, bottomhole flowing pressure pf, fluid viscosity μ, fracture half-length l, fracture height equal to reservoir thickness H, supply radius R, and spacing between fractures d, the formula for single fracture production is derived:

[0140]

[0141] Based on the calculated yield of a single fracture, the total yield of the fracturing section can be calculated, and the optimal number of fractures can be determined based on the total yield of the fracturing section.

[0142] In this example, for a 1200m horizontal section, numerical simulations were performed to determine the number of years of stable production and cumulative production of fractured horizontal wells with 4, 6, 8, 10, 12, and 14 fractures. The basic model parameters remained unchanged, with the fracture half-length set at 200m and the fracture conductivity at 25μm. 2 The cracks are .cm in size and evenly spaced perpendicular to the horizontal wellbore. Simulation results are as follows: Figure 4 The diagram shows the effect of the number of fracturing stages on the stable production time of a fracturing horizontal well.

[0143] Figure 4 Figure a shows a depth of 0.05 mD, figure b shows 0.1 mD, figure c shows 0.25 mD, and figure d shows 0.8 mD. The results indicate that in reservoirs with low permeability, such as... Figure 4 In Figure a, 0.05mD and Figure 4 In Figure b, with a fracture count of 0.1mD, increasing the number of fractures significantly increases the stabilization time. However, when the number of fractures exceeds 12, the increase in stabilization time due to fractures is not significant. In reservoirs with good permeability, such as... Figure 4In the d-figure of 0.8mD, the number of fractures has little impact on the stable production time and plays a role in inter-fracture interference, resulting in a smaller daily production during the production decline period, which is not conducive to the exploitation of the gas reservoir.

[0144] The impact of the number of cracks on cumulative production is as follows: Figure 5 The diagram illustrates the impact of the number of fracturing stages on the cumulative production of a fracturing horizontal well. Figure 5 Figure a in the diagram illustrates the impact of the number of fracturing stages at a depth of 0.05 mD on the cumulative production of a fracturing horizontal well. Figure 5 Figure b in the diagram illustrates the impact of the number of fracturing stages (0.1 mD) on the cumulative production of a fracturing horizontal well. Figure 5 Figure c in the diagram illustrates the impact of the number of fracturing stages (0.25 mD) on the cumulative production of a fracturing horizontal well. Figure 5 The d-plot in the diagram illustrates the impact of the number of fracturing stages (0.8 mD) on the cumulative production of a fracturing horizontal well. From... Figure 5 A comparative analysis of the results under four scenarios showed that as the number of fractures increased from 4 to 8, the cumulative gas production of the fractured horizontal well exhibited a significant upward trend. However, the rate of increase slowed down after the number of fractures reached 8. It is noteworthy that in low-permeability environments, a smaller number of fractures results in lower production rates. Conversely, in areas with better permeability... Figure 5 The d-diagram shows a value of 0.8mD, indicating that a relatively small number of cracks is sufficient to meet production requirements.

[0145] The effect of the number of fractures on the production multiplier and recovery rate of fractured horizontal wells, as follows: Figure 6 As shown in the figure, the results indicate that when the number of fractures increases from 4 to 8, the gas well production multiplier and reservoir recovery rate increase linearly. However, when the number of fractures exceeds 12, the increase in both the gas well production multiplier and reservoir recovery rate slows down. This is because as the number of fractures increases, the fracture spacing decreases, leading to inter-fracture interference during pressure propagation and affecting the production capacity of the fractured horizontal well. Although increasing the number of fractures can accelerate reservoir development, blindly increasing the number of fractures can lead to a significant increase in extraction costs. Fracturing design requires specific optimization of the number of fractures, or the use of unequal-length fracture distribution to reduce inter-fracture interference. Therefore, based on the above analysis, designing 8–12 fractures is more reasonable for a 1200-meter-long horizontal well section.

[0146] It will be understood by those skilled in the art that all or some of the steps, systems, or apparatuses disclosed above, and their functional modules / units, can be implemented as software, firmware, hardware, or suitable combinations thereof. In hardware implementations, the division between functional modules / units mentioned above does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed collaboratively by several physical components. Some or all components may be implemented as software executed by a processor, such as a digital signal processor or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit (ASIC). Such software may be distributed on a computer-readable medium, which may include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and can be accessed by a computer. Furthermore, it is well known to those skilled in the art that communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

Claims

1. A method for determining the fracturing stages in a horizontal well of tight sandstone, characterized in that, The method includes: Determine the initial number of fracturing stages in a horizontal well using logging data and well logging interpretation data; Multiple factors affecting the production of horizontal wells with fractures were identified, and orthogonal experiments were established. The first influencing factor was determined based on the results of the orthogonal experiment. The initial number of fracturing stages is adjusted based on the first influencing factor, and the final number of horizontal well fracturing stages is determined.

2. The method for determining the fracturing stages of a horizontal well in tight sandstone according to claim 1, characterized in that, The determination of multiple fracture-related factors affecting horizontal well production and the establishment of orthogonal experiments include: Numerical simulation analysis was used to determine the relationship between each influencing factor and production capacity. Select multiple factors influencing cracks based on the relationship between influencing factors and production capacity; An orthogonal experiment was established based on the selected factors affecting cracks.

3. The method for determining the fracturing stages of a horizontal well in tight sandstone according to claim 2, characterized in that, The factors affecting cracks include: crack half-length, crack conductivity, and number of cracks.

4. The method for determining the fracturing stages of a horizontal well in tight sandstone according to claim 3, characterized in that, The determination of the first influencing factor based on the orthogonal experiment results includes: For each scheme in the orthogonal experiment, the yield increase multiple and extraction rate were calculated respectively; Based on the production increase multiple and extraction degree corresponding to each scheme, calculate the production increase multiple range and extraction degree range corresponding to each influencing factor; The first influencing factor is determined based on the range of the production increase multiple and the range of the extraction degree.

5. The method for determining the fracturing stages of a horizontal well in tight sandstone according to claim 4, characterized in that, The determination of the first influencing factor based on the range of the yield increase multiple and the range of the extraction degree includes: The range values ​​of the yield increase multiples are sorted to determine the factor corresponding to the largest range value of the yield increase multiple; The extraction degree range values ​​are sorted to determine the factor corresponding to the largest extraction degree range value; If the factor corresponding to the largest range of the yield increase multiple is the same as the factor corresponding to the largest range of the extraction degree, then that factor shall be taken as the first influencing factor. If the factor corresponding to the largest range of the yield increase multiple is different from the factor corresponding to the largest range of the extraction degree, then the factor corresponding to the largest range of the yield increase multiple shall be taken as the first influencing factor.

6. The method for determining the fracturing stages of a horizontal well in tight sandstone according to claim 5, characterized in that, The first influencing factor is the number of cracks.

7. The method for determining the fracturing stages of a horizontal well in tight sandstone according to claim 6, characterized in that, The step of adjusting the initial number of fracturing stages based on the first influencing factor and determining the final number of horizontal well fracturing stages includes: The single fracture yield for each number of initial fracturing stages is determined, and the yield corresponding to different number of stages is determined. The final number of horizontal well fracturing stages is determined based on the production output corresponding to different stages.

8. The method for determining the fracturing stages of a horizontal well in tight sandstone according to claim 7, characterized in that, The formula for the production of a single crack is: In the above formula, P e For reservoir pressure, p f Q is the bottom hole flow pressure, μ is the fluid viscosity, and Q is the fluid viscosity. f For single fracture production, H is reservoir thickness, R is supply radius, k is permeability, l is fracture half-length, d is the spacing between fractures, and N is the production rate. f This represents the number of fracturing stages.

9. An apparatus for determining the fracturing stages in a horizontal well of tight sandstone, characterized in that, The apparatus includes a memory and a processor; the memory is used to store a program for determining the fracturing segments of a tight sandstone horizontal well, and the processor is used to read and execute the program for determining the fracturing segments of a tight sandstone horizontal well, and to execute the method according to any one of claims 1-8.

10. A computer-readable storage medium storing a data processing program, the data processing program being executed by a processor as described in any one of claims 1-8, the method for determining fracturing segments in a tight sandstone horizontal well.

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