Natural fracture model parameter inversion method and system

Abstract

The invention provides a natural fracture model parameter inversion method and system. The inversion method comprises the following steps: S1, establishing a fine reservoir geologic model and a geomechanical model; s2, establishing a natural fracture model based on static data of well logging interpretation and seismic interpretation; s3, establishing a ground stress model; s4, fracturing simulation is carried out to fit a microseism monitoring interpretation result; s5, reservoir fracture distribution and development condition parameters are inversed; s6, performing inversion to re-establish a natural fracture model; and S7, predicting an artificial fracture propagation distribution condition to verify the reliability of the natural fracture model. And the fracture distribution condition of a real reservoir is effectively fitted, so that refined oil reservoir modeling and optimal development scheme making are realized.

Description

Technical Field

[0001] The present invention relates to the field of shale oil geological engineering integrated development, and in particular to a natural fracture model parameter inversion method and system. Background Art

[0002] As the development of shale gas and shale oil matures, the requirements for the accuracy of reservoir modeling are becoming higher and higher. However, shale oil is a very typical "poor reservoir condition" reservoir, and fractures have a great impact on reservoir permeability, fluid properties and production rate. Therefore, in the development of shale oil, the inversion method of natural fracture model parameters is a frontier and difficulty that needs to be studied.

[0003] At present, the inversion method of natural fracture model parameters is mainly based on basic geological research, seismic data interpretation, logging data interpretation, core analysis, etc., and some key parameters and research indicators are extracted to analyze and study the reservoir. However, these methods still have many limitations, such as large data errors and difficulty in calibrating key parameters. "A natural fracture modeling method for reservoirs based on microseismic moment tensor inversion" is a natural fracture modeling method based on static data, which fails to iterate the natural fracture model in combination with the actual fracturing effect of the mine. "A shale gas reservoir fracture modeling method based on microseismic monitoring data" refers to microseismic data points for fracture modeling parameter control, and fails to combine the spatial distribution law of complex fracture networks. "A shale gas reservoir modeling method after microseismic data compression" combines artificial fracture networks constrained by microseismic constraints with natural fractures, but fails to achieve mutual iterative verification of the two. Therefore, a more accurate, reliable and efficient inversion method is needed to guide actual development operations. Summary of the invention

[0004] In view of the above problems, the present invention is proposed to provide a natural fracture model parameter inversion method and system that overcomes the above problems or at least partially solves the above problems.

[0005] According to one aspect of the present invention, a natural fracture model parameter inversion method is provided, the inversion method comprising:

[0006] Step S1: Establish a detailed reservoir geological model and geomechanical model;

[0007] Step S2: Establishing a natural fracture model based on static data from well logging interpretation and seismic interpretation;

[0008] Step S3: Establishing a geostress model;

[0009] Step S4: Carry out fracturing simulation and fitting microseismic monitoring interpretation results;

[0010] Step S5: inverting reservoir fracture distribution and development parameters;

[0011] Step S6: inversion to re-establish the natural fracture model;

[0012] Step S7: predicting the expansion distribution of artificial fractures to verify the reliability of the natural fracture model.

[0013] Optionally, the step S1: establishing a fine reservoir geological model and a geomechanical model specifically includes: establishing a fine reservoir geological model and a geomechanical model based on actual block data.

[0014] Optionally, the step S2: establishing a natural fracture model based on static data of well logging interpretation and seismic interpretation specifically includes: on the basis of the step S1, establishing a natural fracture model based on static data of well logging interpretation and seismic interpretation.

[0015] Optionally, the step S3: establishing a geostress model specifically includes:

[0016] On the basis of step S2, a finite element simulation method is used to carry out a geostress simulation and establish a geostress model using a finite element simulator.

[0017] Optionally, the step S4: carrying out fracturing simulation fitting and microseismic monitoring interpretation results specifically includes:

[0018] On the basis of step S3, a fracturing simulation based on actual mine fracturing construction is carried out through fracturing simulation software, the microseismic monitoring interpretation results are fitted, and a dynamic expansion model of artificial hydraulic fractures that characterizes the actual spatial distribution of the mine fracture network is established;

[0019] Carry out fitting of section-by-section construction pressure curves and microseismic interpretation results.

[0020] Optionally, the key parameters in the process of fitting the stage-by-stage construction pressure curve and the microseismic interpretation results include: reservoir filtration coefficient, rheological coefficient of the fracturing system, wellbore friction, natural fracture density, and natural fracture orientation.

[0021] Optionally, the step S5: inverting reservoir fracture distribution and development parameters specifically includes:

[0022] On the basis of step S4, combined with the basic models such as the lithofacies model established in step S1 and the natural fracture model established based on static data in step S2, statistical analysis and evaluation are performed to determine the natural fracture density parameters and natural fracture orientation parameters of each section.

[0023] Optionally, the step S6: inversion to re-establish the natural fracture model specifically includes:

[0024] On the basis of step S5, the natural fracture model is re-established by inversion according to the natural fracture density parameters and natural fracture orientation parameters of each segment determined by fitting.

[0025] Optionally, the step S7: predicting the expansion distribution of artificial fractures to verify the reliability of the natural fracture model specifically includes: on the basis of step S6, conducting a fracturing simulation of the well to be fractured, and predicting the expansion distribution of artificial fractures.

[0026] The present invention also provides a natural fracture model parameter inversion system, which uses the above-mentioned natural fracture model parameter inversion method, and the inversion system comprises:

[0027] Geological model building module, used to build detailed reservoir geological model and geomechanical model;

[0028] The natural fracture model building module is used to build the natural fracture model based on the static data of well logging interpretation and seismic interpretation;

[0029] A geostress model building module is used to build a geostress model;

[0030] Fracturing simulation fitting module, used to carry out fracturing simulation fitting microseismic monitoring interpretation results;

[0031] Inversion module, used to invert reservoir fracture distribution and development parameters;

[0032] Inversion and reconstruction module, used to invert and re-establish the natural fracture model;

[0033] The distribution prediction module is used to predict the distribution of artificial fracture extension to verify the reliability of the natural fracture model.

[0034] The present invention provides a natural fracture model parameter inversion method and system, the inversion method comprises: step S1: establishing a fine reservoir geological model and a geomechanical model; step S2: establishing a natural fracture model based on static data of logging interpretation and seismic interpretation; step S3: establishing a geostress model; step S4: carrying out fracturing simulation fitting microseismic monitoring interpretation results; step S5: inverting reservoir fracture distribution and development parameters; step S6: inverting and re-establishing a natural fracture model; step S7: predicting the expansion distribution of artificial fractures to verify the reliability of the natural fracture model. Effectively fitting the fracture distribution of the real reservoir, thereby realizing refined reservoir modeling and optimizing development plan formulation.

[0035] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0037] Figure 1 A flow chart of a natural fracture model parameter inversion method provided by an embodiment of the present invention;

[0038] Figure 2 The geological model provided in the embodiment of the present invention takes the permeability attribute model as an example.

[0039] Figure 3 A natural fracture model established based on static data provided in an embodiment of the present invention.

[0040] Figure 4 The geostress model provided in the embodiment of the present invention takes the maximum horizontal principal stress model as an example.

[0041] Figure 5 The fracturing simulation and microseismic fitting results provided by the embodiments of the present invention.

[0042] Figure 6 The invention provides the key parameters of natural fractures inverted according to the fracturing simulation fitting results.

[0043] Figure 7 A natural fracture model re-established based on inversion parameters provided in an embodiment of the present invention.

[0044] Figure 8 The embodiment of the present invention provides a method for carrying out fracturing simulation prediction based on a reliable natural fracture model;

[0045] Fig. 9 The embodiment of the present invention provides a method for conducting adjacent well fracturing simulation and predicting the expansion and distribution of artificial fractures. DETAILED DESCRIPTION

[0046] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0047] The terms "comprises" and "having" and any variations thereof in the description embodiments, claims and drawings of the present invention are intended to cover non-exclusive inclusions, for example, including a series of steps or units.

[0048] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0049] Example 1

[0050] like Figure 1 As shown, a natural fracture model parameter inversion method disclosed in the present invention comprises:

[0051] Step S1: Establish a fine reservoir geological model and geomechanical model based on the basic geological research and reservoir numerical simulation requirements. Through the comprehensive use of multiple data sources such as seismic data, well logging data, core data, microseismic monitoring data, etc., combined with geomechanical models and geostress information, establish a fine reservoir geological model and geomechanical model as the basis of the inversion process.

[0052] Step S2: According to the well logging interpretation and seismic interpretation data, a natural fracture model based on static data is established. On the basis of the reservoir geological and geophysical models established in the first step, combined with actual data, an initial natural fracture model is established. The fracture model includes conventional inherent fractures and natural fractures that change with changes in ground stress.

[0053] Step S3: Conduct geostress simulation and establish a geostress model. Based on the geomechanical model and geophysical model, the reservoir rock mechanical properties and geological structure conditions are considered in the inversion process, and combined with the natural fracture model, a geostress field model is established to provide a basis for fracturing simulation.

[0054] Step S4: Based on the fracturing simulation of the actual mine fracturing construction, the microseismic monitoring interpretation results are fitted. In the actual mine fracturing process, the fracturing effect is monitored in real time through the on-site monitoring points, the microseismic monitoring data is collected and processed and interpreted, and the microseismic monitoring interpretation results and the well-to-well interference in the actual mine fracturing process are fitted. In this process, the natural fracture model needs to be adjusted well by well and section by section, and the parameters need to be adjusted to improve the accuracy and reliability of the inversion model.

[0055] Step S5: Invert the parameters of the real reservoir fracture distribution and development. When the fracturing simulation fitting data reaches a certain scale, the parameters of the real reservoir fracture distribution and development can be inverted by mathematical inversion algorithm. The main parameters are natural fracture density and natural fracture direction.

[0056] Step S6: Re-establish the natural fracture model. Re-establish the natural fracture model based on the inverted natural fracture model parameters. By re-establishing the model, the fracture distribution and development of the real reservoir can be more accurately reflected.

[0057] Step S7: Conduct fracturing simulations for other wells to be fractured and predict the expansion and distribution of artificial fractures. Based on the inverse natural fracture model, conduct fracturing simulations for the wells to be fractured and predict the expansion and distribution of artificial fractures. The prediction results can provide support for optimizing operation design and improving shale oil development efficiency.

[0058] Through the above implementation process, the present invention can achieve accurate inversion of natural fracture model parameters and reservoir fracture distribution with high accuracy and reliability, provide reliable technical support for shale oil development, and promote the improvement of shale oil development level.

[0059] The present invention proposes a natural fracture model parameter inversion method based on geological engineering integrated simulation, aiming to improve the effect of shale oil geological engineering integrated development. The method combines multiple data sources, including seismic, well logging, core, microseismic monitoring and other data, and uses geomechanical models and geostress information to establish a fine artificial hydraulic fracture network model, thereby inverting the natural fracture model parameters of the real reservoir. The present invention can provide more accurate and reliable technical support for shale oil development, and improve mining efficiency and economic benefits.

[0060] Example 2

[0061] The method of the present invention is described in detail below with reference to the accompanying drawings, and the specific steps are as follows:

[0062] (1) Figure 2 Establish the reservoir geological model of the target block. The specific model parameters are as follows:

[0063] ① The grid step size is 30×30 meters,

[0064] ②The number of grid nodes is 233×164×265=10126180,

[0065] ③Complete attribute modeling and reserve calculation fitting;

[0066] (2) Figure 3 According to the well logging interpretation and seismic interpretation data, a natural fracture model based on static data is established;

[0067] (3) Figure 4 A three-dimensional geostress model is established based on the geological model. The main model attributes include: three-dimensional triaxial stress magnitude and direction, three-dimensional rock mechanical properties (Young's modulus, Poisson's ratio, etc.), three-dimensional pore pressure, etc.

[0068] (4) Figure 5Conduct fracturing simulation for actual mine fracturing construction and fit the results of microseismic monitoring interpretation;

[0069] (5) Figure 6 Invert the direction of natural fractures in the real reservoir;

[0070] (6) Figure 7 Invert the density of natural fractures in real reservoirs;

[0071] (7) Figure 8 Re-establish the natural fracture model;

[0072] (8) Fig. 9 Conduct fracturing simulation of adjacent wells and predict the expansion and distribution of artificial fractures.

[0073] Beneficial effects: The natural fracture model parameter inversion method based on integrated geological and engineering simulation proposed in the present invention improves the efficiency and economic benefits of shale oil geological and engineering integrated development. The method integrates multiple data sources to establish a fine reservoir geological and geophysical model, thereby inverting the natural fracture model parameters of the real reservoir. The inversion accuracy and fracture distribution prediction accuracy of this method are significantly improved, providing a reliable basis for optimizing operational design and improving the efficiency of shale oil development. At the same time, the present invention combines different data sources, and applies mathematical models and geomechanical models, closely combining the natural fracture model with shale oil geological engineering practice, providing reliable technical support for shale oil development, and has broad application prospects.

[0074] The above specific implementation methods further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above are only specific implementation methods of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A natural fracture model parameter inversion method, characterized in that: The inversion method comprises: Step S1: Establish a detailed reservoir geological model and geomechanical model; Step S2: Establishing a natural fracture model based on static data from well logging interpretation and seismic interpretation; Step S3: Establishing a geostress model; Step S4: Carry out fracturing simulation and fitting microseismic monitoring interpretation results; Step S5: inverting reservoir fracture distribution and development parameters; Step S6: inversion to re-establish the natural fracture model; Step S7: predicting the expansion distribution of artificial fractures to verify the reliability of the natural fracture model.

2. A natural fracture model parameter inversion method according to claim 1, characterized in that: The step S1: establishing a fine reservoir geological model and a geomechanical model specifically includes: establishing a fine reservoir geological model and a geomechanical model based on actual block data.

3. A natural fracture model parameter inversion method according to claim 1, characterized in that: The step S2: establishing a natural fracture model based on static data of well logging interpretation and seismic interpretation specifically includes: on the basis of the step S1, establishing a natural fracture model based on static data of well logging interpretation and seismic interpretation.

4. A natural fracture model parameter inversion method according to claim 1, characterized in that: The step S3: establishing the geostress model specifically includes: On the basis of step S2, a finite element simulation method is used to carry out a geostress simulation and establish a geostress model using a finite element simulator.

5. A natural fracture model parameter inversion method according to claim 1, characterized in that: The step S4: carrying out fracturing simulation fitting and microseismic monitoring interpretation results specifically includes: On the basis of step S3, a fracturing simulation based on actual mine fracturing construction is carried out through fracturing simulation software, the microseismic monitoring interpretation results are fitted, and a dynamic expansion model of artificial hydraulic fractures that characterizes the actual spatial distribution of the mine fracture network is established; Carry out fitting of section-by-section construction pressure curves and microseismic interpretation results.

6. A natural fracture model parameter inversion method according to claim 5, characterized in that: The key parameters in the process of fitting the stage-by-stage construction pressure curve and the microseismic interpretation results include: reservoir filtration coefficient, rheological coefficient of the fracturing system, wellbore friction, natural fracture density, and natural fracture orientation.

7. A natural fracture model parameter inversion method according to claim 1, characterized in that: The step S5: inverting reservoir fracture distribution and development parameters specifically includes: On the basis of step S4, combined with the basic models such as the lithofacies model established in step S1 and the natural fracture model established based on static data in step S2, statistical analysis and evaluation are performed to determine the natural fracture density parameters and natural fracture orientation parameters of each section.

8. A natural fracture model parameter inversion method according to claim 1, characterized in that: The step S6: inversion to re-establish the natural fracture model specifically includes: On the basis of step S5, the natural fracture model is re-established by inversion according to the natural fracture density parameters and natural fracture orientation parameters of each segment determined by fitting.

9. A natural fracture model parameter inversion method according to claim 1, characterized in that: The step S7: predicting the distribution of artificial fracture expansion to verify the reliability of the natural fracture model specifically includes: based on the step S6, conducting a fracturing simulation of the well to be fractured, and predicting the distribution of artificial fracture expansion.

10. A natural fracture model parameter inversion system, using a natural fracture model parameter inversion method according to any one of claims 1 to 9, characterized in that: The inversion system comprises: Geological model building module, used to build detailed reservoir geological model and geomechanical model; The natural fracture model building module is used to build the natural fracture model based on the static data of well logging interpretation and seismic interpretation; A geostress model building module is used to build a geostress model; Fracturing simulation fitting module, used to carry out fracturing simulation fitting microseismic monitoring interpretation results; Inversion module, used to invert reservoir fracture distribution and development parameters; Inversion and reconstruction module, used to invert and re-establish the natural fracture model; The distribution prediction module is used to predict the distribution of artificial fracture extension to verify the reliability of the natural fracture model.

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