Joint characterization method and device for full-size pore size distribution of deep carbonate gas reservoir

Abstract

The invention discloses a joint characterization method and device for full-size pore size distribution of a deep carbonate gas reservoir. Performing CT scanning on the preprocessed rock sample to obtain a CT scanning image, and constructing a pore throat structure network model; micron-sized cracks and millimeter-sized karst caves in the model are extracted, and a first pore size distribution curve of the cracks and the karst caves is drawn; selecting a target rock sample with uniformly distributed pore throats, and dividing the target rock sample into a first sub-rock sample and a second sub-rock sample; performing a high-pressure mercury injection test on the first sub-rock sample, and drawing a second pore size distribution curve of the nanoscale pore throat; performing a constant-speed mercury injection test on the second sub-rock sample, and drawing a third pore size distribution curve of the micron-sized pore throat; and splicing and normalizing the pore size distribution curves, and drawing a full-size pore size distribution curve of the deep carbonate gas reservoir. According to the scheme, the defect that an existing oil and gas reservoir pore size distribution characterization method is poor in applicability in the deep carbonatite gas reservoir is overcome, and the precision and range of full-size pore size distribution characterization of the gas reservoir are effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of gas reservoir development, and in particular to a method and device for jointly characterizing full-scale pore size distribution in deep carbonate gas reservoirs. Background Art

[0002] With the gradual depletion of shallow and medium-layer oil and gas resources and the continuous development of deep-layer oil and gas theory and technology, deep carbonate gas reservoirs with huge resource potential have become a key area for future fossil energy exploration and development. Deep carbonate gas reservoirs have experienced a long geological history and multiple stages of tectonic and diagenetic processes, resulting in the presence of not only nano- and micron-sized pore throats in the reservoirs, but also the local development of micron-sized fractures and millimeter-sized caves. The irregular distribution of various reservoir media in the vertical and horizontal directions has formed a highly heterogeneous reservoir characteristic and a variety of reservoir types (pore type, fracture type, hole-vuggy type, and fracture-vuggy type), which increases the difficulty of characterizing the full-scale pore size distribution of such gas reservoirs.

[0003] Deep carbonate gas reservoirs simultaneously develop nano- and micron-scale pore throats, micron-scale fractures, and millimeter-scale caves. The pore size distribution range is significantly larger than that of other types of reservoirs. It is impossible to fully and accurately characterize the full-size pore size distribution of this type of gas reservoir using only a single pore throat structure characterization method.

[0004] In summary, based on the above problems, there is an urgent need for a joint characterization method that can comprehensively and accurately describe the full-scale pore size distribution of deep carbonate gas reservoirs. Summary of the Invention

[0005] The present invention provides a combined characterization method and device for full-scale pore size distribution in deep carbonate gas reservoirs, which can comprehensively and accurately describe the full-scale pore size distribution in deep carbonate gas reservoirs.

[0006] According to one aspect of the present invention, a method for joint characterization of full-scale pore size distribution in deep carbonate gas reservoirs is provided, comprising:

[0007] Performing CT scanning on the pre-treated rock sample to obtain a CT scan image, and constructing a pore-throat structure network model based on the CT scan image;

[0008] Setting a segmentation threshold for caves and cracks, extracting micron-scale cracks and millimeter-scale caves in the pore-throat structure network model, and drawing first pore size distribution curves of cracks and caves based on the extraction results;

[0009] Selecting a target rock sample with uniform pore throat distribution according to the extraction situation, and dividing the target rock sample into a first sub-rock sample and a second sub-rock sample;

[0010] Performing a high-pressure mercury injection test on the first sub-rock sample, and plotting a second pore size distribution curve of nano-scale pore throats based on the test results of the high-pressure mercury injection test; performing a constant-rate mercury injection test on the second sub-rock sample, and plotting a third pore size distribution curve of micron-scale pore throats based on the test results of the constant-rate mercury injection test;

[0011] The first pore size distribution curve, the second pore size distribution curve and the third pore size distribution curve are spliced ​​together, the spliced ​​full-size pore size distribution curve is normalized, and a full-size pore size distribution curve representing a deep carbonate gas reservoir is drawn.

[0012] Optionally, the rock samples are obtained by drilling gas wells at different locations in carbonate gas reservoirs;

[0013] The preprocessing comprises:

[0014] After the rock samples were washed with salt, the porosity and permeability were measured in turn;

[0015] Draw a scatter plot of porosity-permeability relationship based on the porosity and permeability data of all rock samples;

[0016] The porosity-permeability relationship scatter diagram is divided into different porosity-permeability distribution areas, and different numbers of rock samples are selected from each area according to the distribution frequency of data points in each distribution area.

[0017] Optionally, extracting micron-scale fractures and millimeter-scale caves from the pore-throat structure network model and drawing first pore size distribution curves of fractures and caves according to the extraction results includes:

[0018] Quantitatively analyze the micron-sized cracks and millimeter-sized caves, and calculate the pore volumes corresponding to the pore diameters of the micron-sized cracks and millimeter-sized caves;

[0019] The pore volume corresponding to each pore diameter is converted into a pore volume percentage according to the total pore volume, and the first pore diameter distribution curve within the preset pore diameter range is drawn.

[0020] Optionally, selecting a target rock sample with uniform pore throat distribution according to the extraction condition, and dividing the target rock sample into a first sub-rock sample and a second sub-rock sample, includes:

[0021] Based on the extraction conditions, the rock samples were classified into pore type, fracture type, hole type and fracture-hole type;

[0022] A rock sample with uniform pore throat distribution is selected from the pore type, fracture type, hole type and fracture-hole type rock samples, and the rock sample is divided into the first sub-rock sample and the second sub-rock sample of equal length.

[0023] Optionally, performing a high-pressure mercury injection test on the first sub-rock sample and drawing a second pore size distribution curve of nanoscale pore throats according to the test result of the high-pressure mercury injection test includes:

[0024] Setting a maximum mercury injection pressure to perform the high-pressure mercury injection test, and obtaining test results including capillary pressure and mercury injection saturation;

[0025] According to the relationship between pore size and capillary pressure, first pore size data is obtained according to the test results, and the second pore size distribution curve is drawn according to the first pore size data;

[0026] The method of performing a constant-rate mercury injection test on the second sub-rock sample and drawing a third pore size distribution curve of micron-scale pore throats according to the test results of the constant-rate mercury injection test comprises:

[0027] Setting the mercury injection rate, performing the constant-rate mercury injection test until the mercury injection pressure reaches a set maximum value, and obtaining test results including capillary pressure and mercury injection saturation;

[0028] According to the relationship between pore diameter and capillary pressure, second pore diameter data is obtained according to the test results, and the third pore diameter distribution curve is drawn according to the second pore diameter data.

[0029] Optionally, the splicing of the pore size distribution curves of the fractures and caves, the pore size distribution curves of the nanoscale pore throats, and the pore size distribution curves of the microscale pore throats includes:

[0030] A coordinate system is established based on fractal theory and a calculation formula for pore fractal dimension, wherein the fractal theory and the calculation formula for pore fractal dimension include:

[0031] lg(1-S Hg )=(3-D)lgr c -(3-D)lgr max ;

[0032] The horizontal axis of the coordinate system is lgr c , the vertical coordinate is lg(1-S Hg );

[0033] Plotting the capillary pressure and mercury injection saturation obtained from the high-pressure mercury injection test and the capillary pressure and mercury injection saturation obtained from the constant-rate mercury injection test into the coordinate system;

[0034] The pore volume percentage corresponding to each pore size of the millimeter-scale caves and micrometer-scale fractures is equivalent to the mercury saturation and plotted in the coordinate system;

[0035] Performing piecewise linear fitting on the drawn portion of the coordinate system to determine whether the fitted lines intersect in the overlapping area;

[0036] When there is an intersection between the fitting lines, the pore size corresponding to the intersection is selected as the splicing point of the overlapping area of ​​the pore size distribution curve; when there is no intersection between the fitting lines, the average curve of the overlapping area of ​​the pore size distribution curve is drawn as the splicing line;

[0037] The first pore size distribution curve, the second pore size distribution curve, and the third pore size distribution curve are plotted in the coordinate system, and overlapping areas of the first pore size distribution curve, the second pore size distribution curve, and the third pore size distribution curve are connected through the splicing points and / or the splicing lines to obtain a continuous full-size pore size distribution curve.

[0038] Optionally, normalizing the spliced ​​full-size pore size distribution curve to draw a full-size pore size distribution curve characterizing a deep carbonate gas reservoir includes:

[0039] Classifying the full-size pore size distribution curves according to rock sample types, normalizing the full-size pore size distribution curves of the rock samples, and drawing four full-size pore size distribution curves representing four types of deep carbonate reservoirs;

[0040] The proportion of each type of reservoir is calculated based on the development frequency of the four types of reservoirs in deep carbonate gas reservoirs. The full-size pore size distribution curve of the reservoir corresponding to the rock sample type is normalized according to the proportion, and a full-size pore size distribution curve representing the entire deep carbonate gas reservoir is drawn.

[0041] According to another aspect of the present invention, a device for joint characterization of full-scale pore size distribution in deep carbonate gas reservoirs is provided, comprising:

[0042] a pore-throat structure network model building unit, configured to perform CT scanning on the pre-processed rock sample to obtain a CT scan image, and to build a pore-throat structure network model based on the CT scan image;

[0043] A first drawing unit is used to set a segmentation threshold for caves and cracks, extract micron-scale cracks and millimeter-scale caves in the pore-throat structure network model, and draw a first pore size distribution curve of the cracks and caves according to the extraction results;

[0044] a rock sample segmentation unit, configured to select a target rock sample with uniform pore throat distribution according to the extraction condition, and segment the target rock sample into a first sub-rock sample and a second sub-rock sample;

[0045] a second drawing unit, configured to perform a high-pressure mercury injection test on the first sub-rock sample, and draw a second pore size distribution curve of nano-scale pore throats according to the test results of the high-pressure mercury injection test; and perform a constant-rate mercury injection test on the second sub-rock sample, and draw a third pore size distribution curve of micron-scale pore throats according to the test results of the constant-rate mercury injection test;

[0046] The curve processing unit is used to splice the first pore size distribution curve, the second pore size distribution curve and the third pore size distribution curve, normalize the spliced ​​full-size pore size distribution curve, and draw a full-size pore size distribution curve representing a deep carbonate gas reservoir.

[0047] According to another aspect of the present invention, an electronic device is provided, comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so as to enable the at least one processor to execute the method for joint characterization of full-size pore size distribution of deep carbonate gas reservoirs as described in any embodiment of the present invention.

[0048] According to another aspect of the present invention, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the method for joint characterization of full-size pore size distribution of deep carbonate gas reservoirs described in any embodiment of the present invention when executed.

[0049] The technical solution of the embodiment of the present invention comprises the following steps: performing a CT scan on a pre-processed rock sample to obtain a CT scan image, constructing a pore throat structure network model based on the CT scan image; setting a segmentation threshold for caves and fractures, extracting micron-scale fractures and millimeter-scale caves in the pore throat structure network model, and drawing a first pore size distribution curve of the fractures and caves based on the extraction results; selecting a target rock sample with uniform pore throat distribution based on the extraction results, and dividing the target rock sample into a first sub-rock sample and a second sub-rock sample; performing a high-pressure mercury injection test on the first sub-rock sample, and drawing a second pore size distribution curve of nano-scale pore throats based on the test results of the high-pressure mercury injection test; performing a constant-rate mercury injection test on the second sub-rock sample, and drawing a third pore size distribution curve of micron-scale pore throats based on the test results of the constant-rate mercury injection test; splicing the first pore size distribution curve, the second pore size distribution curve, and the third pore size distribution curve, normalizing the spliced ​​full-size pore size distribution curve, and drawing a full-size pore size distribution curve characterizing deep carbonate gas reservoirs. The solution of the embodiment of the present invention makes up for the defect of poor applicability of existing oil and gas reservoir pore size distribution characterization methods in deep carbonate gas reservoirs, and effectively improves the accuracy and range of full-size pore size distribution characterization of such gas reservoirs.

[0050] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0052] Figure 1 This is a flow chart of a method for joint characterization of full-scale pore size distribution in deep carbonate gas reservoirs provided in Example 1 of the present invention;

[0053] Figure 2 This is a schematic diagram of CT scanning extraction results of rock sample cracks and caves applicable to the first embodiment of the present invention;

[0054] Figure 3 is a schematic diagram of a first pore size distribution curve applicable to Example 1 of the present invention;

[0055] Figure 4 is a schematic diagram of a second pore size distribution curve applicable to Example 1 of the present invention;

[0056] Figure 5 is a schematic diagram of a third pore size distribution curve applicable to Example 1 of the present invention;

[0057] Figure 6 1 is a schematic diagram of splicing fractal characteristic curves of pore throats of different sizes applicable to the first embodiment of the present invention;

[0058] Figure 7 Schematic diagram of the full-size pore size distribution curve after splicing applicable to Example 1 of the present invention;

[0059] Figure 8 Schematic diagram of full-scale pore size distribution curves of four types of deep carbonate reservoirs applicable to Example 1 of the present invention;

[0060] Figure 9 Schematic diagram of full-scale pore size distribution curve of deep carbonate gas reservoir applicable to Example 1 of the present invention;

[0061] Figure 10 This is a schematic diagram of a device for characterizing the full-scale pore size distribution of deep carbonate gas reservoirs provided in Example 2 of the present invention.

[0062] Figure 11 It is a structural schematic diagram of an electronic device for implementing the method for joint characterization of full-scale pore size distribution of deep carbonate gas reservoirs according to an embodiment of the present invention. DETAILED DESCRIPTION

[0063] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0064] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0065] Example 1

[0066] Figure 1 This is a flow chart of a method for joint characterization of full-size pore size distribution of deep carbonate gas reservoirs provided in Example 1 of the present invention. This embodiment is applicable to the case of characterizing the full-size pore size distribution of deep carbonate gas reservoirs. The method can be executed by a joint characterization device for full-size pore size distribution of deep carbonate gas reservoirs. The joint characterization device for full-size pore size distribution of deep carbonate gas reservoirs can be implemented in the form of hardware and / or software. The joint characterization device for full-size pore size distribution of deep carbonate gas reservoirs can be configured in an electronic device. Figure 1 As shown, the method includes:

[0067] S110 , performing CT scanning on the pre-processed rock sample to obtain a CT scan image, and constructing a pore-throat structure network model based on the CT scan image.

[0068] In the embodiment of the present invention, the rock samples are obtained by drilling gas wells at different locations in carbonate gas reservoirs;

[0069] The preprocessing comprises:

[0070] After the rock samples were washed with salt, the porosity and permeability were measured in turn;

[0071] Draw a scatter plot of porosity-permeability relationship based on the porosity and permeability data of all rock samples;

[0072] The porosity-permeability relationship scatter diagram is divided into different porosity-permeability distribution areas, and different numbers of rock samples are selected from each area according to the distribution frequency of data points in each distribution area.

[0073] Natural rock samples were collected from gas wells drilled at various locations in carbonate gas reservoirs and registered. After salt washing, the samples were sequentially measured for porosity and permeability. A scatter plot of the porosity-permeability relationship was constructed based on the porosity and permeability data for all samples. This scatter plot was then divided into multiple porosity-permeability distribution zones. A different number of rock samples were selected from each zone based on the frequency of data points within each zone for subsequent testing.

[0074] In a preferred embodiment, a large number of natural rock samples are drilled from multiple gas wells at different locations in a carbonate gas reservoir. Standard plunger rock samples with a diameter of 25.4 mm and a length of 50 mm are then produced. The drilled rock samples are numbered, and the well number and depth of the sample are recorded. After the rock samples are washed with methanol and toluene for salt and oil removal, the porosity and permeability of the rock samples are measured and recorded. The porosity and permeability data for each rock sample are plotted as scattered points on a graph paper with porosity as the horizontal axis and the logarithm of permeability as the vertical axis. Based on the distribution range of the porosity and permeability of all rock samples, the scatter plot is divided into multiple porosity-permeability distribution regions. The proportion of data points in each region is calculated based on the number of data points. Based on the proportion, a different number of rock samples are selected from each region for subsequent testing.

[0075] The selected rock samples were scanned using micrometer CT. Preferably, the pixel size was set to 24.74 μm to achieve full coverage of the rock sample. The resulting CT scans were preprocessed, including smoothing the rock sample through denoising and enhancing image contrast using a sharpening algorithm. The images were then segmented into reservoir space and rock skeleton. Figure 2 This is a schematic diagram of CT scanning extraction results of rock sample cracks and caves applicable to the first embodiment of the present invention.

[0076] S120 , setting a segmentation threshold for caves and cracks, extracting micron-scale cracks and millimeter-scale caves in the pore-throat structure network model, and drawing first pore size distribution curves of cracks and caves based on the extraction results.

[0077] In this embodiment of the present invention, step S120 specifically includes:

[0078] Quantitatively analyze the micron-sized cracks and millimeter-sized caves, and calculate the pore volumes corresponding to the pore diameters of the micron-sized cracks and millimeter-sized caves;

[0079] The pore volume corresponding to each pore diameter is converted into a pore volume percentage according to the total pore volume, and the first pore diameter distribution curve within the preset pore diameter range is drawn.

[0080] Specifically, the segmented images were extracted and quantitatively analyzed using the Pore Network Model Extraction module of Avizo software to construct a pore-throat network model of the reservoir space. The resulting pore-throat network model was then extracted using the Separate Object module of Avizo software, with the extraction thresholds set at 5×10⁵ and 2×10⁶ pixel volumes, respectively. The resulting fracture and cave network models were quantitatively analyzed, and the pore volumes corresponding to each pore size were calculated. The pore volumes corresponding to each pore size were then converted to percentages based on the total pore volume. Pore size distribution curves for micron-scale fractures and millimeter-scale caves in the pore size range of 100 μm to 20 mm were plotted. Figure 3 Schematic diagram of a first pore size distribution curve applicable to Example 1 of the present invention.

[0081] S130 , selecting a target rock sample with uniform pore throat distribution according to the extraction situation, and dividing the target rock sample into a first sub-rock sample and a second sub-rock sample.

[0082] In the embodiment of the present invention, step S130 specifically includes: classifying the rock sample into pore type, fracture type, hole type and fracture-hole type according to the extraction situation;

[0083] A rock sample with uniform pore throat distribution is selected from the pore type, fracture type, hole type and fracture-hole type rock samples, and the rock sample is divided into the first sub-rock sample and the second sub-rock sample of equal length.

[0084] Based on the extraction of caves and fractures from CT scans, the rock samples were divided into the following four categories: pore-type (with neither fractures nor caves developed), fracture-type (with developed fractures but not caves developed), pore-vuggy (with developed caves but not fractures developed), and fracture-vuggy (with developed caves and both caves and fractures developed). These correspond to the four reservoir types of deep carbonate gas reservoirs to eliminate the impact of reservoir heterogeneity. Based on the quantitative results of the pore-throat structure from CT scans, several rock samples with uniform pore-throat distribution were selected from the four categories and cut into sub-samples A and B of equal length using a cutting machine. Preferably, each rock sample was divided equally into Part A and Part B, each with a diameter of 25.4 mm and a length of 25 mm. By comparing the pore-throat structural parameters of Part A and Part B, several rock samples with relatively uniform pore-throat distribution were selected from each of the four categories. A rock sample cutter was used to split the selected rock sample into sub-samples A and B of equal length, which were used for high-pressure mercury injection testing and constant-rate mercury injection testing, respectively, to avoid the influence of the internal heterogeneity of a single rock sample on the subsequent splicing of pore size distribution curves of various sizes.

[0085] S140. Perform a high-pressure mercury injection test on the first sub-rock sample, and draw a second pore size distribution curve of nano-scale pore throats based on the test results of the high-pressure mercury injection test; perform a constant-rate mercury injection test on the second sub-rock sample, and draw a third pore size distribution curve of micron-scale pore throats based on the test results of the constant-rate mercury injection test.

[0086] In an embodiment of the present invention, performing a high-pressure mercury injection test on the first sub-rock sample and drawing a second pore size distribution curve of nanoscale pore throats according to the test results of the high-pressure mercury injection test include:

[0087] Setting a maximum mercury injection pressure to perform the high-pressure mercury injection test, and obtaining test results including capillary pressure and mercury injection saturation;

[0088] According to the relationship between pore size and capillary pressure, first pore size data is obtained according to the test results, and the second pore size distribution curve is drawn according to the first pore size data;

[0089] The method of performing a constant-rate mercury injection test on the second sub-rock sample and drawing a third pore size distribution curve of micron-scale pore throats according to the test results of the constant-rate mercury injection test comprises:

[0090] Setting the mercury injection rate, performing the constant-rate mercury injection test until the mercury injection pressure reaches a set maximum value, and obtaining test results including capillary pressure and mercury injection saturation;

[0091] According to the relationship between pore diameter and capillary pressure, second pore diameter data is obtained according to the test results, and the third pore diameter distribution curve is drawn according to the second pore diameter data.

[0092] All sub-rock samples A were subjected to high-pressure mercury injection tests, with the maximum mercury injection pressure set to 200 MPa, corresponding to a minimum identifiable pore size of 3.6 nm. The capillary pressure p was obtained by high-pressure mercury injection testing. c The corresponding mercury saturation S in the process of increasing from 0 to 200 MPa Hg Data, combined with the relationship between pore size and capillary pressure The capillary pressure data is converted into pore size data and the pore size distribution curve of nano-scale pore throats is drawn. c is the capillary pressure, in MPa; σ is the surface tension, in N / m; θ is the wetting contact angle, in degrees; r c is the pore size in μm. The wetting angle meter and surface tension meter were used to measure the θ and σ between mercury and the rock sample surface, respectively.

[0093] The mercury saturation data corresponding to each pore size are plotted on the pore size r. c The horizontal axis is the mercury saturation increment ΔS HgOn the coordinate paper with ordinate as the vertical axis, draw the nano-scale pore size distribution curve with pore size ranging from 3.6nm to 10μm. Figure 4 Schematic diagram of a second pore size distribution curve applicable to the first embodiment of the present invention.

[0094] All sub-rock samples B were subjected to constant-rate mercury injection tests, with the mercury injection rate set at 5×10-5 mL / min until the maximum mercury injection pressure of 6.21 MPa was reached, corresponding to a minimum identifiable pore size of 0.12 μm.

[0095] To obtain the capillary pressure p c The corresponding mercury saturation S in the process of increasing from 0 to 6.21 MPa Hg As the basic data, combined with the relationship between pore size and capillary pressure Substitute the wetting contact angle and surface tension values ​​obtained previously into the formula to convert the capillary pressure data into pore size data.

[0096] The mercury saturation data corresponding to each pore size obtained in the step are plotted on a coordinate paper with pore size as the horizontal axis and mercury saturation increment as the vertical axis, and a micron-level pore size distribution curve with a pore size range of 120nm to 200μm is plotted. Figure 5 Schematic diagram of a third pore size distribution curve applicable to the first embodiment of the present invention.

[0097] S150: splicing the first pore size distribution curve, the second pore size distribution curve, and the third pore size distribution curve, normalizing the spliced ​​full-size pore size distribution curve, and drawing a full-size pore size distribution curve representing a deep carbonate gas reservoir.

[0098] In an embodiment of the present invention, the splicing of the pore size distribution curves of the fractures and caves, the pore size distribution curves of the nanoscale pore throats, and the pore size distribution curves of the microscale pore throats includes:

[0099] A coordinate system is established based on fractal theory and a calculation formula for pore fractal dimension, wherein the fractal theory and the calculation formula for pore fractal dimension include:

[0100] lg(1-S Hg )=(3-D)lgr c -(3-D)lgr max ;

[0101] The horizontal axis of the coordinate system is lgr c , the vertical coordinate is lg(1-S Hg );

[0102] Plotting the capillary pressure and mercury injection saturation obtained from the high-pressure mercury injection test and the capillary pressure and mercury injection saturation obtained from the constant-rate mercury injection test into the coordinate system;

[0103] The pore volume percentage corresponding to each pore size of the millimeter-scale caves and micrometer-scale fractures is equivalent to the mercury saturation and plotted in the coordinate system;

[0104] Performing piecewise linear fitting on the drawn portion of the coordinate system to determine whether the fitted lines intersect in the overlapping area;

[0105] When there is an intersection between the fitting lines, the pore size corresponding to the intersection is selected as the splicing point of the overlapping area of ​​the pore size distribution curve; when there is no intersection between the fitting lines, the average curve of the overlapping area of ​​the pore size distribution curve is drawn as the splicing line;

[0106] The first pore size distribution curve, the second pore size distribution curve, and the third pore size distribution curve are plotted in the coordinate system, and overlapping areas of the first pore size distribution curve, the second pore size distribution curve, and the third pore size distribution curve are connected through the splicing points and / or the splicing lines to obtain a continuous full-size pore size distribution curve.

[0107] Based on fractal theory and pore fractal dimension calculation formula lg(1-S Hg )=(3-D)lgr c -(3-D)lgr max , the pore diameter r of the micron-scale pore throat obtained c and mercury saturation S Hg The data is plotted on the horizontal axis lgr c , the vertical coordinate is lg(1-S Hg ) on the coordinate paper. In the formula, S Hg is the mercury saturation, in %; r max is the maximum pore throat radius, in μm; D is the fractal dimension, dimensionless.

[0108] The pore diameter r of the nanoscale pore throat is obtained c and mercury saturation S Hg The data are plotted on the graph paper prepared in step S6.1.

[0109] The pore sizes of the millimeter-scale caves and micron-scale cracks are calculated. c The corresponding pore volume percentage P V Equivalent to mercury saturation S Hg , plotted on graph paper.

[0110] Perform piecewise linear fitting on three fractal characteristic curves of different sizes on the graph paper to determine whether the fitted lines intersect in the overlapping region. If there is an intersection between the fitted lines, the pore size corresponding to the intersection is selected as the splicing point in the overlapping region of the pore size distribution curve. If there is no intersection between the fitted lines, the average curve of the overlapping region of the pore size distribution curve is plotted as the splicing line to eliminate the differences in the overlapping region of the pore size distribution curve and ensure the continuity of the pore size distribution.

[0111] The obtained micron-scale pore size distribution curve, nano-scale pore size distribution curve, and the obtained micron-scale crack and millimeter-scale cave pore size distribution curves are plotted on the same coordinate paper, and the overlapping areas of the pore size distribution curves of each size are connected through the obtained splicing points or splicing lines to draw a continuous full-size pore size distribution curve. Figure 6 It is a schematic diagram of splicing fractal characteristic curves of pore throats of different sizes applicable to Example 1 of the present invention. Figure 7 It is a schematic diagram of the full-size pore size distribution curve after splicing applicable to Example 1 of the present invention.

[0112] In an embodiment of the present invention, the normalization processing of the spliced ​​full-size pore size distribution curve to draw the full-size pore size distribution curve characterizing the deep carbonate gas reservoir includes:

[0113] Classifying the full-size pore size distribution curves according to rock sample types, normalizing the full-size pore size distribution curves of the rock samples, and drawing four full-size pore size distribution curves representing four types of deep carbonate reservoirs;

[0114] The proportion of each type of reservoir is calculated based on the development frequency of the four types of reservoirs in deep carbonate gas reservoirs. The full-size pore size distribution curve of the reservoir corresponding to the rock sample type is normalized according to the proportion, and a full-size pore size distribution curve representing the entire deep carbonate gas reservoir is drawn.

[0115] The multiple full-scale pore size distribution curves obtained were classified according to four core types (porous, fractured, vuggy, and fracture-vuggy). The multiple full-scale pore size distribution curves for the pore, vuggy, fractured, and fracture-vuggy samples were normalized to produce four full-scale pore size distribution curves representing the four types of deep carbonate reservoirs. Well logging interpretation data was used to determine the frequency of deep carbonate reservoirs of the pore, vuggy, fractured, and fracture-vuggy types in the study area's gas reservoirs, and the proportion of each type of reservoir was calculated accordingly. The four full-scale pore size distribution curves were normalized based on the obtained proportion of each type of reservoir to produce a full-scale pore size distribution curve representing the entire deep carbonate gas reservoir. Figure 8 Schematic diagram of full-scale pore size distribution curves of four types of deep carbonate reservoirs applicable to Example 1 of the present invention. Figure 9It is a schematic diagram of the full-scale pore size distribution curve of a deep carbonate gas reservoir applicable to Example 1 of the present invention.

[0116] The present invention proposes a method for characterizing the full-scale pore size distribution of deep carbonate gas reservoirs, belonging to the technical field of oil and gas reservoir pore structure characterization. Compared with existing oil and gas reservoir pore size distribution characterization methods, the present invention has the following advantages:

[0117] This technology takes into account the wide range of pore size distribution in deep carbonate gas reservoirs. It combines the advantages of high-pressure mercury injection technology in nanoscale pore throat characterization, constant-rate mercury injection technology in micron-scale pore throat characterization, and micron CT scanning technology in micron-scale fracture and millimeter-scale cave characterization to form a joint characterization method for the full-scale pore size distribution of nanometer-micrometer-millimeter scale for this type of gas reservoir.

[0118] This technology takes into account the strong heterogeneity characteristics of deep carbonate gas reservoirs, and divides reservoir types into pore type, fracture type, hole type and fracture-hole type to determine the full-size pore size distribution curve of each type of reservoir respectively; by normalizing the characterization results of rock samples at different positions of the same type of reservoir, full-size pore size distribution curves representing the four types of reservoirs are obtained; then normalization is performed based on the proportion of the four types of reservoirs to obtain the full-size pore size distribution curve representing the deep carbonate gas reservoir, eliminating the influence of locally developed fractures and caves in some reservoirs on the full-size pore size distribution characterization of the entire gas reservoir.

[0119] This technology determines the splicing points or lines by using the fractal characteristic curves of pore throats of different sizes obtained through fractal theory, and splices the pore size distribution curves of each size, eliminating the differences in the overlapping areas of the pore size distribution curves and ensuring the continuity of the curves, thereby achieving a comprehensive and accurate characterization of the full-size pore size distribution of deep carbonate gas reservoirs.

[0120] Therefore, the present invention makes up for the defect of poor applicability of existing oil and gas reservoir pore size distribution characterization methods in deep carbonate gas reservoirs with extremely strong heterogeneity and a wide range of pore size distribution, effectively improves the accuracy and range of full-size pore size distribution characterization of such gas reservoirs, and provides a theoretical basis and data support for further revealing the fluid distribution characteristics and seepage mechanism in the reservoir, as well as evaluating reserve mobility.

[0121] Example 2

[0122] Figure 10 This is a schematic diagram of the structure of a device for joint characterization of full-scale pore size distribution in deep carbonate gas reservoirs provided by the second embodiment of the present invention. Figure 10 As shown, the device includes:

[0123] The pore-throat structure network model building unit 1010 is used to perform CT scanning on the pre-processed rock sample to obtain a CT scan image, and build a pore-throat structure network model based on the CT scan image;

[0124] The first drawing unit 1020 is used to set a segmentation threshold for caves and fractures, extract micron-scale fractures and millimeter-scale caves in the pore-throat structure network model, and draw a first pore size distribution curve of the fractures and caves based on the extraction results;

[0125] A rock sample segmentation unit 1030 is configured to select a target rock sample with uniform pore throat distribution according to the extraction condition, and segment the target rock sample into a first sub-rock sample and a second sub-rock sample;

[0126] The second drawing unit 1040 is configured to perform a high-pressure mercury injection test on the first sub-rock sample, and draw a second pore size distribution curve of nano-scale pore throats based on the test results of the high-pressure mercury injection test; perform a constant-rate mercury injection test on the second sub-rock sample, and draw a third pore size distribution curve of micron-scale pore throats based on the test results of the constant-rate mercury injection test;

[0127] The curve processing unit 1050 is used to splice the pore size distribution curves of the fractures and caves, the pore size distribution curves of the nano-scale pore throats, and the pore size distribution curves of the micron-scale pore throats, normalize the spliced ​​full-size pore size distribution curves, and draw a full-size pore size distribution curve characterizing the deep carbonate gas reservoir.

[0128] Optionally, the rock samples are obtained by drilling gas wells at different locations in carbonate gas reservoirs;

[0129] The preprocessing comprises:

[0130] After the rock samples were washed with salt, the porosity and permeability were measured in turn;

[0131] Draw a scatter plot of porosity-permeability relationship based on the porosity and permeability data of all rock samples;

[0132] The porosity-permeability relationship scatter diagram is divided into different porosity-permeability distribution areas, and different numbers of rock samples are selected from each area according to the distribution frequency of data points in each distribution area.

[0133] Optionally, the first drawing unit 1020 is configured to execute:

[0134] Quantitatively analyze the micron-sized cracks and millimeter-sized caves, and calculate the pore volumes corresponding to the pore diameters of the micron-sized cracks and millimeter-sized caves;

[0135] The pore volume corresponding to each pore diameter is converted into a pore volume percentage according to the total pore volume, and the first pore diameter distribution curve within the preset pore diameter range is drawn.

[0136] Optionally, the rock sample segmentation unit 1030 is configured to perform:

[0137] Based on the extraction conditions, the rock samples were classified into pore type, fracture type, hole type and fracture-hole type;

[0138] A rock sample with uniform pore throat distribution is selected from the pore type, fracture type, hole type and fracture-hole type rock samples, and the rock sample is divided into the first sub-rock sample and the second sub-rock sample of equal length.

[0139] Optionally, the second drawing unit 1040 is configured to perform:

[0140] Setting a maximum mercury injection pressure to perform the high-pressure mercury injection test, and obtaining test results including capillary pressure and mercury injection saturation;

[0141] According to the relationship between pore size and capillary pressure, first pore size data is obtained according to the test results, and the second pore size distribution curve is drawn according to the first pore size data;

[0142] The method of performing a constant-rate mercury injection test on the second sub-rock sample and drawing a third pore size distribution curve of micron-scale pore throats according to the test results of the constant-rate mercury injection test comprises:

[0143] Setting the mercury injection rate, performing the constant-rate mercury injection test until the mercury injection pressure reaches a set maximum value, and obtaining test results including capillary pressure and mercury injection saturation;

[0144] According to the relationship between pore diameter and capillary pressure, second pore diameter data is obtained according to the test results, and the third pore diameter distribution curve is drawn according to the second pore diameter data.

[0145] Optionally, the curve processing unit 1050, when executing the splicing of the pore size distribution curves of the fractures and caves, the pore size distribution curves of the nanoscale pore throats, and the pore size distribution curves of the microscale pore throats, specifically performs:

[0146] A coordinate system is established based on fractal theory and a calculation formula for pore fractal dimension, wherein the fractal theory and the calculation formula for pore fractal dimension include:

[0147] lg(1-S Hg )=(3-D)lgr c -(3-D)lgr max ;

[0148] The horizontal axis of the coordinate system is lgr c , the vertical coordinate is lg(1-S Hg );

[0149] Plotting the capillary pressure and mercury injection saturation obtained from the high-pressure mercury injection test and the capillary pressure and mercury injection saturation obtained from the constant-rate mercury injection test into the coordinate system;

[0150] The pore volume percentage corresponding to each pore size of the millimeter-scale caves and micrometer-scale fractures is equivalent to the mercury saturation and plotted in the coordinate system;

[0151] Performing piecewise linear fitting on the drawn portion of the coordinate system to determine whether the fitted lines intersect in the overlapping area;

[0152] When there is an intersection between the fitting lines, the pore size corresponding to the intersection is selected as the splicing point of the overlapping area of ​​the pore size distribution curve; when there is no intersection between the fitting lines, the average curve of the overlapping area of ​​the pore size distribution curve is drawn as the splicing line;

[0153] The first pore size distribution curve, the second pore size distribution curve, and the third pore size distribution curve are plotted in the coordinate system, and overlapping areas of the first pore size distribution curve, the second pore size distribution curve, and the third pore size distribution curve are connected through the splicing points and / or the splicing lines to obtain a continuous full-size pore size distribution curve.

[0154] Optionally, the curve processing unit 1050, when performing the normalization processing on the spliced ​​full-size pore size distribution curve to draw the full-size pore size distribution curve representing the deep carbonate gas reservoir, specifically performs:

[0155] Classifying the full-size pore size distribution curves according to rock sample types, normalizing the full-size pore size distribution curves of the rock samples, and drawing four full-size pore size distribution curves representing four types of deep carbonate reservoirs;

[0156] The proportion of each type of reservoir is calculated based on the development frequency of the four types of reservoirs in deep carbonate gas reservoirs. The full-size pore size distribution curve of the reservoir corresponding to the rock sample type is normalized according to the proportion, and a full-size pore size distribution curve representing the entire deep carbonate gas reservoir is drawn.

[0157] The device for joint characterization of full-size pore size distribution of deep carbonate gas reservoirs provided in an embodiment of the present invention can execute the joint characterization method for full-size pore size distribution of deep carbonate gas reservoirs provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the execution method.

[0158] Example 3

[0159] Figure 11A schematic diagram of the structure of an electronic device 10 that can be used to implement an embodiment of the present invention is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices (such as helmets, glasses, watches, etc.) and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present invention described and / or claimed herein.

[0160] like Figure 11 As shown, the electronic device 10 includes at least one processor 11 and a memory, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc., which is communicatively connected to the at least one processor 11. The memory stores a computer program that can be executed by the at least one processor. The processor 11 can perform various appropriate actions and processes according to the computer program stored in the read-only memory (ROM) 12 or the computer program loaded from the storage unit 18 into the random access memory (RAM) 13. Various programs and data required for the operation of the electronic device 10 can also be stored in the RAM 13. The processor 11, ROM 12, and RAM 13 are connected to each other via a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0161] Multiple components in the electronic device 10 are connected to the I / O interface 15, including an input unit 16, such as a keyboard, a mouse, etc.; an output unit 17, such as various types of displays, speakers, etc.; a storage unit 18, such as a magnetic disk, an optical disk, etc.; and a communication unit 19, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 19 allows the electronic device 10 to exchange information / data with other devices via a computer network such as the Internet and / or various telecommunication networks.

[0162] The processor 11 can be any general-purpose and / or specialized processing component with processing and computing capabilities. Some examples of the processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various specialized artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. The processor 11 executes the various methods and processes described above, such as the method for combined characterization of full-scale pore size distribution in deep carbonate gas reservoirs.

[0163] In some embodiments, the method for jointly characterizing the full-scale pore size distribution of deep carbonate gas reservoirs can be implemented as a computer program, which is tangibly contained in a computer-readable storage medium, such as a storage unit 18. In some embodiments, part or all of the computer program can be loaded and / or installed on the electronic device 10 via the ROM 12 and / or the communication unit 19. When the computer program is loaded into the RAM 13 and executed by the processor 11, one or more steps of the method for jointly characterizing the full-scale pore size distribution of deep carbonate gas reservoirs described above can be performed. Alternatively, in other embodiments, the processor 11 can be configured to execute the method for jointly characterizing the full-scale pore size distribution of deep carbonate gas reservoirs in any other appropriate manner (for example, by means of firmware).

[0164] Various embodiments of the systems and techniques described herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), system-on-chip systems (SOCs), programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments can include being implemented in one or more computer programs that are executable and / or interpreted on a programmable system that includes at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0165] Computer programs for implementing the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when the computer program is executed by the processor, the functions / operations specified in the flowcharts and / or block diagrams are implemented. The computer program may be executed entirely on the machine, partially on the machine, as a stand-alone software package, partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0166] In the context of the present invention, computer-readable storage media can be tangible media that can contain or store a computer program for use with an instruction execution system, device or equipment or used in combination with an instruction execution system, device or equipment. Computer-readable storage media can include but are not limited to electronic, magnetic, optical, electromagnetic, infrared or semiconductor systems, devices or equipment, or any suitable combination of the foregoing. Alternatively, computer-readable storage media can be machine-readable signal media. More specific examples of machine-readable storage media can include electrical connections based on one or more lines, portable computer disks, hard disks, random access memories (RAM), read-only memories (ROM), erasable programmable read-only memories (EPROM or flash memory), optical fibers, portable compact disk read-only memories (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0167] To provide interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user can provide input to the electronic device. Other types of devices can also be used to provide interaction with the user; for example, the feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including acoustic input, voice input, or tactile input).

[0168] The systems and techniques described herein can be implemented in a computing system that includes back-end components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes front-end components (e.g., a user computer with a graphical user interface or web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such back-end components, middleware components, or front-end components. The components of the system can be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0169] A computing system may include clients and servers. The clients and servers are typically remote from each other and typically interact via a communication network. This client-server relationship arises through computer programs running on the respective computers, creating a client-server relationship. The server may be a cloud server, also known as a cloud computing server or cloud host. This server is a hosting product within the cloud computing service ecosystem that addresses the management difficulties and limited scalability of traditional physical hosting and VPS services.

[0170] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the present invention can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of the present invention can be achieved. This is not limited herein.

[0171] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A combined characterization method for full-scale pore size distribution in deep carbonate gas reservoirs, characterized by: include: Performing CT scanning on the pre-treated rock sample to obtain a CT scan image, and constructing a pore-throat structure network model based on the CT scan image; Setting a segmentation threshold for caves and cracks, extracting micron-scale cracks and millimeter-scale caves in the pore-throat structure network model, and drawing first pore size distribution curves of cracks and caves based on the extraction results; Selecting a target rock sample with uniform pore throat distribution according to the extraction situation, and dividing the target rock sample into a first sub-rock sample and a second sub-rock sample; Performing a high-pressure mercury injection test on the first sub-rock sample, and plotting a second pore size distribution curve of nano-scale pore throats based on the test results of the high-pressure mercury injection test; performing a constant-rate mercury injection test on the second sub-rock sample, and plotting a third pore size distribution curve of micron-scale pore throats based on the test results of the constant-rate mercury injection test; The first pore size distribution curve, the second pore size distribution curve and the third pore size distribution curve are spliced ​​together, the spliced ​​full-size pore size distribution curve is normalized, and a full-size pore size distribution curve representing a deep carbonate gas reservoir is drawn.

2. The method according to claim 1, characterized in that The rock samples are obtained by drilling gas wells at different locations in carbonate gas reservoirs; The preprocessing comprises: After the rock samples were washed with salt, the porosity and permeability were measured in turn; Draw a scatter plot of porosity-permeability relationship based on the porosity and permeability data of all rock samples; The porosity-permeability relationship scatter diagram is divided into different porosity-permeability distribution areas, and different numbers of rock samples are selected from each area according to the distribution frequency of data points in each distribution area.

3. The method according to claim 1, characterized in that The extracting of micron-scale fractures and millimeter-scale cavities in the pore-throat structure network model and drawing first pore size distribution curves of fractures and cavities according to the extraction results includes: Quantitatively analyze the micron-sized cracks and millimeter-sized caves, and calculate the pore volumes corresponding to the pore diameters of the micron-sized cracks and millimeter-sized caves; The pore volume corresponding to each pore diameter is converted into a pore volume percentage according to the total pore volume, and the first pore diameter distribution curve within the preset pore diameter range is drawn.

4. The method according to claim 1, wherein The step of selecting a target rock sample with uniform pore throat distribution according to the extraction condition and dividing the target rock sample into a first sub-rock sample and a second sub-rock sample comprises: Based on the extraction conditions, the rock samples were classified into pore type, fracture type, hole type and fracture-hole type; A rock sample with uniform pore throat distribution is selected from the pore type, fracture type, hole type and fracture-hole type rock samples, and the rock sample is divided into the first sub-rock sample and the second sub-rock sample of equal length.

5. The method according to claim 2, characterized in that The step of performing a high-pressure mercury injection test on the first sub-rock sample and drawing a second pore size distribution curve of nano-scale pore throats according to the test result of the high-pressure mercury injection test comprises: Setting a maximum mercury injection pressure to perform the high-pressure mercury injection test, and obtaining test results including capillary pressure and mercury injection saturation; According to the relationship between pore size and capillary pressure, first pore size data is obtained according to the test results, and the second pore size distribution curve is drawn according to the first pore size data; The method of performing a constant-rate mercury injection test on the second sub-rock sample and drawing a third pore size distribution curve of micron-scale pore throats according to the test results of the constant-rate mercury injection test comprises: Setting the mercury injection rate, performing the constant-rate mercury injection test until the mercury injection pressure reaches a set maximum value, and obtaining test results including capillary pressure and mercury injection saturation; According to the relationship between pore diameter and capillary pressure, second pore diameter data is obtained according to the test results, and the third pore diameter distribution curve is drawn according to the second pore diameter data.

6. The method according to claim 5, characterized in that The splicing of the pore size distribution curves of the fractures and caves, the pore size distribution curves of the nanoscale pore throats, and the pore size distribution curves of the microscale pore throats includes: A coordinate system is established based on fractal theory and a calculation formula for pore fractal dimension, wherein the fractal theory and the calculation formula for pore fractal dimension include: lg(1-S Hg )=(3-D)lg r c -(3-D)lg r max ; The horizontal axis of the coordinate system is lg r c , the vertical coordinate is lg(1-S Hg ); Plotting the capillary pressure and mercury injection saturation obtained from the high-pressure mercury injection test and the capillary pressure and mercury injection saturation obtained from the constant-rate mercury injection test into the coordinate system; The pore volume percentage corresponding to each pore size of the millimeter-scale caves and micrometer-scale fractures is equivalent to the mercury saturation and plotted in the coordinate system; Performing piecewise linear fitting on the drawn portion of the coordinate system to determine whether the fitted lines intersect in the overlapping area; When there is an intersection between the fitting lines, the pore size corresponding to the intersection is selected as the splicing point of the overlapping area of ​​the pore size distribution curve; when there is no intersection between the fitting lines, the average curve of the overlapping area of ​​the pore size distribution curve is drawn as the splicing line; The first pore size distribution curve, the second pore size distribution curve, and the third pore size distribution curve are plotted in the coordinate system, and overlapping areas of the first pore size distribution curve, the second pore size distribution curve, and the third pore size distribution curve are connected through the splicing points and / or the splicing lines to obtain a continuous full-size pore size distribution curve.

7. The method according to claim 6, characterized in that The normalization process of the spliced ​​full-size pore size distribution curve is performed to draw a full-size pore size distribution curve representing a deep carbonate gas reservoir, including: Classifying the full-size pore size distribution curves according to rock sample types, normalizing the full-size pore size distribution curves of the rock samples, and drawing four full-size pore size distribution curves representing four types of deep carbonate reservoirs; The proportion of each type of reservoir is calculated based on the development frequency of the four types of reservoirs in deep carbonate gas reservoirs. The full-size pore size distribution curve of the reservoir corresponding to the rock sample type is normalized according to the proportion, and a full-size pore size distribution curve representing the entire deep carbonate gas reservoir is drawn.

8. A combined characterization device for full-scale pore size distribution in deep carbonate gas reservoirs, characterized by: include: a pore-throat structure network model building unit, configured to perform CT scanning on the pre-processed rock sample to obtain a CT scan image, and to build a pore-throat structure network model based on the CT scan image; A first drawing unit is used to set a segmentation threshold for caves and cracks, extract micron-scale cracks and millimeter-scale caves in the pore-throat structure network model, and draw a first pore size distribution curve of the cracks and caves according to the extraction results; a rock sample segmentation unit, configured to select a target rock sample with uniform pore throat distribution according to the extraction condition, and segment the target rock sample into a first sub-rock sample and a second sub-rock sample; a second drawing unit, configured to perform a high-pressure mercury injection test on the first sub-rock sample, and draw a second pore size distribution curve of nano-scale pore throats according to the test results of the high-pressure mercury injection test; and perform a constant-rate mercury injection test on the second sub-rock sample, and draw a third pore size distribution curve of micron-scale pore throats according to the test results of the constant-rate mercury injection test; The curve processing unit is used to splice the pore size distribution curves of the fractures and caves, the pore size distribution curves of the nano-scale pore throats, and the pore size distribution curves of the micron-scale pore throats, normalize the spliced ​​full-size pore size distribution curves, and draw a full-size pore size distribution curve characterizing deep carbonate gas reservoirs.

9. An electronic device, characterized in that: The electronic device includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the method for joint characterization of full-size pore size distribution of deep carbonate gas reservoirs according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the method for joint characterization of full-size pore size distribution of deep carbonate gas reservoirs according to any one of claims 1 to 7 when executed.

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