Method for identifying hydrocarbon-generating parent material tamazonia

Abstract

The invention relates to the technical field of identification of hydrocarbon-generating parent material tamazonia, in particular to an identification method of hydrocarbon-generating parent material tamazonia, which realizes visual characterization of the internal microstructure of algae through acid treatment, screen classification and FIB-SEM three-dimensional imaging technologies. According to the method, the limitation of a traditional two-dimensional imaging technology is broken through, the identification basis is expanded from the external form to the internal structure, and the identification precision and reliability are remarkably improved. The specific implementation mode comprises three core steps of sample pretreatment, three-dimensional imaging and structure reconstruction, and efficient and accurate identification of Tasmania algae and similar algae is realized by optimizing process parameters and an algorithm model. Experimental results show that the method improves the identification accuracy to 98% or above, and provides key technical support for oil-gas exploration.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of identifying hydrocarbon source material Tasmania algae, and particularly relates to a method for identifying hydrocarbon source material Tasmania algae. BACKGROUND

[0002] In the prior art, the identification of hydrocarbon source material algae mainly relies on organic petrology and two-dimensional imaging technology. The comparative file CN115187982B discloses an algae detection method, which realizes algae recognition through a deep learning model, but the technology can only obtain the external morphological characteristics of algae and cannot analyze the internal microstructure. Another comparative file CN105954197A uses a polarized microscope reflection light system to identify hydrocarbon source material, but is limited by the two-dimensional imaging resolution and is difficult to distinguish similar algae species.

[0003] The traditional technology has the following defects: (1) Morphological identification limitation: Tasmania algae and blue-green algae, green algae are highly similar in two-dimensional morphology, and the recognition accuracy of the traditional method is less than 60%; (2) Structure damage problem: diagenesis leads to the destruction of the internal structure of algae, and two-dimensional imaging technology cannot accurately capture three-dimensional features; (3) Identification bottleneck: the existing technology only relies on external morphology for identification, which often leads to misjudgment in hydrocarbon source rock evaluation, affecting the efficiency of oil and gas exploration. SUMMARY

[0004] The purpose of the present application is to provide a method for identifying hydrocarbon source material Tasmania algae, in order to solve the technical problems existing in the prior art.

[0005] In order to achieve the above-mentioned purpose of the application, the technical scheme adopted by the present application is as follows: A method for identifying hydrocarbon source material Tasmania algae, comprising the following steps: Step 1: pretreatment of the algae sample; Step 2: FIB-SEM cutting; Step 3: FIB-SEM three-dimensional reconstruction.

[0006] Further, the pretreatment of the algae sample specifically comprises the following steps: Step 1: take a rock sample, crush the rock into particles by a crusher, weigh 40 g of the sample, wash it with pure water, and further dry it in an oven at 40℃; Step 2: acid treatment, specifically comprising the following steps: S2.1: add 300 mL of 10% dilute hydrochloric acid to the sample prepared in step 1 to soak the sample until there is no obvious reaction, and remove the calcareous impurities; S2.2: Wash repeatedly 5-6 times with ultrapure water until pH is 7; S2.3: Slowly add 300 mL of 40% HF to remove silica until no obvious reaction, and shake the sample every 24 h or so to make it react fully, and continue to treat for 5 days; Step three: Step sample collection, specifically including the following steps: S3.1: Remove the acid solution, and wash 5-6 times with ultrapure water until the sample solution pH is 7; S3.2: Transfer the sample to a 500 mL beaker and heat on a hot plate at 150°C for 6 h until the supernatant is clear; S3.3: After the sample is reduced to room temperature, remove the pyrite and wood carbon particles that are not dissolved by elutriation, and sieve the remaining residues with 5 μm, 40 μm and 200 μm screens with a diameter of 10 cm, respectively; S3.4: Put the sieved products into centrifuge tubes, respectively.

[0007] Step four: Take the 5-40 μm sieved products obtained in step three, uniformly disperse them on conductive glue, and dry at room temperature; after the sample is completely dried, use an ion sputtering gold plating instrument to perform gold plating treatment on the surface of the sample, with a gold spraying voltage of 20 kV and a gold spraying time of 120 s, to enhance its conductivity, and the gold thickness is 0.5-1 μm.

[0008] Further, the FIB-SEM cutting includes the following steps: Step one: Put the prepared sample into the FIB-SEM workbench to extract vacuum, adjust the working distance to 5 mm when taking electron microscope photos, position to a single algal sample, and further perform gold plating treatment on the surface of the alga to prevent damage to the surface structure of the alga during gallium ion cutting.

[0009] Step two: After selecting a suitable section position, rotate the sample table by 54° to make the Ga ion beam perpendicular to the fixed plane of the sample, and then use a gallium ion beam voltage of 30 Kv and 100 nA to continuously cut the selected area, with a cutting resolution of 15*15*30 nm, and a focused ion beam (FIB) peeling off the sample layer by layer, and a scanning electron microscope synchronously collecting the topographic information of each layer, with electron microscope imaging parameters: acceleration voltage 5 kV, beam current 300 pA.

[0010] Further, the FIB-SEM three-dimensional reconstruction includes the following steps: Step one: Select the medium offset module in the Mutual Info method of the software (Dragonfly 2024) to calibrate the secondary electron image of the alga; Step two: use intelligent segmentation wizard to establish deep learning training for its internal structure, apply the trained module to the algae data model, and then process the island function to retain the effective area of more than 8 pixel points, thereby effectively improving the clarity of the internal microstructure of the fossil algae.

[0011] Further, the diameter of the rock particles after the sample is broken is 1-2 mm.

[0012] Further, after the sample is gold-plated, a nitrogen blowing instrument is used to gently blow the surface of the sample to remove the attached loose particles.

[0013] Further, the thickness of the FIB-SEM cutting gold treatment is 20-100 nm.

[0014] As an improvement, the beneficial effects of the present application are: The present application relates to a method for identifying a hydrocarbon-generating mother material of Tasmania algae, which realizes the visualization of the internal microstructure of algae through acid treatment, screen classification and FIB-SEM three-dimensional imaging technology. This method breaks through the limitations of traditional two-dimensional imaging technology, expands the identification basis from external morphology to internal structure, and significantly improves the identification accuracy and reliability. The specific implementation method includes three core steps of sample pretreatment, three-dimensional imaging and structure reconstruction, which realizes the efficient and accurate identification of Tasmania algae and similar algae by optimizing process parameters and algorithm models. The experimental results show that the identification accuracy of the method is improved to more than 98%, which provides key technical support for oil and gas exploration. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 The present application is a microstructure of the surface of Tasmania algae; Figure 2 The present application is a microstructure of the internal structure of Tasmania algae; Figure 3 The present application is a three-dimensional modeling diagram of Tasmania algae; Figure 4 The present application is a strawberry-like pyrite selected by sieving 5 μm or less product for electron microscope observation; Figure 5 The present application is a microstructure of naked kelp algae selected by sieving 40-200 μm product for electron microscope observation; Figure 6 The present application is a microstructure of the internal structure of naked kelp algae; Figure 7 The present application is a microstructure of FIB-SEM cutting blue-green algae; Figure 8 The present application is a microstructure of the internal structure of blue-green algae; DETAILED DESCRIPTION

[0016] To make the content of this invention easier to understand, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings.

[0017] Example 1: Sample source: Rock samples from the Late Permian Dalong Formation in the Sichuan Basin. Reagents and instruments: 10% hydrochloric acid, 40% hydrofluoric acid, 5 μm, 40 μm and 200 μm sieves, FIB-SEM (ZeissCrossbeam 550), DELL workstation.

[0018] The identification steps are as follows: S1: Preprocessing of algal samples: Take a rock sample, crush it into particles with a diameter of 1-2 mm using a crusher, weigh 40 g of the sample, place it in a 1000 ml plastic bucket, wash it with pure water, and then dry it in an oven at 40℃.

[0019] Acid treatment: to step Soak the sample in 300 mL of 10% dilute hydrochloric acid until there is no obvious reaction to remove calcium impurities; then rinse repeatedly with ultrapure water 5-6 times until the pH is 7; then slowly add 300 mL of 40% HF to remove silica until there is no obvious reaction, and shake the sample every 24 hours to ensure a full reaction, and continue the treatment for 5 days.

[0020] Sample collection: After removing the acid solution, wash the sample solution 5-6 times with ultrapure water until the pH reaches 7. Then, transfer the sample to a 500 mL beaker and heat on a hot plate at 150°C for 6 hours until the supernatant becomes clear. After cooling to room temperature, remove undissolved mineral particles such as pyrite and carbonaceous particles from the wood by washing. The remaining residue is then sieved through 10 cm diameter sieves of 5 μm, 40 μm, and 200 μm. The sieved products are then placed into centrifuge tubes.

[0021] Take steps The sieved product, ranging from 5 to 40 μm, obtained was uniformly dispersed on a conductive adhesive and dried at room temperature. After the sample was completely dry, gold plating was performed on the sample surface using an ion sputtering gold plating instrument. The sputtering voltage was 20 kV, the sputtering time was 120 s, and the gold plating thickness was 0.5–1 μm. After gold plating, the sample surface was gently blown with a nitrogen purging device to remove any loose particles that may have adhered.

[0022] S2: FIB-SEM cutting and reconstruction.

[0023] The sample prepared in step 1 was placed in the FIB-SEM workbench and vacuumed. The working distance was adjusted to 5 mm when taking electron microscope photos. The single algal sample was positioned and further gallium treatment was performed on the algal surface (thickness of 20-100 nm) to prevent the algal surface structure from being damaged during gallium ion cutting.

[0024] After selecting the appropriate section position, the sample stage was rotated by 54° so that the Ga ion beam was perpendicular to the fixed plane of the sample. Then, the selected area was continuously cut using a gallium ion beam voltage of 30 Kv and 100 nA, with a cutting resolution of 15*15*30 nm. The focused ion beam (FIB) peeled off the sample layer by layer, and the scanning electron microscope synchronously collected the topographic information of each layer. The electron microscope imaging parameters were: acceleration voltage 5 kV, beam current 300 pA.

[0025] The obtained high-resolution secondary electron image was imported into the Dragonfly software for three-dimensional reconstruction. First, the medium offset module in the Mutual Info method of the software was selected to calibrate the secondary electron image of the algae. Further, the intelligent segmentation wizard was used to establish a deep learning training of the internal structure. The trained module was applied to the algal data model, and then the effective area with more than 8 pixels was retained through the function of processing the isolated island, thereby effectively improving the clarity of the internal microstructure of the fossil algae.

[0026] The microstructure of the Tasmania algae and other algae (cyanobacteria, green algae) is similar, both being spherical and elliptical, and it is difficult to distinguish them only based on their appearance (see Figure 1 ). However, there are a large number of cyst structures inside the Tasmania algae, and the internal structure appears typical ball-in-ball (see Figure 2 and Figure 3 ).

[0027] Comparative Example 1 Unlike Example 1, the product with a particle size of less than 5 μm was selected for electron microscope observation. The sieved product with a particle size of less than 5 μm was mainly strawberry-like pyrite (see Figure 4 ).

[0028] Comparative Example 2 Unlike Example 1, the product with a particle size of 40-200 μm was selected for electron microscope observation.

[0029] The sieved product with a particle size of 40-200 μm was mainly naked kelp algae, which had a honeycomb appearance (see Figure 5), the interior is also a honeycomb structure (see Figure 6 ).

[0030] Comparative Example 3 The same as step of embodiment 1, but the selected FIB-SEM cut object is different.

[0031] Figure 7 The appearance microstructure of blue algae is shown, which is similar to the appearance of Tasmania algae, and it is difficult to distinguish them only by appearance. However, the interior of blue algae is mostly solid structure (see Figure 8 ).

[0032] The above only is the preferred embodiment of the present application patent, and does not use to limit the present application patent, any modification, equivalent replacement and improvement etc. made in the spirit and principle of the present application patent should be included in the protection scope of the present application patent.

Claims

1. A method for identifying Tasmanian algae, a hydrocarbon-generating parent material, characterized in that, Includes the following steps: Step 1: Pretreatment of algal samples; Step 2: FIB-SEM cutting; Step 3: FIB-SEM 3D Reconstruction.

2. The method for identifying the hydrocarbon-generating parent material *Tasmanian algae* according to claim 1, characterized in that, The pretreatment of the algal samples specifically includes the following steps: Step 1: Take a rock sample, crush the rock into particles using a crusher, weigh 40 g of the sample, place it in a 1000 ml plastic bucket, wash it with pure water, and then dry it in an oven at 40℃. Step Two: Acid Treatment, which specifically includes the following steps: S2.1: Add 300 mL of 10% dilute hydrochloric acid to the sample prepared in step one and soak the sample until there is no obvious reaction to remove calcium impurities. S2.2: Rinse repeatedly with ultrapure water 5-6 times until the pH reaches 7; S2.3: Slowly add 300 mL of 40% HF to remove silica until there is no obvious reaction. Shake the sample approximately every 24 hours to ensure a complete reaction. Continue this treatment for 5 days. Step 3: Sample collection, which includes the following steps: S3.1: Remove the acid solution and rinse with ultrapure water 5-6 times until the pH of the sample solution is 7; S3.2: Transfer the sample to a 500 mL beaker and heat it on a hot plate at 150°C for 6 h until the supernatant becomes clear; S3.3: After the sample has cooled to room temperature, remove undissolved mineral particles such as pyrite and carbonaceous particles from wood by washing, and sieve the remaining residue through 5 μm, 40 μm and 200 μm sieves with a diameter of 10 cm respectively. S3.4: Transfer the sieved products into centrifuge tubes respectively; Step 4: Take the 5-40 μm sieved product obtained in Step 3, disperse it evenly on the conductive adhesive, and dry it at room temperature; after the sample is completely dry, use an ion sputtering gold plating instrument to perform gold plating on the sample surface, with a gold sputtering voltage of 20 kV and a gold sputtering time of 120 s to enhance its conductivity, and the gold plating thickness is 0.5-1 μm.

3. The method for identifying the hydrocarbon-generating parent material *Tasmanian algae* according to claim 2, characterized in that, The FIB-SEM cutting includes the following steps: Step 1: Place the prepared sample into the FIB-SEM stage and draw a vacuum. When taking electron microscope images, adjust the working distance to 5mm, locate a single algal sample, and further perform gold plating on the algal surface to prevent gallium ion cutting from damaging the algal surface structure. Step 2: After selecting a suitable cutting position, rotate the sample stage by 54° to make the Ga ion beam perpendicular to the fixed plane of the sample. Then, use a gallium ion beam voltage of 30 kV and 100 nA to continuously cut the selected area with a cutting resolution of 15*15*30nm. Focused ion beam (FIB) peels off the sample layer by layer, and scanning electron microscope simultaneously acquires the morphology information of each layer. Electron microscope imaging parameters: accelerating voltage 5 kV, beam current 300 pA.

4. The method for identifying the hydrocarbon-generating parent material *Tasmanian algae* according to claim 1, characterized in that, The FIB-SEM three-dimensional reconstruction includes the following steps: Step 1: Select the medium offset module in the (Dragonfly 2024) method of the software to calibrate the secondary electron image of algae; Step 2: Use the intelligent segmentation wizard to build a deep learning training for its internal structure, apply the trained module to the algae data model, and then use the island processing function to retain the effective areas with more than 8 pixels, thereby effectively improving the clarity of the internal microstructure of fossil algae.

5. The method for identifying the hydrocarbon-generating parent material *Tasmanian algae* according to claim 2, characterized in that, The diameter of the rock particles after the sample was crushed was 1 to 2 mm.

6. The method for identifying the hydrocarbon-generating parent material *Tasmanian algae* according to claim 5, characterized in that, After the sample is gold-plated, a nitrogen blower is used to gently blow the sample surface to remove any loose particles adhering to it.

7. The method for identifying the hydrocarbon-generating parent material *Tasmanian algae* according to claim 3, characterized in that, The thickness of the gold plating treatment during FIB-SEM cutting is 20–100 nm.

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