Rock brittleness evaluation method and device based on detection while drilling technology

Abstract

The invention relates to a rock brittleness evaluation method and device based on a detection-while-drilling technology, and relates to the technical field of geotechnical engineering in-situ tests.The method comprises the steps that the total consumed energy needed by digital drilling equipment in the process of conducting shale gas exploration on shale to be evaluated is determined; determining equipment cutting energy required by the digital drilling equipment in the process of carrying out shale gas exploration on the to-be-evaluated shale according to the total consumed energy; determining the cutting energy of the to-be-evaluated shale in unit volume according to the equipment cutting energy, and determining a rock brittleness index according to the cutting energy of the to-be-evaluated shale in unit volume; and evaluating the rock brittleness of the shale to be evaluated according to the rock brittleness index. The accuracy of the rock brittleness index is improved.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to the technical field of in-situ testing in geotechnical engineering. Specifically, the present disclosure relates to a method for evaluating rock brittleness based on logging-while-drilling technology and an apparatus for evaluating rock brittleness based on logging-while-drilling technology. Background Art

[0002] In some related technical solutions, a rock brittleness index can be determined based on an empirical formula of rock mechanical parameters, and then the rock brittleness can be evaluated based on the rock brittleness index. However, this method only considers the macroscopic mechanical properties of the rock and ignores the microscopic structural characteristics of the rock, resulting in a low accuracy rate of the obtained rock brittleness index.

[0003] It should be noted that the information disclosed in the background art above is only used to enhance the understanding of the background of the present disclosure, and thus may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

[0004] The purpose of the present disclosure is to provide a method for evaluating rock brittleness based on logging-while-drilling technology and an apparatus for evaluating rock brittleness based on logging-while-drilling technology, so as to at least overcome to a certain extent the problem of low accuracy rate of the rock brittleness index caused by the limitations and defects of related technologies.

[0005] According to one aspect of the present disclosure, a method for evaluating rock brittleness based on logging-while-drilling technology is provided, including:

[0006] Determining the total energy consumption required by a digital drilling device during shale gas exploration of a shale to be evaluated;

[0007] Determining the equipment cutting energy required by the digital drilling device during shale gas exploration of the shale to be evaluated according to the total energy consumption;

[0008] Determining the cutting energy per unit volume of the shale to be evaluated according to the equipment cutting energy, and determining a rock brittleness index according to the cutting energy per unit volume of the shale to be evaluated;

[0009] Evaluating the rock brittleness of the shale to be evaluated according to the rock brittleness index.

[0010] In an exemplary embodiment of the present disclosure, determining the total energy consumption required by the digital drilling device during shale gas exploration of the shale to be evaluated includes:

[0011] Determining the equipment parameters of the digital drilling device required for shale gas exploration of the shale to be evaluated;

[0012] Determine the equipment input energy required by the digital drilling equipment during the shale gas exploration of the shale to be evaluated according to the equipment parameters;

[0013] Determine the total energy consumption required by the digital drilling equipment during the shale gas exploration of the shale to be evaluated according to the preset equipment energy conservation formula and the equipment input energy.

[0014] In an exemplary embodiment of the present disclosure, the equipment parameters include the while-drilling parameters and bit parameters of the digital drilling equipment;

[0015] Among them, the while-drilling parameters include at least one of the drilling pressure, drilling torque, equipment rotation speed, drilling time, and drilling depth required by the digital drilling equipment during the shale gas exploration of the shale to be evaluated;

[0016] The bit parameters include the distance length between the current cutting point and the center cutting point of the cutting edge of the digital drilling equipment and the total length of the cutting edge.

[0017] In an exemplary embodiment of the present disclosure, determining the equipment input energy required by the digital drilling equipment during the shale gas exploration of the shale to be evaluated according to the equipment parameters includes:

[0018] Determine the first input energy generated by the drilling torque during the shale gas exploration of the shale to be evaluated according to the drilling torque, equipment rotation speed, and drilling time;

[0019] Determine the second input energy generated by the drilling pressure during the shale gas exploration of the shale to be evaluated according to the drilling pressure and drilling depth;

[0020] Determine the equipment input energy required by the digital drilling equipment during the shale gas exploration of the shale to be evaluated according to the first input energy and the second input energy.

[0021] In an exemplary embodiment of the present disclosure, determining the equipment cutting energy required by the digital drilling equipment during the shale gas exploration of the shale to be evaluated according to the total energy consumption includes:

[0022] Determine the equipment dissipation energy required by the digital drilling equipment during the shale gas exploration of the shale to be evaluated, and determine the equipment cutting energy required by the digital drilling equipment during the shale gas exploration of the shale to be evaluated according to the equipment dissipation energy and the total energy consumption.

[0023] In an exemplary embodiment of the present disclosure, the equipment cutting energy includes the energy required for the digital drilling equipment to cut and break rocks of the shale to be evaluated during shale gas exploration; the equipment dissipation energy includes the sum of the energy consumed by equipment friction, equipment heat exchange, forced vibration, and acoustic wave attenuation generated by the digital drilling equipment during shale gas exploration.

[0024] In an exemplary embodiment of the present disclosure, determining the equipment dissipation energy required by the digital drilling equipment during shale gas exploration of the shale to be evaluated includes:

[0025] Determine the friction dissipation energy according to the drilling pressure, equipment rotation speed, drilling time required by the digital drilling equipment during shale gas exploration of the shale to be evaluated, the distance between the current cutting point and the center cutting point of the cutting edge of the digital drilling equipment, and the total length of the cutting edge;

[0026] Determine the liquid dissipation energy required by the digital drilling equipment during shale gas exploration of the shale to be evaluated according to the rock quality of the shale to be evaluated and the radial drilling speed of the digital drilling equipment, and determine the equipment dissipation energy according to the friction dissipation energy and the liquid dissipation energy.

[0027] In an exemplary embodiment of the present disclosure, determining the cutting energy per unit volume of the shale to be evaluated according to the equipment cutting energy includes:

[0028] Determine the rock cutting volume of the shale to be evaluated according to the drilling depth required by the digital drilling equipment during shale gas exploration of the shale to be evaluated and the thickness of the blade bit of the digital drilling equipment;

[0029] Determine the cutting energy per unit volume of the shale to be evaluated according to the rock cutting volume and the equipment cutting energy.

[0030] In an exemplary embodiment of the present disclosure, determining the rock brittleness index of the shale to be evaluated according to the cutting energy per unit volume of the shale to be evaluated includes:

[0031]

[0032] where BI is the rock brittleness index, U d is the equipment dissipation energy, U c is the equipment cutting energy, V b is the Poisson's ratio of the shale to be evaluated, U f is the friction dissipation energy, U w is the liquid dissipation energy, SE is the cutting energy per unit volume of the shale to be evaluated, V cis the rock cutting volume.

[0033] According to one aspect of the present disclosure, there is provided a rock brittleness evaluation device based on measurement-while-drilling technology, including:

[0034] A total energy consumption determination module, configured to determine the total energy consumption required by a digital drilling device during shale gas exploration of the shale to be evaluated;

[0035] An equipment cutting energy determination module, configured to determine the equipment cutting energy required by the digital drilling device during shale gas exploration of the shale to be evaluated according to the total energy consumption;

[0036] A rock brittleness index determination module, configured to determine the cutting energy per unit volume of the shale to be evaluated according to the equipment cutting energy, and determine a rock brittleness index according to the cutting energy per unit volume of the shale to be evaluated;

[0037] A rock brittleness evaluation module, configured to evaluate the rock brittleness of the shale to be evaluated according to the rock brittleness index.

[0038] A rock brittleness evaluation method based on measurement-while-drilling technology provided by an embodiment of the present disclosure includes: determining the total energy consumption required by a digital drilling device during shale gas exploration of the shale to be evaluated; then determining the equipment cutting energy required by the digital drilling device during shale gas exploration of the shale to be evaluated according to the total energy consumption; further determining the cutting energy per unit volume of the shale to be evaluated according to the equipment cutting energy, and determining a rock brittleness index according to the cutting energy per unit volume of the shale to be evaluated; and finally evaluating the rock brittleness of the shale to be evaluated according to the rock brittleness index. Since the rock brittleness index can be determined based on the energy generated and consumed by the digital drilling device during drilling, without determining the rock brittleness index based on the macro-mechanics and micro-structure of the shale to be evaluated, the problem in the prior art that the accuracy of the obtained rock brittleness index is relatively low due to only considering the macro-mechanical properties of the rock and ignoring the micro-structure characteristics of the rock is solved, and the accuracy of the obtained rock brittleness index is improved.

[0039] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings here are incorporated into the specification and form a part of this specification, showing embodiments consistent with the present disclosure, and are used together with the specification to explain the principles of the present disclosure. Obviously, the accompanying drawings in the following description are only some embodiments of the present disclosure, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts.

[0041] Figure 1 Schematically shows a flowchart of a rock brittleness assessment method based on measurement-while-drilling technology according to an exemplary embodiment of the present disclosure.

[0042] Figure 2 Schematically shows an example diagram of the relationship between the intrinsic specific energy and the SE index according to an exemplary embodiment of the present disclosure.

[0043] Figure 3 Schematically shows an example diagram of the relationship between the brittleness index BIM and BI according to an exemplary embodiment of the present disclosure.

[0044] Figure 4 Schematically shows an example diagram of a digital drilling device according to an exemplary embodiment of the present disclosure.

[0045] Figure 5 Schematically shows a structural example diagram of a drill bit of a digital drilling device according to an exemplary embodiment of the present disclosure.

[0046] Figure 6 Schematically shows an example diagram of the force analysis of a drill bit during the drilling process according to an exemplary embodiment of the present disclosure.

[0047] Figure 7 Schematically shows a structural example diagram of a rock brittleness assessment device based on measurement-while-drilling technology according to an exemplary embodiment of the present disclosure.

[0048] Figure 8 Schematically shows an electronic device for implementing a rock brittleness assessment method based on measurement-while-drilling technology according to an exemplary embodiment of the present disclosure. Detailed implementation manners

[0049] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of the embodiments of the present disclosure. However, those skilled in the art will recognize that the technical solutions of the present disclosure may be practiced without one or more of the specific details, or may be implemented using other methods, components, devices, steps, etc. In other instances, well-known technical solutions are not shown or described in detail to avoid obscuring the various aspects of the present disclosure.

[0050] In addition, the accompanying drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and thus repeated descriptions thereof will be omitted. Some of the block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities may be implemented in software, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0051] In recent years, China has actively formulated shale gas exploration and development plans aimed at increasing the proportion of clean energy in the energy structure. With the increasingly severe climate problems such as air pollution and global warming, the demand for clean energy has become more urgent. As a relatively clean fossil energy, natural gas is regarded as one of the important alternatives to traditional energy sources such as coal. In the process of exploiting tight oil and gas fields such as shale gas, hydraulic fracturing technology is a very effective production-increasing means. However, as mentioned above, the brittleness of rocks directly affects the efficiency and success of the hydraulic fracturing process. Therefore, conducting research on rock brittleness and improving the accuracy of the internal brittleness evaluation method of reservoir rocks is of great significance for improving the research on shale gas fracturing mechanisms.

[0052] Currently, scholars at home and abroad have proposed various calculation methods for rock brittleness indices, such as empirical formula methods based on rock mechanical parameters, methods based on microstructural analysis, etc. However, due to the complexity and diversity of rock properties, these methods still have certain limitations in practical applications. For example, the empirical formula method based on rock mechanical parameters often only considers the macroscopic mechanical properties of rocks and ignores the microstructural characteristics of rocks; although the method based on microstructural analysis can more accurately reflect the brittle nature of rocks, it is difficult to be widely applied in practical engineering due to high testing costs, complex operations, etc.

[0053] Based on this, in the exemplary embodiment of the present example, a method for evaluating rock brittleness based on measurement-while-drilling technology is first provided. This method can run on terminal devices, servers, server clusters, cloud servers, etc. Of course, those skilled in the art can also run the method of the present disclosure on other platforms according to requirements, and no special limitation is made in this exemplary embodiment. Specifically, referring to Figure 1 as shown, the method for evaluating rock brittleness based on measurement-while-drilling technology may include the following steps:

[0054] Step S110. Determine the total energy consumption required by the digital drilling equipment during the shale gas exploration of the shale to be evaluated;

[0055] Step S120. Determine the equipment cutting energy required by the digital drilling equipment during the shale gas exploration of the shale to be evaluated according to the total energy consumption;

[0056] Step S130. Determine the cutting energy per unit volume of the shale to be evaluated according to the equipment cutting energy, and determine the rock brittleness index according to the cutting energy per unit volume of the shale to be evaluated;

[0057] Step S140. Evaluate the rock brittleness of the shale to be evaluated according to the rock brittleness index.

[0058] In the method for evaluating rock brittleness based on measurement-while-drilling technology described above, by determining the total energy consumption required by the digital drilling equipment during the shale gas exploration of the shale to be evaluated; then determining the equipment cutting energy required by the digital drilling equipment during the shale gas exploration of the shale to be evaluated according to the total energy consumption; then determining the cutting energy per unit volume of the shale to be evaluated according to the equipment cutting energy, and determining the rock brittleness index according to the cutting energy per unit volume of the shale to be evaluated; and finally evaluating the rock brittleness of the shale to be evaluated according to the rock brittleness index; since the rock brittleness index can be determined based on the energy generated and consumed by the digital drilling equipment during the drilling process, without determining the rock brittleness index based on the macroscopic mechanics and microscopic structure of the shale to be evaluated, thus solving the problem in the prior art that the accuracy of the obtained rock brittleness index is relatively low due to only considering the macroscopic mechanical properties of the rock and ignoring the microscopic structural characteristics of the rock, and improving the accuracy of the obtained rock brittleness index.

[0059] Hereinafter, the method for evaluating rock brittleness based on measurement-while-drilling technology recorded in the exemplary embodiment of the present disclosure will be explained and described in detail with reference to the accompanying drawings.

[0060] First, the technical implementation principle of the exemplary embodiments of the present disclosure will be explained and described. Specifically, the rock brittleness evaluation method based on the measurement-while-drilling technology provided by the exemplary embodiments of the present disclosure can accurately evaluate the mechanical parameters (i.e., the rock brittleness index) of rocks based on digital drilling technology, so as to solve the problems of insufficient accuracy in rock brittleness evaluation and failure to consider in-situ conditions in existing methods; further, compared with previous brittleness evaluation indexes, the present disclosure introduces the cutting energy SE index of rocks per unit volume, and by removing the influence of friction and cooling water, the accuracy of the brittleness evaluation index is improved; moreover, in the process of determining the rock brittleness by the exemplary embodiments of the present disclosure, the brittleness of rocks can be evaluated only through digital drilling tests, which has the advantages of simple operation, low cost, high speed, etc., and has broad application potential and market prospects.

[0061] Secondly, a further explanation and description will be given to Figure 1 the rock brittleness evaluation method based on the measurement-while-drilling technology shown in

[0062] In step S110, determine the total energy consumption required for the digital drilling equipment during the shale gas exploration of the shale to be evaluated.

[0063] Specifically, the specific determination process of the total energy consumption required for the digital drilling equipment during the shale gas exploration of the shale to be evaluated can be achieved through the following method: determine the equipment parameters of the digital drilling equipment required for the shale gas exploration of the shale to be evaluated; according to the equipment parameters, determine the equipment input energy required for the digital drilling equipment during the shale gas exploration of the shale to be evaluated; according to the preset equipment energy conservation formula and the equipment input energy, determine the total energy consumption required for the digital drilling equipment during the shale gas exploration of the shale to be evaluated. Specifically, the equipment parameters recorded here may include the measurement-while-drilling parameters and the bit parameters of the digital drilling equipment; the measurement-while-drilling parameters recorded here may include the drilling pressure F, drilling torque M, equipment rotation speed ω, drilling time t, and drilling depth h required for the digital drilling equipment during the shale gas exploration of the shale to be evaluated, etc.; the bit parameters recorded here may include the distance length r between the current cutting point and the center cutting point of the cutting edge of the digital drilling equipment and the total length L of the cutting edge.

[0064] In an exemplary embodiment, according to device parameters, the device input energy required for a digital drilling device in the process of shale gas exploration of the shale to be evaluated can be determined in the following manner: According to the drilling torque, device rotation speed, and drilling time, determine the first input energy generated by the drilling torque in the process of shale gas exploration of the shale to be evaluated; According to the drilling pressure and drilling depth, determine the second input energy generated by the drilling pressure in the process of shale gas exploration of the shale to be evaluated; According to the first input energy and the second input energy, determine the device input energy required for the digital drilling device in the process of shale gas exploration of the shale to be evaluated. Specifically, the specific determination processes of the first input energy and the second input energy recorded here can be obtained through the following formula (1) and formula (2):

[0065]

[0066] Wherein, W m is the first input energy, that is, the work done by the drilling torque; W f is the second input energy, that is, the work done by the drilling pressure; t is the drilling time, ω is the rotation speed of the digital drilling device, M is the drilling torque; h is the drilling depth, and F is the drilling pressure.

[0067] Further, after obtaining the first input energy and the second input energy, the first input energy and the second input energy can be subjected to a summation operation to obtain the device input energy required for the digital drilling device in the process of shale gas exploration of the shale to be evaluated. It should also be supplemented here that in the process of the summation operation, direct summation can be performed, or weighted summation can be used to achieve it. This example does not make special restrictions on this.

[0068] Furthermore, after obtaining the device input energy, the total consumption energy required for the digital drilling device in the process of shale gas exploration of the shale to be evaluated can be determined according to the preset device energy conservation formula and the device input energy. Among them, the preset device energy conservation formula recorded here can be specifically shown as the following formula (3):

[0069] W m +W f =U c +U d ; Formula (3)

[0070] Wherein, U c is the device cutting energy, U d is the device dissipation energy, and the device cutting energy U c and the device dissipation energy U d together are the total consumption energy.

[0071] In step S120, the equipment cutting energy required for the digital drilling equipment during shale gas exploration of the shale to be evaluated is determined according to the total energy consumption.

[0072] Specifically, the specific calculation process of the equipment cutting energy can be achieved in the following manner: Determine the equipment dissipation energy required for the digital drilling equipment during shale gas exploration of the shale to be evaluated, and determine the equipment cutting energy required for the digital drilling equipment during shale gas exploration of the shale to be evaluated according to the equipment dissipation energy and the total energy consumption; wherein, the equipment cutting energy U recorded herein c , that is, the energy required for the digital drilling equipment to cut and break the rock of the shale to be evaluated during shale gas exploration; the equipment dissipation energy U recorded herein d , that is, the sum of the energy consumed by the equipment friction generated between the digital drilling equipment and the shale to be evaluated, the energy consumed by the equipment heat exchange generated between the digital drilling equipment and the shale to be evaluated, the energy consumed by the forced vibration generated between the digital drilling equipment and the shale to be evaluated, and the energy consumed by the acoustic wave attenuation generated between the digital drilling equipment and the shale to be evaluated during shale gas exploration.

[0073] In an exemplary embodiment, the equipment dissipation energy required for the digital drilling equipment during shale gas exploration of the shale to be evaluated can be determined in the following manner: Determine the friction dissipation energy according to the drilling pressure, equipment rotation speed, drilling time required for the digital drilling equipment during shale gas exploration of the shale to be evaluated, the distance length between the current cutting point and the center cutting point of the cutting edge of the digital drilling equipment, and the total length of the cutting edge; Determine the liquid dissipation energy required for the digital drilling equipment during shale gas exploration of the shale to be evaluated according to the rock quality of the shale to be evaluated and the radial drilling speed of the digital drilling equipment, and determine the equipment dissipation energy according to the friction dissipation energy and the liquid dissipation energy. Specifically, the specific determination process of the equipment dissipation energy can be achieved through the following steps:

[0074] First, the specific expression form of the equipment dissipation energy can be achieved through the following formula (4):

[0075] U d =U f +U w ; Formula (4)

[0076] Wherein, U d is the equipment dissipation energy, U f is the friction dissipation energy, and U w is the liquid dissipation energy.

[0077] Secondly, on each tiny cross-section of the cutting edge of the digital drilling equipment, the torque caused by the friction between the cutting edge and the shale to be evaluated during the drilling process can be expressed by the following formula (5):

[0078]

[0079] where M f is the torque caused by the friction between the cutting edge and the shale to be evaluated during the drilling process, μ is the friction coefficient between the cutting edge and the shale to be evaluated during the drilling process; d(·) is the differential function; t is the drilling time, ω is the rotational speed of the digital drilling equipment, F is the drilling pressure, r is the distance length between the current cutting point and the central cutting point of the cutting edge of the digital drilling equipment, and L is the total length of the cutting edge.

[0080] Then, the energy dU f consumed by friction on each tiny segment dr can be expressed by the following formula (6):

[0081]

[0082] Furthermore, by integrating the frictional dissipation energy dU f along the drilling direction of the cutting edge, the frictional dissipation energy can be obtained; at the same time, considering the frictional energy of the two cutting edges on the drill bit, the total frictional energy (i.e., the frictional dissipation energy) U f can be expressed by the following formula (7):

[0083] U f = πωFtμ(L - r); Formula (7)

[0084] Even further, in the process of determining the liquid dissipation energy, first, based on the relatively stable characteristic of the driving force received by the cooling water, it is assumed that the cooling water moves at a constant speed; on this premise, the energy consumed by the liquid in the drill hole of the digital drilling equipment can be expressed by the following formulas (8) - (11):

[0085]

[0086]

[0087] m = ρV c ; Formula (10)

[0088]

[0089] where U w is the liquid dissipation energy, v w is the radial velocity of the drill bit, m is the rock mass of the shale to be evaluated, ρ is the rock density of the shale to be evaluated, d is the blade thickness of the drill bit, V cis the rock cutting volume of the shale to be evaluated; h is the drilling depth, and r is the distance length between the current cutting point and the central cutting point of the cutting edge of the digital drilling equipment.

[0090] Further, substituting formulas (9) - (11) into (8), we can obtain:

[0091]

[0092] It can be undoubtedly known from the above - recorded content that the specific calculation process of the equipment - dissipated energy can be shown as the following formula (12):

[0093]

[0094] Further, during the rock - drilling process, a large amount of fine - grained and medium - grained rock debris will be generated, and these debris will have a frictional effect on the drill bit; during the actual drilling process, the friction will hinder the drill bit from cutting the rock; therefore, considering the cutting effect, the SE index is introduced to express the equipment cutting energy U c . Among them, the equipment cutting energy recorded here can be expressed by the following formula (14):

[0095]

[0096] Among them, the SE index is the cutting energy per unit volume of the shale to be evaluated, h is the drilling depth, d is the blade thickness of the drill bit; V c is the rock cutting volume of the shale to be evaluated.

[0097] In step S130, determine the cutting energy per unit volume of the shale to be evaluated according to the equipment cutting energy, and determine the rock brittleness index according to the cutting energy per unit volume of the shale to be evaluated.

[0098] In this exemplary embodiment, first, determine the SE index of the cutting energy per unit volume of the shale to be evaluated; specifically, it can be achieved in the following way: Determine the rock cutting volume of the shale to be evaluated according to the drilling depth required during the shale - gas exploration of the digital drilling equipment for the shale to be evaluated and the blade drill bit thickness of the digital drilling equipment; Determine the cutting energy per unit volume of the shale to be evaluated according to the rock cutting volume and the equipment cutting energy. Specifically, in the actual application process, substituting formulas (1), (2), (13), and (13) into formula (3), the following formula (14) can be obtained, and then the SE index of the cutting energy per unit volume of the shale to be evaluated can be obtained. Specifically:

[0099]

[0100] Wherein, t is the drilling time, ω is the rotational speed of the digital drilling equipment, M is the drilling torque; h is the drilling depth, F is the drilling pressure; μ is the friction coefficient between the cutting edge and the shale to be evaluated during the drilling process; r is the distance length between the current cutting point and the central cutting point of the cutting edge of the digital drilling equipment, L is the total length of the cutting edge; d is the blade thickness of the drill bit.

[0101] Secondly, according to the cutting energy of the shale to be evaluated per unit volume, determine the rock brittleness index; specifically, the specific calculation process of the rock brittleness index can be shown by the following formula (16):

[0102]

[0103] Wherein, BI is the rock brittleness index, U d is the energy dissipated by the equipment, U c is the cutting energy of the equipment, V b is the Poisson's ratio of the shale to be evaluated, U f is the frictional dissipation energy, U w is the liquid dissipation energy, SE is the cutting energy of the shale to be evaluated per unit volume, V c is the rock cutting volume.

[0104] Furthermore, during the process of calculating the brittleness index of the rock, the brittleness index BIM based on energy consumption can also be calculated; specifically, the specific calculation process of the brittleness index BIM based on energy consumption can be shown by the following formula (17):

[0105]

[0106] Wherein, ε is the rock strain coefficient of the shale to be evaluated, σ is the rock stress of the shale to be evaluated, U e is the elastic strain energy of the shale to be evaluated, U is the total strain energy of the shale to be evaluated, E is the elastic modulus of the shale to be evaluated; the rock strain coefficient ε of the shale to be evaluated, the rock stress σ of the shale to be evaluated, the elastic strain energy U e of the shale to be evaluated, the total strain energy U of the shale to be evaluated, and the elastic modulus E of the shale to be evaluated can all be obtained by looking up the table.

[0107] In step S140, evaluate the rock brittleness of the shale to be evaluated according to the rock brittleness index.

[0108] Specifically, after obtaining the rock brittleness index, the rock brittleness of the shale to be evaluated can be evaluated based on the rock brittleness index; then, based on the obtained rock brittleness evaluation results, shale oil and gas development guidance, geological model establishment, and mineral composition analysis are carried out; among them, in the process of shale oil and gas development, the brittleness of the rock is an important index for evaluating the fracturability of shale; rocks with high brittleness are more likely to form complex fracture networks during the fracturing process, thereby increasing the productivity of shale gas wells; therefore, accurately evaluating the brittleness of shale is of great significance for optimizing the design of fracturing programs, improving the efficiency and economy of oil and gas development; further, in rock engineering, brittleness evaluation can also help engineers understand the failure characteristics of rocks when stressed, so as to consider the bearing capacity and stability of rocks during design; for example, in underground engineering construction, understanding the brittleness characteristics of rocks can avoid the occurrence of sudden disasters such as rock bursts; furthermore, in the process of establishing a geological model, by analyzing the mineral composition and microstructure of rocks, a geological model can be established to predict the brittleness of rocks; based on this, it not only helps to identify favorable fracturing targets, but also provides a scientific basis for oil and gas exploration and development; finally, in the process of mineral composition analysis, brittleness evaluation is usually based on the mineral composition of rocks, especially the content of brittle minerals (such as quartz); moreover, a high content of brittle minerals usually means that the rock has high brittleness, which is particularly important in the fracturing design of shale reservoirs.

[0109] Next, the rock brittleness evaluation method based on the measurement-while-drilling technology recorded in the exemplary embodiments of the present disclosure will be further explained and described in conjunction with specific experimental verification processes.

[0110] The first stage: the preparation stage; specifically, the triaxial compression and tensile tests of rocks can be carried out on a WDT-1500 multi-functional material testing machine; among them, in the specific test process, this instrument can perform triaxial compression and tensile tests on rock specimens under static and dynamic load conditions; at the same time, the maximum axial load that this instrument can provide is 1800 kN, the maximum confining pressure is 80 MPa, and the load error does not exceed 0.1%; further, triaxial compression and tensile tests are carried out on limestone, marble, sandstone, and granite under confining pressures of 10 MPa, 20 MPa, 30 MPa, and 40 MPa.

[0111] Secondly, a drilling test is carried out based on the digital drilling test equipment. Specifically, during the drilling experiment, the sampling rate of the drilling parameters of the digital drilling equipment is set to 0.02 s / time; meanwhile, the maximum confining pressure provided by the equipment is 80 MPa. Before the test starts, a pre-drilling test should be carried out first to test whether the parameters of the equipment are normal. In the actual application process, a diamond bit with a diameter of 8 mm is used in this test; and, drilling tests are carried out on limestone, marble, sandstone, and granite under confining pressures of 10 MPa, 20 MPa, 30 MPa, and 40 MPa. The drilling speed is set within the range of 0.1 - 1.2 mm / min, and the rotation speed is set to 200 - 600 rpm. The data collected from the test is shown in Table 1.

[0112] Table 1 Summary of test parameters for different confining pressures and lithologies

[0113]

[0114] Note: ε0 is the intrinsic specific energy of the rock.

[0115] In the second stage, based on the rock brittleness evaluation method based on the real-time measurement while drilling technology recorded in the exemplary embodiments of the present disclosure, the rock brittleness index is determined.

[0116] In the third stage, a comparative analysis of the measured results of the optimal load for rock breaking by indentation and the predicted results obtained from the exemplary embodiments of the present disclosure is carried out. Specifically, during the comparative analysis process, first, a digital drilling test is carried out to obtain the parameters required by the exemplary embodiments of the present disclosure, and calculate the SE, BI, and BIM of the rock; uniaxial compression and triaxial compression tests are carried out on four rock types to obtain the triaxial compression strength, rock tensile strength, and intrinsic specific energy of the rock under different confining pressure conditions; meanwhile, in order to verify the accuracy of the brittleness index calculation method proposed by the model established based on the digital drilling test, linear fittings are respectively performed on the intrinsic specific energy ε0 and SE, and BI and BIM, and the obtained results are respectively Figure 2 and Figure 3 as shown; meanwhile, from Figure 2 and Figure 3 it can be seen that the rock brittleness evaluation method proposed by the exemplary embodiments of the present disclosure has a relatively high degree of correlation with the intrinsic specific energy of the rock and BIM.

[0117] Based on the digital drilling experiment, the parameters while drilling and the bit parameters of the digital drilling equipment are obtained (wherein, the digital drilling equipment used can be referred to Figure 4 as shown, and for the structural schematic diagram of the bit used, reference can be made to Figure 5 as shown; meanwhile, for the schematic diagram of the force distribution of the bit during the drilling process, reference can be made to Figure 6 as shown), and then the brittleness evaluation of the rock is carried out in combination with the corresponding theory. This method takes into account the influence of friction and cooling water on rock fragmentation, introduces the cutting energy SE, and improves the reliability of the evaluation.2 All are above 0.9, indicating a relatively high degree of correlation. This method has a simple calculation process, saves time and effort compared with traditional methods, and has broad application prospects.

[0118] Moreover, the rock brittleness evaluation method based on the measurement-while-drilling technology described in the exemplary embodiments of the present disclosure also has the following advantages: on the one hand, digital drilling experiments have significant cost-effectiveness and operational simplicity, and the requirements for expensive and complex equipment in traditional methods are significantly reduced, thanks to the application of integrated sensors and automatic data acquisition systems, thereby saving costs and enhancing economic benefits; on the other hand, digital drilling technology facilitates real-time monitoring and evaluation, especially when carried out at the engineering site, ensuring the authenticity of data and the reflection of on-site conditions, thus improving the accuracy of brittleness evaluation; in contrast, laboratory tests often struggle to truly simulate the complexity of the on-site environment; furthermore, digital drilling technology can simulate dynamic loading conditions, accurately reflecting the stress state of rocks in the actual geological environment; this dynamic simulation is in sharp contrast to the static loading conditions commonly used in traditional laboratory tests and is of great significance for in-depth understanding of the behavior of rocks under different stress levels. At the same time, digital drilling experiments optimize the management of drilling parameters and improve operation efficiency by continuously monitoring key indicators during the drilling process through a data acquisition system.

[0119] The following are the device embodiments of the present disclosure, which can be used to implement the method embodiments of the present disclosure. For details not disclosed in the device embodiments of the present disclosure, please refer to the method embodiments of the present disclosure.

[0120] The exemplary embodiments of the present disclosure also provide a rock brittleness evaluation device based on the measurement-while-drilling technology. Specifically, as shown in Figure 7 the rock brittleness evaluation device based on the measurement-while-drilling technology may include a total energy consumption determination module 710, a device cutting energy determination module 720, a rock brittleness index determination module 730, and a rock brittleness evaluation module 740. Among them:

[0121] The total energy consumption determination module 710 can be used to determine the total energy consumption required for the digital drilling equipment during the shale gas exploration of the shale to be evaluated.

[0122] The device cutting energy determination module 720 can be used to determine the device cutting energy required for the digital drilling equipment during the shale gas exploration of the shale to be evaluated according to the total energy consumption.

[0123] The rock brittleness index determination module 730 can be used to determine the cutting energy per unit volume of the shale to be evaluated according to the device cutting energy, and determine the rock brittleness index according to the cutting energy per unit volume of the shale to be evaluated.

[0124] The rock brittleness evaluation module 740 can be used to evaluate the rock brittleness of the shale to be evaluated according to the rock brittleness index.

[0125] In an exemplary embodiment of the present disclosure, determining the total energy consumption required for the digital drilling equipment during the shale gas exploration of the shale to be evaluated includes: determining the equipment parameters of the digital drilling equipment required for the shale gas exploration of the shale to be evaluated; according to the equipment parameters, determining the equipment input energy required for the digital drilling equipment during the shale gas exploration of the shale to be evaluated; and according to the preset equipment energy conservation formula and the equipment input energy, determining the total energy consumption required for the digital drilling equipment during the shale gas exploration of the shale to be evaluated.

[0126] In an exemplary embodiment of the present disclosure, the equipment parameters include the while-drilling parameters and bit parameters of the digital drilling equipment; wherein, the while-drilling parameters include at least one of the drilling pressure, drilling torque, equipment rotation speed, drilling time, and drilling depth required for the digital drilling equipment during the shale gas exploration of the shale to be evaluated; the bit parameters include the distance length between the current cutting point and the center cutting point of the cutting edge of the digital drilling equipment and the total length of the cutting edge.

[0127] In an exemplary embodiment of the present disclosure, according to the equipment parameters, determining the equipment input energy required for the digital drilling equipment during the shale gas exploration of the shale to be evaluated includes: according to the drilling torque, equipment rotation speed, and drilling time, determining the first input energy generated by the drilling torque during the shale gas exploration of the shale to be evaluated; according to the drilling pressure and drilling depth, determining the second input energy generated by the drilling pressure during the shale gas exploration of the shale to be evaluated; and according to the first input energy and the second input energy, determining the equipment input energy required for the digital drilling equipment during the shale gas exploration of the shale to be evaluated.

[0128] In an exemplary embodiment of the present disclosure, according to the total energy consumption, determining the equipment cutting energy required for the digital drilling equipment during the shale gas exploration of the shale to be evaluated includes: determining the equipment dissipation energy required for the digital drilling equipment during the shale gas exploration of the shale to be evaluated, and according to the equipment dissipation energy and the total energy consumption, determining the equipment cutting energy required for the digital drilling equipment during the shale gas exploration of the shale to be evaluated.

[0129] In an exemplary embodiment of the present disclosure, the equipment cutting energy includes the energy required for the digital drilling equipment to cut and break rocks of the shale to be evaluated during shale gas exploration; the equipment dissipation energy includes the sum of the energy consumed by equipment friction, equipment heat exchange, forced vibration, and acoustic wave attenuation generated by the digital drilling equipment during shale gas exploration.

[0130] In an exemplary embodiment of the present disclosure, determining the equipment dissipation energy required by the digital drilling equipment during shale gas exploration of the shale to be evaluated includes: determining the frictional dissipation energy according to the drilling pressure, equipment rotation speed, drilling time, the distance between the current cutting point and the center cutting point of the cutting edge of the digital drilling equipment, and the total length of the cutting edge during the shale gas exploration of the shale to be evaluated by the digital drilling equipment; determining the liquid dissipation energy required by the digital drilling equipment during shale gas exploration of the shale to be evaluated according to the rock quality of the shale to be evaluated and the radial drilling speed of the digital drilling equipment, and determining the equipment dissipation energy according to the frictional dissipation energy and the liquid dissipation energy.

[0131] In an exemplary embodiment of the present disclosure, determining the cutting energy per unit volume of the shale to be evaluated according to the equipment cutting energy includes: determining the rock cutting volume of the shale to be evaluated according to the drilling depth required by the digital drilling equipment during shale gas exploration of the shale to be evaluated and the thickness of the blade bit of the digital drilling equipment; determining the cutting energy per unit volume of the shale to be evaluated according to the rock cutting volume and the equipment cutting energy.

[0132] In an exemplary embodiment of the present disclosure, determining the rock brittleness index of the shale to be evaluated according to the cutting energy per unit volume of the shale to be evaluated includes:

[0133]

[0134] where BI is the rock brittleness index, U d is the equipment dissipation energy, U c is the equipment cutting energy, V b is the Poisson's ratio of the shale to be evaluated, U f is the frictional dissipation energy, U w is the liquid dissipation energy, SE is the cutting energy per unit volume of the shale to be evaluated, V c is the rock cutting volume.

[0135] The specific details of each module in the above rock brittleness evaluation device based on the measurement-while-drilling technology have been described in detail in the corresponding rock brittleness evaluation method based on the measurement-while-drilling technology, so they will not be elaborated here.

[0136] It should be noted that although several modules or units of a device for action execution are mentioned in the above detailed description, this division is not mandatory. In fact, according to the embodiments of the present disclosure, the features and functions of two or more of the above-described modules or units can be embodied in one module or unit. Conversely, the features and functions of one module or unit described above can be further divided and embodied by multiple modules or units.

[0137] In addition, although the steps of the methods in the present disclosure are described in a specific order in the drawings, this does not require or imply that these steps must be performed in that specific order, or that all the steps shown must be performed to achieve the desired result. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined into one step for execution, and / or one step may be decomposed into multiple steps for execution, etc.

[0138] In an exemplary embodiment of the present disclosure, an electronic device capable of implementing the above method is also provided. Those skilled in the art can understand that various aspects of the present disclosure can be implemented as a system, method, or program product. Therefore, various aspects of the present disclosure can be specifically implemented in the following forms, namely: a complete hardware implementation, a complete software implementation (including firmware, microcode, etc.), or an implementation combining hardware and software aspects, which can be collectively referred to as a circuit, module, or system here.

[0139] Refer to the following Figure 8 to describe the electronic device 800 according to this embodiment of the present disclosure. Figure 8 The electronic device 800 shown is merely an example and should not impose any limitation on the functions and usage scope of the embodiments of the present disclosure.

[0140] As Figure 8 shown, the electronic device 800 is presented in the form of a general-purpose computing device. The components of the electronic device 800 may include but are not limited to: at least one of the above-mentioned processing units 810, at least one of the above-mentioned storage units 820, a bus 830 connecting different system components (including the storage unit 820 and the processing unit 810), and a display unit 840.

[0141] Among them, the storage unit stores program codes, and the program codes can be executed by the processing unit 810, so that the processing unit 810 executes the steps according to various exemplary embodiments of the present disclosure described in the above "Exemplary Method" section of this specification. For example, the processing unit 810 can execute as Figure 1Step S110 shown in : Determine the total energy consumption required by the digital drilling equipment during the shale gas exploration of the shale to be evaluated; Step S120: Determine the equipment cutting energy required by the digital drilling equipment during the shale gas exploration of the shale to be evaluated according to the total energy consumption; Step S130: Determine the cutting energy per unit volume of the shale to be evaluated according to the equipment cutting energy, and determine the rock brittleness index according to the cutting energy per unit volume of the shale to be evaluated; Step S140: Evaluate the rock brittleness of the shale to be evaluated according to the rock brittleness index.

[0142] The storage unit 820 may include a readable medium in the form of a volatile storage unit, such as a random access storage unit (RAM) 8201 and / or a cache storage unit 8202, and may further include a read-only storage unit (ROM) 8203.

[0143] The storage unit 820 may also include a program / utility 8204 having a set (at least one) of program modules 8205. Such program modules 8205 include, but are not limited to: an operating system, one or more application programs, other program modules, and program data. Each or some combination of these examples may include the implementation of a network environment.

[0144] The bus 830 may represent one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, a graphics acceleration port, a processing unit, or a local bus using any of a variety of bus structures.

[0145] The electronic device 800 may also communicate with one or more external devices 900 (such as a keyboard, a pointing device, a Bluetooth device, etc.), may also communicate with one or more devices that enable a user to interact with the electronic device 800, and / or may communicate with any device that enables the electronic device 800 to communicate with one or more other computing devices (such as a router, a modem, etc.). Such communication may be carried out through the input / output (I / O) interface 850. And, the electronic device 800 may also communicate with one or more networks (such as a local area network (LAN), a wide area network (WAN), and / or a public network, such as the Internet) through the network adapter 860. As shown in the figure, the network adapter 860 communicates with other modules of the electronic device 800 through the bus 830. It should be understood that although not shown in the figure, other hardware and / or software modules may be used in conjunction with the electronic device 800, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems, etc.

[0146] Those skilled in the art can easily understand from the description of the above embodiments that the exemplary embodiments described herein can be implemented by software or by a combination of software and necessary hardware. Therefore, the technical solutions according to the embodiments of the present disclosure can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (such as a CD-ROM, a USB flash drive, a mobile hard disk, etc.) or on a network, and includes several instructions to enable a computing device (such as a personal computer, a server, a terminal device, or a network device, etc.) to execute the method according to the embodiments of the present disclosure.

[0147] In an exemplary embodiment of the present disclosure, there is also provided a computer-readable storage medium having stored thereon a program product capable of implementing the above-described method of this specification. In some possible embodiments, various aspects of the present disclosure can also be implemented in the form of a program product, which includes program code. When the program product runs on a terminal device, the program code is used to cause the terminal device to execute the steps according to various exemplary embodiments of the present disclosure described in the above "Exemplary Method" section of this specification.

[0148] The program product for implementing the above method according to the embodiments of the present disclosure may adopt a portable compact disc read-only memory (CD-ROM) and include program code, and may run on a terminal device, such as a personal computer. However, the program product of the present disclosure is not limited thereto. In this document, the readable storage medium may be any tangible medium that contains or stores a program, and the program can be used by or in combination with an instruction execution system, apparatus, or device.

[0149] The program product may adopt any combination of one or more readable media. The readable media may be a readable signal medium or a readable storage medium. The readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the above. More specific examples (non-exhaustive list) of the readable storage medium include: an electrical connection having one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0150] A computer-readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, in which readable program code is carried. Such a propagated data signal may take many forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the foregoing. The readable signal medium may also be any readable medium other than a readable storage medium, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device.

[0151] The program code contained on the readable medium may be transmitted with any appropriate medium, including but not limited to wireless, wired, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

[0152] The program code for performing the operations of the present disclosure may be written in any combination of one or more programming languages, including object-oriented programming languages such as Java, C++, etc., and also including conventional procedural programming languages such as the "C" language or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, executed as a stand-alone software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server. In the case of a remote computing device, the remote computing device may be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computing device (e.g., by using an Internet service provider to connect through the Internet).

[0153] In addition, the above drawings are only schematic illustrations of the processes included in the method according to the exemplary embodiments of the present disclosure, and are not for limiting purposes. It is easy to understand that the processes shown in the above drawings do not indicate or limit the chronological order of these processes. Additionally, it is also easy to understand that these processes may be executed synchronously or asynchronously, for example, in multiple modules.

[0154] Those skilled in the art will readily conceive of other embodiments of the present disclosure after considering the specification and practicing the invention herein. This application is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include known common knowledge or conventional technical means in the technical field not invented by the present disclosure. The specification and embodiments are only to be considered as exemplary, and the true scope and spirit of the present disclosure are pointed out by the claims.

Claims

1. A method for evaluating rock brittleness based on measurement-while-drilling technology, characterized in that Including: Determine the total energy consumption required for the digital drilling equipment during shale gas exploration of the shale to be evaluated; Determine the equipment cutting energy required for the digital drilling equipment during shale gas exploration of the shale to be evaluated according to the total energy consumption; Determine the cutting energy per unit volume of the shale to be evaluated according to the equipment cutting energy, and determine the rock brittleness index according to the cutting energy per unit volume of the shale to be evaluated; Evaluate the rock brittleness of the shale to be evaluated according to the rock brittleness index.

2. The method for evaluating rock brittleness based on the measurement-while-drilling technology according to claim 1, characterized in that, Determine the total energy consumption required for the digital drilling equipment during shale gas exploration of the shale to be evaluated, including: Determine the equipment parameters of the digital drilling equipment required for shale gas exploration of the shale to be evaluated; Determine the equipment input energy required for the digital drilling equipment during shale gas exploration of the shale to be evaluated according to the equipment parameters; Determine the total energy consumption required for the digital drilling equipment during shale gas exploration of the shale to be evaluated according to the preset equipment energy conservation formula and the equipment input energy.

3. The method for evaluating rock brittleness based on the measurement-while-drilling technology according to claim 2, characterized in that, The equipment parameters include the while-drilling parameters and bit parameters of the digital drilling equipment; Among them, the while-drilling parameters include at least one of the drilling pressure, drilling torque, equipment rotation speed, drilling time, and drilling depth required for the digital drilling equipment during shale gas exploration of the shale to be evaluated; The bit parameters include the distance length between the current cutting point and the center cutting point of the cutting edge of the digital drilling equipment and the total length of the cutting edge.

4. The method for evaluating rock brittleness based on the measurement-while-drilling technology according to claim 3, wherein Determine the equipment input energy required for the digital drilling equipment during shale gas exploration of the shale to be evaluated according to the equipment parameters, including: Determine the first input energy generated by the drilling torque during shale gas exploration of the shale to be evaluated according to the drilling torque, equipment rotation speed, and drilling time; Determine the second input energy generated by the drilling pressure during shale gas exploration of the shale to be evaluated according to the drilling pressure and drilling depth; Determine the equipment input energy required for the digital drilling equipment during shale gas exploration of the shale to be evaluated according to the first input energy and the second input energy.

5. The method for evaluating rock brittleness based on the measurement-while-drilling technology according to claim 1, characterized in that, Determine the equipment cutting energy required for the digital drilling equipment during shale gas exploration of the shale to be evaluated according to the total energy consumption, including: Determine the equipment dissipation energy required for the digital drilling equipment during shale gas exploration of the shale to be evaluated, and determine the equipment cutting energy required for the digital drilling equipment during shale gas exploration of the shale to be evaluated according to the equipment dissipation energy and the total energy consumption.

6. The method for evaluating rock brittleness based on the measurement-while-drilling technology according to claim 5, wherein The equipment cutting energy includes the energy required for the digital drilling equipment to cut and break rocks during shale gas exploration of the shale to be evaluated; The equipment dissipation energy includes the sum of the energy consumed by equipment friction, equipment heat exchange, forced vibration, and acoustic wave attenuation generated by the digital drilling equipment during shale gas exploration.

7. The method for evaluating rock brittleness based on measurement-while-drilling technology according to claim 5, wherein Determine the equipment dissipation energy required for the digital drilling equipment during the shale gas exploration of the shale to be evaluated, including: Determine the frictional dissipation energy according to the drilling pressure, equipment rotation speed, drilling time required for the digital drilling equipment during the shale gas exploration of the shale to be evaluated, the distance length between the current cutting point and the center cutting point of the cutting edge of the digital drilling equipment, and the total length of the cutting edge; Determine the liquid dissipation energy required for the digital drilling equipment during the shale gas exploration of the shale to be evaluated according to the rock quality of the shale to be evaluated and the radial drilling speed of the digital drilling equipment, and determine the equipment dissipation energy according to the frictional dissipation energy and the liquid dissipation energy.

8. The method for evaluating rock brittleness based on the measurement-while-drilling technology according to claim 1, wherein Determine the cutting energy per unit volume of the shale to be evaluated according to the equipment cutting energy, including: Determine the rock cutting volume of the shale to be evaluated according to the drilling depth required for the digital drilling equipment during the shale gas exploration of the shale to be evaluated and the thickness of the blade bit of the digital drilling equipment; Determine the cutting energy per unit volume of the shale to be evaluated according to the rock cutting volume and the equipment cutting energy.

9. The method for evaluating rock brittleness based on the measurement-while-drilling technology according to claim 1, wherein Determine the rock brittleness index of the shale to be evaluated according to the cutting energy per unit volume of the shale to be evaluated, including: Among them, BI is the brittleness index of the rock, U d is the dissipated energy of the equipment, U c is the cutting energy of the equipment, V b is the Poisson's ratio of the shale to be evaluated, U f is the frictional dissipated energy, U w is the liquid dissipated energy, SE is the cutting energy per unit volume of the shale to be evaluated, V c is the rock cutting volume.

10. A rock brittleness evaluation device based on measurement-while-drilling technology, characterized in that including: A total consumption energy determination module for determining the total consumption energy required for the digital drilling equipment during the shale gas exploration of the shale to be evaluated; An equipment cutting energy determination module for determining the equipment cutting energy required for the digital drilling equipment during the shale gas exploration of the shale to be evaluated according to the total consumption energy; A rock brittleness index determination module for determining the cutting energy per unit volume of the shale to be evaluated according to the equipment cutting energy, and determining the rock brittleness index according to the cutting energy per unit volume of the shale to be evaluated; A rock brittleness evaluation module for evaluating the rock brittleness of the shale to be evaluated according to the rock brittleness index.

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