Multi-scale rock physical combination parameter characterization method based on pseudo capillary force model
The data of NMR and mercury infusion method are converted and combined through the pseudocapillary force model, which solves the test scale differences and accuracy problems in pore structure characterization, and realizes efficient evaluation and classification of complex reservoirs.
Patent Information
- Application Number
- CN202510590887.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-08
- Publication Date
- 2025-08-01
AI Technical Summary
The traditional mercury insulator and nuclear magnetic resonance methods have problems such as large differences in test scales, high data acquisition costs, insufficient accuracy of nanopore characterization, and the need to optimize the joint analysis model in pore structure characterization.
The pseudocapillary force model is used to convert the relaxation time of the nuclear magnetic resonance test into the pore radius, and is combined with the pore radius of the mercury injected test to establish a pseudocapillary force model to form a cumulative pore distribution curve of the pore throat radius, and a joint comparison is performed to characterize the pore throat size.
It realizes the unified scale planning and analysis of pore structure parameters under different testing methods, which is suitable for reservoir evaluation and classification of complex reservoir types, improving the accuracy and efficiency of pore structure characterization.
Smart Images
Figure CN120404527A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the technical field of pore throat characterization, and particularly to a method for characterizing multi-scale rock physical combination parameters based on a pseudo-capillary force model. Background Art
[0002] The characterization of pore structure is of great significance for oil and gas reservoir evaluation and development. Different pore structure characteristics directly affect the reservoir storage performance, fluid transmission ability, and ultimate recovery rate. Accurately characterizing the parameters of pore structure, such as pore size distribution, connectivity, and permeability, is the key to reservoir classification and quality evaluation.
[0003] Traditionally, pore structure characterization mainly relies on laboratory testing methods, such as Mercury Intrusion Capillary Pressure (MICP) and Nuclear Magnetic Resonance (NMR). The mercury intrusion method is a classic pore structure characterization method that can measure the pore size distribution from the nanoscale to the microscale in rock samples. Its principle is based on the process of mercury invading pores under different pressures, providing a detailed pore size distribution curve and related capillary pressure characteristics. The nuclear magnetic resonance method indirectly characterizes the pore size, connectivity, and saturation distribution by measuring the hydrogen nucleus relaxation time (T2 or T1) of the saturated fluid in the pores, and has unique advantages especially in non-destructive characterization and dynamic analysis. In recent years, the method of jointly characterizing pore structure by combining the mercury intrusion method and the nuclear magnetic resonance method, and their complementarity in pore structure characterization, can more comprehensively and efficiently characterize pore structure, significantly improving the accuracy of low-permeability reservoir evaluation.
[0004] However, there are still some problems in the joint characterization of mercury intrusion and nuclear magnetic resonance methods: the test scales of the two experiments are quite different, the data acquisition cost is relatively high, the characterization accuracy of nano-pores is lacking, and the joint analysis models and methods of the two methods still need to be further optimized. Summary of the Invention
[0005] Aiming at the above deficiencies in the prior art, a method for characterizing multi-scale rock physical combination parameters based on a pseudo-capillary force model provided by this application solves the problem of insufficient characterization ability of complex pore structures in traditional methods.
[0006] In order to achieve the above invention purpose, the technical solution adopted by this application is as follows: The method for characterizing multi-scale rock physical combination parameters based on a pseudo-capillary force model provided by this application includes: S1: Obtain nuclear magnetic resonance test experimental data and pressure pump test experimental data; S2: converting the relaxation time in the nuclear magnetic resonance test experimental data into pore radius information, and combining the converted pore radius information with the pore radius in the pressure pump test experimental data; S3: Based on the analysis of the combined results, a pseudo capillary force model is established with the cumulative porosity as the reference parameter; S4: According to the pseudo capillary force model, the data converted by different methods are converted into a cumulative porosity distribution curve of pore throat radius, and the pore throat size is characterized by joint comparison based on the cumulative porosity distribution curve.
[0007] Furthermore, the S1 specifically includes: A nuclear magnetic resonance test experiment and a pressure pump test experiment are simultaneously performed on the same rock sample to obtain test experimental data of the same rock sample; the test experimental data of the pressure pump test experiment is the relationship between the mercury injection pressure and the mercury injection volume, and the test experimental data of the nuclear magnetic resonance test experiment is the relaxation time T2 distribution.
[0008] Furthermore, the S2 specifically includes: S201: Convert the relaxation time in the nuclear magnetic resonance test experimental data into pore radius information. The conversion formula is as follows:
[0009] in, is the relaxation time, is the relaxation rate, is the pore surface area, is the pore volume, is the pore shape factor, is the pore radius; S202: The converted pore radius information is combined with the pore radius in the pressure pump test experimental data.
[0010] Furthermore, the S3 specifically includes: S301: constructing pore size distribution maps based on the nuclear magnetic resonance test data and the pressure pump test data respectively; S302: Calculating a single porosity component based on the pore size distribution diagram of the nuclear magnetic resonance test experiment and the pore size distribution diagram of the pressure pump test experiment; S303: Obtaining cumulative porosity based on the single porosity component; S304: Establishing a pore size distribution map based on the cumulative porosity to form a pseudo capillary force model.
[0011] Furthermore, the S4 specifically includes: After different rock classification types and different methods are subjected to steps S1, S2, and S3, new pore throat radius and cumulative porosity are obtained. Cumulative porosity distribution curves are formed with the pore throat radius as the horizontal coordinate and the cumulative porosity as the vertical coordinate, and a joint comparative analysis is performed based on the cumulative porosity distribution curves.
[0012] The beneficial effects of this application are as follows: Based on the complementary advantages of mercury intrusion and nuclear magnetic resonance, this application combines feature extraction from mercury intrusion curves with multidimensional feature analysis of nuclear magnetic resonance T2 distribution. On the basis of the simultaneous analysis of pore size and relaxation time, a simultaneous method using a pseudo-capillary model is established to address the problem of insufficient characterization of complex pore structures in traditional methods. This application can achieve unified scale planning and analysis of pore structure parameters under different testing methods, and is applicable to complex reservoir types such as shale, tight sandstone, and carbonate rock, providing a theoretical basis and data support for reservoir evaluation and classification. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other embodiments can also be obtained based on these drawings.
[0014] Figure 1 A schematic flow chart of a method for characterizing multi-scale rock physics combination parameters based on a pseudo capillary force model provided in an embodiment of the present application.
[0015] Figure 2 Schematic diagram of pore structure distribution based on relaxation time T2 of NMR nuclear magnetic resonance provided in the embodiments of the present application.
[0016] Figure 3 Schematic diagram of pore structure distribution obtained by converting NMR relaxation time T2 into pore radius provided in the examples of the present application.
[0017] Figure 4 Schematic diagram of the combined pore structure distribution of NMR and mercury intrusion experiments provided in the examples of this application.
[0018] Figure 5 Schematic diagram of the pseudo capillary model provided in the embodiments of the present application.
[0019] Figure 6 Schematic diagram of joint comparative characterization of cumulative porosity distribution curves based on pseudo-capillary model using different experimental methods provided in the embodiments of the present application. DETAILED DESCRIPTION
[0020] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field based on this application are within the scope of protection of this application.
[0021] In recent years, scholars have begun exploring methods for characterizing pore structure using a combination of mercury intrusion and nuclear magnetic resonance (NMR) methods, and significant progress has been made. For example, Liu Jiajia combined mercury intrusion test results with NMR T2 distribution curves, discovered their complementarity in pore structure characterization, and proposed a pore size distribution correction method based on joint data analysis. Guan Yao et al., through mercury intrusion testing and NMR analysis of shale samples, revealed the correlation between fracture development and pore connectivity, significantly improving the accuracy of low-permeability reservoir evaluation. Liu Jia et al. studied the multi-scale characteristics of complex pore structures in sandstones, developed a collaborative evaluation model based on NMR T2 distribution and mercury intrusion capillary pressure curves, and proposed a new quantitative evaluation method for pore connectivity.
[0022] Although significant progress has been made in the combined characterization of mercury intrusion and nuclear magnetic resonance, some problems still exist: for example, the difference in the test scales of the two experiments, the high cost of data acquisition, the need to improve the characterization accuracy of nanopores, and the need to further optimize the combined analysis models and methods of the two methods.
[0023] Based on this, the embodiment of the present application provides a method for characterizing multi-scale rock physics combination parameters based on a pseudo capillary force model. Figure 1 , Figure 1 FIG. 1 is a flow chart of a method for characterizing multi-scale rock physics combination parameters based on a pseudo-capillary force model provided in an embodiment of the present application, including: S1: Obtain nuclear magnetic resonance test data and pressure pump test data.
[0024] Furthermore, a nuclear magnetic resonance test experiment and a pressure pump test experiment are simultaneously performed on the same rock sample to obtain test experimental data of the same rock sample; the test experimental data of the pressure pump test experiment is the relationship between the mercury injection pressure and the mercury injection volume, and the test experimental data of the nuclear magnetic resonance test experiment is the relaxation time T2 distribution.
[0025] S2: converting the relaxation time in the nuclear magnetic resonance test experimental data into pore radius information, and combining the converted pore radius information with the pore radius in the pressure pump test experimental data.
[0026] Furthermore, the S2 specifically includes: S201: Convert the relaxation time in the nuclear magnetic resonance test experimental data into pore radius information, and the conversion formula is as follows:
[0027] where is the relaxation time, is the relaxation rate, is the pore surface area, is the pore volume, is the pore shape factor, is the pore radius; S202: Combine the converted pore radius information with the pore radius in the pressure pump test experimental data.
[0028] In an embodiment of the present application, in spherical pores is 3, and in cylindrical pores is 2; r is the pore radius, with the unit of μm. The nuclear magnetic resonance relaxation time T2 is changed through the formula. The schematic diagram of the r pore diameter can be seen in Figure 2 and Figure 3 .
[0029] S3: Analyze according to the combined result to obtain a pseudo-capillary force model established based on the cumulative porosity as the reference parameter.
[0030] Further, the S3 specifically includes: S301: Construct pore size distribution diagrams based on the nuclear magnetic resonance test experimental data and the pressure pump test experimental data respectively; S302: Calculate the single porosity component based on the pore size distribution diagram of the nuclear magnetic resonance test experiment and the pore size distribution diagram of the pressure pump test experiment respectively; S303: Obtain the cumulative porosity based on the single porosity component; S304: Establish a pore size distribution diagram based on the cumulative porosity to form a pseudo-capillary force model.
[0031] In an embodiment of the present application, although the porosities measured by nuclear magnetic resonance method and mercury intrusion method are similar, due to the fact that on the pore structure distribution diagram, the data points of nuclear magnetic resonance are denser, it will cause a large difference in the ordinate of the pore structure distribution diagram, making it difficult to compare. As shown in Figure 4 , Figure 4 is the combined schematic diagram of the pore structures of nuclear magnetic resonance and mercury intrusion experiments provided by the embodiment of the present application. The blue color represents mercury intrusion, and the red color represents nuclear magnetic resonance. Due to the large number of nuclear magnetic resonance data points, the porosity component of each point is low as a whole, resulting in the overall curve being lower than that of mercury intrusion.
[0032] It is understandable that in the pore size distribution diagrams of NMR and MICP, the ordinate represents the number of test points for each pore radius. However, since the test points of NMR are denser than those of mercury intrusion, one MICP test point is equivalent to several NMR test points with similar radii, resulting in the ordinate value of the NMR reaction being much higher than that of the MICP. To avoid this, we have established a pseudo-hair management model, which can be found in Figure 5 , the vertical axis of NMR and MICP is marked as the cumulative pore radius to avoid this scale unevenness problem.
[0033] S4: According to the pseudo capillary force model, the data converted by different methods are converted into a cumulative porosity distribution curve of pore throat radius, and the pore throat size is characterized by joint comparison based on the cumulative porosity distribution curve.
[0034] Furthermore, the S4 specifically includes: After different rock classification types and different methods are subjected to steps S1, S2, and S3, new pore throat radius and cumulative porosity are obtained. Cumulative porosity distribution curves are formed with the pore throat radius as the horizontal coordinate and the cumulative porosity as the vertical coordinate, and a joint comparative analysis is performed based on the cumulative porosity distribution curves.
[0035] In one embodiment of the present application, the data of the converted application of the pseudo capillary force model are summarized and merged, so that a horizontal comparison between multiple experimental data can be performed and the data can be quickly applied to solve engineering problems. Figure 6 To merge the renderings, different colors represent different rock classification types. The differences in methods can be seen in the characteristics of the data, which include nuclear magnetic resonance, mercury injection (different scales and pressure settings), and semi-permeable membrane plate method. It can be seen that although different experimental methods have different intervals on the same graph, the pseudo-capillary force model can integrate the scales of all experiments and conduct horizontal comparisons. NMR has a more complete data volume, which means that NMR contributes data from 0.001-1000. Through horizontal comparison, the ultimate goal of quickly solving engineering problems can be achieved.
[0036] This application leverages the complementary strengths of mercury intrusion and nuclear magnetic resonance (NMR) methods, combining feature extraction from mercury intrusion curves with multidimensional analysis of the NMR T2 distribution. This approach, based on the simultaneous analysis of pore size and relaxation time, establishes a simultaneous approach using a pseudo-capillary model to address the inadequate characterization of complex pore structures in traditional methods. This application enables unified scale planning and analysis of pore structure parameters under different testing methods, applicable to complex reservoir types such as shale, tight sandstone, and carbonate rock, providing a theoretical basis and data support for reservoir evaluation and classification.
[0037] Each embodiment in this specification is described in a related manner. For the same or similar parts among the embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. In particular, for the embodiments of the device, electronic device, computer-readable storage medium, and computer program product, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can refer to the partial description of the method embodiments.
[0038] The above description is only a preferred embodiment of the present application and is not intended to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application are all included in the protection scope of the present application.
Claims
1. A method for characterizing multi-scale rock physical composite parameters based on a pseudo-capillary force model, characterized in that, include: S1: Acquire nuclear magnetic resonance test data and pressure pump test data; S2: converting the relaxation time in the nuclear magnetic resonance test experimental data into pore radius information, and combining the converted pore radius information with the pore radius in the pressure pump test experimental data; S3: Based on the analysis of the combined results, a pseudo capillary force model is established with the cumulative porosity as the reference parameter; S4: According to the pseudo capillary force model, the data converted by different methods are converted into a cumulative porosity distribution curve of pore throat radius, and the pore throat size is characterized by joint comparison based on the cumulative porosity distribution curve.
2. The characterization method of multi-scale rock physical combination parameters based on the pseudo-capillary pressure model according to claim 1, wherein Said S1 specifically includes: A nuclear magnetic resonance test experiment and a pressure pump test experiment are simultaneously performed on the same rock sample to obtain test experimental data of the same rock sample; the test experimental data of the pressure pump test experiment is the relationship between the mercury injection pressure and the mercury injection volume, and the test experimental data of the nuclear magnetic resonance test experiment is the relaxation time T2 distribution.
3. The characterization method of multi-scale rock physical combined parameters based on the pseudo-capillary force model according to claim 1, characterized in that, The S2 specifically includes: S201: Convert the relaxation time in the nuclear magnetic resonance test experimental data into pore radius information. The conversion formula is as follows: Among them, is the relaxation time, is the relaxation rate, is the pore surface area, is the pore volume, is the pore shape factor, is the pore radius; S202: The converted pore radius information is combined with the pore radius in the pressure pump test experimental data.
4. The characterization method of multi-scale rock physical combination parameters based on the pseudo-capillary pressure model according to claim 1, characterized in that, The S3 specifically includes: S301: constructing pore size distribution maps based on the nuclear magnetic resonance test data and the pressure pump test data respectively; S302: Calculating a single porosity component based on the pore size distribution diagram of the nuclear magnetic resonance test experiment and the pore size distribution diagram of the pressure pump test experiment; S303: Obtaining cumulative porosity based on the single porosity component; S304: Establishing a pore size distribution map based on the cumulative porosity to form a pseudo capillary force model.
5. The characterization method of multi-scale rock physical combination parameters based on the pseudo-capillary pressure model according to claim 1, characterized in that The S4 specifically includes: After different rock classification types and different methods are subjected to steps S1, S2, and S3, new pore throat radius and cumulative porosity are obtained. Cumulative porosity distribution curves are formed with the pore throat radius as the horizontal coordinate and the cumulative porosity as the vertical coordinate, and a joint comparative analysis is performed based on the cumulative porosity distribution curves.