Resistivity anisotropy characterization method and apparatus

Abstract

A resistivity anisotropy characterization method, comprising: acquiring bedding structure information and physical property information which are obtained by means of measuring a plurality of rock samples of a target formation (101); acquiring the resistivities of each rock sample which are measured at a plurality of preset measurement angles (102); on the basis of the resistivities of each rock sample at different preset measurement angles, determining the pattern of the resistivities of the corresponding rock sample varying with the preset measurement angles (103); on the basis of the pattern of the resistivities of each rock sample varying with the preset measurement angles, the bedding structure information and the physical property information, determining a rock resistivity anisotropy coefficient (104); and on the basis of the rock resistivity anisotropy coefficient, correcting a logging resistivity (105). In this way, the problem in the prior art of the impacts of a rock bedding structure on rock resistivity anisotropy not being taken into account is solved. The present disclosure further relates to a resistivity anisotropy characterization apparatus, a device, a readable storage medium and a program product.

Description

Resistivity Anisotropy Characterization Method and Apparatus

[0001] Related applications

[0002] This application claims priority to Chinese Patent Application No. 202411321249.2, filed on September 20, 2024, and incorporates the entire contents of the aforementioned patent application as part of this application. Technical Field

[0003] This disclosure relates to the field of petroleum exploration and development technology, and in particular to a method and apparatus for characterizing resistivity anisotropy. Background Technology

[0004] This section is intended to provide background or context for the embodiments of this disclosure set forth in the claims. The description herein is not an admission that it is prior art simply because it is included in this section.

[0005] Commonly used methods for evaluating formation resistivity anisotropy involve measuring the resistivity of rocks in different directions to construct a resistivity anisotropy calculation model, thereby evaluating resistivity anisotropy. This method is the most commonly used method for evaluating resistivity anisotropy in highly deviated and horizontal wells. Through rock physics joint analysis experiments, the influence of dip angle, lithology, physical properties, oil-bearing properties, and source rocks on resistivity anisotropy has been clarified. However, existing methods often only consider macroscopic formation structural factors such as layer thickness and dip angle, neglecting the fact that rock bedding structure factors also lead to variations in formation resistivity anisotropy. Furthermore, due to the high cost and difficulty of coring in highly deviated and horizontal wells, continuous core samples cannot be obtained, thus failing to generate continuous rock resistivity anisotropy characterization results. Summary of the Invention

[0006] This disclosure provides a method for characterizing resistivity anisotropy, addressing the technical problem in the prior art that the influence of rock bedding structure on rock resistivity anisotropy is not considered, and forming continuous rock resistivity anisotropy characterization results. The method includes:

[0007] Multiple rock samples from the target layer were measured to obtain bedding structure information and physical property information; bedding structure information includes bedding density, mineral type and content; physical property information includes, but is not limited to, porosity.

[0008] Obtain the resistivity of each rock sample measured from multiple preset measurement angles;

[0009] Based on the resistivity of each rock sample at different preset measurement angles, the law governing the change of the resistivity of the corresponding rock sample with the preset measurement angle is determined.

[0010] According to the change rule of the resistivity of each rock sample with the preset measurement angle, the bedding structure information, and the physical property information, a resistivity anisotropy coefficient of the rock is determined.

[0011] The logging resistivity is corrected according to the resistivity anisotropy coefficient of the rock.

[0012] The embodiment of the present disclosure further provides a resistivity anisotropy characterization device to solve the technical problem that the influence of the rock bedding structure on the resistivity anisotropy of the rock is not considered in the prior art, and to form a continuous resistivity anisotropy characterization result. The device comprises:

[0013] A bedding structure information acquisition module is configured to acquire bedding structure information and physical property information of a plurality of rock samples of a target layer. The bedding structure information includes bedding density, mineral type and content. The physical property information includes, but is not limited to, porosity.

[0014] A rock sample resistivity measurement module is configured to acquire the resistivity of each rock sample measured from a plurality of preset measurement angles.

[0015] A resistivity change rule determination module is configured to determine the change rule of the resistivity of each rock sample with the preset measurement angle according to the resistivity of each rock sample at different preset measurement angles.

[0016] A resistivity anisotropy coefficient determination module is configured to determine the resistivity anisotropy coefficient of the rock according to the change rule of the resistivity of each rock sample with the preset measurement angle, the bedding structure information, and the physical property information.

[0017] A logging resistivity correction module is configured to correct the logging resistivity according to the resistivity anisotropy coefficient of the rock.

[0018] The embodiment of the present disclosure further 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 resistivity anisotropy characterization method described above is implemented.

[0019] The embodiment of the present disclosure further provides a computer readable storage medium, which stores a computer program. When the computer program is executed by a processor, the resistivity anisotropy characterization method described above is implemented.

[0020] The embodiment of the present disclosure further provides a computer program product, which comprises a computer program. When the computer program is executed by a processor, the resistivity anisotropy characterization method described above is implemented.

[0021] In the embodiments of the present disclosure, the bedding structure information and the physical property information of the destination layer are obtained by measuring a plurality of rock samples of the destination layer; the bedding structure information includes bedding density, mineral type and content; the physical property information includes, but is not limited to, porosity; the resistivity of the rock samples measured from a plurality of preset measurement angles is obtained; the law of the resistivity of each rock sample changing with the preset measurement angle is determined according to the resistivity of each rock sample at different preset measurement angles, without a large number of rock samples, the anisotropy coefficient of rock resistivity can be determined according to the law of the resistivity of each rock sample changing with the preset measurement angle, the bedding structure information and the physical property information; the logging resistivity is corrected according to the anisotropy coefficient of rock resistivity, and a continuous rock resistivity anisotropy calculation result is formed, thereby solving the problem that the influence of the rock bedding structure on the rock resistivity anisotropy is not considered in the prior art. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present disclosure, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor. In the drawings:

[0023] FIG. 1 is a flowchart of a resistivity anisotropy characterization method in the embodiments of the present disclosure;

[0024] FIG. 2 is a schematic diagram of resistivity measurement of six rock samples at different angles in the embodiments of the present disclosure;

[0025] FIG. 3 is a resistivity variation law of six rock samples at different measurement angles in the embodiments of the present disclosure;

[0026] FIG. 4 is a resistivity anisotropy coefficient variation law of six rock samples at different measurement angles in the embodiments of the present disclosure;

[0027] FIG. 5 is a schematic diagram of a rock sample with well-developed resistivity-increasing mineral bedding in the embodiments of the present disclosure, and it can be seen that the bedding density of the resistivity-increasing mineral bedding (gray brick pattern) is obviously greater than that of the resistivity-reducing mineral bedding (black pattern);

[0028] FIG. 6 is a schematic diagram of a rock sample with well-developed resistivity-reducing mineral in the embodiments of the present disclosure, and it can be seen that the bedding density of the resistivity-reducing mineral bedding (black pattern) is obviously greater than that of the resistivity-increasing mineral bedding (gray brick pattern);

[0029] FIG. 7 is a schematic diagram of a homogeneous rock sample in the embodiments of the present disclosure;

[0030] FIG. 8 is a graph of the relationship between the bedding structure index and the regression coefficient in the embodiments of the present disclosure;

[0031] Figure 9 is a schematic diagram of the wellbore inclination direction consistent with the target layer inclination direction in the embodiment of the present disclosure;

[0032] Figure 10 is a schematic diagram of the wellbore inclination direction inconsistent with the target layer inclination direction in the embodiment of the present disclosure;

[0033] Figure 11 is a comparison chart of the resistivity correction results of a high angle well A (left) and a vertical well B (right) in the embodiment of the present disclosure;

[0034] Figure 12 is a comparison chart of the original resistivity curve before and after correction of well A in the embodiment of the present disclosure;

[0035] Figure 13 is a comparison chart of the saturation calculated by the original resistivity and the oil production profile of a production fluid profile in an example well in the embodiment of the present disclosure;

[0036] Figure 14 is a comparison chart of the saturation calculated by the corrected resistivity and the oil production profile of a production fluid profile in an example well in the embodiment of the present disclosure;

[0037] Figure 15 is a schematic diagram of a resistivity anisotropy characterization device in the embodiment of the present disclosure. DETAILED DESCRIPTION

[0038] To make the purpose, technical solutions and advantages of the embodiments of the present disclosure clearer, further detailed description of the embodiments of the present disclosure will be given below with reference to the drawings. Herein, the illustrative embodiments of the present disclosure and their descriptions are used to explain the present disclosure, but not as a limitation of the present disclosure.

[0039] Figure 1 is a flow chart of a resistivity anisotropy characterization method in the embodiment of the present disclosure, which comprises:

[0040] Step 101, obtaining the bedding structure information and physical property information measured from a plurality of rock samples of the target layer; the bedding structure information includes bedding density, mineral type and content; the physical property information includes but is not limited to porosity;

[0041] Step 102, obtaining the resistivity of each rock sample measured from a plurality of preset measurement angles;

[0042] Step 103, determining the rule of the resistivity of the corresponding rock sample changing with the preset measurement angle according to the resistivity of each rock sample at different preset measurement angles;

[0043] Step 104, determining the rock resistivity anisotropy coefficient according to the rule of the resistivity of each rock sample changing with the preset measurement angle, the bedding structure information and the physical property information;

[0044] Step 105, correcting the logging resistivity according to the rock resistivity anisotropy coefficient.

[0045] The following specifically describes each step.

[0046] In step 101, obtain bedding structure information and physical property information of a plurality of rock samples of a target layer; the bedding structure information includes bedding density, mineral types and content; the physical property information includes, but is not limited to, porosity.

[0047] In specific embodiments, the physical property information includes, but is not limited to, porosity, permeability, and pore structure.

[0048] In specific embodiments, the core of the target layer is sampled. For example, the core can be sampled using a pressurized coring tool and a sand card coring tool, and the sampling principle is that the sampled rock samples have different bedding densities. The bedding density of the rock sample can be calculated by the following formula:

[0049] where D is the bedding density of the rock sample, strip / cm; N is the number of beddings observed by the rock sample, strip; and h is the side length of the square rock sample, cm. 密度 层理

[0050] After sampling, the bedding interface can be identified and the bedding density can be calculated based on binocular microscope observation or core scanning imaging, the mineral types and content can be obtained by X-ray diffraction (XRD) analysis, Maipscan and other means, and the physical property information can be obtained by using porosimeter, permeameter and other equipment and mercury injection experiment method.

[0051] In step 102, the electrical resistivity of each rock sample measured from a plurality of preset measurement angles is obtained; and in step 103, the law of the electrical resistivity of the corresponding rock sample changing with the preset measurement angle is determined according to the electrical resistivity of each rock sample at different preset measurement angles.

[0052] In specific embodiments, the electrical resistivity of the rock sample at n different angles is measured. The n angles need to have the following relationship: 0°≤θ_1<θ_2<...<θ_n≤90°. FIG. 2 is a schematic diagram of the electrical resistivity measurement of six rock samples at different angles in an embodiment of the present disclosure, and FIG. 3 is the change of the electrical resistivity of the six rock samples at different measurement angles in an embodiment of the present disclosure. As can be seen from FIG. 3, with the increase of the angle, all samples show a trend of increasing electrical resistivity. Due to the differences in bedding density, mineral composition and physical properties of the six rock samples, the measured values of the electrical resistivity at the same angle are quite different.

[0053] ​​In step 104, the rock resistivity anisotropy coefficient is determined according to the law of the resistivity of each rock sample varying with the preset measurement angle, the bedding structure information and the physical property information. In an embodiment, the rock resistivity anisotropy coefficient is determined according to the law of the resistivity of each rock sample varying with the preset measurement angle, the bedding structure information and the physical property information, comprising:

[0054] According to the law of the resistivity of each rock sample varying with the preset measurement angle, the initial rock resistivity anisotropy coefficient expression is determined;

[0055] According to the bedding structure information and the initial rock resistivity anisotropy coefficient expression, the final rock resistivity anisotropy coefficient expression is determined.

[0056] In specific embodiments, the resistivity anisotropy coefficients of different rock samples are obtained The measurement angle θ is taken as the independent variable i The measurement angle θ is taken as the independent variable, and the two form a cross plot as shown in FIG. 4, which is the change law of the resistivity anisotropy coefficients of six rock samples at different measurement angles in an embodiment of the present disclosure. The resistivity anisotropy coefficients of different rock samples can be obtained The measurement angle θ is taken as the independent variable i The fitting relationship of the measurement angle θ is taken as the independent variable

[0057] In an embodiment, the initial rock resistivity anisotropy coefficient expression is determined according to the following formula:

[0058] Wherein, f j (θ i ) is the initial rock resistivity anisotropy coefficient expression, Rj(θ1) is the rock sample resistivity of the jth rock sample at the preset measurement angle θ i Rj(θ1) is the rock sample resistivity of the jth rock sample at the preset measurement angle θ Rj(θ1) is the rock sample resistivity of the jth rock sample at the preset measurement angle θ Rj(θ1) is the rock sample resistivity of the jth rock sample at the preset measurement angle θ i Rj(θ1) is the rock sample resistivity of the jth rock sample at the preset measurement angle θ j is the regression parameter affecting the rock resistivity anisotropy coefficient of the jth rock sample, and b is the regression constant of the jth rock sample.

[0059] In specific embodiments, taking three rock samples numbered 2-10-28, 2-16-28, and 3-8-32 in FIG. 4 as examples, the slopes are different, indicating that factors related to rock structure, in addition to the measurement angle, are related to the anisotropy of resistivity. Therefore, it is necessary to measure the associated experiments related to the rock structure. From the initial expression of the anisotropy of resistivity of the rock, a j is an important parameter for controlling the anisotropy of resistivity, and the greater the regression coefficient a j , the greater the anisotropy of resistivity of the rock, and vice versa. Therefore, to further analyze the influencing factors of the slope a, it is necessary to conduct associated experiments on the mineral composition and porosity of the rock sample, and at the same time, to count the bedding density (as shown in Table 1). FIG. 5 is a schematic diagram of a rock sample with well-developed resistive mineral bedding in the embodiments of the present disclosure, and it can be seen that the bedding density of the resistive mineral bedding (gray brick pattern) is obviously greater than that of the conductive mineral bedding (black pattern); FIG. 6 is a schematic diagram of a rock sample with well-developed conductive minerals in the embodiments of the present disclosure, and it can be seen that the bedding density of the conductive mineral bedding (black pattern) is obviously greater than that of the resistive mineral bedding (gray brick pattern); and FIG. 7 is a schematic diagram of a homogeneous rock sample. FIGS. 5, 6, and 7 are simplified schematic diagrams of the three rock samples 2-10-28, 2-16-28, and 3-8-32, respectively, and it can be seen that the two samples 2-10-28 and 2-16-28 have similar bedding density and porosity, but the sample 2-10-28 has more resistive minerals, and the sample has a stronger resistive effect on the current, so the anisotropy of resistivity of the sample is greater, while the resistive minerals of the sample 2-16-28 are less, and the conductive minerals are more, so the anisotropy of resistivity is relatively small. The sample 3-8-32 has the smallest bedding density, and the content of resistive and conductive minerals is small, and the rock is homogeneous, so the anisotropy of resistivity of the rock is small. Since the porosity also has a control effect on the anisotropy of resistivity, the regression coefficient a should be controlled by the bedding density, mineral composition, and porosity to change the resistivity. From FIG. 4, it can be seen that the regression constant b (i.e., the intercept on the axis of the anisotropy of resistivity) is a very small number close to 1. In order to facilitate calculation, the regression constant b is generally equal to 1, because when θ = 0°,

[0060] Table 1 Rock structure information of six rock samples

[0061] In an embodiment, the final expression of the anisotropy of resistivity of the rock is determined according to the following formula: f j (θ i ) = g(bs, θ i ).

[0062] wherein g() is a function of bedding structure index bs and measurement angle θ i , the bedding structure index is obtained according to the bedding structure information, D 密度 is the bedding density of the rock sample, V 增阻矿物含量 is the mineral content causing the increase of the resistivity of the rock sample, V 减阻矿物含量 is the mineral content causing the decrease of the resistivity of the rock sample, and Φ is the porosity.

[0063] FIG. 8 is a graph of the relationship between the bedding structure index and the regression coefficient in the embodiment of the present disclosure. The regression coefficient a is an important parameter for controlling the increase coefficient of the resistivity anisotropy. As the analysis above shows that the resistivity anisotropy coefficient is mainly affected by the bedding density, the resistivity-increasing and resistivity-decreasing minerals, and the porosity, a function relationship between the bedding structure index bs and the regression coefficient a can be established as follows: a=k(bs)=0.071e 0.0711·bs

[0064] The function relationship between the bedding structure index and the regression coefficient, combined with the final expression of the resistivity anisotropy coefficient of the rock, gives: f j (θ i ) = g(bs, θ i ) = k(bs) · θ i + b = 0.071e 0.711·bs · θ i + 1

[0065] wherein k() is a function for calculating the regression coefficient a.

[0066] In the specific embodiment, in the calculation of the actual logging data, the bedding density is obtained by the micro-resistivity scanning imaging logging, the effective porosity is calculated by any one of the density logging, the acoustic logging, and the nuclear magnetic resonance logging, and the resistivity-increasing mineral, the mineral causing the increase of the resistivity, and the mineral causing the decrease of the resistivity can be calculated by the element logging or by the optimal mineral interpretation model.

[0067] In step 105, the logging resistivity is corrected according to the resistivity anisotropy coefficient of the rock.

[0068] In the embodiment of the present disclosure, after the logging resistivity is corrected, the influence of the bedding structure and the formation dip angle on the resistivity can be eliminated, and thus more accurate resistivity data can be obtained. Further, the corrected logging resistivity can provide a reliable basis for the formation oil-bearing property evaluation and the production capacity judgment, and provide guidance for oil and gas development.

[0069] In one embodiment, the logging resistivity is corrected according to the resistivity anisotropy coefficient of the rock, including:

[0070] According to the actual logging resistivity and the anisotropy coefficient of rock resistivity in the actual logging data, the corrected logging resistivity is calculated.

[0071] In an embodiment, the rock sample resistivity is corrected according to a rock sample resistivity correction coefficient, including:

[0072] When the wellbore inclination direction is consistent with the target layer inclination direction, the corrected rock sample resistivity is calculated according to the following formula:

[0073] Wherein, θ 顺层 is the angle between the wellbore and the target layer when the wellbore inclination direction is consistent with the target layer inclination direction, g(bs, θ 顺层 ) is a function with the bedding structure index bs and the measurement angle θ 顺层 as the independent variables, R0 is the corrected logging resistivity, and R T is the actual logging resistivity.

[0074] When the wellbore inclination direction is inconsistent with the target layer inclination direction, the corrected rock sample resistivity is calculated according to the following formula:

[0075] Wherein, θ 逆层 is the angle between the wellbore and the target layer when the wellbore inclination direction is inconsistent with the target layer inclination direction, g(bs, θ 逆层 ) is a function with the bedding structure index bs and the measurement angle θ 逆层 as the independent variables, R0 is the corrected logging resistivity, and R T is the actual logging resistivity.

[0076] FIG. 9 is a schematic diagram when the wellbore inclination direction is consistent with the target layer inclination direction in the embodiment of the present disclosure. In specific embodiments, the angle between the wellbore and the target layer when the wellbore inclination direction is consistent with the target layer inclination direction is: θ 顺层 = 90° - θ 井斜 + θ 地层倾角 .

[0077] FIG. 10 is a schematic diagram when the wellbore inclination direction is inconsistent with the target layer inclination direction in the embodiment of the present disclosure. The angle between the wellbore and the target layer when the wellbore inclination direction is inconsistent with the target layer inclination direction is: θ 逆层 = 90° - θ 井斜 - θ 地层倾角 .

[0078] Wherein, θ 井斜 is the inclination angle, and θ 地层倾角 is the layer inclination angle.

[0079] Figure 11 is a comparison chart of the experimental results of the high-deviation well A and the vertical well B in the embodiment of the present disclosure, in specific embodiments, where GR is the natural gamma ray curve, and RT is the formation resistivity curve. Figure 11 shows the formation comparison of well A and well B, and it can be seen that the resistivity of the No. 1, No. 3, and No. 5 high-gamma mudstone layers decreases significantly, especially the original resistivity of the No. 3 layer of well A is close to the resistivity of the No. 2 and No. 4 layers, and the corrected No. 3 layer of well A decreases significantly, and the formation comparison effect with well B is better. At the same time, attention is paid to the No. 6 layer of well B, and the resistivity curve of which obviously presents the characteristics of "high in the upper and low in the lower". The original resistivity curve of the No. 6 layer of well A does not change significantly, but the corrected resistivity curve obviously presents the characteristics of "high in the upper and low in the lower". After correction, the resistivity of the high-deviation well is more comparable with the resistivity of the vertical well.

[0080] Figure 12 is a comparison chart of the original resistivity curve and the corrected resistivity curve of well A in the embodiment of the present disclosure, in specific embodiments, where CALI is the caliper curve, AC is the acoustic time curve, DEN is the density curve, CNL is the neutron porosity curve, SO original is the oil saturation curve calculated by the original resistivity RT, and SO corrected is the oil saturation curve calculated by the corrected resistivity R0. Figure 12 from left to right: the first track is the lithology curve track; the second track is the depth track; the third track is the resistivity curve track, which respectively shows the original resistivity curve RT (dashed line) and the corrected resistivity curve R0 (solid line); the fourth track is the three porosity curve track; the fifth track is the comparison of the oil saturation calculated by the corrected resistivity curve (solid line) and the oil saturation calculated by the original resistivity curve (dashed line) after correction by the method of the present disclosure; the sixth and seventh tracks are the segmented and clustered tracks; the eighth track is the oil test result (oil layer); and the ninth track is the oil production measured by the industry profile. The fluid production profile is measured in the 5-18 layer. In order to compare the effect of the resistivity calculated oil saturation before and after correction, Figure 13 is a comparison chart of the original resistivity calculated saturation and the oil production of the fluid production profile of an example well in the embodiment of the present disclosure, and Figure 14 is a comparison chart of the corrected resistivity calculated saturation and the oil production of the fluid production profile of an example well in the embodiment of the present disclosure; the saturation calculated by the original resistivity curve and the fluid production profile (Figure 13), and the saturation calculated by the corrected resistivity curve and the fluid production profile (Figure 14) are used to form cross-plot respectively. It can be seen that the oil saturation calculated by the original resistivity has no correlation with the fluid production profile (Figure 13). As shown in Figure 14, the oil saturation calculated by the corrected resistivity can be obviously divided into two parts, although the numerical range of the oil saturation of the two parts is close, the upper elliptical area has developed fractures and has large oil production, and the lower elliptical area has underdeveloped fractures and has small oil production, and the oil saturation of the two areas of the formation has obvious positive correlation with the fluid production profile in general.

[0081] The embodiment of the present disclosure also provides a resistivity anisotropy characterization device, as follows. Since the device solves the problem by the similar principle as the resistivity anisotropy characterization method, the implementation of the device can be referred to the implementation of the resistivity anisotropy characterization method, and the repeated parts will not be described herein.

[0082] FIG. 15 is a schematic diagram of a resistivity anisotropy characterization device according to an embodiment of the present disclosure, which includes:

[0083] The bedding structure information acquisition module 1501 is configured to acquire the bedding structure information and the physical property information measured from a plurality of rock samples of the target formation. The bedding structure information includes bedding density, mineral type and content. The physical property information includes, but is not limited to, porosity.

[0084] The rock sample resistivity measurement module 1502 is configured to acquire the resistivity of each rock sample measured from a plurality of preset measurement angles.

[0085] The resistivity variation rule determination module 1503 is configured to determine the rule of the resistivity of each rock sample varying with the preset measurement angle according to the resistivity of each rock sample at different preset measurement angles.

[0086] The resistivity anisotropy coefficient determination module 1504 is configured to determine the rock resistivity anisotropy coefficient according to the rule of the resistivity of each rock sample varying with the preset measurement angle, the bedding structure information and the physical property information.

[0087] The logging resistivity correction module 1505 is configured to correct the logging resistivity according to the rock resistivity anisotropy coefficient.

[0088] In an embodiment, the resistivity anisotropy coefficient determination module 1504 is specifically configured to:

[0089] determine an initial rock resistivity anisotropy coefficient expression according to the rule of the resistivity of each rock sample varying with the preset measurement angle;

[0090] determine a final rock resistivity anisotropy coefficient expression according to the bedding structure information and the initial rock resistivity anisotropy coefficient expression.

[0091] In an embodiment, the initial rock resistivity anisotropy coefficient expression is determined according to the following formula:

[0092] wherein f j (θ i ) is the initial rock resistivity anisotropy coefficient expression, is the rock sample resistivity of the jth rock sample at the preset measurement angle θ i . the initial rock resistivity anisotropy coefficient of the jth rock sample at a preset measurement angle θ the initial rock resistivity anisotropy coefficient of the jth rock sample at a preset measurement angle θ i j a is a regression parameter affecting the rock resistivity anisotropy coefficient of the jth rock sample, and b is a regression constant of the jth rock sample.

[0093] In an embodiment, the final rock resistivity anisotropy coefficient expression is determined according to the following formula: j (θ i )=g(bs,θ i );

[0094] where g() is a function with the bedding structure index bs and the measurement angle θ i as arguments, the bedding structure index is obtained according to the bedding structure information, D 密度 is the bedding density of the rock sample, V 增阻矿物含量 is the mineral content that increases the rock resistivity of the rock sample, V 减阻矿物含量 is the mineral content that decreases the rock resistivity of the rock sample, and Φ is the porosity.

[0095] In an embodiment, the resistivity correction module is specifically configured to:

[0096] When the wellbore inclination direction is consistent with the target layer inclination direction, the corrected rock sample resistivity is calculated according to the following formula:

[0097] where θ 顺层 is the included angle between the wellbore and the target layer when the wellbore inclination direction is consistent with the target layer inclination direction, g(bs, θ 顺层 ) is a function with the bedding structure index bs and the measurement angle θ 顺层 as arguments, R0 is the corrected rock sample resistivity, and R T is the actual rock sample resistivity.

[0098] When the wellbore inclination direction is inconsistent with the target layer inclination direction, the corrected rock sample resistivity is calculated according to the following formula:

[0099] where θ 逆层 is the included angle between the wellbore and the target layer when the wellbore inclination direction is inconsistent with the target layer inclination direction, g(bs, θ 逆层 ) is a function with the bedding structure index bs and the measurement angle θ 逆层 as arguments, R0 is the corrected rock sample resistivity, and R T ​The actual rock sample resistivity.

[0100] In an embodiment, the logging resistivity correction module 1505 is specifically configured to:

[0101] According to the actual logging resistivity in the actual logging data and the rock resistivity anisotropy coefficient, the corrected logging resistivity is calculated.

[0102] The embodiment of the present disclosure further provides a computer device, including a memory, a processor and a computer program stored in the memory and executable on the processor, and the processor implements the above-mentioned resistivity anisotropy characterization method when executing the computer program.

[0103] The embodiment of the present disclosure further provides a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement the above-mentioned resistivity anisotropy characterization method.

[0104] The embodiment of the present disclosure further provides a computer program product, which includes a computer program, and the computer program is executed by a processor to implement the above-mentioned resistivity anisotropy characterization method.

[0105] In the embodiment of the present disclosure, the bedding structure information and the physical property information of a plurality of rock samples of a target layer are obtained; the bedding structure information includes bedding density, mineral type and content; the physical property information includes, but is not limited to, porosity; the resistivity of the rock samples measured from a plurality of preset measurement angles is obtained; according to the resistivity of each rock sample at different preset measurement angles, the rule of the resistivity of the corresponding rock sample changing with the preset measurement angle is determined; without a large number of rock samples, the rock resistivity anisotropy coefficient can be determined according to the rule of the resistivity of each rock sample changing with the preset measurement angle, the bedding structure information and the physical property information; the logging resistivity is corrected according to the rock resistivity anisotropy coefficient, and a continuous rock resistivity anisotropy calculation result is formed, thereby solving the problem that the influence of the rock bedding structure on the rock resistivity anisotropy is not considered in the prior art.

[0106] Those skilled in the art should understand that the embodiments of the present disclosure can be provided as a method, a system or a computer program product. Therefore, the present disclosure can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Moreover, the present disclosure can take the form of a computer program product implemented on one or more computer usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer usable program code.

[0107] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks.

[0108] These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart block or blocks.

[0109] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks.

[0110] The specific embodiments described above are intended to be illustrative of the present disclosure and are not intended to limit the scope of the present disclosure. Various modifications of the above-described modes of practice could be made by those skilled in the art without departing from the spirit and scope of the present disclosure. Accordingly, the scope of the present disclosure should be determined not with the foregoing description alone, but instead should be determined in accordance with the appended claims.

Claims

1. A method of characterizing resistivity anisotropy, comprising: The method comprises the following steps: obtaining bedding structure information and physical property information of a plurality of rock samples of a target layer; the bedding structure information comprises bedding density, mineral type and content; the physical property information comprises but is not limited to porosity; obtaining the resistivity of each rock sample measured from a plurality of preset measurement angles; determining the change rule of the resistivity of each rock sample with the preset measurement angle according to the resistivity of each rock sample at different preset measurement angles; determining the resistivity anisotropy coefficient of the rock according to the change rule of the resistivity of each rock sample with the preset measurement angle, the bedding structure information and the physical property information; correcting the logging resistivity according to the resistivity anisotropy coefficient of the rock.

2. The method of claim 1, wherein, determining the resistivity anisotropy coefficient of the rock according to the change rule of the resistivity of each rock sample with the preset measurement angle, the bedding structure information and the physical property information, comprising: determining an initial resistivity anisotropy coefficient expression of the rock according to the change rule of the resistivity of each rock sample with the preset measurement angle; determining a final resistivity anisotropy coefficient expression of the rock according to the bedding structure information and the initial resistivity anisotropy coefficient expression.

3. The method of claim 2, wherein, The initial rock resistivity anisotropy coefficient expression is determined according to the following formula: wherein f j (θ i ) is an initial rock resistivity anisotropy coefficient expression, for the jth rock sample at a preset measurement angle of θ i for the jth rock sample at a preset measurement angle of θ for the jth rock sample at a preset measurement angle of θ1, is an initial rock resistivity anisotropy coefficient of the jth rock sample at a preset measurement angle of θ i is an initial rock resistivity anisotropy coefficient of the jth rock sample at a preset measurement angle of θ 4. The method of claim 2, wherein, The final resistivity anisotropy coefficient expression of the rock is determined according to the following formula: f j (θ i )=g(bs,θ i ); where g() is a function of bedding structure index bs and measurement angle θ i , bs is obtained from bedding structure information, D 密度 is the bedding density of the rock sample, V 增阻矿物含量 is the mineral content that increases the resistivity of the rock sample, V 减阻矿物含量 is the mineral content that decreases the resistivity of the rock sample, and Φ is the porosity.

5. The method of claim 1, wherein, correcting the logging resistivity according to the resistivity anisotropy coefficient of the rock, comprising: calculating the corrected logging resistivity according to the actual logging resistivity in the actual logging data and the resistivity anisotropy coefficient of the rock.

6. The method of claim 5, wherein, calculating the corrected logging resistivity according to the actual logging resistivity in the actual logging data and the resistivity anisotropy coefficient of the rock, comprising: When the wellbore tilt direction is consistent with the destination layer tilt direction, the corrected logging resistivity is calculated according to the following formula: Wherein, θ 顺层 is the angle between the wellbore and the target formation when the wellbore inclination direction is consistent with the target formation inclination direction, g(bs, θ 顺层 ) is a function with the bedding structure index bs and the measurement angle θ 顺层 as the arguments, R0 is the corrected logging resistivity, and R T is the actual logging resistivity; When the wellbore tilt direction is not consistent with the destination layer tilt direction, the corrected logging resistivity is calculated according to the following formula: Wherein, θ 逆层 is the angle between the wellbore and the target formation when the wellbore inclination direction is inconsistent with the target formation inclination direction, g(bs, θ 逆层 ) is a function with the bedding structure index bs and the measurement angle θ 逆层 as the independent variables, R0 is the corrected logging resistivity, and R T is the actual logging resistivity.

7. A resistivity anisotropy characterization apparatus, characterized in that, The method comprises the following steps: a bedding structure information acquisition module is configured to obtain bedding structure information and physical property information of a plurality of rock samples of a target layer; the bedding structure information comprises bedding density, mineral type and content; the physical property information comprises but is not limited to porosity; a rock sample resistivity measurement module is configured to obtain the resistivity of each rock sample measured from a plurality of preset measurement angles; a resistivity change rule determination module is configured to determine the change rule of the resistivity of each rock sample with the preset measurement angle according to the resistivity of each rock sample at different preset measurement angles; a resistivity anisotropy coefficient determination module is configured to determine the resistivity anisotropy coefficient of the rock according to the change rule of the resistivity of each rock sample with the preset measurement angle, the bedding structure information and the physical property information; a logging resistivity correction module is configured to correct the logging resistivity according to the resistivity anisotropy coefficient of the rock.

8. The apparatus of claim 7, wherein, The resistivity anisotropy coefficient determination module is specifically configured to: determine an initial resistivity anisotropy coefficient expression of the rock according to the change rule of the resistivity of each rock sample with the preset measurement angle; determine a final resistivity anisotropy coefficient expression of the rock according to the bedding structure information and the initial resistivity anisotropy coefficient expression.

9. The apparatus of claim 8, wherein, The initial rock resistivity anisotropy coefficient expression is determined according to the following formula: wherein f i (θ i ) is an initial rock resistivity anisotropy coefficient expression, the rock sample resistivity of the jth rock sample at a preset measurement angle of θ i ​ for the jth rock sample at a preset measurement angle of θ1, is an initial rock resistivity anisotropy coefficient of the jth rock sample at a preset measurement angle of θ i is an initial rock resistivity anisotropy coefficient of the jth rock sample at a preset measurement angle of θ 10. The apparatus of claim 8, wherein, The final resistivity anisotropy coefficient expression of the rock is determined according to the following formula: f j (θ i )=g(bs,θ i ); where g() is a function of bedding structure index bs and measurement angle θ i , the bedding structure index is obtained according to the bedding structure information, D 密度 is the bedding density of the rock sample, V 增阻矿物含量 is the mineral content causing the increase of the rock sample resistivity, V 减阻矿物含量 is the mineral content causing the decrease of the rock sample resistivity, and Φ is the porosity.

11. The apparatus of claim 7, wherein, The logging resistivity correction module is specifically configured to: calculate the corrected logging resistivity according to the actual logging resistivity in the actual logging data and the resistivity anisotropy coefficient of the rock.

12. The apparatus of claim 11, wherein, The resistivity correction module is specifically used for: When the wellbore tilt direction is consistent with the destination layer tilt direction, the corrected rock sample resistivity is calculated according to the following formula: Wherein, θ 顺层 is the angle between the wellbore and the target formation when the wellbore inclination direction is consistent with the target formation inclination direction, g(bs, θ 顺层 ) is a function with the bedding structure index bs and the measurement angle θ 顺层 as the independent variables, R0 is the corrected logging resistivity, and R T is the actual logging resistivity; When the wellbore tilt direction is not consistent with the destination layer tilt direction, the corrected rock sample resistivity is calculated according to the following formula: where θ 逆层 is the angle between the borehole and the target formation when the borehole inclination direction is inconsistent with the target formation inclination direction, g(bs, θ 逆层 ) is a function with the bedding structure index bs and the measurement angle θ 逆层 as arguments, R0 is the corrected logging resistivity, and R T is the actual logging resistivity.

13. A computer device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor executes the computer program to realize the method in any one of claims 1 to 6.

14. A computer-readable storage medium, characterized in that, The computer readable storage medium stores a computer program, and the computer program is executed by the processor to realize the method in any one of claims 1 to 6.

15. A computer program product, characterised in that, The computer program product comprises a computer program, and the computer program is executed by the processor to realize the method in any one of claims 1 to 6.

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