Pore ​​identification method, electronic device and medium based on oblique polarization

Abstract

This application discloses a pore identification method, electronic device, and medium based on cross-polarization. The method may include: determining the difference between the reservoir space and the surrounding minerals through single polarization observation; if the difference between the reservoir space and the surrounding minerals is small, performing cross-polarization observation to identify the mineral type and determine the degree of pore development; and adjusting the angle of the polarizer to perform cross-polarization observation to identify the pores. The present invention adjusts the position of the polarizer of a polarizing microscope to form cross-polarization, which, when used with a mineral test plate, "highlights" pores under appropriate lighting conditions without affecting mineral identification and pore type determination, facilitating manual identification statistics or image acquisition for software quantitative analysis.

Description

Technical Field

[0001] The present invention relates to the field of petroleum exploration and development, and more particularly to a pore identification method based on oblique polarization, an electronic device and a medium. Background Art

[0002] Pores refer to the portions of reservoir rock (reservoir) that are not filled with solid matter and are where fluids such as oil and natural gas are stored. Based on their genesis, reservoir pores are divided into primary and secondary pores. The former are generated simultaneously with rock formation and are controlled by the original structural components of the rock; the latter are formed during or after diagenesis through component dissolution, fragmentation, or shrinkage. Based on their morphology and size, pores can be divided into three categories: pores, holes, and fractures. Pores and holes have an aspect ratio of <6:1, pores have a diameter of ≤2mm, and holes have a diameter of >2mm. Fractures have an aspect ratio of >6:1. Identifying pore genesis, studying their morphology, and their interrelationships are fundamental to reservoir research.

[0003] Cast thin sections are the most intuitive and basic means for pore type identification, morphological observation, surface ratio statistics and structural analysis, and are also the prerequisite for achieving quantitative pore image analysis.

[0004] The core technology of cast thin section production is to use a cast instrument to inject colored glue into the pores of reservoir rocks under high temperature and high pressure conditions, so as to achieve the purpose of "highlighting" the pores with prominent colors (blue or red), which is convenient for manual identification of cast thin sections or human-computer interaction using image analysis software to perform pore statistics.

[0005] Although cast thin sections have a very prominent advantage in directly observing pores, the preparation method and process of cast thin sections determine that this method has certain defects, which are analyzed as follows:

[0006] (1) Sampling

[0007] The production of cast thin sections requires drilling a plug sample with a diameter of 2.5 cm, so there are certain requirements for the shape, size and looseness of the sample. Logging cuttings samples, samples with too small a mass and loose samples are not suitable for making cast thin sections.

[0008] (2) Sample preparation and perfusion process

[0009] ① The vacuum infusion process requires that the sample be evacuated for 1-4 hours (the difference between the vacuum degree in the system and the atmospheric pressure on that day is ≤400MPa), and then continue to evacuate for 15 minutes after the injection liquid is injected. During this process, loose samples may fall off or particles may move.

[0010] ② During the high-temperature, high-pressure infusion process, the high-temperature and high-pressure conditions can persist for several hours. For example, when infusing an epoxy resin formulation, the pressure must be maintained at a steady state of 65°C and 45 MPa for 4 hours, followed by a steady state of 95°C and 45 MPa for 8 hours. When infusing an organic glass formulation, the pressure must be maintained at a steady state of 100°C and 8 MPa for 1 hour, followed by a steady state of 140°C and 15-20 MPa for 5 hours. During this high-temperature, high-pressure infusion process, relatively loose samples can experience the movement of particles such as mud and even erosion, distorting the original sample's pore structure.

[0011] ③ During the high-temperature and high-pressure perfusion process, the continuous high temperature state and the strong adsorption of fine particles such as clay minerals will cause a large amount of dye to be adsorbed, which will then create the illusion of an inflated surface area, affecting pore observation and statistics.

[0012] ④ Tight reservoir samples often have poor perfusion effects with colored injection fluids due to their low porosity and permeability. Samples with relatively isolated pores (poor pore connectivity) also have poor perfusion effects with colored injection fluids. The above situations can all create the illusion of low surface area, which also affects pore observation and statistics.

[0013] In summary, cast thin sections are not suitable for cuttings or too small samples, loose samples, samples with high content of muddy and other particles, tight reservoir samples, and samples with poor pore connectivity.

[0014] Therefore, it is necessary to develop a pore identification method, electronic equipment and medium based on oblique polarization.

[0015] The information disclosed in the background technology section of the present invention is only intended to deepen the understanding of the general background technology of the present invention, and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art. Summary of the Invention

[0016] The present invention proposes a pore identification method, electronic device and medium based on oblique polarization. By adjusting the position of the polarizer of a polarizing microscope, oblique polarization can be formed. When used with a mineral test plate, the pores can be "highlighted" under appropriate lighting conditions without affecting mineral identification and pore type recognition, thereby facilitating manual identification statistics or collecting images for software quantitative analysis.

[0017] In a first aspect, an embodiment of the present disclosure provides a pore identification method based on cross-polarization, comprising:

[0018] Through single polarized light observation, the difference between the reservoir space and its surrounding minerals can be determined;

[0019] If the difference between the reservoir space and its surrounding minerals is small, cross-polarized light observation is performed to identify the mineral type and determine the degree of pore development;

[0020] Adjust the angle of the polarizer and perform cross-polarization observation to identify pores.

[0021] Preferably, the angle at which the two polarizers deviate from the vertical state is 8° to 15°.

[0022] Preferably, it also includes:

[0023] Before adjusting the angle of the polarizer, the pores were confirmed using a mineral test plate.

[0024] Preferably, if the mineral type is identified as a reservoir mainly composed of high interference color minerals, a mica test plate is used to confirm the pores.

[0025] Preferably, if the mineral type is identified as a reservoir mainly composed of low interference color minerals, a gypsum test plate is used to confirm the pores.

[0026] Preferably, it also includes:

[0027] The pore distribution field of the oblique polarized light is used to identify the pore type, pore size, throat width, and pore connectivity, and manually count the pores, or take photos and color the pores through software to achieve pore statistics.

[0028] Preferably, adjusting the angle of the polarizer includes:

[0029] If the adjustment device is above the stage, adjust the angle of the upper polarizer;

[0030] If the adjustment device is below the stage, adjust the angle of the lower polarizer.

[0031] Preferably, it also includes:

[0032] If the reservoir space is significantly different from the surrounding minerals, thin section identification and manual direct pore counting are performed, or images are collected and software is used to perform pore counting.

[0033] As a specific implementation of the embodiment of the present disclosure,

[0034] In a second aspect, an embodiment of the present disclosure further provides an electronic device, the electronic device comprising:

[0035] a memory storing executable instructions;

[0036] A processor runs the executable instructions in the memory to implement the pore identification method based on cross-polarization.

[0037] In a third aspect, an embodiment of the present disclosure further provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the pore identification method based on cross-polarization is implemented.

[0038] The methods and apparatus of the present invention have other features and advantages that will be apparent from or will be described in detail in the accompanying drawings and subsequent detailed descriptions incorporated herein, which together serve to explain the specific principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0040] Figure 1 A flow chart showing the steps of a pore identification method based on cross-polarization according to an embodiment of the present invention is shown.

[0041] Figure 2a and Figure 2b Schematic diagrams of pore identification of a core slice observed under single polarization and under cross polarization according to an embodiment of the present invention are respectively shown.

[0042] Figure 3 A schematic diagram of pore identification by cross-polarized light observation of a core slice according to an embodiment of the present invention is shown.

[0043] Figure 4 A schematic diagram of pore statistics of a core slice observed under cross-polarized light according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0044] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0045] The present invention provides a pore identification method based on cross-polarization, comprising:

[0046] Through single polarized light observation, the difference between the reservoir space and its surrounding minerals can be determined;

[0047] If the difference between the reservoir space and its surrounding minerals is small, cross-polarized light observation is performed to identify the mineral type and determine the degree of pore development;

[0048] Adjust the angle of the polarizer and perform cross-polarization observation to identify pores.

[0049] In one example, the angle of the two polarizers deviating from the vertical state is 8° to 15°.

[0050] In one example, it also includes:

[0051] Before adjusting the angle of the polarizer, confirm the porosity using a mineral test plate.

[0052] In one example, if the mineral type is identified as a reservoir composed mainly of high interference color minerals, a mica test plate is used to confirm the porosity.

[0053] In one example, if the mineral type of a reservoir is identified as being mainly composed of low interference color minerals, a gypsum test plate is used for porosity confirmation.

[0054] In one example, it also includes:

[0055] The pore distribution field of the oblique polarized light is used to identify the pore type, pore size, throat width, and pore connectivity, and then manually count the pores. Alternatively, photos can be taken and the pores can be colored using software to achieve pore statistics.

[0056] In one example, adjusting the angle of the polarizer includes:

[0057] If the adjustment device is above the stage, adjust the angle of the upper polarizer;

[0058] If the adjustment device is below the stage, adjust the angle of the lower polarizer.

[0059] In one example, it also includes:

[0060] If the reservoir space is significantly different from the surrounding minerals, thin section identification and manual direct pore counting are performed, or images are collected and software is used to perform pore counting.

[0061] Specifically, thin section identification is a technical method for identifying minerals and rocks using a polarizing microscope. The core work is to identify minerals based on the single polarization, crossed polarization, and conoscopic characteristics (for identification of difficult minerals) exhibited by the mineral's crystallization characteristics. The lithology is then identified based on the mineral type, combination, and rock structure and structural characteristics. Single polarization characteristics include color, pleochroism, absorption, protrusions, roughness, and cleavage; crossed polarization characteristics include interference color, extinction type, extinction angle, and twinning type; and conoscopic characteristics include the number and nature of optical axes.

[0062] The principle of using a polarizing microscope for mineral identification is: the microscope is equipped with two mutually perpendicular polarizing devices (polarizers), and natural light becomes polarized light that is consistent with (parallel to) its direction after passing through the lower polarizer. The direction is perpendicular to the upper polarizer and cannot pass through the upper polarizer, so it appears "completely black" when observed under orthogonal polarization; different minerals have different crystal optical characteristics and can be divided into two categories: homogeneous and inhomogeneous. Isometric minerals and amorphous are homogeneous. When light propagates in them, the homogeneous body will not cause the lower polarization to deflect, and it appears "completely black" under orthogonal polarization, that is, total extinction; the lower polarization will appear "completely black" when passing through the inhomogeneous body. When the crystal is rotated, the polarization direction will be deflected (refraction) due to the influence of the optical orientation of the crystal, that is, the polarized light is no longer perpendicular to the upper polarizer, and a certain component of light will pass through the upper polarizer, and the interference color of the mineral can be observed in the field of view of the eyepiece; when the stage is rotated one circle (360 degrees), the interference color of the mineral will show four bright and four dark phenomena (fourfold extinction); different minerals have different maximum interference colors, and the positions of the four times of extinction (characterized by the extinction angle) are different, so the interference color characteristics are an important basis for identifying minerals; the cross-section of uniaxial crystal minerals perpendicular to the optical axis also shows total extinction characteristics under orthogonal polarization because the optical body is circular.

[0063] Pores in reservoir rocks (reservoir formations) are essentially empty holes, cavities, and cracks that appear completely black under crossed polarized light. Therefore, they can be identified using a standard thin section under a polarizing microscope. Specifically, the following steps are necessary: ​​① Under single polarized light or no polarization, the pores appear brightfield. ② When observed using crossed polarized light, the polarization direction of the lower polarized light passing through these pores remains unaffected and remains perpendicular to the upper polarizer, resulting in a completely black (total extinction) appearance under crossed polarized light. However, in practice, using this "total extinction" feature for pore identification has two drawbacks: ① The completely black state hinders the accurate identification of pore details and outlines; ② The completely black pores are difficult to distinguish from the completely extinct mineral sections, hindering face ratio analysis.

[0064] In response to the above two problems in using total extinction characteristics to identify pores, long-term thin section identification practice found that: although the verticality of the upper and lower polarizers of the polarizing microscope is a prerequisite for mineral identification, when the upper and lower polarizers are not vertical, that is, in the oblique polarization state, the "pores" observed in the field of view appear as a "bright field" with a certain grayscale; the smaller the angle of the two polarizers deviating from the vertical state, that is, the closer to the vertical state, the lower the pore brightness, and the closer the interference color characteristics of the mineral are to the orthogonal polarization state; on the contrary, the greater the angle of the two polarizers deviating from the vertical state, that is, the closer to parallel, the higher the pore brightness, and the more the interference color characteristics of the mineral deviate from the orthogonal polarization state.

[0065] Using single polarized light observation, determine the difference between the reservoir space and the surrounding minerals. Observe the overall appearance of the rock, focusing on the color, protrusions, roughness, pleochroism, and internal structural characteristics of the rock's main mineral components. Compare the differences between the production field and the surrounding areas with residual production glue, or compare the production field and obvious cracks and holes to determine the difficulty of identifying the pores in the reservoir rock (reservoir). Generally, pores between colored minerals, highly protruding minerals, minerals with many inclusions, minerals with large grains, and pores with large pore sizes are easy to identify using single polarized light. This can be done through thin section identification and manual pore counting, or by collecting images and using software to count pores. Conversely, pores between colorless minerals, low-protrusion minerals, clean minerals, and fine minerals are more difficult to identify, and smaller pores are easily missed. This method can be used for pore identification.

[0066] If the reservoir space differs little from the surrounding minerals, cross-polarized light observation is performed to identify the mineral type and preliminarily determine the degree of porosity. The interference colors, extinction characteristics, and twinning patterns of the rock's constituent minerals are observed, and the mineral species is determined in combination with single-polarized light characteristics. Lithologic identification is performed to determine the reservoir rock type. Geological constraints are established through petrogenic analysis to identify the primary pore types and their distribution in thin sections. Pore types vary across reservoir rock types. For example, primary pores in sandstone primarily include (residual) intergranular and intercrystalline pores, while secondary pores primarily include granular solution pores, intergranular solution pores, and various fractures. Similarly, in granular carbonate rocks, primary pores primarily include intergranular, intragranular, biogenic, obscured, and intercrystalline pores, while secondary pores primarily include intragranular / intercrystalline solution pores, intracrystalline / intercrystalline solution pores, structural fractures, and dissolution fractures. Generally, the pores of tight sandstone reservoirs composed of felsic with low interference color and carbonate rocks composed of heteromorphic grains are difficult to identify and count. However, this method can effectively identify and count the pore structures.

[0067] In the single polarization state, select a suspected pore and place it in the center of the field of view; then insert the upper polarizer, if it is a pore, it will be completely extinct; then insert a gypsum or mica test plate, the "extinction color" will appear as level I purple-red interference color and level I gray-white interference color, and the pore outline will be clear; rotate the stage, the pore color will not change, but the interference color of the mineral will increase or decrease by one level order, and increase or decrease by one color order respectively.

[0068] The gypsum test plate is an essential accessory for polarizing microscopes. Its optical path difference is approximately 550 mm, equivalent to one order of mineral interference color, hence its name, the 1λ test plate. Under crossed polarization, the gypsum test plate exhibits a first-order purplish-red interference color. Adding the gypsum test plate can raise or lower the mineral interference color by one order. Under crossed polarization, pores appear completely black. Inserting the gypsum test plate reveals a first-order purplish-red interference color, clearly revealing pore outlines and making it suitable for microscopic measurement.

[0069] Mica test plates are also essential accessories for polarizing microscopes. With an optical path difference of approximately 147 mm, equivalent to one color sequence of mineral interference colors, they are also called 1 / 4λ test plates. Under crossed polarization, mica test plates exhibit a grayish-white interference color of level I. Adding a mica test plate can raise or lower the mineral interference color by one color sequence. Pores appear completely black under crossed polarization, but upon insertion of the mica test plate, they exhibit a grayish-white interference color of level I, clearly revealing pore outlines and making them suitable for microscopic measurement.

[0070] When identifying reservoirs composed primarily of high-interference-color minerals, mica test plates are preferred for pore confirmation. When identifying reservoirs composed primarily of low-interference-color minerals, gypsum test plates are preferred for pore confirmation. Using gypsum and mica test plates can improve pore detail observation and contour identification under crossed polarization conditions.

[0071] Adjust the angle of the polarizer to perform cross-polarization observation and identify pores. Based on single-polarization and cross-polarization observations, select a suspected pore and place it at the center of the field of view. Fine-tune the position of the polarizer in the "cross-polarization" state to obtain the cross-polarization state. At this time, the pores in the reservoir rock (reservoir) appear as "bright colors" with a certain grayscale and clear outlines, and the interference colors of the surrounding minerals will change slightly. Rotating the stage will not change the grayscale of the pores, but the interference colors of the surrounding minerals will still change from bright to dark.

[0072] Both theoretical analysis and actual observations show that the smaller the deviation of the two polarizers from the vertical state, the darker the pore brightness, and the less it affects the observation of the mineral interference color characteristics; when the angle of the two polarizers from the vertical state is between 8° and 15°, the grayscale of the pores is easy to observe, and the interference color of the mineral is close to the orthogonal polarization state and basically does not affect the identification and recognition.

[0073] Whether to adjust the upper polarizer or the lower polarizer depends on the orthogonal polarization adjustment device of the polarizing microscope: when the adjustment device is under the stage, adjust the lower polarizer; when the adjustment device is attached to the orthogonal polarizer, adjust the upper polarizer.

[0074] The pore type identification, pore size, throat width, and pore connectivity are manually counted for the pore distribution field obtained in the oblique polarization state or by inserting a gypsum test board. A large number of photos can also be taken and the pores can be "colored" through processing software to achieve the purpose of computer quantitative statistics.

[0075] Based on observations of rock thin sections using single polarization, crossed polarization, and cross-polarization, this method utilizes the "bright field" phenomenon, where pores appear at a certain grayscale under crossed polarization. By adjusting the position of the polarizer, direct pore observation, microscopic measurement, and statistics can be achieved. Furthermore, using gypsum and mica test plates under crossed polarization, pores can also be "highlighted," facilitating observation and measurement.

[0076] The present invention also provides an electronic device, which includes: a memory storing executable instructions; and a processor running the executable instructions in the memory to implement the above-mentioned pore identification method based on oblique polarization.

[0077] The present invention also provides a computer-readable storage medium storing a computer program, which implements the above-mentioned pore identification method based on cross-polarization when executed by a processor.

[0078] To facilitate understanding of the solutions and effects of the embodiments of the present invention, three specific application examples are given below. Those skilled in the art should understand that these examples are only for facilitating understanding of the present invention, and any specific details thereof are not intended to limit the present invention in any way.

[0079] Example 1

[0080] Figure 1 A flow chart showing the steps of a pore identification method based on cross-polarization according to an embodiment of the present invention is shown.

[0081] like Figure 1 As shown, the pore identification method based on cross-polarization includes: step 101, judging the difference between the reservoir space and the surrounding minerals through single polarization observation; step 102, if the difference between the reservoir space and the surrounding minerals is small, then performing orthogonal polarization observation to identify the mineral type and determine the degree of pore development; step 103, adjusting the angle of the polarizer, performing cross-polarization observation, and identifying the pores.

[0082] The Mesozoic Shaximiao Formation sandstones in the study area are products of braided river-deltaic sedimentation with near provenance, ample provenance, and rapid deposition. High plastic debris content in the parent rock, rapid burial compaction, and multi-stage filling and cementation contribute to the low porosity and low permeability of this dense reservoir, resulting in relatively high-quality reservoirs only locally. Because core extraction is expensive, cores are extremely valuable, prohibiting large-scale sampling, resulting in a relatively small number of cast thin section samples. Furthermore, the effectiveness of colored glue injection in dense sandstones is variable, limiting the understanding, research, and statistical analysis of pore structure.

[0083] To address these issues, the study fully utilized the original ordinary thin sections preserved in the oil field, and carried out pore identification and observation statistics through comprehensive observation with single polarization, orthogonal polarization, and oblique polarization, supplemented by gypsum test plates.

[0084] Figure 2a and Figure 2b Schematic diagrams of pore identification of a core slice observed under single polarization and under cross polarization according to an embodiment of the present invention are respectively shown.

[0085] like Figure 2aAs shown in Figure 2, the reservoir structure is dense under single polarized light, and the pores are generally underdeveloped. Because the felsic minerals are colorless and have low protrusions, the optical properties of the pores and minerals are small under single polarized light, making them difficult to identify. Figure 2b As shown in the figure, the pores are completely extinct when observed under orthogonal polarization. However, due to the small particles of the nearby mud fillings (impurities) and low interference color, the pore outline and morphology are difficult to observe and the pore structure is difficult to measure.

[0086] Figure 3 A schematic diagram of pore identification by cross-polarized light observation of a core slice according to an embodiment of the present invention is shown.

[0087] like Figure 3 As shown, the polarizer angle is adjusted to about 10° to obtain the oblique polarization effect, and the interference color of the skeleton particles changes with Figure 2b Compared with the original data, the changes are not significant, so it does not affect the identification of minerals; the structure of the mud filling material near the pores is clear, the parts where the pores are developed are gray, and the pore outlines are clear. They are mainly composite pores of intergranular pores and mineral dissolution pores, with irregular shapes and uneven distribution.

[0088] Figure 4 A schematic diagram of pore statistics of a core slice observed with oblique polarized light according to an embodiment of the present invention is shown. The change in mineral interference color is small and does not affect identification. The mud filling material (matrix) near the pores has a clear structure, and the pore outline and structure can be directly observed. The pore genesis types are mainly residual intergranular pores and feldspar solution pores, and rock debris solution pores are also seen. The three types of pores constitute composite pores with irregular morphology and a maximum pore diameter of about 200 μm.

[0089] In summary, the present invention overcomes the difficulty of the lack of cast thin sections and its own limitations, saves money and time, and achieves the purpose of systematically studying and comparing the heterogeneity of reservoirs in the plane and vertical directions, providing a scientific and objective basis for the evaluation and prediction of relatively high-quality reservoirs.

[0090] Example 2

[0091] The present disclosure provides an electronic device including: a memory storing executable instructions; and a processor running the executable instructions in the memory to implement the above-mentioned pore identification method based on oblique polarization.

[0092] An electronic device according to an embodiment of the present disclosure includes a memory and a processor.

[0093] The memory is used to store non-transitory computer-readable instructions. Specifically, the memory may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may include, for example, random access memory (RAM) and / or cache memory. The non-volatile memory may include, for example, read-only memory (ROM), a hard disk, flash memory, etc.

[0094] The processor may be a central processing unit (CPU) or other form of processing unit having data processing capability and / or instruction execution capability, and may control other components in the electronic device to perform desired functions. In one embodiment of the present disclosure, the processor is used to execute the computer-readable instructions stored in the memory.

[0095] Those skilled in the art should understand that in order to solve the technical problem of how to obtain a good user experience, this embodiment may also include well-known structures such as a communication bus and an interface, and these well-known structures should also be included in the scope of protection of this disclosure.

[0096] For detailed description of this embodiment, please refer to the corresponding description in the aforementioned embodiments, which will not be repeated here.

[0097] Example 3

[0098] An embodiment of the present disclosure provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, the pore identification method based on cross-polarization is implemented.

[0099] According to an embodiment of the present disclosure, a computer-readable storage medium stores non-transitory computer-readable instructions, which, when executed by a processor, execute all or part of the steps of the aforementioned methods of the embodiments of the present disclosure.

[0100] The above-mentioned computer-readable storage media include, but are not limited to, optical storage media (e.g., CD-ROMs and DVDs), magneto-optical storage media (e.g., MOs), magnetic storage media (e.g., magnetic tapes or mobile hard disks), media with built-in rewritable non-volatile memory (e.g., memory cards), and media with built-in ROM (e.g., ROM cartridges).

[0101] Those skilled in the art should understand that the above description of the embodiments of the present invention is only for the purpose of illustrative purposes only to illustrate the beneficial effects of the embodiments of the present invention, and is not intended to limit the embodiments of the present invention to any given examples.

[0102] While various embodiments of the present invention have been described above, the above description is intended to be illustrative, not exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A pore identification method based on cross polarization, characterized in that: include: Through single polarized light observation, the difference between the reservoir space and its surrounding minerals can be determined; If the difference between the reservoir space and its surrounding minerals is small, cross-polarized light observation is performed to identify the mineral type and determine the degree of pore development; Adjust the angle of the polarizer to observe the polarized light and identify the pores; Among them, also include: Before adjusting the angle of the polarizer, the pores are confirmed by using a mineral test plate; Among them, if the mineral type is identified as a reservoir composed mainly of high interference color minerals, a mica test plate is used to confirm the pores; Among them, if the mineral type is identified as a reservoir composed mainly of low interference color minerals, gypsum test plates are used for pore confirmation; Among them, the angle of the two polarizers deviating from the vertical state is 8°~15°.

2. The pore identification method based on cross-polarization according to claim 1, wherein: Also includes: The pore distribution field of the oblique polarized light is used to identify the pore type, pore size, throat width, and pore connectivity, and manually count the pores, or take photos and color the pores through software to achieve pore statistics.

3. The pore identification method based on cross-polarization according to claim 1, wherein: Adjusting the angle of the polarizer includes: If the adjustment device is above the stage, adjust the angle of the upper polarizer; If the adjustment device is below the stage, adjust the angle of the lower polarizer.

4. The pore identification method based on cross-polarization according to claim 1, wherein: Also includes: If the reservoir space is significantly different from the surrounding minerals, thin section identification and manual direct pore counting are performed, or images are collected and software is used to perform pore counting.

Images