Quantitative calculation method for pore evolution of tight sandstone reservoir under polarizing microscope

Abstract

The invention discloses a quantitative calculation method for pore evolution of a tight sandstone reservoir under a polarizing microscope, and relates to the technical field of mineral resource development, and the method comprises the following steps: obtaining pore evolution parameters of a rock casting body slice by using a microscope; determining an initial porosity value based on the percentage ratio of the mineral particles of each particle size; calculating the porosity value of the compacted rock on the basis of the residual intergranular pore surface porosity, the cement content surface porosity and the cement corrosion surface porosity; calculating a compaction coefficient based on the deepest buried depth value of the rock, the initial porosity value and the porosity value of the compacted rock; based on the initial porosity value, the compaction coefficient and the depth values of the rock at the multiple depths, the compaction porosity reduction rate of the rock at the corresponding depth is calculated; calculating the cement porosity reduction rate based on the cement content surface porosity and the cement corrosion hole surface porosity; and calculating the corrosion porosity based on the initial porosity value, the particle corrosion pore surface porosity and the cement corrosion pore surface porosity. According to the method, the pore evolution process of the tight sandstone is reproduced.

Description

Technical Field

[0001] The present application relates to the technical field of mineral resource development, and in particular to a quantitative calculation method for pore evolution of tight sandstone reservoirs under a polarizing microscope. Background Art

[0002] Tight sandstone gas is one of the most important unconventional oil and gas resources in the world. At present, the exploration and development technology of tight sandstone gas is becoming more and more mature, but there are still many technical problems. Tight sandstone reservoirs are highly heterogeneous, and reservoir evolution is usually subject to the comprehensive constraints of early sedimentation, later diagenesis and structural evolution. Therefore, the study of reservoir evolution process has always been the focus of tight sandstone reservoir research. In the complex water-rock process of compaction, cementation, dissolution, etc., the pores of tight sandstone sometimes become smaller and sometimes increase. The evolution process lasts for hundreds of millions of years, which also makes the study of reservoir pore evolution "irreproducible" difficult. Summary of the invention

[0003] The purpose of this application is to provide a quantitative calculation method for the pore evolution of tight sandstone reservoirs under a polarizing microscope, which reproduces the pore evolution process of tight sandstone.

[0004] To achieve the above objectives, this application provides the following solutions:

[0005] The present application provides a quantitative calculation method for pore evolution of tight sandstone reservoirs under a polarizing microscope, including:

[0006] Preparing a rock cast thin section of a rock; the rock being a dense sandstone;

[0007] The pore evolution parameters of the rock casting thin section are obtained by using a microscope; the pore evolution parameters include: the percentage of mineral particles of each particle size, the residual intergranular pore surface ratio, the cement content surface ratio, the particle dissolution pore surface ratio, the cement dissolution pore surface ratio, the deepest rock burial depth value and the comprehensive dissolution pore surface ratio; the comprehensive dissolution pore surface ratio includes: the particle dissolution pore surface ratio and the cement dissolution pore surface ratio, and the cement dissolution pore surface ratio includes: the dissolution pore intragranular surface ratio and the dissolution pore intergranular surface ratio;

[0008] Determine the initial porosity value based on the percentage of mineral particles of each particle size;

[0009] Calculate the porosity value of the rock after compaction based on the residual intergranular pore surface ratio, the cement content pore surface ratio and the cement dissolution pore surface ratio;

[0010] Calculating a compaction coefficient based on the deepest buried depth of the rock, the initial porosity value, and the porosity value of the rock after compaction;

[0011] Calculating the compaction porosity reduction ratio of the rock at the corresponding depth based on the initial porosity value, the compaction coefficient and the depth values ​​of the rock at multiple depths;

[0012] Calculating the cementation porosity reduction of the rock based on the initial porosity value, the cement content porosity and the cement dissolution porosity;

[0013] The dissolution porosity of the rock is calculated based on the initial porosity value, the particle dissolution pore surface ratio and the cement dissolution pore surface ratio.

[0014] Optionally, the method further includes:

[0015] Based on the initial porosity value and the porosity value of the rock after compaction, the compaction ratio is calculated.

[0016] Optionally, the method further includes:

[0017] Based on the porosity value of the rock after compaction, the surface porosity of the cement content and the surface porosity of the cement dissolution pores, the porosity value of the rock after cementation is calculated.

[0018] Optionally, the method further includes:

[0019] The porosity value of the rock after dissolution is calculated based on the porosity value of the rock after cementation, the comprehensive dissolution pore surface ratio and the cement dissolution pore surface ratio.

[0020] Optionally, the porosity value of the rock after compaction is calculated based on the residual intergranular pore surface ratio, the cement content pore surface ratio and the cement dissolution pore surface ratio, including:

[0021] The residual intergranular pore surface ratio, the cement content pore surface ratio and the cement dissolution pore surface ratio are input into the first porosity calculation formula to obtain the porosity value of the rock after compaction; the first porosity calculation formula is:

[0022]

[0023] in, is the porosity value of rock after compaction; φ C is the residual intergranular pore surface ratio; φ J is the surface ratio of cement content; φ JR It is the surface area ratio of cement dissolution pores.

[0024] Optionally, the compaction coefficient is calculated based on the deepest buried depth value of the rock, the initial porosity value and the porosity value of the rock after compaction, including:

[0025] The deepest buried depth of the rock, the initial porosity value and the porosity value after rock compaction are input into the compaction coefficient calculation formula to obtain the compaction coefficient; the compaction coefficient calculation formula is:

[0026]

[0027] in, is the porosity value of the rock after compaction; is the initial porosity value; e is the natural constant; C1 is the compaction coefficient; Z max The maximum depth of rock burial.

[0028] Optionally, based on the initial porosity value, the compaction coefficient and the depth values ​​of the rock at multiple depths, calculating the compaction porosity reduction ratio of the rock at the corresponding depth includes:

[0029] The initial porosity value, the compaction coefficient and the depth values ​​of the dense sandstone at multiple depths are respectively input into the compaction porosity reduction calculation formula to obtain the compaction porosity reduction of the rock at the corresponding depth; the compaction porosity reduction calculation formula is:

[0030]

[0031] Among them, A1 is the compaction porosity reduction ratio; is the initial porosity value; e is the natural constant; C1 is the compaction coefficient; Z1 is the depth value.

[0032] Optionally, the cementation-reduced porosity of the rock is calculated based on the initial porosity value, the cement content porosity, and the cement dissolution porosity, including:

[0033] The initial porosity value, the cement content porosity and the cement dissolution porosity are input into a cementation porosity reduction calculation formula to obtain the cementation porosity reduction of the rock; the cementation porosity reduction calculation formula is:

[0034]

[0035] Among them, A2 is the cementation porosity reduction ratio; φ J is the surface ratio of cement content; φ JR is the surface area ratio of cement dissolution pores; is the initial porosity value.

[0036] Optionally, the dissolution porosity of the rock is calculated based on the initial porosity value, the particle dissolution pore surface ratio and the cement dissolution pore surface ratio, including:

[0037] The initial porosity value, the particle dissolution pore surface ratio and the cement dissolution pore surface ratio are input into the dissolution porosity calculation formula to obtain the dissolution porosity of the rock; the dissolution porosity calculation formula is:

[0038]

[0039] Among them, A3 is the dissolution porosity; φ R is the particle dissolution pore surface ratio; φ JR is the surface area ratio of cement dissolution pores; is the initial porosity value.

[0040] Optionally, the compaction rate is calculated based on the initial porosity value and the porosity value of the rock after compaction, comprising:

[0041] The initial porosity value and the porosity value after rock compaction are input into the compaction rate calculation formula to obtain the compaction rate; the compaction rate calculation formula is:

[0042]

[0043] Among them, R1 is the compaction rate; is the initial porosity value; is the porosity value of the rock after compaction.

[0044] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0045] The present application discloses a quantitative calculation method for the pore evolution of tight sandstone reservoirs under a polarizing microscope. With the help of a microscope, different particle skeleton compositions and pore types of the reservoir are manually identified on rock casting thin sections, the pore evolution parameters of different types of pores in the rock are obtained, and the pore evolution process of tight sandstone is reproduced, providing new support for the densification process and prediction of tight sandstone reservoirs. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0047] Figure 1 A schematic diagram of the process flow of a quantitative calculation method for pore evolution of tight sandstone reservoirs under a polarizing microscope provided in Example 1 of the present application;

[0048] Figure 2 Schematic diagram of the identification of different minerals and pore types in the first rock cast thin section under a polarizing microscope;

[0049] Figure 3 Schematic diagram of the identification of different minerals and pore types in the first rock cast thin section under a polarizing microscope;

[0050] Figure 4 This is the pore evolution curve of sandstone samples. DETAILED DESCRIPTION

[0051] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0052] The purpose of this application is to provide a quantitative calculation method for the pore evolution of tight sandstone reservoirs under a polarizing microscope, aiming to reproduce the pore evolution process of tight sandstone.

[0053] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0054] In an exemplary embodiment, Figure 1 As shown, the quantitative calculation method for pore evolution of tight sandstone reservoir under polarizing microscope in this embodiment includes:

[0055] Step 1: Prepare a rock cast thin section of the rock; the rock is a dense sandstone.

[0056] Specifically, the thickness of the rock cast slice includes but is not limited to 0.02 mm.

[0057] Step 2: Use a microscope to obtain the pore evolution parameters of the rock casting thin section.

[0058] Among them, the pore evolution parameters include: the percentage of mineral particles of each particle size, the residual intergranular pore surface ratio, the cement content surface ratio, the particle dissolution pore surface ratio, the cement dissolution pore surface ratio, the deepest rock burial depth and the comprehensive dissolution pore surface ratio; the comprehensive dissolution pore surface ratio includes: the comprehensive dissolution pore surface ratio includes: the particle dissolution pore surface ratio and the cement dissolution pore surface ratio; the cement dissolution pore surface ratio includes: the dissolution pore intragranular surface ratio and the dissolution pore intergranular surface ratio.

[0059] Specifically, the microscope is a polarizing microscope. The display of each pore evolution parameter under the polarizing microscope is as follows: Figure 2 and Figure 3 shown.

[0060] Step 3: Determine the initial porosity value based on the percentage of mineral particles of each size.

[0061] Specifically, the initial porosity value It is mainly based on the percentage of mineral particles of different sizes identified under the polarizing microscope of the collected rock casting thin sections, including the particle size values ​​of different particles (>200 sample points) of quartz, feldspar, rock fragments and other debris particles under a microscope field of view, and calculates the particle probability cumulative curve. and Using the formula Calculate the initial porosity value in, It is the particle size corresponding to the cumulative probability of 25% on the particle probability cumulative curve; It is the particle size corresponding to the cumulative probability of 75% on the particle probability cumulative curve.

[0062] Step 4: Calculate the porosity of the rock after compaction based on the residual intergranular pore surface ratio, cement content pore surface ratio, and cement dissolution pore surface ratio.

[0063] As an optional implementation, step 4 includes:

[0064] The porosity of the residual intergranular pores, the porosity of the cement content and the porosity of the cement dissolution pores are input into the first porosity calculation formula to obtain the porosity value of the rock after compaction; the first porosity calculation formula is:

[0065]

[0066] in, is the porosity value of rock after compaction; φ C is the residual intergranular pore surface ratio; φ J is the surface ratio of cement content; φ JR It is the surface area ratio of cement dissolution pores.

[0067] Step 5: Calculate the compaction coefficient based on the deepest buried depth of the rock, the initial porosity value, and the porosity value after rock compaction.

[0068] As an optional implementation, step 5 includes:

[0069] The deepest buried depth of the rock, the initial porosity value and the porosity value after rock compaction are input into the compaction coefficient calculation formula to obtain the compaction coefficient; the compaction coefficient calculation formula is:

[0070]

[0071] in, is the porosity value of the rock after compaction; is the initial porosity value; e is the natural constant; C1 is the compaction coefficient; Z max The maximum depth of rock burial.

[0072] Step 6: Based on the initial porosity value, the compaction coefficient and the depth values ​​of the rock at multiple depths, calculate the compaction porosity reduction ratio of the rock at the corresponding depth.

[0073] As an optional implementation, step 6 includes:

[0074] The initial porosity value, compaction coefficient and the depth values ​​of dense sandstone at multiple depths are respectively input into the compaction porosity reduction calculation formula to obtain the compaction porosity reduction of the rock at the corresponding depth; the compaction porosity reduction calculation formula is:

[0075]

[0076] Among them, A1 is the compaction porosity reduction ratio; is the initial porosity value; e is the natural constant; C1 is the compaction coefficient; Z1 is the depth value.

[0077] Step 7: Calculate the cementation reduction porosity of the rock based on the initial porosity value, the cement content porosity, and the cement dissolution pore porosity.

[0078] As an optional implementation, step 7 includes:

[0079] The initial porosity value, cement content porosity and cement dissolution porosity are input into the cementation porosity reduction calculation formula to obtain the cementation porosity reduction of the rock; the cementation porosity reduction calculation formula is:

[0080]

[0081] Among them, A2 is the cementation porosity reduction ratio; φ J is the surface ratio of cement content; φ JR is the surface area ratio of cement dissolution pores; is the initial porosity value.

[0082] Step 8: Calculate the dissolution porosity of the rock based on the initial porosity value, the particle dissolution pore surface ratio, and the cement dissolution pore surface ratio.

[0083] As an optional implementation, step 8 includes:

[0084] The initial porosity value, particle dissolution pore surface ratio and cement dissolution pore surface ratio are input into the dissolution porosity calculation formula to obtain the dissolution porosity of the rock; the dissolution porosity calculation formula is:

[0085]

[0086] Among them, A3 is the dissolution porosity; φ R is the particle dissolution pore surface ratio; φ JR is the surface area ratio of cement dissolution pores; is the initial porosity value.

[0087] Specifically, after step 8, the method further includes:

[0088] The pore evolution process of rock is restored based on the compaction porosity reduction, cementation porosity reduction and dissolution porosity increase at different depths.

[0089] As an optional implementation, the method further includes:

[0090] Based on the initial porosity value and the porosity value after rock compaction, the compaction ratio is calculated.

[0091] As an optional implementation, the compaction rate is calculated based on the initial porosity value and the porosity value of the rock after compaction, including:

[0092] The initial porosity value and the porosity value after rock compaction are input into the compaction rate calculation formula to obtain the compaction rate; the compaction rate calculation formula is:

[0093]

[0094] Among them, R1 is the compaction rate; is the initial porosity value; is the porosity value of the rock after compaction.

[0095] As an optional implementation, the method further includes:

[0096] Based on the porosity value of rock after compaction, the surface porosity of cement content and the surface porosity of cement dissolution pores, the porosity value of rock after cementation is calculated.

[0097] Specifically, based on the porosity value of rock after compaction, the surface porosity of cement content and the surface porosity of cement dissolution pores, the porosity value of rock after cementation is calculated, including:

[0098] The porosity value of the rock after compaction, the surface porosity of the cement content and the surface porosity of the cement dissolution pores are input into the second porosity calculation formula to obtain the porosity value of the rock after cementation; the second porosity calculation formula is:

[0099]

[0100] in, It is the porosity value of rock after cementation.

[0101] As an optional implementation, the method further includes:

[0102] The porosity value of rock after dissolution is calculated based on the porosity value of rock after cementation, the comprehensive dissolution pore surface ratio and the cement dissolution pore surface ratio.

[0103] Specifically, based on the porosity value of rock after cementation, the surface ratio of comprehensive dissolution pores and the surface ratio of cement dissolution pores, the porosity value of rock after dissolution is calculated, including:

[0104] The porosity value after rock cementation, the comprehensive dissolution pore surface ratio and the cement dissolution pore surface ratio are input into the third porosity calculation formula to obtain the porosity value after rock dissolution; the third porosity calculation formula is:

[0105]

[0106] in, It is the porosity value after rock dissolution.

[0107] The method of the present application is further illustrated by using two samples of coarse-grained lithic quartz sandstone, both of which have minerals and pore surface ratios as shown in Table 1.

[0108] Table 1 Mineral and pore surface ratios are shown in Table

[0109]

[0110] The specific steps include:

[0111] Step 1: Preparation of rock cast thin sections of dense sandstone, namely Sample 1 and Sample 2.

[0112] Step 2: Use a microscope to obtain the pore evolution parameters of sample 1 and sample 2.

[0113] Step 3: According to the formula: Calculate the initial rock porosity values ​​of sample 1 and sample 2 respectively Sample 1 It is 38.3%, and the φ0 of sample 2 is 36.7%.

[0114] Step 4: According to the formula: Calculate the porosity values ​​of sample 1 and sample 2 after compaction Sample 1 5.0% for sample 2 It is 5.0%.

[0115] Step 5: Based on the deepest buried depth of the rock (3500m), the initial porosity value and the porosity value after rock compaction, according to the formula: The compaction coefficients C1 of sample 1 and sample 2 were calculated respectively. The C1 of sample 1 was -0.00078, and the C1 of sample 2 was -0.00091.

[0116] Step 6: Based on the initial porosity value, compaction coefficient and the depth value of the rock at any depth (for example, 2000m), according to the formula: The compaction porosity reduction ratio A1 at the corresponding depths of sample 1 and sample 2 was calculated respectively. The compaction porosity reduction ratio A1 of sample 1 at 2000m was 87.6%, and the compaction porosity reduction ratio A1 of sample 2 at 2000m was 83.3%.

[0117] Step 7: Based on the initial porosity value, cement content porosity and cement dissolution pore porosity, according to the formula: The cementation porosity reduction ratio A2 of sample 1 and sample 2 was calculated respectively. The cementation porosity reduction ratio A2 of sample 1 was 13.1%, and the cementation porosity reduction ratio A2 of sample 2 was 15.0%.

[0118] Step 8: Based on the initial porosity value, the particle dissolution pore surface ratio and the cement dissolution pore surface ratio, according to the formula: The dissolution porosity A3 of sample 1 and sample 2 were calculated respectively. The dissolution porosity A3 of sample 1 was 13.1%, and the dissolution porosity A3 of sample 2 was 28.6%.

[0119] After step 8, the pore evolution process of the rock is restored based on the compaction porosity reduction, cementation porosity reduction and dissolution porosity increase at different depths, and the following is obtained: Figure 4 Pore ​​evolution curve of sandstone sample shown.

[0120] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0121] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A quantitative calculation method for pore evolution of tight sandstone reservoirs under a polarizing microscope, characterized in that: The method comprises: Preparing a rock cast thin section of a rock; the rock being a dense sandstone; The pore evolution parameters of the rock casting thin section are obtained by using a microscope; the pore evolution parameters include: the percentage of mineral particles of each particle size, the residual intergranular pore surface ratio, the cement content surface ratio, the particle dissolution pore surface ratio, the cement dissolution pore surface ratio, the deepest rock burial depth value and the comprehensive dissolution pore surface ratio; the comprehensive dissolution pore surface ratio includes: the particle dissolution pore surface ratio and the cement dissolution pore surface ratio, and the cement dissolution pore surface ratio includes: the dissolution pore intragranular surface ratio and the dissolution pore intergranular surface ratio; Determine the initial porosity value based on the percentage of mineral particles of each particle size; Calculate the porosity value of the rock after compaction based on the residual intergranular pore surface ratio, the cement content pore surface ratio and the cement dissolution pore surface ratio; Calculating a compaction coefficient based on the deepest buried depth of the rock, the initial porosity value, and the porosity value of the rock after compaction; Calculating the compaction porosity reduction ratio of the rock at the corresponding depth based on the initial porosity value, the compaction coefficient and the depth values ​​of the rock at multiple depths; Calculating the cementation porosity reduction of the rock based on the initial porosity value, the cement content porosity and the cement dissolution porosity; The dissolution porosity of the rock is calculated based on the initial porosity value, the particle dissolution pore surface ratio and the cement dissolution pore surface ratio.

2. The quantitative calculation method for pore evolution of tight sandstone reservoirs under polarizing microscope according to claim 1 is characterized in that: The method further comprises: Based on the initial porosity value and the porosity value of the rock after compaction, the compaction ratio is calculated.

3. The quantitative calculation method for pore evolution of tight sandstone reservoirs under polarizing microscope according to claim 1, characterized in that: The method further comprises: Based on the porosity value of the rock after compaction, the surface porosity of the cement content and the surface porosity of the cement dissolution pores, the porosity value of the rock after cementation is calculated.

4. The quantitative calculation method for pore evolution of tight sandstone reservoirs under polarizing microscope according to claim 1, characterized in that: The method further comprises: The porosity value of the rock after dissolution is calculated based on the porosity value of the rock after cementation, the comprehensive dissolution pore surface ratio and the cement dissolution pore surface ratio.

5. The quantitative calculation method for pore evolution of tight sandstone reservoirs under polarizing microscope according to claim 1, characterized in that: Based on the residual intergranular pore surface ratio, the cement content pore surface ratio and the cement dissolution pore surface ratio, the porosity value of the rock after compaction is calculated, including: The residual intergranular pore surface ratio, the cement content pore surface ratio and the cement dissolution pore surface ratio are input into the first porosity calculation formula to obtain the porosity value of the rock after compaction; the first porosity calculation formula is: in, is the porosity value of rock after compaction; φ C is the residual intergranular pore surface ratio; φ J is the surface ratio of cement content; φ JR It is the surface area ratio of cement dissolution pores.

6. The quantitative calculation method for pore evolution of tight sandstone reservoirs under polarizing microscope according to claim 1, characterized in that: Based on the deepest buried depth value of the rock, the initial porosity value and the porosity value of the rock after compaction, the compaction coefficient is calculated, including: The deepest buried depth of the rock, the initial porosity value and the porosity value after rock compaction are input into the compaction coefficient calculation formula to obtain the compaction coefficient; the compaction coefficient calculation formula is: in, is the porosity value of rock after compaction; is the initial porosity value; e is the natural constant; C1 is the compaction coefficient; Z max The maximum depth of rock burial.

7. The quantitative calculation method for pore evolution of tight sandstone reservoirs under polarizing microscope according to claim 1, characterized in that: Based on the initial porosity value, the compaction coefficient and the depth values ​​of the rock at multiple depths, calculating the compaction porosity reduction ratio of the rock at the corresponding depth, including: The initial porosity value, the compaction coefficient and the depth values ​​of the dense sandstone at multiple depths are respectively input into the compaction porosity reduction calculation formula to obtain the compaction porosity reduction of the rock at the corresponding depth; the compaction porosity reduction calculation formula is: Among them, A1 is the compaction porosity reduction ratio; is the initial porosity value; e is the natural constant; C1 is the compaction coefficient; Z1 is the depth value.

8. The quantitative calculation method for pore evolution of tight sandstone reservoirs under polarizing microscope according to claim 1, characterized in that: Calculating the cementation porosity reduction of the rock based on the initial porosity value, the cement content porosity and the cement dissolution porosity comprises: The initial porosity value, the cement content porosity and the cement dissolution porosity are input into a cementation porosity reduction calculation formula to obtain the cementation porosity reduction of the rock; the cementation porosity reduction calculation formula is: Among them, A2 is the cementation porosity reduction ratio; φ J is the surface ratio of cement content; φ JR is the surface area ratio of cement dissolution pores; is the initial porosity value.

9. The quantitative calculation method for pore evolution of tight sandstone reservoirs under polarizing microscope according to claim 1, characterized in that: The dissolution porosity of the rock is calculated based on the initial porosity value, the particle dissolution pore surface ratio and the cement dissolution pore surface ratio, including: The initial porosity value, the particle dissolution pore surface ratio and the cement dissolution pore surface ratio are input into the dissolution porosity calculation formula to obtain the dissolution porosity of the rock; the dissolution porosity calculation formula is: Among them, A3 is the dissolution porosity; φ R is the particle dissolution pore surface ratio; φ JR is the surface area ratio of cement dissolution pores; is the initial porosity value.

10. The quantitative calculation method for pore evolution of tight sandstone reservoirs under polarizing microscope according to claim 2, characterized in that: Based on the initial porosity value and the porosity value of the rock after compaction, the compaction rate is calculated, including: The initial porosity value and the porosity value after rock compaction are input into the compaction rate calculation formula to obtain the compaction rate; the compaction rate calculation formula is: Among them, R1 is the compaction rate; is the initial porosity value; is the porosity value of the rock after compaction.

Images