Logging evaluation method, system and equipment for crack effectiveness and medium

Abstract

The invention provides a logging evaluation method, system and equipment for crack effectiveness and a medium. The logging evaluation method comprises the following steps that oil-based mud imaging logging information is processed and explained based on logging information, and natural cracks around a well are picked up; obtaining crustal stress parameters according to the one-dimensional rock mechanical model, the longitudinal and transverse waves and the density data, picking up induction joints in imaging logging through electric imaging logging data, and determining the horizontal principal stress direction through well wall caving; rock core observation is performed based on rock core data, and different crack types are divided; determining stress parameter change rules of different crack types in combination with the oil-based mud electric imaging and the stress parameters, associating the different crack types with the corresponding stress parameters, and establishing corresponding relation rules of the different crack types and the stress parameters; according to stress parameter change rules corresponding to different crack types, full-well target layer crack effectiveness analysis is carried out based on the oil-based mud electric imaging and the stress parameters, the crack effectiveness of different well sections is determined, and an effective crack distribution area is judged.

Description

Technical Field

[0001] The invention belongs to the technical field of fracture logging, and in particular relates to a fracture effectiveness logging evaluation method, system, equipment and medium. Background Art

[0002] With the continuous deepening of oil and gas exploration and development, oil and gas exploration has gradually shifted from conventional oil and gas reservoirs to unconventional oil and gas reservoirs, and gradually shifted from medium and shallow layers to deep and ultra-deep layers, and entered the complex field of deep and ultra-deep layers. In particular, ultra-deep tight sandstones with extensive cracks under strong tectonic compression stress are becoming more and more the focus and hotspot of sedimentary research. It is not only an important field of future oil and gas exploration, but also an inevitable choice to help ensure the stability of energy and national energy security. At present, the evaluation of reservoir fracture effectiveness under the background of water-based mud has been relatively mature, but the evaluation of reservoir fracture effectiveness under the background of oil-based mud has always been a difficult problem that needs to be solved urgently in the oil and gas industry. So far, there is still no set of widely applicable technical methods to fundamentally solve the problem of effective evaluation of fractures under oil-based mud.

[0003] Specific production practices have shown that fractures significantly improve the seepage capacity of ultra-deep tight sandstone reservoirs and are a key factor in controlling the production capacity of tight sandstone reservoirs. During the geological history, tight sandstone reservoirs were subjected to strong tectonic compression, resulting in the widespread development of natural fractures. Natural fractures are subsequently affected by diagenetic evolution. Some fractures are often filled with minerals such as quartz and calcite to form filled fractures without seepage capacity, while others are not completely filled and retain some seepage capacity to form semi-filled fractures. There are also unfilled fractures that are not filled with any minerals. There will be great differences in the effectiveness of the three types of fractures, but natural fractures cannot be effectively identified in the context of oil-based mud as in water-based mud. In imaging logging under water-based mud, unfilled fractures appear as low-resistance dark sinusoidal lines, fully filled fractures such as calcite appear as high-resistance bright sinusoidal lines, and semi-filled fractures appear as partially high-resistance bright and partially low-resistance dark sinusoidal lines. Oil-based mud is resistant to high temperature and salt-calcium erosion, is conducive to well wall stability, has good lubricity, and causes little damage to oil and gas layers. It is widely used in various drilling platforms. However, it also brings technical difficulties to geologists in analysis and interpretation. Therefore, at present, there is an urgent need to develop a method for evaluating the effectiveness of natural fractures in the context of oil-based mud, so as to point out new directions for tight sandstone reservoir fractures and further production capacity evaluation, and provide a geological basis. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a well logging evaluation method, system, equipment and medium for fracture effectiveness, which can perform more accurate well logging identification of fractures in the background of oil-based mud.

[0005] The present invention is achieved through the following technical solutions:

[0006] A well logging evaluation method for fracture effectiveness comprises the following steps:

[0007] Obtain single well logging data and core data;

[0008] Processing and interpretation of oil-based mud imaging logging data based on logging data, as well as picking up natural fractures around the well;

[0009] The ground stress parameters are obtained based on the one-dimensional rock mechanics model, P-wave and S-wave and density data, and the horizontal principal stress direction is determined by picking up the induced fractures and wellbore collapse in the imaging logging through the electrical imaging logging data;

[0010] Conduct core observation based on core data and classify different fracture types;

[0011] Combine oil-based mud electrical imaging and stress parameters to determine the change rules of stress parameters of different fracture types, associate different fracture types with corresponding stress parameters, and establish the corresponding relationship between different fracture types and stress parameters;

[0012] According to the changing rules of stress parameters corresponding to different fracture types, the effectiveness of fractures in the target layer of the whole well is analyzed based on oil-based mud electrical imaging and stress parameters, the effectiveness of fractures in different well sections is determined, and the distribution area of ​​effective fractures is determined.

[0013] Furthermore, the logging data includes oil-based mud electrical imaging logging data, P-wave and S-wave time difference logging data, and density logging data.

[0014] Furthermore, the process of processing and interpreting the oil-based mud imaging logging data based on the logging data is as follows:

[0015] Based on the imaging logging processing module, the original data of oil-based mud electrical imaging is loaded, and static and dynamic images are obtained after well inclination and azimuth data quality control, magnetic declination correction, acceleration correction, and button electrode equalization processing.

[0016] Furthermore, the process of obtaining the ground stress parameters according to the one-dimensional rock mechanics model, P-wave and S-wave and density data, and determining the horizontal principal stress direction by picking up the induced fractures and wellbore collapse in the imaging logging through the electrical imaging logging data is as follows:

[0017] Based on the extrapolation method, Eaton's method and the poroelastic medium stress model, the overburden formation pressure, pore fluid pressure, maximum horizontal principal stress and minimum horizontal principal stress are obtained;

[0018]

[0019]

[0020]

[0021]

[0022] Where P0 is the overlying formation pressure, MPa, ρ b is the density logging, g / cm3, g is the gravitational constant, 9.8N / kg; P p is the pore pressure, MPa, P pn is the normal compaction pore pressure, MPa, α is the Biot coefficient, usually taken as 1, Δt0 is the time difference of mudstone logging acoustic wave at the calculation point, μs / ft, Δt n is the acoustic time difference of the normal compaction trend line of mudstone corresponding to the calculation point, μs / ft, n is the Eaton coefficient, ranging from 3 to 9; SH max SH m9n is the maximum and minimum horizontal principal stress, MPa, υ is Poisson's ratio, dimensionless, E is Young's modulus, GPa, ε H , ε h is the coefficient related to the maximum and minimum horizontal principal stresses;

[0023] Wellbore collapse is used to indicate the minimum horizontal principal stress orientation, and induced fractures are used to indicate the maximum horizontal principal stress orientation.

[0024] Furthermore, the process of performing core observation based on core data and classifying different fracture types is as follows: the fractures are classified into three categories according to the filling state, including unfilled fractures, semi-filled fractures and fully filled fractures.

[0025] Furthermore, the process of combining oil-based mud electrical imaging and stress parameters to determine the change law of stress parameters of different fracture types, associating different fracture types with corresponding stress parameters, establishing the corresponding relationship law between different fracture types and stress parameters and determining the effectiveness of fractures is as follows:

[0026] Find three typical fractures in the coring section, including unfilled fractures, semi-filled fractures and fully filled fractures;

[0027] Based on core calibration logging, conventional logging, imaging logging, core and horizontal stress difference are in one-to-one correspondence.

[0028] Furthermore, the criteria for establishing the correspondence between different crack types and stress parameters and judging the crack effectiveness are as follows: the lower the horizontal stress difference, the better the crack effectiveness, and as the angle between the crack direction and the horizontal stress difference increases, the crack effectiveness decreases.

[0029] A well logging evaluation system for fracture effectiveness, comprising:

[0030] Acquisition module, used to obtain single well logging data and core data;

[0031] The picking module is used to process and interpret the oil-based mud imaging logging data based on the logging data, and to pick up the natural fractures around the well;

[0032] The processing module is used to obtain the ground stress parameters according to the one-dimensional rock mechanics model, P-wave and S-wave and density data, and to determine the horizontal principal stress direction by picking up the induced fractures and wellbore collapse in the imaging logging through the electrical imaging logging data;

[0033] The classification module is used to observe the core and classify different fracture types based on the core data;

[0034] The correlation module is used to determine the change law of stress parameters of different fracture types by combining oil-based mud electrical imaging and stress parameters, associate different fracture types with corresponding stress parameters, and establish the corresponding relationship law between different fracture types and stress parameters;

[0035] The output module is used to analyze the effectiveness of fractures in the target layer of the whole well based on the variation law of stress parameters corresponding to different fracture types, oil-based mud electrical imaging and stress parameters, determine the effectiveness of fractures in different well sections, and determine the distribution area of ​​effective fractures.

[0036] A computer device comprises 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 steps of a well logging evaluation method for fracture effectiveness are implemented.

[0037] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of a well logging evaluation method for fracture effectiveness.

[0038] Compared with the prior art, the present invention has the following beneficial technical effects:

[0039] The present invention provides a logging evaluation method, system, equipment and medium for fracture effectiveness, comprising the following steps: obtaining single well logging data and core data; processing and interpreting oil-based mud imaging logging data based on the logging data, and picking up natural fractures around the well; obtaining ground stress parameters according to a one-dimensional rock mechanics model, longitudinal and transverse waves and density data, and picking up induced fractures and wellbore collapse in imaging logging through electrical imaging logging data to determine the direction of horizontal principal stress; performing core observation based on core data and classifying different fracture types; determining the variation law of stress parameters of different fracture types in combination with oil-based mud electrical imaging and stress parameters, associating different fracture types with corresponding stress parameters, and establishing the corresponding relationship law between different fracture types and stress parameters; performing fracture effectiveness analysis of the target layer of the whole well based on oil-based mud electrical imaging and stress parameters according to the variation law of stress parameters corresponding to different fracture types, determining the fracture effectiveness of different well sections, and determining the effective fracture distribution area; the present application comprehensively considers the control effect of stress on fracture development under the background of strong tectonic compression stress in foreland basins, and effectively combines electrical imaging and ground stress for analysis. Combining sensitive stress parameters under the background of oil-based mud can effectively overcome the difficulty of fracture evaluation under the background of oil-based mud, and greatly improve the effectiveness and accuracy of fracture evaluation under oil-based mud. It can effectively protect the reservoir and improve the accuracy of geological interpretation, which can reduce costs and increase efficiency, and provide a new method for reservoir fracture interpretation and production capacity evaluation. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 A flow chart of a well logging evaluation method for fracture effectiveness in an embodiment of the present invention;

[0041] Figure 2 This is a schematic diagram of oil-based mud electrical imaging processing and interpretation and stress parameter calculation in the embodiments of this specification;

[0042] Figure 3 This is a schematic diagram of different fracture types observed in a dense sandstone core of an embodiment of this specification;

[0043] Figure 4 This is a schematic diagram of imaging logging + stress parameters + stress parameters corresponding to different fracture types under the core in the embodiment of this specification;

[0044] Figure 5 This is a schematic diagram of the effectiveness evaluation of fractures in the target layer of a single well of the high-yield well XX1 in the embodiment of this specification;

[0045] Figure 6 This is a schematic diagram of the effectiveness evaluation of fractures in the target layer of a single well of the low-yield well XX2 in the embodiment of this specification;

[0046] Figure 7 This is a functional structural diagram of a well logging evaluation device for determining the effectiveness of tight sandstone reservoir fractures in combination with ground stress in an oil-based mud background according to an embodiment of this specification. DETAILED DESCRIPTION

[0047] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0048] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0049] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0050] As a type of unconventional reservoir with wide distribution and huge potential for oil and gas resources, tight sandstone reservoirs play a very important role in the global energy structure. With the increasing maturity of exploration technology, deep-ultra-deep tight sandstone has become a new hotspot for oil and gas exploration. Deep-ultra-deep tight sandstone reservoirs have undergone complex diagenesis and tectonic transformation over a long period of geological history, and have the characteristics of poor physical properties and complex pore structure. At the same time, due to strong tectonic compression, natural fractures are developed, and fractures play a key role in the later dissolution transformation and oil and gas seepage. Actual production practice also shows that fractures are the main controlling factor of tight sandstone reservoir production capacity. Therefore, the effectiveness evaluation of tight sandstone reservoir fractures has important guiding significance for capacity construction and increasing reserves and production.

[0051] The present invention provides a well logging evaluation method for fracture effectiveness, comprising the following steps:

[0052] Obtain single well logging data and core data;

[0053] Processing and interpretation of oil-based mud imaging logging data based on logging data, as well as picking up natural fractures around the well;

[0054] The ground stress parameters are obtained based on the one-dimensional rock mechanics model, P-wave and S-wave and density data, and the horizontal principal stress direction is determined by picking up the induced fractures and wellbore collapse in the imaging logging through the electrical imaging logging data;

[0055] Conduct core observation based on core data and classify different fracture types;

[0056] Combine oil-based mud electrical imaging and stress parameters to determine the change rules of stress parameters of different fracture types, associate different fracture types with corresponding stress parameters, and establish the corresponding relationship between different fracture types and stress parameters;

[0057] According to the changing rules of stress parameters corresponding to different fracture types, the effectiveness of fractures in the target layer of the whole well is analyzed based on oil-based mud electrical imaging and stress parameters, the effectiveness of fractures in different well sections is determined, and the distribution area of ​​effective fractures is determined.

[0058] Preferably, the logging data includes oil-based mud electrical imaging logging data, P-wave and S-wave time-difference logging data, and density logging data.

[0059] Preferably, the process of processing and interpreting the oil-based mud imaging logging data obtained based on the logging data is:

[0060] Based on the imaging logging processing module, the original data of oil-based mud electrical imaging is loaded, and static and dynamic images are obtained after well inclination and azimuth data quality control, magnetic declination correction, acceleration correction, and button electrode equalization processing.

[0061] Preferably, the process of obtaining the ground stress parameters according to the one-dimensional rock mechanics model, P-wave and S-wave and density data, and determining the direction of the horizontal principal stress by picking up the induced fractures and wellbore collapse in the imaging logging through the electrical imaging logging data is as follows:

[0062] Based on the extrapolation method, Eaton's method and the poroelastic medium stress model, the overburden formation pressure, pore fluid pressure, maximum horizontal principal stress and minimum horizontal principal stress are obtained;

[0063]

[0064]

[0065]

[0066]

[0067] Where P0 is the overlying formation pressure, MPa, ρ b is the density logging, g / cm3, g is the gravitational constant, 9.8N / kg; P p is the pore pressure, MPa, P pnis the normal compaction pore pressure, MPa, α is the Biot coefficient, usually taken as 1, Δt0 is the time difference of mudstone logging acoustic wave at the calculation point, μs / ft, Δt n is the acoustic time difference of the normal compaction trend line of mudstone corresponding to the calculation point, μs / ft, n is the Eaton coefficient, ranging from 3 to 9; SH max SH min is the maximum and minimum horizontal principal stress, MPa, υ is Poisson's ratio, dimensionless, E is Young's modulus, GPa, ε H , ε h is the coefficient related to the maximum and minimum horizontal principal stresses;

[0068] Wellbore collapse is used to indicate the minimum horizontal principal stress orientation, and induced fractures are used to indicate the maximum horizontal principal stress orientation.

[0069] Preferably, the process of performing core observation based on core data and classifying different fracture types is as follows: the fractures are classified into three categories according to the filling state, including unfilled fractures, semi-filled fractures and fully filled fractures.

[0070] Preferably, the process of combining oil-based mud electrical imaging and stress parameters to determine the variation law of stress parameters of different fracture types, associating different fracture types with corresponding stress parameters, establishing the corresponding relationship law between different fracture types and stress parameters and determining the effectiveness of fractures is as follows:

[0071] Find three typical fractures in the coring section, including unfilled fractures, semi-filled fractures and fully filled fractures;

[0072] Based on core calibration logging, conventional logging, imaging logging, core and horizontal stress difference are in one-to-one correspondence.

[0073] Preferably, the criteria for establishing the correspondence between different crack types and stress parameters and judging the crack effectiveness are: the lower the horizontal stress difference, the better the crack effectiveness, and as the angle between the crack direction and the horizontal stress difference increases, the crack effectiveness decreases.

[0074] Embodiment 1:

[0075] During the Himalayan period, the Cretaceous clastic rocks in the Kuche Depression continued to be strongly squeezed, and the rocks broke to form large-scale structural fractures, mainly high-angle fractures and network fractures. Effective fractures can connect isolated pores, significantly improve the permeability of the reservoir, and reduce the physical property lower limit of the effective reservoir. Studies have found that structural fractures formed under strong stress environments are sensitive to stress parameters. Specifically, the horizontal stress difference of rigid granular sandstone with developed effective fractures and good matrix properties is small. Since the internal accumulated ground stress can be released through the fractures, the overall environment is in a relatively low stress field, which can form a favorable reservoir body; on the other hand, if the fractures are filled with sand bodies that are dense as a whole, the current ground stress cannot be released through the fractures, which will form a high stress concentration area in the current stress field.

[0076] Considering that low-value stress areas not only correspond to fracture development, under-compacted mudstone and high-porosity matrix properties can also form low-stress areas. At the same time, electrical imaging logging under oil-based mud can only identify the sine lines of fracture development, and cannot judge the effectiveness of fractures based on the light and dark tones of the fracture sine lines. Therefore, the present invention combines the two to give full play to each other's advantages and realize the evaluation of the effectiveness of tight sandstone reservoir fractures under the background of oil-based mud.

[0077] See also Figure 1 The present embodiment provides a logging evaluation method for determining the effectiveness of fractures in tight sandstone reservoirs in combination with ground stress in the context of oil-based mud. In the present embodiment, the subject of the fracture effectiveness logging evaluation method is an electronic device or server system with loading, storage, and computing processing functions.

[0078] The method comprises the following specific steps:

[0079] S110: Acquire single well logging data and core data; wherein the logging data includes oil-based mud electrical imaging logging data, P-wave and S-wave time difference logging data, and density logging data;

[0080] S120: Complete the processing and interpretation of oil-based mud imaging logging data based on the imaging logging module, and complete the picking of natural fractures around the well based on the imaging logging images;

[0081] S130: Based on the one-dimensional rock mechanics model, the longitudinal and transverse waves and density data are used to complete the calculation of the size of the ground stress parameters. The stress parameters include: maximum and minimum horizontal principal stresses, overlying formation pressure and horizontal stress difference (SHmax-Shmin). The direction of the maximum horizontal principal stress is determined by picking up the induced fractures and wellbore collapse in the imaging logging through the electrical imaging logging data;

[0082] S140: Observe the core according to the core data of the coring section and classify different fracture types, where the fracture types include filled fractures, semi-filled fractures and unfilled fractures;

[0083] S150: Based on core calibration logging, combined with oil-based mud electrical imaging and stress parameters, the changing rules of stress parameters of different fracture types are determined, including selecting four typical characteristic sections: unfilled, semi-filled, fully filled and no fracture areas, associating different fracture types with corresponding stress parameters, and establishing and saving the corresponding relationship between different fracture types and stress parameters.

[0084] S160: According to the stress parameter variation law corresponding to different fracture types, the effectiveness of the target layer fractures in the whole well is analyzed based on the oil-based mud electrical imaging and stress parameters, the effectiveness of fractures in different well sections is determined, and the effective fracture distribution area is determined.

[0085] In steps S120 and S130 of the above embodiment, based on the imaging logging processing module, the original data of oil-based mud electrical imaging is loaded, and after well inclination and azimuth data quality control, magnetic declination correction, acceleration correction, and button electrode equalization processing, static and dynamic images are finally formed; according to one-dimensional rock mechanics modeling, Young's modulus and Poisson's ratio are obtained based on longitudinal and transverse wave and density logging, and the overlying formation pressure, pore fluid pressure, maximum and minimum horizontal principal stresses are calculated based on the extrapolation method, Eaton method, and porous elastic medium stress model using formulas (1)-(4).

[0086]

[0087]

[0088]

[0089]

[0090] Where P0 is the overlying formation pressure, MPa, ρ b is the density logging, g / cm3, g is the gravitational constant, 9.8N / kg; P p is the pore pressure, MPa, P pn is the normal compaction pore pressure, MPa, α is the Biot coefficient, usually taken as 1, Δt0 is the time difference of mudstone logging acoustic wave at the calculation point, μs / ft, Δt n is the acoustic time difference of the normal compaction trend line of mudstone corresponding to the calculation point, μs / ft, n is the Eaton coefficient, ranging from 3 to 9; SH max SH min is the maximum and minimum horizontal principal stress, MPa, υ is Poisson's ratio, dimensionless, E is Young's modulus, GPa, ε H , ε h are coefficients related to the maximum and minimum horizontal principal stresses.

[0091] Through imaging logging, the characteristics of wellbore collapse and drilling induced fracture development are picked up. Wellbore collapse indicates the minimum horizontal principal stress orientation, and induced fractures indicate the maximum horizontal principal stress orientation. The rose diagram shows the work area. Figure 2 The minimum horizontal principal stress orientation of the wells shown is 50-23°, and the maximum horizontal principal stress orientation is 140-320°.

[0092] The overall imaging logging static and dynamic images, stress parameter size, including Young's modulus, Poisson's ratio, maximum and minimum horizontal principal stress, horizontal stress difference and ground stress orientation, etc. Figure 2 shown.

[0093] In step S140 of the above embodiment, the fracture types are classified by core physical observation. Fractures can be classified according to occurrence, filling state, formation mechanism, etc. This study mainly analyzes the effectiveness of fractures, so fractures are divided into three categories according to the filling state: unfilled fractures, semi-filled fractures and fully filled fractures ( Figure 3 The study area is mainly filled with calcareous material, with a small amount of muddy filling.

[0094] In step S150 of the above embodiment, well A with more coring and complete logging data is selected, and steps based on S10, S120, and S130 are repeated. Natural fractures are picked up on the imaging logging, and a one-dimensional rock mechanics model is established. The stress parameters are calculated, and the horizontal stress difference (SHmax-Shmin) is selected as the sensitive parameter. Three typical fractures (unfilled fractures, semi-filled fractures, and fully filled fractures) are found in the coring section. Based on core calibration logging, conventional logging + imaging logging + core + horizontal stress difference (SHmax-Shmin) are in a one-to-one correspondence.

[0095] Firstly, a typical fracture-free well section of the target layer of a single well was selected, 5838.5-5842.5 m. The small changes in stress parameters in this section mainly reflect the changes in reservoir physical and lithological properties and have nothing to do with fractures. Based on the horizontal stress difference (SHmax-Shmin), the values ​​of m=30 and n=31.5 were constructed by mathematical fitting as the low and high values ​​of the fracture-free section. The interval (30, 31.5) is the stress parameter value corresponding to the fracture-free section, where m and n can be determined artificially or obtained by mathematical statistical fitting.

[0096] Analyze the change law of stress parameters in the corresponding well section compared with the interval (30,31.5), and establish the corresponding relationship between different fracture types and stress parameters ( Figure 4). The A section has semi-filled fractures. The local fractures are filled with calcite and are white in color. The unfilled parts are dark lines. The imaging logging corresponds to the development of multiple sinusoidal lines. The corresponding horizontal stress difference is slightly lower than the (30, 31.5) interval. The B section has fully filled fractures filled with calcite. The fractures in the core are all filled with white calcite. Sinusoidal lines can be picked up in the imaging to correspond to them. The horizontal stress difference is higher than the (30, 31.5) interval. The fractures are invalid fractures. The increase in resistivity and density curve in conventional logging also corresponds to the tight invalid reservoir caused by carbonate cementation along the fractures. The C section has unfilled fractures. The core fractures are dark lines. There is local dissolution and expansion along the fractures. The imaging logging also corresponds to the development of natural fractures. The horizontal stress difference is significantly lower than the (30, 31.5) interval. Different fracture types are associated with corresponding stress parameters, and the corresponding relationship between different fracture types and stress parameters is established, such as Figure 4 shown.

[0097] On the whole, as the horizontal stress difference increases, the effectiveness of the cracks decreases until the cracks become completely ineffective. We are still in the late Himalayan period, and the current stress field is the inherited development of the ancient stress field. The in-situ stress accumulated inside the sand body can be released through effective cracks. The more developed the effective cracks are, the lower the current stress field is. Filling cracks will affect the effectiveness of the cracks, so that the stress cannot be effectively released and accumulates to form a strong stress field with a high stress value. Therefore, combining in-situ stress can effectively evaluate the cracks in the background of oil-based mud.

[0098] In step S160 of the above embodiment, according to the stress parameter variation law corresponding to different fracture types, the effectiveness analysis of the target layer fractures of two wells with a large production capacity difference in the study area is performed based on oil-based mud electrical imaging and stress parameters, the effectiveness of fractures in different well sections is determined, and the effective fracture distribution area is determined.

[0099] like Figure 5As shown, the high-yield well XX1 selected a typical non-fracture well section. Based on mathematical fitting, the stress interval (m, n) of the non-fracture well section was defined as m=25, n=27.5. The well logging data is complete, especially the UPXL acoustic imaging of Baker Hughes. The reliability of the present invention can be further verified by comparing the EI oil-based electrical imaging and stress parameters with the UPXL acoustic imaging. The electrical imaging of section A picked up 4 natural fractures. The corresponding depth of the developed fractures, the horizontal stress difference is higher than the (m, n) interval, and it is judged to be an invalid fracture. Three obvious bright sine lines can be shown in the acoustic imaging, indicating that the fracture is a high-resistance filling fracture. The rose drawing shows that the angle between the direction of the fully filled fracture and the maximum horizontal stress direction is larger than that of other fracture types (the larger the angle between the direction of the fracture and the maximum horizontal stress direction, the worse the fracture effectiveness); the electrical imaging of section B picked up two fractures. Combined with the stress difference, the stress difference of the upper fracture is slightly lower than (m, n), which is a semi-filled fracture, and the stress difference of the lower fracture is between (m, n). The interval is judged as a filled fracture. The sinusoidal lines representing the fractures in the upper part of the acoustic imaging are thin and not obvious in some parts, corresponding to semi-filled fractures. The dark sinusoidal lines of the lower fractures correspond to mud-filled fractures. The rose diagram shows that the angle between the semi-filled fractures and the maximum horizontal principal stress in the whole well is small. The electrical imaging fractures in section C are very developed, and the corresponding horizontal stress difference is much smaller than the (m, n) interval, indicating that the fracture effectiveness is very good. It can also be confirmed in the acoustic imaging that the sinusoidal lines of the natural fractures are relatively thick and obvious dissolution holes can be seen along the fractures. The rose diagram shows that the angle between the unfilled fractures and the maximum horizontal principal stress in the whole well section is the smallest. The comparison and verification of UPXL acoustic imaging further verifies the reliability of the logging evaluation method for the effectiveness of fractures in tight sandstone reservoirs combined with ground stress under the background of oil-based mud described in the present invention.

[0100] Figure 6 As shown, for the lower productivity XX2 well, the above steps S110-S160 were repeated. In the test oil layer section 5080.5-5223m with a total thickness of 134.5m, EI electrical imaging picked up a total of 32 filled fractures, 6 semi-filled fractures and 10 unfilled fractures. Figure 5 The oil test section 4802-4900m of the XX1 well is 98m thick in total. EI electrical imaging picked up 10 filled fractures, 7 semi-filled fractures and 15 unfilled fractures. By comparison, it can be seen that the higher the proportion of effective fracture development, the better the communication effect of the fractures on the matrix physical properties, the higher the improvement of the reservoir seepage capacity, and the higher the single well production capacity. The analysis results are consistent with the oil test conclusions.

[0101] In general, the lower the horizontal stress difference, the better the fracture effectiveness, and as the angle between the fracture direction and the horizontal stress difference increases, the fracture effectiveness decreases, ∠ fully filled fracture angle > ∠ half filled fracture angle > ∠ unfilled fracture angle. Therefore, combined with the in-situ stress, the effectiveness of tight sandstone reservoir fractures under the background of oil-based mud can be effectively evaluated.

[0102] It can be seen from the specific implementation cases provided in the above embodiments of this specification that in the embodiments of this specification, single well logging data and core data can be obtained; wherein the logging data include oil-based mud electrical imaging logging data, P-wave and S-wave time-difference logging data and density logging data; oil-based mud imaging logging data processing and interpretation are completed based on the imaging logging module, and natural fractures around the well are picked up based on the imaging logging images; according to the one-dimensional rock mechanics model, the P-wave and S-wave and density data are used to complete the calculation of the size of the ground stress parameters, and the stress parameters include: maximum and minimum horizontal principal stresses, overlying formation pressure and horizontal stress difference, and the induced stress in the imaging logging is picked up through the electrical imaging logging data. The maximum horizontal principal stress direction is determined by the cracks and wellbore collapse; according to the core data of the coring section, the core is observed and different fracture types are divided, including filled fractures, semi-filled fractures and unfilled fractures; according to the core calibration logging, combined with the oil-based mud electrical imaging and stress parameters, the stress parameter variation law of different fracture types is determined, and the different fracture types are associated with the corresponding stress parameters, and the corresponding relationship between different fracture types and stress parameters is established and saved; according to the stress parameter variation law corresponding to different fracture types, the effectiveness of the fractures in the target layer of the whole well is analyzed based on the oil-based mud electrical imaging and stress parameters, the effectiveness of fractures in different well sections is determined, and the effective fracture distribution area is determined. Combining the imaging logging of oil-based mud with stress parameters can effectively overcome the difficulty of fracture evaluation under the background of oil-based mud, thereby greatly improving the effectiveness and accuracy of fracture evaluation under oil-based mud, and pointing out a new direction for the evaluation of tight sandstone reservoir fractures and further production capacity.

[0103] The present invention provides a well logging evaluation system for fracture effectiveness, comprising:

[0104] Acquisition module, used to obtain single well logging data and core data;

[0105] The picking module is used to process and interpret the oil-based mud imaging logging data based on the logging data, and to pick up the natural fractures around the well;

[0106] The processing module is used to obtain the ground stress parameters according to the one-dimensional rock mechanics model, P-wave and S-wave and density data, and to determine the horizontal principal stress direction by picking up the induced fractures and wellbore collapse in the imaging logging through the electrical imaging logging data;

[0107] The classification module is used to observe the core and classify different fracture types based on the core data;

[0108] The correlation module is used to determine the change law of stress parameters of different fracture types by combining oil-based mud electrical imaging and stress parameters, associate different fracture types with corresponding stress parameters, and establish the corresponding relationship law between different fracture types and stress parameters;

[0109] The output module is used to analyze the effectiveness of fractures in the target layer of the whole well based on the variation law of stress parameters corresponding to different fracture types, oil-based mud electrical imaging and stress parameters, determine the effectiveness of fractures in different well sections, and determine the distribution area of ​​effective fractures.

[0110] The present invention further provides an embodiment as follows: Figure 7 This is a functional structural diagram of an integrated device for information acquisition, loading, processing, analysis and evaluation according to an embodiment of the present specification. The device may specifically include the following structural modules.

[0111] The receiving and storing module 710 is used to receive, load and store single well core data and logging data;

[0112] Data processing module 720, including electrical imaging processing and one-dimensional rock force module, completes the processing and interpretation of oil-based mud electrical imaging, the picking of natural fractures around the well, the calculation of stress parameter size and the determination of direction;

[0113] The fracture effectiveness evaluation module 730 is used to determine the change law of stress parameters of different fracture types based on core calibration logging, combined with oil-based mud electrical imaging and stress parameters, establish and save the corresponding relationship between different fracture types and stress parameters, and conduct single-well fracture effectiveness analysis, that is, combined with the size and direction of ground stress, to conduct effectiveness logging evaluation on the fractures picked up in a single well in a tight sandstone reservoir under the background of oil-based mud.

[0114] After reading this specification, those skilled in the art can conceive of any combination of some or all of the embodiments listed in this specification without creative work, and these combinations are also within the scope of disclosure and protection of this specification.

[0115] In the 1990s, improvements to a technology could be clearly distinguished as hardware improvements (for example, improvements to the circuit structure of diodes, transistors, switches, etc.) or software improvements (improvements to the method flow). However, with the development of technology, many improvements to the method flow today can be regarded as direct improvements to the hardware circuit structure. Designers almost always obtain the corresponding hardware circuit structure by programming the improved method flow into the hardware circuit. Therefore, it cannot be said that an improvement in a method flow cannot be implemented using a hardware entity module. For example, a programmable logic device (PLD) (such as a field programmable gate array (FPGA)) is such an integrated circuit whose logical function is determined by the user's programming of the device. Designers can "integrate" a digital system on a PLD by programming it themselves, without having to ask a chip manufacturer to design and produce a dedicated integrated circuit chip. Moreover, nowadays, instead of manually making integrated circuit chips, this kind of programming is mostly implemented by "logic compiler" software, which is similar to the software compiler used when developing and writing programs, and the original code before compilation must also be written in a specific programming language, which is called hardware description language (HDL). There is not only one HDL, but many kinds, such as ABEL (Advanced Boolean Expression Language), AHDL (Altera Hardware Description Language), Confluence, CUPL (Cornell University Programming Language), HDCal, JHDL (Java Hardware Description Language), Lava, Lola, MyHDL, PALASM, RHDL (Ruby Hardware Description Language), etc. The most commonly used ones are VHDL (Very-High-Speed ​​Integrated Circuit Hardware Description Language) and Verilog2. Those skilled in the art should also know that it is only necessary to program the method flow slightly in the above-mentioned hardware description languages ​​and program it into the integrated circuit, and then it is easy to obtain the hardware circuit that implements the logic method flow.

[0116] In another embodiment of the present invention, a computer device is provided, the computer device includes a processor and a memory, the memory is used to store a computer program, the computer program includes program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, and is specifically suitable for loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding function; the processor described in the embodiment of the present invention can be used for the operation of a well logging evaluation method for fracture effectiveness.

[0117] In another embodiment of the present invention, the present invention also provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a computer device for storing programs and data. It is understandable that the computer-readable storage medium here can include both the built-in storage medium in the computer device and the extended storage medium supported by the computer device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space, and these instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the corresponding steps of the logging evaluation method for fracture effectiveness in the above embodiment.

[0118] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, 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 disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0119] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of 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.

[0120] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate 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 A function specified in one or more boxes.

[0121] 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 instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0122] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for evaluating fracture effectiveness through logging, characterized in that: The following steps are involved: Obtain single well logging data and core data; Processing and interpretation of oil-based mud imaging logging data based on logging data, as well as picking up natural fractures around the well; The ground stress parameters are obtained based on the one-dimensional rock mechanics model, P-wave and S-wave and density data, and the horizontal principal stress direction is determined by picking up the induced fractures and wellbore collapse in the imaging logging through the electrical imaging logging data; Conduct core observation based on core data and classify different fracture types; Combine oil-based mud electrical imaging and stress parameters to determine the change rules of stress parameters of different fracture types, associate different fracture types with corresponding stress parameters, and establish the corresponding relationship between different fracture types and stress parameters; According to the changing rules of stress parameters corresponding to different fracture types, the effectiveness of fractures in the target layer of the whole well is analyzed based on oil-based mud electrical imaging and stress parameters, the effectiveness of fractures in different well sections is determined, and the distribution area of ​​effective fractures is determined.

2. A well logging evaluation method for fracture effectiveness according to claim 1, characterized in that: The logging data include oil-based mud electrical imaging logging data, P-wave and S-wave time difference logging data and density logging data.

3. A well logging evaluation method for fracture effectiveness according to claim 1, characterized in that: The process of processing and interpreting the oil-based mud imaging logging data based on the logging data is as follows: Based on the imaging logging processing module, the original data of oil-based mud electrical imaging is loaded, and static and dynamic images are obtained after well inclination and azimuth data quality control, magnetic declination correction, acceleration correction, and button electrode equalization processing.

4. A method for evaluating fracture effectiveness by logging according to claim 1, characterized in that: The process of obtaining the ground stress parameters according to the one-dimensional rock mechanics model, P-wave and S-wave and density data, and determining the horizontal principal stress direction by picking up the induced fractures and wellbore collapse in the imaging logging through the electrical imaging logging data is as follows: Based on the extrapolation method, Eaton's method and the poroelastic medium stress model, the overburden formation pressure, pore fluid pressure, maximum horizontal principal stress and minimum horizontal principal stress are obtained; Where P0 is the overlying formation pressure, MPa, ρ b is the density logging, g / cm3, g is the gravitational constant, 9.8N / kg; P p is the pore pressure, MPa, P pn is the normal compaction pore pressure, MPa, α is the Biot coefficient, usually taken as 1, Δt0 is the time difference of mudstone logging acoustic wave at the calculation point, μs / ft, Δt n is the acoustic time difference of the normal compaction trend line of mudstone corresponding to the calculation point, μs / ft, n is the Eaton coefficient, ranging from 3 to 9; SH max SH min is the maximum and minimum horizontal principal stress, MPa, υ is Poisson's ratio, dimensionless, E is Young's modulus, GPa, ε H , ε h is the coefficient related to the maximum and minimum horizontal principal stresses; Wellbore collapse is used to indicate the minimum horizontal principal stress orientation, and induced fractures are used to indicate the maximum horizontal principal stress orientation.

5. The method for evaluating fracture effectiveness by logging according to claim 1, characterized in that: The process of performing core observation based on core data and classifying different fracture types is as follows: fractures are classified into three categories according to filling status, including unfilled fractures, semi-filled fractures and fully filled fractures.

6. The method for evaluating fracture effectiveness by logging according to claim 1, characterized in that: The process of combining oil-based mud electrical imaging and stress parameters to determine the change law of stress parameters of different fracture types, associating different fracture types with corresponding stress parameters, establishing the corresponding relationship law between different fracture types and stress parameters, and determining the effectiveness of fractures is as follows: Find three typical fractures in the coring section, including unfilled fractures, semi-filled fractures and fully filled fractures; Based on core calibration logging, conventional logging, imaging logging, core and horizontal stress difference are in one-to-one correspondence.

7. The method for evaluating fracture effectiveness by logging according to claim 1, characterized in that: The criteria for establishing the corresponding relationship between different crack types and stress parameters and judging the crack effectiveness are as follows: the lower the horizontal stress difference, the better the crack effectiveness, and as the angle between the crack direction and the horizontal stress difference increases, the crack effectiveness decreases.

8. A well logging evaluation system for fracture effectiveness, characterized in that: A well logging evaluation method for fracture effectiveness based on any one of claims 1 to 7, comprising: Acquisition module, used to obtain single well logging data and core data; The picking module is used to process and interpret the oil-based mud imaging logging data based on the logging data, and to pick up the natural fractures around the well; The processing module is used to obtain the ground stress parameters according to the one-dimensional rock mechanics model, P-wave and S-wave and density data, and to determine the horizontal principal stress direction by picking up the induced fractures and wellbore collapse in the imaging logging through the electrical imaging logging data; The classification module is used to observe the core and classify different fracture types based on the core data; The correlation module is used to determine the change law of stress parameters of different fracture types by combining oil-based mud electrical imaging and stress parameters, associate different fracture types with corresponding stress parameters, and establish the corresponding relationship law between different fracture types and stress parameters; The output module is used to analyze the effectiveness of fractures in the target layer of the whole well based on the variation law of stress parameters corresponding to different fracture types, oil-based mud electrical imaging and stress parameters, determine the effectiveness of fractures in different well sections, and determine the distribution area of ​​effective fractures.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the well logging evaluation method for fracture effectiveness as described in any one of claims 1-7 are implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the steps of a well logging evaluation method for fracture effectiveness as described in any one of claims 1 to 7 are implemented.

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