Horizontal well sweet spot classification and evaluation method, drilling rate calculation method and related devices

Abstract

The present invention discloses a method for classifying and evaluating sweet spots in horizontal wells, a method for calculating drilling encounter rates, and related devices. The method comprises determining the depth interval corresponding to each sweet spot segment based on pre-acquired natural gamma and density logging data corresponding to two types of sweet spots in a target layer of a pilot vertical well; normalizing the natural gamma and density logging data corresponding to each type of sweet spot segment to determine the difference between the normalized natural gamma value and the density value corresponding to each type of sweet spot segment; determining a numerical limit chart for the difference between the two types of sweet spots based on the difference and the depth interval corresponding to each type of sweet spot segment; normalizing the pre-acquired natural gamma and density logging data of a horizontal well corresponding to the pilot vertical well to determine the difference between the normalized natural gamma value and the density value of the horizontal well; and classifying all logging sampling data points of the horizontal well into sweet spot types based on the difference between the numerical limit chart and the horizontal well, thereby obtaining corresponding sweet spot type classification results.

Description

Technical Field

[0001] The invention relates to a horizontal well sweet spot classification and evaluation method, a drilling rate calculation method and related devices. Background Art

[0002] my country boasts abundant tight reservoir oil and gas resources, with production capacity development steadily advancing, production rapidly increasing, and its share expanding. After nearly a decade of sustained exploration and research, breakthroughs have been achieved in tight reservoir oil and gas development in basins such as the Ordos, Junggar, and Songliao basins. For example, the Changqing Oilfield, utilizing short horizontal wells, highly deviated wells with water injection, and long horizontal wells with advanced energy injection, has achieved annual production exceeding 4 million tons. The Xinjiang Mahu Oilfield, utilizing a development strategy characterized by "multi-layer systems, small well spacing, long horizontal sections, and dense cutting," achieved a breakthrough in both production and construction, exceeding 2 million tons. The Daqing Oilfield, employing a "combined vertical and horizontal wells + fracture network + volumetric fracturing + platform-based" model, has reduced investment and increased internal rate of return. Tight reservoir oil and gas development has become the primary focus of capacity development in new areas, and horizontal well development has become a key method for developing tight oil reservoirs. Therefore, accurately identifying and classifying the types of sweet spots encountered by horizontal wells and determining the location of high-quality sweet spots are of great geological significance for improving single-well fracturing productivity and calculating the estimated ultimate recovery (EUR) of a single well. Summary of the Invention

[0003] In order to better implement the classification and evaluation of sweet spots in horizontal wells and the calculation of the drilling rate of sweet spots, the embodiments of the present application provide a method for classifying and evaluating sweet spots in horizontal wells, a method for calculating the drilling rate, and related devices.

[0004] In a first aspect, an embodiment of the present application provides a method for classifying and evaluating sweet spots in horizontal wells, the method comprising:

[0005] Determine the depth interval corresponding to each type of sweet spot based on the natural gamma and density logging data corresponding to the two types of sweet spots in the target layer of the pilot vertical well obtained in advance;

[0006] Normalizing the natural gamma and density logging data corresponding to each type of sweet spot segment, and determining the difference between the normalized natural gamma value and the density value corresponding to each type of sweet spot segment;

[0007] Determining a numerical limit chart of the difference values ​​corresponding to two types of sweet spots according to the difference value and depth interval corresponding to each type of sweet spot segment;

[0008] Normalizing the natural gamma and density logging data of the horizontal well corresponding to the pilot vertical well obtained in advance, and determining the difference between the normalized natural gamma value and the density value of the horizontal well;

[0009] According to the difference between the numerical limit plate and the horizontal well, all well logging sampling data points of the horizontal well are divided into sweet spot types to obtain corresponding sweet spot type division results.

[0010] In an optional implementation of the embodiment of the present application, normalizing the natural gamma and density logging data corresponding to each type of sweet spot segment and determining the difference between the normalized natural gamma value and the density value corresponding to each type of sweet spot segment includes:

[0011] Normalizing the natural gamma and density logging data corresponding to each type of sweet spot segment to determine the normalized natural gamma value and density value corresponding to each type of sweet spot segment;

[0012] The normalized natural gamma value and the density value corresponding to each type of sweet spot segment are subtracted to determine the difference between the normalized natural gamma value and the density value corresponding to each type of sweet spot segment.

[0013] In an optional implementation of the embodiment of the present application, normalizing the natural gamma and density logging data corresponding to each type of sweet spot segment to determine the normalized natural gamma value and density value corresponding to each type of sweet spot segment includes:

[0014] According to the natural gamma logging data corresponding to each type of sweet spot segment, the normalized natural gamma value corresponding to each type of sweet spot segment is calculated based on the following formula 1:

[0015]

[0016] Wherein, GR' is the normalized natural gamma value corresponding to each type of sweet spot segment; GR is the original natural gamma value corresponding to each type of sweet spot segment obtained in advance; min(GR) is the minimum natural gamma value in the natural gamma logging data corresponding to each type of sweet spot segment; max(GR) is the maximum natural gamma value in the natural gamma logging data corresponding to each type of sweet spot segment;

[0017] According to the density logging data corresponding to each type of sweet spot segment, the normalized density value corresponding to each type of sweet spot segment is calculated based on the following formula 2:

[0018]

[0019] Wherein, RHOB' is the normalized density value corresponding to each type of sweet spot segment; RHOB is the original density value corresponding to each type of sweet spot segment obtained in advance; min(RHOB) is the minimum density value in the density logging data corresponding to each type of sweet spot segment; and max(RHOB) is the maximum density value in the density logging data corresponding to each type of sweet spot segment.

[0020] In an optional implementation of the embodiment of the present application, the subtraction of the normalized natural gamma value and the density value corresponding to each type of sweet spot segment to determine the difference between the normalized natural gamma value and the density value corresponding to each type of sweet spot segment includes:

[0021] According to the normalized natural gamma value and density value corresponding to each type of sweet spot segment, the difference between the normalized natural gamma value and the density value corresponding to each type of sweet spot segment is calculated based on the following formula 3:

[0022] D = GR' - RHOB' Formula 3;

[0023] Wherein, D is the difference between the normalized natural gamma value and the density value corresponding to each type of sweet spot segment; GR' is the normalized natural gamma value corresponding to each type of sweet spot segment; RHOB' is the normalized density value corresponding to each type of sweet spot segment.

[0024] In an optional implementation of the embodiment of the present application, the sweet spot type classification is performed on all logging sampling data points of the horizontal well according to the difference between the numerical limit plate and the horizontal well, and the corresponding sweet spot type classification result is obtained, including:

[0025] Establish a rectangular coordinate distribution diagram using the difference of the horizontal well as the ordinate and the depth of all well logging sampling data points of the horizontal well as the ordinate;

[0026] Determine the limit difference of the sweet spot classification according to the numerical limit plate and the two types of sweet spot segments of the target layer of the pilot hole vertical well;

[0027] According to the numerical limit plate, the limit difference of the sweet spot classification and the rectangular coordinate distribution diagram, the sweet spots developed at the depths corresponding to all the logging sampling data points of the horizontal well are divided into two types of sweet spots, and the corresponding sweet spot type classification results are obtained.

[0028] In a second aspect, an embodiment of the present application provides a method for calculating the drilling rate of a horizontal well sweet spot, the method comprising:

[0029] Obtaining a sweet spot type classification result according to the horizontal well sweet spot classification evaluation method described in the first aspect;

[0030] The drilling rate of each type of sweet spot in the horizontal well is determined according to the pre-acquired sampling rate of the well logging data and the sweet spot type classification result.

[0031] In an optional implementation of the embodiment of the present application, determining the drilling rate of each sweet spot type of the horizontal well according to the pre-obtained well logging data sampling rate and the sweet spot type classification result includes:

[0032] According to the previously obtained sampling rate of logging data and the classification result of the sweet spot type, the drilling rate of the two types of sweet spots in the horizontal well is calculated based on the following formula 4:

[0033] C = (P × S) / L Formula 4;

[0034] Where C is the drilling rate of each type of sweet spot in the horizontal well; P is the sampling rate of the pre-acquired logging data; S is the total number of sample points in each type of sweet spot; and L is the total length of the horizontal section of the horizontal well.

[0035] In a third aspect, an embodiment of the present application provides a horizontal well sweet spot classification and evaluation device, the device comprising:

[0036] The first determination module is used to determine the depth interval corresponding to each type of sweet spot segment based on the natural gamma and density logging data corresponding to the two types of sweet spots of the target layer of the pilot vertical well obtained in advance;

[0037] A second determination module is configured to normalize the natural gamma and density logging data corresponding to each type of sweet spot segment, and determine the difference between the normalized natural gamma value and the density value corresponding to each type of sweet spot segment;

[0038] a third determining module, configured to determine a numerical limit plate of the difference values ​​corresponding to two types of sweet spots according to the difference values ​​and depth intervals corresponding to each type of sweet spot segment;

[0039] a fourth determination module, configured to normalize the natural gamma and density logging data of the horizontal well corresponding to the pilot vertical well obtained in advance, and determine the difference between the normalized natural gamma value and the density value of the horizontal well;

[0040] A classification module is used to classify all logging sampling data points of the horizontal well into sweet spot types according to the difference between the numerical limit plate and the horizontal well, and obtain corresponding sweet spot type classification results.

[0041] In a fourth aspect, an embodiment of the present application provides a device for calculating the sweet spot drilling rate of a horizontal well, the device comprising:

[0042] The first determination module is used to determine the depth interval corresponding to each type of sweet spot segment based on the natural gamma and density logging data corresponding to the two types of sweet spots of the target layer of the pilot vertical well obtained in advance;

[0043] A second determination module is configured to normalize the natural gamma and density logging data corresponding to each type of sweet spot segment, and determine the difference between the normalized natural gamma value and the density value corresponding to each type of sweet spot segment;

[0044] a third determining module, configured to determine a numerical limit plate of the difference values ​​corresponding to two types of sweet spots according to the difference values ​​and depth intervals corresponding to each type of sweet spot segment;

[0045] a fourth determination module, configured to normalize the natural gamma and density logging data of the horizontal well corresponding to the pilot vertical well obtained in advance, and determine the difference between the normalized natural gamma value and the density value of the horizontal well;

[0046] a classification module, configured to classify all well logging sampling data points of the horizontal well into sweet spot types according to the difference between the numerical limit plate and the horizontal well, and obtain corresponding sweet spot type classification results;

[0047] The fifth determination module is configured to determine the drilling rate of each sweet spot type in the horizontal well according to the pre-acquired sampling rate of the logging data and the sweet spot type classification result.

[0048] In a fifth aspect, an embodiment of the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-mentioned method for classifying and evaluating sweet spots in horizontal wells, and / or the method for calculating the drilling rate of sweet spots in horizontal wells.

[0049] In a sixth aspect, an embodiment of the present application provides a computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the method for classifying and evaluating horizontal well sweet spots, and / or the method for calculating the drilling rate of horizontal well sweet spots, as described above, is implemented.

[0050] In a seventh aspect, an embodiment of the present application provides a computer program product comprising instructions. When the computer program product is run on a computer device, the computer device executes the horizontal well sweet spot classification and evaluation method and / or the horizontal well sweet spot drilling rate calculation method as described above.

[0051] In an eighth aspect, an embodiment of the present application provides a chip, which includes a processor and a communication interface, the communication interface and the processor are coupled, and the processor is used to run computer programs or instructions to implement the horizontal well sweet spot classification and evaluation method as described above, and / or the horizontal well sweet spot drilling rate calculation method.

[0052] The beneficial effects of the above technical solutions provided by the embodiments of the present application include at least:

[0053] The horizontal well sweet spot classification and evaluation method provided in the embodiment of the present application can directly classify the sweet spot type for each logging sampling data point of the horizontal well by determining the numerical limit chart of the normalized difference between the natural gamma and density logging data corresponding to the two types of sweet spots obtained based on the pilot vertical well, thereby realizing the classification and evaluation of the horizontal well sweet spots and clarifying the development location of the high-quality sweet spot development section of the horizontal well. The method is easy to operate and improves the efficiency of horizontal well sweet spot classification. It has important geological guidance significance for targeted optimization of fracturing schemes, improving single well fracturing productivity and single well EUR calculation.

[0054] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purposes and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings.

[0055] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0057] Figure 1 A schematic diagram of the steps of the horizontal well sweet spot classification and evaluation method provided in an embodiment of the present application;

[0058] Figure 2 A rectangular coordinate distribution diagram of well logging data of a target section of a pilot vertical well in a certain study area provided in an embodiment of the present application;

[0059] Figure 3 for Figure 2 A schematic diagram of the distribution of depth intervals corresponding to two types of sweet spots in the target section of a pilot vertical well in a certain study area;

[0060] Figure 4 for Figure 2 A numerical limit chart of the difference between the normalized natural gamma value and the density value corresponding to two types of sweet spots in the target section of the pilot vertical well in a certain study area;

[0061] Figure 5 for Figure 2 Schematic diagram of the classification and evaluation results of the target sweet spot at 3200-3500 meters in the horizontal well corresponding to the pilot vertical well in a certain study area;

[0062] Figure 6 A schematic diagram of the steps of a method for calculating the sweet spot drilling rate of a horizontal well provided in an embodiment of the present application;

[0063] Figure 7 A schematic diagram of the structure of a horizontal well sweet spot classification and evaluation device provided in an embodiment of the present application;

[0064] Figure 8 A schematic diagram of the structure of a device for calculating the sweet spot drilling rate of a horizontal well provided in an embodiment of the present application. DETAILED DESCRIPTION

[0065] In the following description, specific details such as specific system structures and techniques are provided for purposes of illustration rather than limitation to facilitate a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid obscuring the description of the present application with unnecessary detail.

[0066] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or collections thereof.

[0067] It will also be understood that the term "and / or" used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0068] As used in this specification and the appended claims, the term "if" can be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0069] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0070] References to "one embodiment" or "some embodiments" in this specification mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in one or more embodiments of the present application. Thus, phrases such as "in one embodiment," "in some embodiments," "in other embodiments," and "in other embodiments" appearing in various places in this specification do not necessarily refer to the same embodiment, but rather mean "one or more but not all embodiments," unless otherwise specifically emphasized. The terms "including," "comprising," "having," and variations thereof all mean "including but not limited to," unless otherwise specifically emphasized.

[0071] It should be understood that the size of the serial numbers of the steps in the following embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0072] In order to illustrate the technical solution of the present application, specific embodiments are provided below.

[0073] The inventors discovered that existing horizontal well technologies suffer from low individual well production and wide variations in productivity. However, actual production demonstrates that sweet spots in unconventional oil and gas reservoirs exhibit significant heterogeneity, both in plan and within the layers. Therefore, identifying and classifying sweet spots encountered by horizontal wells and pinpointing the location of high-quality sweet spots are crucial for optimizing fracturing strategies, improving individual well fracturing productivity, and calculating the Estimated Value (EUR) of individual wells. Based on this, the inventors, through further research and development, have pioneered a novel technical solution, resulting in the present invention, which provides a method for classifying and evaluating sweet spots in horizontal wells, a method for calculating drilling rate, and related devices.

[0074] Example 1

[0075] The present invention provides a method for classifying and evaluating sweet spots in horizontal wells. Figure 1 As shown, the method includes:

[0076] S101: Determine the depth interval corresponding to each type of sweet spot segment based on pre-obtained natural gamma ray and density logging data corresponding to two types of sweet spots in the target layer of the pilot vertical well.

[0077] In an embodiment of the present application, based on the sedimentary geological characteristics and reserve abundance of the study area obtained in advance, combined with the daily oil production included in the pre-obtained test production data of different depth sections of the pilot vertical well, the different depth sections are divided into two types of sweet spots. For example, the daily oil production of a certain depth section is 4 to 5 tons, which can be divided into a first type of sweet spot; the daily oil production of a certain depth section is 2 to 3 tons, which can be divided into a second type of sweet spot, wherein the threshold value of the daily oil production used to divide the sweet spot type is determined according to actual production needs. After determining the two types of sweet spot segments of the target layer of the pilot vertical well, the natural gamma logging data and density logging data corresponding to the two types of sweet spot segments of the target layer are plotted in a rectangular coordinate system, and then the depth intervals corresponding to the two types of sweet spot segments are obtained.

[0078] S102: Normalizing the natural gamma and density logging data corresponding to each type of sweet spot segment, and determining the difference between the normalized natural gamma value and the density value corresponding to each type of sweet spot segment.

[0079] In the above step S102, normalizing the natural gamma and density logging data corresponding to each type of sweet spot segment and determining the difference between the normalized natural gamma value and the density value corresponding to each type of sweet spot segment specifically includes:

[0080] Normalizing the natural gamma and density logging data corresponding to each type of sweet spot segment to determine the normalized natural gamma value and density value corresponding to each type of sweet spot segment;

[0081] The normalized natural gamma value and the density value corresponding to each type of sweet spot segment are subtracted to determine the difference between the normalized natural gamma value and the density value corresponding to each type of sweet spot segment.

[0082] In the embodiment of the present application, normalizing the natural gamma and density logging data corresponding to each type of sweet spot segment to determine the normalized natural gamma value and density value corresponding to each type of sweet spot segment specifically includes:

[0083] According to the natural gamma logging data corresponding to each type of sweet spot segment, the normalized natural gamma value corresponding to each type of sweet spot segment is calculated based on the following formula 1:

[0084]

[0085] Wherein, GR' is the normalized natural gamma value corresponding to each type of sweet spot segment; GR is the original natural gamma value corresponding to each type of sweet spot segment obtained in advance; min(GR) is the minimum natural gamma value in the natural gamma logging data corresponding to each type of sweet spot segment; max(GR) is the maximum natural gamma value in the natural gamma logging data corresponding to each type of sweet spot segment;

[0086] According to the density logging data corresponding to each type of sweet spot segment, the normalized density value corresponding to each type of sweet spot segment is calculated based on the following formula 2:

[0087]

[0088] Wherein, RHOB' is the normalized density value corresponding to each type of sweet spot segment; RHOB is the original density value corresponding to each type of sweet spot segment obtained in advance; min(RHOB) is the minimum density value in the density logging data corresponding to each type of sweet spot segment; and max(RHOB) is the maximum density value in the density logging data corresponding to each type of sweet spot segment.

[0089] In the embodiment of the present application, the difference between the normalized natural gamma value and the density value corresponding to each type of sweet spot segment is determined, specifically including:

[0090] According to the normalized natural gamma value and density value corresponding to each type of sweet spot segment, the difference between the normalized natural gamma value and the density value corresponding to each type of sweet spot segment is calculated based on the following formula 3:

[0091] D = GR' - RHOB' Formula 3;

[0092] Wherein, D is the difference between the normalized natural gamma value and the density value corresponding to each type of sweet spot segment; GR' is the normalized natural gamma value corresponding to each type of sweet spot segment; RHOB' is the normalized density value corresponding to each type of sweet spot segment.

[0093] In the implementation of this application, the natural gamma logging data and density logging data corresponding to the two types of sweet spots in the target layer are normalized using the above formulas 1 and 2, respectively. The resulting values ​​of the normalized natural gamma logging data and density logging data are mapped to the range [0, 1]. The normalized natural gamma value and density value are then subtracted to obtain the difference between the normalized natural gamma value and density value corresponding to each type of sweet spot. A rectangular coordinate system diagram is then established, with the difference between the natural gamma value and the density value as the ordinate of the rectangular coordinate system and the depth data corresponding to each logging data sampling point as the abscissa of the rectangular coordinate system.

[0094] S103: Determine a numerical limit chart of the difference values ​​corresponding to two types of sweet spots according to the difference values ​​and depth intervals corresponding to each type of sweet spot segment.

[0095] In an embodiment of the present application, based on the distribution interval characteristics of the difference between the normalized natural gamma value and the density value corresponding to the two types of sweet spot segments and the depth interval corresponding to the two types of sweet spot segments in the rectangular coordinate system, a numerical limit chart of the difference between the normalized natural gamma value and the density value corresponding to the two types of sweet spot segments is obtained.

[0096] S104: normalizing the natural gamma and density logging data of the horizontal well corresponding to the pilot vertical well obtained in advance, and determining the difference between the normalized natural gamma value and the density value of the horizontal well.

[0097] In this embodiment of the present application, the previously obtained gamma ray logging data and density logging data of the horizontal well corresponding to the pilot well are normalized, the difference between the normalized gamma ray and density values ​​is calculated, and the difference is plotted in a rectangular coordinate system. The normalization of the gamma ray and density logging data in step S102 is performed to obtain normalized gamma and density values, respectively, and the resulting values ​​are mapped to the range [0, 1].

[0098] Based on the natural gamma logging data of the horizontal well, the normalized natural gamma value of the horizontal well is calculated based on the following formula 1:

[0099]

[0100] Where GR' is the normalized natural gamma value of the horizontal well; GR is the original natural gamma value of the horizontal well obtained in advance; min(GR) is the minimum natural gamma value in the natural gamma logging data of the horizontal well; max(GR) is the maximum natural gamma value in the natural gamma logging data of the horizontal well;

[0101] Based on the density logging data of the horizontal well, the normalized density value of the horizontal well is calculated based on the following formula 2:

[0102]

[0103] Where RHOB' is the normalized density value of the horizontal well; RHOB is the original density value of the horizontal well obtained in advance; min(RHOB) is the minimum density value in the density logging data of the horizontal well; and max(RHOB) is the maximum density value in the density logging data of the horizontal well.

[0104] According to the normalized natural gamma value and density value of the horizontal well, the difference between the normalized natural gamma value and the density value of the horizontal well is calculated based on the following formula 3:

[0105] D = GR' - RHOB' Formula 3;

[0106] Where D is the difference between the normalized natural gamma value and the density value of the horizontal well; GR' is the normalized natural gamma value of the horizontal well; and RHOB' is the normalized density value of the horizontal well.

[0107] After obtaining the difference between the natural gamma value and the density value of the horizontal well, a rectangular coordinate distribution diagram is established with the difference between the natural gamma value and the density value as the ordinate of the rectangular coordinate system and the depth data corresponding to each logging data sampling point as the abscissa of the rectangular coordinate system.

[0108] S105: According to the numerical limit plate and the difference value of the horizontal well, all the well logging sampling data points of the horizontal well are divided into sweet spot types to obtain corresponding sweet spot type division results.

[0109] In the above step S105, the sweet spot type classification is performed on all the logging sampling data points of the horizontal well according to the difference between the numerical limit plate and the horizontal well to obtain the corresponding sweet spot type classification result, which specifically includes:

[0110] Establish a rectangular coordinate distribution diagram using the difference of the horizontal well as the ordinate and the depth of all well logging sampling data points of the horizontal well as the ordinate;

[0111] Determine the limit difference of the sweet spot classification according to the numerical limit plate and the two types of sweet spot segments of the target layer of the pilot hole vertical well;

[0112] According to the numerical limit plate, the limit difference of the sweet spot classification and the rectangular coordinate distribution diagram, the sweet spots developed at the depths corresponding to all the logging sampling data points of the horizontal well are divided into two types of sweet spots, and the corresponding sweet spot type classification results are obtained.

[0113] In the embodiment of the present application, according to the numerical limit plate of the difference between the normalized natural gamma value and the density value corresponding to the two types of sweet spots obtained in step S103, combined with the numerical distribution of the difference between the normalized natural gamma value and the density value of the horizontal well, a rectangular coordinate distribution diagram is obtained. In the numerical limit plate of the difference between the normalized natural gamma value and the density value corresponding to the two types of sweet spots, according to the division of the two types of sweet spots in the target layer of the pilot hole vertical well, the boundary difference of the sweet spot classification can be determined according to the division boundary, that is, the difference between the normalized natural gamma value and the density value corresponding to the sweet spot division boundary, and the size relationship between the difference between the normalized natural gamma value and the density value corresponding to different depths of the two types of sweet spots and the boundary difference of the sweet spot classification is determined. For example, the differences corresponding to different depths in the first type of sweet spot segment are all greater than 0.10, and the differences corresponding to different depths in the second type of sweet spot segment are all less than 0.10. Based on the limit difference values ​​of the sweet spot classification, a straight line is drawn on the rectangular coordinate distribution diagram with the limit difference values ​​of the sweet spot classification as the ordinate. The sweet spot developed at the depth corresponding to each well sampling data point in the horizontal section of the horizontal well is divided into two types of sweet spots, and the corresponding sweet spot type classification results are obtained. For example, if the differences corresponding to different depths in the first sweet spot segment in the numerical limit plate are all greater than 0.10, and the differences corresponding to different depths in the second sweet spot segment are all less than 0.10, then in the rectangular coordinate distribution diagram, the sweet spots developed at the depths corresponding to the well sampling data points above the straight line with the limit difference values ​​of the sweet spot classification as the ordinate are classified as the first sweet spot, and the sweet spots developed at the depths corresponding to the well sampling data points below the straight line with the limit difference values ​​of the sweet spot classification as the second sweet spot.

[0114] In a specific embodiment, based on the sedimentary geological characteristics and reserve abundance of a certain study area, combined with the daily oil production included in the oil test production data of different depth sections of the pilot vertical well, the sweet spots of the target section are divided into Class I sweet spots and Class II sweet spots. The natural gamma logging data and density logging data corresponding to the two types of sweet spots in the target layer are obtained through actual measurement and calculation, as shown in Table 1 below:

[0115] Table 1

[0116]

[0117]

[0118] After obtaining the natural gamma logging data and density logging data corresponding to the two types of sweet spots in the target layer, plot them in the rectangular coordinate system and obtain the following: Figure 2 The rectangular coordinate distribution diagram of the logging data of the target section of the pilot vertical well is shown in the figure. From this, the distribution of the depth intervals corresponding to the two types of sweet spots can be obtained as follows: Figure 3 As shown, Figure 3The left side of the middle image shows the distribution of Class I sweet spots and their corresponding depth ranges, and the right side shows the distribution of Class II sweet spots and their corresponding depth ranges.

[0119] The natural gamma and density logging data corresponding to the two types of sweet spots of the target layer are normalized, and the difference between the normalized natural gamma value and the density value is calculated as shown in Table 2. The difference between the natural gamma value and the density value is the ordinate of the rectangular coordinate system, and the depth data corresponding to each logging data sampling point is the abscissa of the rectangular coordinate system. The results are plotted in the rectangular coordinate system to establish the following: Figure 4 The numerical limit plate of the difference between the normalized natural gamma value and the density value corresponding to the two types of sweet spots is shown. The sweet spots of type I and type II are divided according to the daily oil production data of the pilot well test production data. The corresponding differences at different depths in the type I sweet spot are all greater than 0.10, and the corresponding differences at different depths in the type II sweet spot are all less than 0.10. Therefore, the horizontal dotted line at the difference of 0.10 is the boundary dividing the two types of sweet spots, that is, the boundary difference of the sweet spot classification is 0.10.

[0120] Table 2

[0121]

[0122]

[0123] The natural gamma and density logging data of the horizontal well corresponding to the pilot vertical well obtained in advance are normalized, and the difference between the normalized natural gamma value and the density value of the horizontal well is calculated, as shown in Table 3 below. The original logging data and the normalized logging data corresponding to the target section of the horizontal well with a depth of 3200-3236 meters are shown in the table below:

[0124] Table 3

[0125]

[0126]

[0127]

[0128]

[0129]

[0130]

[0131]

[0132]

[0133] Based on the numerical limit chart of the difference between the normalized natural gamma value and the density value corresponding to the two types of sweet spots, the sweet spots developed at the depth corresponding to each logging sampling data point of the horizontal well are classified. Taking the depth range of 3200-3500 meters as an example, the classification evaluation results of the sweet spots in the target section of the horizontal well are as follows: Figure 5 As shown in the figure, the dotted line is the dotted line of the boundary difference of 0.10 of the sweet spot classification obtained in the numerical boundary plate of the difference between the normalized natural gamma value and the density value corresponding to the two types of sweet spots. According to the position of the boundary difference of the two types of sweet spots relative to the sweet spot classification in the numerical boundary plate, that is, the differences corresponding to different depths of type I sweet spots are all greater than 0.10, and the differences corresponding to different depths of type II sweet spots are all less than 0.10. The sweet spots developed at the depth corresponding to the logging sampling data points above the dotted line in the figure can be divided into type I sweet spots, and the sweet spots developed at the depth corresponding to the logging sampling data points below the dotted line can be divided into type II sweet spots.

[0134] Through the above-mentioned classification and evaluation process of the horizontal well sweet spots in the study area, it can be found that the horizontal well sweet spot classification and evaluation method provided by the embodiment of the present invention can accurately determine the development location of the high-quality sweet spot development section of the horizontal well, and has created a new era in technology for the development of horizontal wells in tight oil reservoir development. According to the classification and evaluation results of the horizontal well sweet spots, an optimized fracturing plan for horizontal well development can be proposed in a targeted manner, which is conducive to improving the single-well fracturing production capacity and single-well EUR calculation, and has achieved unexpected technical effects.

[0135] The horizontal well sweet spot classification and evaluation method provided in the embodiment of the present application is based on the numerical limit plate of the normalized difference between the natural gamma and density logging data corresponding to the two types of sweet spots obtained by the pilot vertical well, and the sweet spot type is divided for each logging sampling data point of the horizontal well, thereby realizing the classification and evaluation of the horizontal well sweet spots and clarifying the development location of the high-quality sweet spot development section of the horizontal well. This method has important geological guidance significance for the targeted optimization of fracturing schemes, improving the single well fracturing productivity and single well EUR calculation.

[0136] Example 2

[0137] Based on the same inventive concept, the present application also provides a method for calculating the drilling rate of a horizontal well sweet spot, referring to Figure 6 As shown, the method includes:

[0138] S101: Determine the depth interval corresponding to each type of sweet spot based on the natural gamma ray and density logging data corresponding to two types of sweet spots in the target layer of the pilot vertical well obtained in advance;

[0139] S102: normalizing the natural gamma and density logging data corresponding to each type of sweet spot segment, and determining the difference between the normalized natural gamma value and the density value corresponding to each type of sweet spot segment;

[0140] S103: determining a numerical limit plate of the difference values ​​corresponding to two types of sweet spots according to the difference value and depth interval corresponding to each type of sweet spot segment;

[0141] S104: normalizing the natural gamma and density logging data of the horizontal well corresponding to the pilot vertical well obtained in advance, and determining the difference between the normalized natural gamma value and the density value of the horizontal well;

[0142] S105: performing sweet spot classification on all well logging sampling data points of the horizontal well according to the difference between the numerical limit plate and the horizontal well, and obtaining corresponding sweet spot classification results;

[0143] S106: Determine the drilling rate of each sweet spot type of the horizontal well according to the pre-acquired sampling rate of the logging data and the sweet spot type classification result.

[0144] In the embodiment of the present invention, the specific implementation of the above steps S101 to S105 can refer to the detailed description of the corresponding steps in the horizontal well sweet spot classification and evaluation method described in the above embodiment 1, and will not be repeated here.

[0145] In the embodiment of the present application, the above step S106 determines the drilling rate of each sweet spot of the horizontal well according to the pre-obtained well logging data sampling rate and the sweet spot type classification result, specifically including:

[0146] According to the previously obtained sampling rate of logging data and the classification result of the sweet spot type, the drilling rate of the two types of sweet spots in the horizontal well is calculated based on the following formula 4:

[0147] C = (P × S) / L Formula 4;

[0148] Where C is the drilling rate of each type of sweet spot in the horizontal well; P is the sampling rate of the pre-acquired logging data; S is the total number of sample points in each type of sweet spot; and L is the total length of the horizontal section of the horizontal well.

[0149] In a specific embodiment, after obtaining the sweet spot type classification results of the horizontal well as the method of Example 1, the logging data sampling rate can be determined to be 0.125 by the logging instrument. The number of logging sampling data points, i.e., the number of sampling points, the total length, and the horizontal section length of the two types of sweet spots obtained based on actual measurements are shown in Table 4 below, which is a table showing the calculation results of the drilling rate of the two types of sweet spots in the horizontal well:

[0150] Table 4

[0151] Number of Class I dessert samples 642.00 Total length of Class I sweet spot (m) 80.25 Number of sample points for Class II desserts 1759.00 Total length of Class II sweet spot (m) 219.88 Horizontal section length (m) 300.00 Type I sweet spot drilling rate (%) 26.75 Type II sweet spot drilling rate (%) 73.29

[0152] As shown in Table 4 above, the number of Class I sweet spot sampling points is 642.00, the total length of the Class I sweet spot is 80.25 meters, the horizontal section length is 300.00, and the logging sampling rate is 0.125. Substituting these data into the above formula 4, the drilling rate of the Class I sweet spot is 26.75%:

[0153] C=(P×S) / L=(0.125×642.00) / 300.00=26.75%;

[0154] The number of Class II sweet spot sampling points is 1759.00, the total length of the Class II sweet spot is 219.88 meters, the horizontal section length is 300.00, and the logging sampling rate is 0.125. Substituting these data into the above formula 4, the drilling rate of the Class I sweet spot is 73.29%:

[0155] C=(P×S) / L=(0.125×1759.00) / 300.00=73.29%.

[0156] The method for calculating the sweet spot drilling rate of horizontal wells provided in the embodiment of the present application divides each logging sampling data point of the horizontal well into sweet spot types based on the numerical limit chart of the normalized difference between the natural gamma and density logging data corresponding to the two types of sweet spots obtained from the pilot vertical well, thereby realizing the classification evaluation of the sweet spots of the horizontal well, thereby calculating the drilling rate of the two types of sweet spots and clarifying the development location of the high-quality sweet spot development section of the horizontal well. This method has important geological guidance significance for targeted optimization of fracturing schemes, improving single-well fracturing productivity and single-well EUR calculation.

[0157] Example 3

[0158] Based on the same inventive concept, the present application also provides a horizontal well sweet spot classification and evaluation device, referring to Figure 7 As shown, the device includes:

[0159] The first determination module 101 is used to determine the depth interval corresponding to each type of sweet spot segment based on the natural gamma ray and density logging data corresponding to the two types of sweet spots of the target layer of the pilot vertical well obtained in advance;

[0160] The second determining module 102 is configured to normalize the natural gamma and density logging data corresponding to each type of sweet spot segment, and determine the difference between the normalized natural gamma value and the density value corresponding to each type of sweet spot segment;

[0161] A third determining module 103 is configured to determine a numerical limit plate of the difference values ​​corresponding to two types of sweet spots according to the difference value and depth interval corresponding to each type of sweet spot segment;

[0162] The fourth determination module 104 is configured to normalize the natural gamma and density logging data of the horizontal well corresponding to the pilot vertical well obtained in advance, and determine the difference between the normalized natural gamma value and the density value of the horizontal well;

[0163] The classification module 105 is configured to classify all the logging sampling data points of the horizontal well into sweet spot types according to the difference between the numerical limit plate and the horizontal well, and obtain corresponding sweet spot type classification results.

[0164] Example 4

[0165] Based on the same inventive concept, the present application also provides a device for calculating the drilling rate of a horizontal well sweet spot, referring to Figure 8 As shown, the device includes:

[0166] The first determination module 101 is used to determine the depth interval corresponding to each type of sweet spot segment based on the natural gamma ray and density logging data corresponding to the two types of sweet spots of the target layer of the pilot vertical well obtained in advance;

[0167] The second determining module 102 is configured to normalize the natural gamma and density logging data corresponding to each type of sweet spot segment, and determine the difference between the normalized natural gamma value and the density value corresponding to each type of sweet spot segment;

[0168] A third determining module 103 is configured to determine a numerical limit plate of the difference values ​​corresponding to two types of sweet spots according to the difference value and depth interval corresponding to each type of sweet spot segment;

[0169] The fourth determination module 104 is configured to normalize the natural gamma and density logging data of the horizontal well corresponding to the pilot vertical well obtained in advance, and determine the difference between the normalized natural gamma value and the density value of the horizontal well;

[0170] A classification module 105 is configured to classify all well logging sampling data points of the horizontal well into sweet spot types according to the difference between the numerical limit plate and the horizontal well, and obtain corresponding sweet spot type classification results;

[0171] The fifth determining module 106 is configured to determine the drilling rate of each sweet spot type of the horizontal well according to the pre-acquired sampling rate of the logging data and the sweet spot type classification result.

[0172] Example 5

[0173] Based on the same inventive concept, an embodiment of the present application also provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, it implements the horizontal well sweet spot classification and evaluation method described in the above embodiment 1, and / or the horizontal well sweet spot drilling rate calculation method described in the above embodiment 2.

[0174] Example 6

[0175] Based on the same inventive concept, an embodiment of the present application also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the method for classifying and evaluating sweet spots in horizontal wells as described in the first embodiment above, and / or the method for calculating the drilling rate of sweet spots in horizontal wells as described in the second embodiment above are implemented.

[0176] Example 7

[0177] Based on the same inventive concept, an embodiment of the present application also provides a computer program product comprising instructions. When the computer program product is run on a computer device, the computer device executes the horizontal well sweet spot classification and evaluation method described in the above embodiment 1, and / or the horizontal well sweet spot drilling rate calculation method described in the above embodiment 2.

[0178] Example 8

[0179] Based on the same inventive concept, an embodiment of the present application also provides a chip, which includes a processor and a communication interface, the communication interface and the processor are coupled, and the processor is used to run computer programs or instructions to implement the horizontal well sweet spot classification and evaluation method described in the above embodiment one, and / or the horizontal well sweet spot drilling rate calculation method described in the above embodiment two.

[0180] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage and optical storage, etc.) containing computer-usable program code.

[0181] The present invention is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0182] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0183] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 The steps for the function specified in one or more boxes.

[0184] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for classifying and evaluating sweet spots in horizontal wells, characterized in that: include: Determine the depth interval corresponding to each type of sweet spot based on the natural gamma and density logging data corresponding to the two types of sweet spots in the target layer of the pilot vertical well obtained in advance; Normalizing the natural gamma and density logging data corresponding to each type of sweet spot segment, and determining the difference between the normalized natural gamma value and the density value corresponding to each type of sweet spot segment; Determining a numerical limit chart of the difference values ​​corresponding to two types of sweet spots according to the difference value and depth interval corresponding to each type of sweet spot segment; Normalizing the natural gamma and density logging data of the horizontal well corresponding to the pilot vertical well obtained in advance, and determining the difference between the normalized natural gamma value and the density value of the horizontal well; According to the difference between the numerical limit plate and the horizontal well, all well logging sampling data points of the horizontal well are divided into sweet spot types to obtain corresponding sweet spot type division results.

2. The method according to claim 1, wherein Normalizing the natural gamma and density logging data corresponding to each type of sweet spot segment and determining the difference between the normalized natural gamma value and the density value corresponding to each type of sweet spot segment includes: Normalizing the natural gamma and density logging data corresponding to each type of sweet spot segment to determine the normalized natural gamma value and density value corresponding to each type of sweet spot segment; The normalized natural gamma value and the density value corresponding to each type of sweet spot segment are subtracted to determine the difference between the normalized natural gamma value and the density value corresponding to each type of sweet spot segment.

3. The method according to claim 2, wherein Normalizing the natural gamma and density logging data corresponding to each type of sweet spot segment to determine the normalized natural gamma value and density value corresponding to each type of sweet spot segment includes: According to the natural gamma logging data corresponding to each type of sweet spot segment, the normalized natural gamma value corresponding to each type of sweet spot segment is calculated based on the following formula 1: Wherein, GR' is the normalized natural gamma value corresponding to each type of sweet spot segment; GR is the original natural gamma value corresponding to each type of sweet spot segment obtained in advance; min(GR) is the minimum natural gamma value in the natural gamma logging data corresponding to each type of sweet spot segment; max(GR) is the maximum natural gamma value in the natural gamma logging data corresponding to each type of sweet spot segment; According to the density logging data corresponding to each type of sweet spot segment, the normalized density value corresponding to each type of sweet spot segment is calculated based on the following formula 2: Wherein, RHOB' is the normalized density value corresponding to each type of sweet spot segment; RHOB is the original density value corresponding to each type of sweet spot segment obtained in advance; min(RHOB) is the minimum density value in the density logging data corresponding to each type of sweet spot segment; and max(RHOB) is the maximum density value in the density logging data corresponding to each type of sweet spot segment.

4. The method according to claim 2, wherein The step of subtracting the normalized natural gamma value and the density value corresponding to each type of sweet spot segment to determine the difference between the normalized natural gamma value and the density value corresponding to each type of sweet spot segment includes: According to the normalized natural gamma value and density value corresponding to each type of sweet spot segment, the difference between the normalized natural gamma value and the density value corresponding to each type of sweet spot segment is calculated based on the following formula 3: Wherein, D is the difference between the normalized natural gamma value and the density value corresponding to each type of sweet spot segment; GR' is the normalized natural gamma value corresponding to each type of sweet spot segment; RHOB' is the normalized density value corresponding to each type of sweet spot segment.

5. The method according to claim 1, wherein The sweet spot classification is performed on all well logging sampling data points of the horizontal well according to the difference between the numerical limit plate and the horizontal well, to obtain corresponding sweet spot classification results, including: Establish a rectangular coordinate distribution diagram with the difference of the horizontal well as the vertical coordinate and the depth of all the well logging sampling data points of the horizontal well as the horizontal coordinate; Determine the limit difference of the sweet spot classification according to the numerical limit plate and the two types of sweet spot segments of the target layer of the pilot hole vertical well; According to the numerical limit plate, the limit difference of the sweet spot classification and the rectangular coordinate distribution diagram, the sweet spots developed at the depths corresponding to all the logging sampling data points of the horizontal well are divided into two types of sweet spots, and the corresponding sweet spot type classification results are obtained.

6. A method for calculating the drilling rate of sweet spots in horizontal wells, characterized in that: include: Obtaining a sweet spot type classification result according to the horizontal well sweet spot classification evaluation method according to any one of claims 1 to 5; The drilling rate of each type of sweet spot in the horizontal well is determined according to the pre-acquired sampling rate of the well logging data and the sweet spot type classification result.

7. The method according to claim 6, wherein Determining the drilling rate of each type of sweet spot in the horizontal well according to the pre-obtained well logging data sampling rate and the sweet spot type classification result includes: According to the previously obtained sampling rate of logging data and the classification result of the sweet spot type, the drilling rate of the two types of sweet spots in the horizontal well is calculated based on the following formula 4: Where C is the drilling rate of each type of sweet spot in the horizontal well; P is the sampling rate of the pre-acquired logging data; S is the total number of sample points in each type of sweet spot; and L is the total length of the horizontal section of the horizontal well.

8. A horizontal well sweet spot classification and evaluation device, characterized in that: include: The first determination module is used to determine the depth interval corresponding to each type of sweet spot segment based on the natural gamma and density logging data corresponding to the two types of sweet spots of the target layer of the pilot vertical well obtained in advance; A second determination module is configured to normalize the natural gamma and density logging data corresponding to each type of sweet spot segment, and determine the difference between the normalized natural gamma value and the density value corresponding to each type of sweet spot segment; a third determining module, configured to determine a numerical limit plate of the difference values ​​corresponding to two types of sweet spots according to the difference values ​​and depth intervals corresponding to each type of sweet spot segment; a fourth determination module, configured to normalize the natural gamma and density logging data of the horizontal well corresponding to the pilot vertical well obtained in advance, and determine the difference between the normalized natural gamma value and the density value of the horizontal well; A classification module is used to classify all logging sampling data points of the horizontal well into sweet spot types according to the difference between the numerical limit plate and the horizontal well, and obtain corresponding sweet spot type classification results.

9. A device for calculating the drilling rate of sweet spots in horizontal wells, characterized in that: include: The first determination module is used to determine the depth interval corresponding to each type of sweet spot segment based on the natural gamma and density logging data corresponding to the two types of sweet spots of the target layer of the pilot vertical well obtained in advance; A second determination module is configured to normalize the natural gamma and density logging data corresponding to each type of sweet spot segment, and determine the difference between the normalized natural gamma value and the density value corresponding to each type of sweet spot segment; a third determining module, configured to determine a numerical limit plate of the difference values ​​corresponding to two types of sweet spots according to the difference values ​​and depth intervals corresponding to each type of sweet spot segment; a fourth determination module, configured to normalize the natural gamma and density logging data of the horizontal well corresponding to the pilot vertical well obtained in advance, and determine the difference between the normalized natural gamma value and the density value of the horizontal well; a classification module, configured to classify all well logging sampling data points of the horizontal well into sweet spot types according to the difference between the numerical limit plate and the horizontal well, and obtain corresponding sweet spot type classification results; The fifth determination module is configured to determine the drilling rate of each sweet spot type in the horizontal well according to the pre-acquired sampling rate of the logging data and the sweet spot type classification result.

10. A computer-readable storage medium storing instructions, which, when executed on a terminal, causes the terminal to execute the method for classifying and evaluating sweet spots in horizontal wells according to any one of claims 1 to 5, and / or the method for calculating the drilling rate of sweet spots in horizontal wells according to claim 6 or 7.

11. A computer device, characterized in that: The method comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the method for classifying and evaluating sweet spots in horizontal wells according to any one of claims 1 to 5 and / or the method for calculating the drilling rate of sweet spots in horizontal wells according to claim 6 or 7 is implemented.

12. A computer program product comprising instructions, which, when executed on a computer device, causes the computer device to execute the method for classifying and evaluating sweet spots in horizontal wells according to any one of claims 1 to 5, and / or the method for calculating the drilling rate of sweet spots in horizontal wells according to claim 6 or 7.

13. A chip comprising a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is configured to execute a computer program or instruction to implement the method for classifying and evaluating sweet spots in horizontal wells according to any one of claims 1 to 5, and / or the method for calculating the drilling rate of sweet spots in horizontal wells according to claim 6 or 7.

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