Quantitative characterization method for occurrence state of mixed rock type shale oil

Abstract

The invention discloses a method for quantitatively characterizing the occurrence state of mixed rock type shale oil, which belongs to the technical field of petroleum geological exploration and comprises the following steps: step 1, obtaining soluble organic matters, namely chloroform bitumen A and primary rock sample residues from a rock sample, and calculating the content of the chloroform bitumen A; step 2, obtaining chloroform bitumen 'B' and secondary rock sample residues from the primary rock sample residues, and calculating the content of the chloroform bitumen 'B'; step 3, obtaining soluble organic matters called as chloroform bitumen 'C' and residual rock samples from the secondary rock sample residues, and calculating the content of the chloroform bitumen 'C'; and step 4, obtaining soluble organic matters from the residual rock sample, namely chloroform bitumen 'D', and calculating the content of the chloroform bitumen 'D'. And quantitatively characterizing the ratio of free / adsorbed state oil of retained hydrocarbon in different lithofacies in the mixed rock type shale oil reservoir system by using the contents of the chloroform bitumen A, the chloroform bitumen B, the chloroform bitumen C and the chloroform bitumen D, so that the problem that the occurrence state of the mixed rock type shale oil is difficult to accurately and quantitatively characterize is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum geological exploration, and in particular relates to a method for quantitatively characterizing the occurrence state of mixed rock type shale oil. Background Art

[0002] Continental shale oil reservoirs are generally characterized by complex rock composition, fine grain size, small reservoir space scale and strong heterogeneity. Compared with marine shales, they have more complex lithology, reservoir space type and accumulation characteristics. Therefore, continental shales have the concept of "mixed fine-grained sedimentary rocks". The Lucaogou Formation in the Jimusar Depression of the Junggar Basin is a very typical fine-grained mixed sedimentary system. Due to the development of micro-nano pore throat system, the distribution of shale oil is very dispersed and complex, with strong heterogeneity and diverse occurrence states, including free state and adsorbed state. How to scientifically and accurately characterize the occurrence form of shale oil in the reservoir is an important basis for the evaluation of shale oil mobility and is directly related to the effect of shale oil production.

[0003] At present, the study of quantitative characterization of the occurrence state is a relatively weak topic in the field of shale oil research. The quantitative characterization of the occurrence state of mixed rock-type shale oil is still in the exploratory stage at home and abroad, and qualitative characterization is more common. Predecessors have clarified that shale oil has free and adsorbed states based on image recognition such as high-resolution FE-SEM and conventional geochemical methods (pyrolysis, extraction method), molecular dynamics simulation and other technologies. However, there is no recognized satisfactory method for the quantitative characterization of shale oil in different occurrence states in mixed rock-type reservoirs in these states. How to quantitatively characterize the adsorption state, adsorption amount, content / proportion of shale oil in different occurrence states, etc., is still lacking in targeted and effective research and characterization. For example, the chloroform asphalt "A" obtained by conventional Soxhlet extraction can only represent the total oil content, and the standard rock pyrolysis parameter "S1" can only represent part of the free shale oil. It cannot distinguish the occurrence state of shale oil, and cannot clearly distinguish the occurrence state of retained hydrocarbons in fine-grained mixed rocks with complex components. In other words, it is not clear how much hydrocarbons are free, semi-free, adsorbed with carbonate minerals, and adsorbed with silicate minerals. There is a lack of a complete geochemical experimental characterization method. Traditional Soxhlet extraction can only extract all soluble organic matter in rocks, that is, the traditionally defined chloroform asphalt "A", and cannot distinguish the relative content of soluble organic matter such as free and adsorbed. The results of numerical simulation (molecular mechanics and molecular dynamics) also need to be tested and corrected by relevant experiments: the force field and potential field parameters between solid and oil in molecular simulation are the key parameters that affect the simulation results. Whether their selection is appropriate needs to be defined by whether the results of numerical simulation are close to the experimental results under the same conditions. In view of this, how to accurately and quantitatively characterize the occurrence state of mixed rock-type shale oil is one of the important issues that need to be solved in this field. Summary of the invention

[0004] The present invention provides a method for quantitatively characterizing the occurrence state of mixed sedimentary rock type shale oil, which solves the problem that the occurrence state of mixed sedimentary rock type shale oil is difficult to accurately and quantitatively characterize.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A method for quantitatively characterizing the occurrence state of mixed rock type shale oil comprises the following steps:

[0007] Step 1: crush the rock sample after drying, and use reagents to perform Soxhlet extraction. The soluble organic matter obtained is called chloroform asphalt "A" and the primary rock sample residue. Calculate the content of chloroform asphalt "A";

[0008] Step 2: freeze-dry the primary rock sample residue, weigh and grind it, and then use a reagent to perform Soxhlet extraction to obtain chloroform asphalt "B" and secondary rock sample residue, and calculate the content of chloroform asphalt "B";

[0009] Step 3, freeze-dry the secondary rock sample residue after extraction, weigh it and place it in a container for acid hydrolysis; freeze-dry the residue after acid hydrolysis of the sample, extract it with a reagent Soxhlet, and the soluble organic matter obtained is called chloroform asphalt "C" and the residual rock sample, and calculate the content of chloroform asphalt "C";

[0010] Step 4: Weigh the remaining rock sample again and place it in a container, and hydrolyze it with a mixed solution of hydrofluoric acid and hydrochloric acid. After freeze-drying the sample residue after acid hydrolysis, extract it with a Soxhlet reagent. The soluble organic matter obtained is called chloroform asphalt "D". Calculate the content of chloroform asphalt "D".

[0011] Furthermore, in step 1, the reagent is a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7.

[0012] Furthermore, in step 1, the Soxhlet extraction time is 36h-72h.

[0013] Furthermore, in step 2, the primary rock sample residue is ground manually.

[0014] Furthermore, in step 3, the acid hydrolysis process is as follows: hydrochloric acid is added to the container and heated in a water bath at 70°C-90°C, and stirred to fully dissolve the carbonate minerals; after cooling, the aqueous solution is removed by centrifugation, and the solution is repeatedly rinsed until the solution is neutral.

[0015] Furthermore, in step 3, the hydrochloric acid is 50% hydrochloric acid.

[0016] Furthermore, in step 4, the acidolysis process is: repeatedly treating with a mixed solution of hydrofluoric acid and hydrochloric acid, and heating in a water bath at 70° C.-90° C. to completely dissolve the silicate minerals in the rock sample.

[0017] Furthermore, in step 4, in the mixed solution of hydrofluoric acid and hydrochloric acid, the volume ratio of pure hydrofluoric acid to 50% hydrochloric acid is 1:2.

[0018] Furthermore, after step 4 is completed, another rock sample powder is taken for multi-step pyrolysis to obtain non-polar free hydrocarbons, weakly polar free hydrocarbons, strongly polar adsorbed hydrocarbons and kerogen pyrolysis hydrocarbons, and the ratio of free hydrocarbons to total retained hydrocarbons obtained by multi-step pyrolysis is compared with the step-by-step extraction results to determine whether the change trends of the two are the same;

[0019] The ratio of free hydrocarbons to total retained hydrocarbons obtained by multi-stage pyrolysis is: (S 1-1 +S 1-2 ) / (S 1-1 +S 1-2 +S 2-1 );

[0020] The step-by-step extraction results are: (A+B) / (A+B+C+D);

[0021] Among them, S 1-1 is the content of non-polar free hydrocarbons, S 1-2 is the content of weakly polar free hydrocarbons, S 2-1 is the content of adsorbed hydrocarbons with strong polarity, S 2-1 is the content of hydrocarbons generated by kerogen pyrolysis;

[0022] A is the content of chloroform pitch "A", B is the content of chloroform pitch "B", C is the content of chloroform pitch "C", and D is the content of chloroform pitch "D".

[0023] Furthermore, the temperature was kept constant at 200°C for 1 min-5 min to obtain non-polar free hydrocarbons, and then the temperature was increased to 350°C at 25°C / min-30°C / min and kept constant for 1 min-5 min to obtain weakly polar free hydrocarbons, and then the temperature was increased to 450°C at 25°C / min-30°C / min and kept constant for 1 min-5 min to obtain strongly polar adsorbed hydrocarbons S 2-1 Finally, the temperature is raised to 600°C at a rate of 25°C / min-30°C / min to obtain kerogen pyrolysis and hydrocarbon generation.

[0024] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0025] The method of the present invention subdivides the conventional Soxhlet extract chloroform asphalt "A" into four types of soluble organic matter, which are defined as chloroform asphalt "A", chloroform asphalt "B", chloroform asphalt "C", and chloroform asphalt "D", respectively, and can obtain soluble organic matter in free state in macropores, soluble organic matter in semi-free state in matrix pores, soluble organic matter bound to carbonate minerals (encapsulated / adsorbed), and soluble organic matter bound to silicate minerals or kerogen (encapsulated / adsorbed). According to the content of chloroform asphalt "A", chloroform asphalt "B", chloroform asphalt "C" and chloroform asphalt "D", the proportion of free / adsorbed oil of retained hydrocarbons in different lithologies in the mixed rock type shale oil reservoir system, as well as the content and group composition of retained hydrocarbons in different occurrence states, molecular geochemical characteristics and other information can be quantitatively characterized.

[0026] The present invention selects samples of multiple different lithofacies to conduct multi-solvent step-by-step extraction experiments, which can intuitively obtain the proportion of hydrocarbons in different occurrence states in different lithofacies samples, so as to intuitively reflect the favorable lithofacies in the mixed rock type shale oil formation that are more conducive to production and utilization.

[0027] The present invention compares the contents of chloroform asphalt "A", chloroform asphalt "B", chloroform asphalt "C" and chloroform asphalt "D" obtained by step-by-step extraction with the proportions of free hydrocarbons and adsorbed hydrocarbons obtained by staged pyrolysis. The two methods confirm each other, which can optimize the accuracy of the experiment and improve the credibility of the quantitative characterization results. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the multi-solvent step-by-step extraction process;

[0029] Figure 2a The content ratio of hydrocarbons in different occurrence states in typical samples of 9 different lithofacies;

[0030] Figure 2b Corresponding fluorescence photos of typical samples of 9 different lithofacies;

[0031] Figure 3 This is a line graph showing the changing trend of the ratio of free hydrocarbons to total hydrocarbons in typical samples obtained by the step-by-step pyrolysis method and the step-by-step extraction method. DETAILED DESCRIPTION

[0032] In order to make the purpose and technical solution of the present invention clearer and easier to understand, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0033] Reference Figure 1, a quantitative characterization method for the occurrence state of mixed rock type shale oil. Based on the conventional Soxhlet extraction, this method uses different types of solvents to extract the rock four times step by step, and finally obtains shale oil in different occurrence states. Another sample is taken for a step-by-step pyrolysis experiment to compare the step-by-step pyrolysis, and finally the accuracy of the quantitative characterization results of soluble organic matter in different occurrence states in the rock can be verified. The specific steps include the following:

[0034] Step 1: Dry 50g of rock sample at 50℃ and crush it into 5-10mm particle size. Use a mixed reagent of dichloromethane and methanol with a volume ratio of 93:7 to Soxhlet extraction for 72h. The soluble organic matter obtained is called chloroform asphalt "A". Calculate the content of chloroform asphalt "A". Chloroform asphalt "A" characterizes the soluble organic matter existing in large pores and cracks in a free state.

[0035] Step 2: After freeze-drying the rock sample residue after extraction, weigh the sample and grind it to 150 mesh by gentle manual method, and extract it for 72 hours in a Soxhlet extractor with a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7 to obtain chloroform bitumen "B". Calculate the content of chloroform bitumen "B", which represents soluble organic matter that exists in the matrix pores in a free state or is attached to the kerogen or mineral surface in a semi-free state (free-adsorbed state).

[0036] Step 3. After freeze-drying the rock sample residue after extraction, weigh it and place it in a beaker, slowly add 50% hydrochloric acid (volume ratio 1:1) and heat it in a water bath at 70℃-90℃ for 3h, stir it to make it fully react, and ensure that the carbonate minerals are fully dissolved; after cooling, transfer it to a plastic centrifuge bottle, centrifuge to remove the aqueous solution, add ultrapure water and rinse it repeatedly until the solution is neutral. After freeze-drying the residue after acid hydrolysis of the sample, Soxhlet extraction is performed for 72h with a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7. The soluble organic matter obtained is called chloroform asphalt "C". Calculate the content of chloroform asphalt "C". Chloroform asphalt "C" characterizes organic matter that is chemically adsorbed or encapsulated with carbonate minerals and clay minerals.

[0037] Step 4. Weigh the remaining rock sample again and place it in a PE plastic bottle. Repeatedly treat it with a mixed solution of hydrofluoric acid and hydrochloric acid (the volume ratio of pure hydrofluoric acid to 50% hydrochloric acid is 1:2) and heat it in a water bath at 70℃-90℃ to completely dissolve the silicate minerals in the rock sample. After freeze-drying the sample residue after acid hydrolysis, Soxhlet extraction is performed for 72 hours with a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7. The soluble organic matter obtained is called chloroform asphalt "D". Calculate the content of chloroform asphalt "D". Chloroform asphalt "D" characterizes the organic matter that is chemically adsorbed or encapsulated with silicate minerals.

[0038] Step 5: Take another 100 mg of rock sample powder ground to about 100 mesh and conduct a multi-step pyrolysis experiment at 200°C for 1 min-5 min to obtain S 1-1 Then, the temperature was raised to 350°C at 25°C / min-30°C / min and kept at this temperature for 1min-5min to obtain S 1-2 Then, the temperature was raised to 450℃ at 25℃ / min-30℃ / min and kept at this temperature for 1min-5min to obtain S 2-1 Finally, the temperature was raised to 600℃ at 25℃ / min-30℃ / min to obtain S 2-2 , S 1-1 , S 1-2 , S 2-1 and S 2-2 The four parameters represent the contents of non-polar free hydrocarbons, weakly polar free hydrocarbons, strongly polar adsorbed hydrocarbons and kerogen pyrolysis hydrocarbons. 1-1 +S 1-2 ) / (S 1-1 +S 1-2 +S 2-1 ) is compared with the value of (A+B) / (A+B+C+D) in the step-by-step extraction result to determine whether the changing trends of the two are the same.

[0039] Based on the contents of chloroform asphalt "A", chloroform asphalt "B", chloroform asphalt "C" and chloroform asphalt "D" obtained in the above steps, the ratio of free / adsorbed oil in retained hydrocarbons can also be calculated using the formula: (A+B) / (C+D).

[0040] In the above steps, chloroform bitumen "A" can characterize the soluble organic matter existing in free state in large pores and cracks, chloroform bitumen "B" can characterize the soluble organic matter existing in free state in matrix pores or attached to kerogen or mineral surface in semi-free state (free-adsorbed state), while chloroform bitumen "C" and "D" respectively characterize the organic matter tightly bound or wrapped by chemical adsorption with carbonate minerals and clay minerals / kerogen. The last step aims to combine the staged pyrolysis results (S 1-1 +S 1-2 ) / (S 1-1 +S 1-2 +S 2-1 ) is compared with the value of ("A"+"B") / ("A"+"B"+"C"+"D") in the step-by-step extraction results, that is, the ratio of free hydrocarbons to total retained hydrocarbons is compared. The two should have the same change trend, so as to verify the rationality and accuracy of the experiment.

[0041] Among them, S 1-1 is the content of non-polar free hydrocarbons, S1-2 is the content of weakly polar free hydrocarbons, S 2-1 is the content of adsorbed hydrocarbons with strong polarity, S 2-1 is the content of hydrocarbons generated by kerogen pyrolysis;

[0042] A is the content of chloroform pitch "A", B is the content of chloroform pitch "B", C is the content of chloroform pitch "C", and D is the content of chloroform pitch "D".

[0043] Example 1

[0044] In this embodiment, dolomitic siltstone is used as the rock sample.

[0045] A method for quantitatively characterizing the occurrence state of mixed rock type shale oil comprises the following steps:

[0046] Step 1. Dry 50 g of rock sample at 50°C and crush it into 5 particle size. Use a mixed reagent of dichloromethane and methanol with a volume ratio of 93:7 for Soxhlet extraction for 72 hours. The soluble organic matter obtained is called chloroform asphalt "A". Calculate the content of chloroform asphalt "A".

[0047] Step 2: freeze-dry the rock sample residue after extraction, weigh it and grind it to 150 mesh by gentle manual method, extract it with a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7 in a Soxhlet extractor for 72 hours to obtain chloroform asphalt "B", and calculate the content of chloroform asphalt "B".

[0048] Step 3: After freeze drying the rock sample residue after extraction, weigh it and place it in a beaker, slowly add 50% hydrochloric acid (volume ratio 1:1) and heat it in a 70℃ water bath for 3h, stir it to make it fully react, and ensure that the carbonate minerals are fully dissolved; after cooling, transfer it to a plastic centrifuge bottle, centrifuge to remove the aqueous solution, add ultrapure water and rinse it repeatedly until the solution is neutral. After freeze drying the residue after acid hydrolysis of the sample, use Soxhlet extraction with a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7 for 72h. The soluble organic matter obtained is called chloroform asphalt "C", and the content of chloroform asphalt "C" is calculated.

[0049] Step 4. Weigh the remaining rock sample again and place it in a PE plastic bottle. Repeatedly treat it with a mixed solution of hydrofluoric acid and hydrochloric acid (the volume ratio of pure hydrofluoric acid to 50% hydrochloric acid is 1:2) and heat it in a 70°C water bath for 3 hours to completely dissolve the silicate minerals in the rock sample. After freeze-drying the sample residue after acid hydrolysis, Soxhlet extraction is performed for 72 hours using a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7. The soluble organic matter obtained is called chloroform asphalt "D", and the content of chloroform asphalt "D" is calculated.

[0050] Step 5: Take another 100 mg of rock sample powder ground to about 100 mesh and conduct a multi-step pyrolysis experiment at 200 °C for 1 min to obtain S 1-1 Then the temperature was raised to 350℃ at 25℃ / min and kept at this temperature for 1min to test S 1-2 Then, the temperature was raised to 450℃ at 25℃ / min and kept at this temperature for 1min to test S 2-1 Finally, the temperature was raised to 600℃ at 25℃ / min to test S 2-2 , S 1-1 , S 1-2 , S 2-1 and S 2-2 The four parameters represent non-polar free hydrocarbons, weakly polar free hydrocarbons, strongly polar adsorbed hydrocarbons and kerogen pyrolysis hydrocarbons.

[0051] Example 2

[0052] In this embodiment, dolomite is used as the rock sample.

[0053] A method for quantitatively characterizing the occurrence state of mixed rock type shale oil comprises the following steps:

[0054] Step 1. Dry 50g of rock sample at 50℃ and crush it into 5-10mm particle size. Use Soxhlet extraction with a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7 for 72h. The soluble organic matter obtained is called chloroform asphalt "A". Calculate the content of chloroform asphalt "A".

[0055] Step 2: After freeze-drying the extracted rock sample residue, weigh it and grind it to 100 mesh by gentle manual method, extract it with a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7 in a Soxhlet extractor for 72 hours to obtain chloroform asphalt "B", and calculate the content of chloroform asphalt "B".

[0056] Step 3: After freeze-drying the rock sample residue after extraction, weigh it and place it in a beaker, slowly add 50% hydrochloric acid (volume ratio 1:1) and heat it in an 80℃ water bath for 3h, stir it to make it fully react, and ensure that the carbonate minerals are fully dissolved; after cooling, transfer it to a plastic centrifuge bottle, centrifuge to remove the aqueous solution, add ultrapure water and rinse it repeatedly until the solution is neutral. After freeze-drying the residue after acid hydrolysis of the sample, use Soxhlet extraction with a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7 for 72h. The soluble organic matter obtained is called chloroform asphalt "C", and the content of chloroform asphalt "C" is calculated.

[0057] Step 4. Weigh the remaining rock sample again and place it in a PE plastic bottle. Repeatedly treat it with a mixed solution of hydrofluoric acid and hydrochloric acid (the volume ratio of pure hydrofluoric acid to 50% hydrochloric acid is 1:2) and heat it in an 80°C water bath for 3 hours to completely dissolve the silicate minerals in the rock sample. After freeze-drying the sample residue after acid hydrolysis, Soxhlet extraction is performed for 72 hours using a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7. The soluble organic matter obtained is called chloroform asphalt "D", and the content of chloroform asphalt "D" is calculated.

[0058] Step 5: Take another 100 mg of rock sample powder ground to about 100 mesh and conduct a multi-step pyrolysis experiment at 200°C for 2 min to obtain S 1-1 Then the temperature was raised to 350℃ at 26℃ / min and kept at this temperature for 2min to test S 1-2 Then, the temperature was raised to 450℃ at 26℃ / min and kept at this temperature for 2min to test S 2-1 Finally, the temperature was raised to 600℃ at 26℃ / min to test S 2-2 , S 1-1 , S 1-2 , S 2-1 and S 2-2 The four parameters represent non-polar free hydrocarbons, weakly polar free hydrocarbons, strongly polar adsorbed hydrocarbons and kerogen pyrolysis hydrocarbons.

[0059] Example 3

[0060] In this example, silt marl is used as the rock sample.

[0061] A method for quantitatively characterizing the occurrence state of mixed rock type shale oil comprises the following steps:

[0062] Step 1. Dry 50g of rock sample at 50℃ and crush it into 5-10mm particle size. Use Soxhlet extraction with a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7 for 72h. The soluble organic matter obtained is called chloroform asphalt "A". Calculate the content of chloroform asphalt "A".

[0063] Step 2: After freeze-drying the extracted rock sample residue, weigh it and grind it to 100 mesh by gentle manual method, extract it with a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7 in a Soxhlet extractor for 72 hours to obtain chloroform asphalt "B", and calculate the content of chloroform asphalt "B".

[0064] Step 3: After freeze drying the rock sample residue after extraction, weigh it and place it in a beaker, slowly add 50% hydrochloric acid (volume ratio 1:1) and heat it in a 90℃ water bath for 4h, stir it to make it fully react, and ensure that the carbonate minerals are fully dissolved; after cooling, transfer it to a plastic centrifuge bottle, centrifuge to remove the aqueous solution, add ultrapure water and rinse it repeatedly until the solution is neutral. After freeze drying the residue after acid hydrolysis of the sample, use Soxhlet extraction with a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7 for 72h. The soluble organic matter obtained is called chloroform asphalt "C", and the content of chloroform asphalt "C" is calculated.

[0065] Step 4. Weigh the remaining rock sample again and place it in a PE plastic bottle. Repeatedly treat it with a mixed solution of hydrofluoric acid and hydrochloric acid (the volume ratio of pure hydrofluoric acid to 50% hydrochloric acid is 1:2) and heat it in a 90°C water bath for 4 hours to completely dissolve the silicate minerals in the rock sample. After freeze-drying the sample residue after acid hydrolysis, Soxhlet extraction is performed for 72 hours using a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7. The soluble organic matter obtained is called chloroform asphalt "D", and the content of chloroform asphalt "D" is calculated.

[0066] Step 5: Take another 100 mg of rock sample powder ground to about 100 mesh and conduct a multi-step pyrolysis experiment at 200 °C for 3 min to obtain S 1-1 Then the temperature was raised to 350℃ at 27℃ / min and kept at this temperature for 3min to test S 1-2 Then, the temperature was raised to 450℃ at 27℃ / min and kept at this temperature for 3min to test S 2-1 Finally, the temperature was raised to 600℃ at 27℃ / min to test S 2-2 , S 1-1 , S 1-2 , S 2-1 and S 2-2 The four parameters represent non-polar free hydrocarbons, weakly polar free hydrocarbons, strongly polar adsorbed hydrocarbons and kerogen pyrolysis hydrocarbons.

[0067] Example 4

[0068] In this example, silt-containing micrite dolomite is used as the rock sample.

[0069] A method for quantitatively characterizing the occurrence state of mixed rock type shale oil comprises the following steps:

[0070] Step 1. Dry 50g of rock sample at 50℃ and crush it into 5-10mm particle size. Use Soxhlet extraction with a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7 for 72h. The soluble organic matter obtained is called chloroform asphalt "A". Calculate the content of chloroform asphalt "A".

[0071] Step 2: freeze-dry the rock sample residue after extraction, weigh it and grind it to 150 mesh by gentle manual method, extract it with a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7 in a Soxhlet extractor for 72 hours to obtain chloroform asphalt "B", and calculate the content of chloroform asphalt "B".

[0072] Step 3: After freeze drying the rock sample residue after extraction, weigh it and place it in a beaker, slowly add 50% hydrochloric acid (volume ratio 1:1) and heat it in a 75℃ water bath for 3h, stir it to make it fully react, and ensure that the carbonate minerals are fully dissolved; after cooling, transfer it to a plastic centrifuge bottle, centrifuge to remove the aqueous solution, add ultrapure water and rinse it repeatedly until the solution is neutral. After freeze drying the residue after acid hydrolysis of the sample, use Soxhlet extraction with a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7 for 72h. The soluble organic matter obtained is called chloroform asphalt "C", and the content of chloroform asphalt "C" is calculated.

[0073] Step 4. Weigh the remaining rock sample again and place it in a PE plastic bottle. Repeatedly treat it with a mixed solution of hydrofluoric acid and hydrochloric acid (the volume ratio of pure hydrofluoric acid to 50% hydrochloric acid is 1:2) and heat it in a 75°C water bath for 3 hours to completely dissolve the silicate minerals in the rock sample. After freeze-drying the sample residue after acid hydrolysis, Soxhlet extraction is performed for 72 hours using a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7. The soluble organic matter obtained is called chloroform asphalt "D", and the content of chloroform asphalt "D" is calculated.

[0074] Step 5: Take another 100 mg of rock sample powder ground to about 100 mesh and conduct a multi-step pyrolysis experiment at 200 °C for 4 min to obtain S 1-1 Then the temperature was raised to 350℃ at 28℃ / min and kept at this temperature for 4min to test S 1-2 Then, the temperature was raised to 450℃ at 28℃ / min and kept at this temperature for 4min to test S 2-1 Finally, the temperature was raised to 600℃ at 28℃ / min to test S 2-2 , S 1-1 , S 1-2 , S 2-1 and S 2-2 The four parameters represent non-polar free hydrocarbons, weakly polar free hydrocarbons, strongly polar adsorbed hydrocarbons and kerogen pyrolysis hydrocarbons.

[0075] Example 5

[0076] In this example, shale J-1 is used as the rock sample.

[0077] A method for quantitatively characterizing the occurrence state of mixed rock type shale oil comprises the following steps:

[0078] Step 1. Dry 50g of rock sample at 50℃ and crush it into 5-10mm particle size. Use Soxhlet extraction with a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7 for 72h. The soluble organic matter obtained is called chloroform asphalt "A". Calculate the content of chloroform asphalt "A".

[0079] Step 2: freeze-dry the rock sample residue after extraction, weigh it and grind it to 150 mesh by gentle manual method, extract it with a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7 in a Soxhlet extractor for 72 hours to obtain chloroform asphalt "B", and calculate the content of chloroform asphalt "B".

[0080] Step 3: After freeze drying the rock sample residue after extraction, weigh it and place it in a beaker, slowly add 50% hydrochloric acid (volume ratio 1:1) and heat it in a water bath at 85°C for 3 hours, stir it to make it fully react, and ensure that the carbonate minerals are fully dissolved; after cooling, transfer it to a plastic centrifuge bottle, centrifuge to remove the aqueous solution, add ultrapure water and rinse it repeatedly until the solution is neutral. After freeze drying the residue after acid hydrolysis of the sample, use Soxhlet extraction with a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7 for 72 hours. The soluble organic matter obtained is called chloroform asphalt "C", and the content of chloroform asphalt "C" is calculated.

[0081] Step 4. Weigh the remaining rock sample again and place it in a PE plastic bottle. Repeatedly treat it with a mixed solution of hydrofluoric acid and hydrochloric acid (the volume ratio of pure hydrofluoric acid to 50% hydrochloric acid is 1:2) and heat it in an 85°C water bath for 3 hours to completely dissolve the silicate minerals in the rock sample. After freeze-drying the sample residue after acid hydrolysis, Soxhlet extraction is performed for 72 hours using a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7. The soluble organic matter obtained is called chloroform asphalt "D", and the content of chloroform asphalt "D" is calculated.

[0082] Step 5: Take another 100 mg of rock sample powder ground to about 100 mesh and conduct a multi-step pyrolysis experiment at 200°C for 5 min to obtain S 1-1 Then the temperature was raised to 350℃ at 29℃ / min and kept at this temperature for 5min to test S 1-2 Then, the temperature was raised to 450℃ at 29℃ / min and kept at this temperature for 5min to test S 2-1 Finally, the temperature was raised to 600℃ at 29℃ / min to test S 2-2 , S 1-1 , S 1-2 , S 2-1 and S 2-2 The four parameters represent non-polar free hydrocarbons, weakly polar free hydrocarbons, strongly polar adsorbed hydrocarbons and kerogen pyrolysis hydrocarbons.

[0083] Example 6

[0084] In this example, silt-containing shale is used as the rock sample.

[0085] A method for quantitatively characterizing the occurrence state of mixed rock type shale oil comprises the following steps:

[0086] Step 1. Dry 50g of rock sample at 50℃ and crush it into 5-10mm particle size. Use Soxhlet extraction with a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7 for 72h. The soluble organic matter obtained is called chloroform asphalt "A". Calculate the content of chloroform asphalt "A".

[0087] Step 2: freeze-dry the rock sample residue after extraction, weigh it and grind it to 150 mesh by gentle manual method, extract it with a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7 in a Soxhlet extractor for 72 hours to obtain chloroform asphalt "B", and calculate the content of chloroform asphalt "B".

[0088] Step 3: After freeze drying the rock sample residue after extraction, weigh it and place it in a beaker, slowly add 50% hydrochloric acid (volume ratio 1:1) and heat it in a 75℃ water bath for 3h, stir it to make it fully react, and ensure that the carbonate minerals are fully dissolved; after cooling, transfer it to a plastic centrifuge bottle, centrifuge to remove the aqueous solution, add ultrapure water and rinse it repeatedly until the solution is neutral. After freeze drying the residue after acid hydrolysis of the sample, use Soxhlet extraction with a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7 for 72h. The soluble organic matter obtained is called chloroform asphalt "C", and the content of chloroform asphalt "C" is calculated.

[0089] Step 4. Weigh the remaining rock sample again and place it in a PE plastic bottle. Repeatedly treat it with a mixed solution of hydrofluoric acid and hydrochloric acid (the volume ratio of pure hydrofluoric acid to 50% hydrochloric acid is 1:2) and heat it in a 75°C water bath for 3 hours to completely dissolve the silicate minerals in the rock sample. After freeze-drying the sample residue after acid hydrolysis, Soxhlet extraction is performed for 72 hours using a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7. The soluble organic matter obtained is called chloroform asphalt "D", and the content of chloroform asphalt "D" is calculated.

[0090] Step 5: Take another 100 mg of rock sample powder ground to about 100 mesh and conduct a multi-step pyrolysis experiment at 200 °C for 1 min to obtain S 1-1 Then the temperature was raised to 350℃ at 30℃ / min and kept at this temperature for 1min to test S 1-2 Then, the temperature was raised to 450℃ at 30℃ / min and kept at this temperature for 1min to test S 2-1 Finally, the temperature was raised to 600℃ at 30℃ / min to test S 2-2 , S 1-1 , S 1-2 , S2-1 and S 2-2 The four parameters represent non-polar free hydrocarbons, weakly polar free hydrocarbons, strongly polar adsorbed hydrocarbons and kerogen pyrolysis hydrocarbons.

[0091] Example 7

[0092] In this example, shale J-176 is used as the rock sample.

[0093] A method for quantitatively characterizing the occurrence state of mixed rock type shale oil comprises the following steps:

[0094] Step 1. Dry 50g of rock sample at 50℃ and crush it into 5-10mm particle size. Use Soxhlet extraction with a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7 for 72h. The soluble organic matter obtained is called chloroform asphalt "A". Calculate the content of chloroform asphalt "A".

[0095] Step 2: freeze-dry the rock sample residue after extraction, weigh it and grind it to 150 mesh by gentle manual method, extract it with a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7 in a Soxhlet extractor for 72 hours to obtain chloroform asphalt "B", and calculate the content of chloroform asphalt "B".

[0096] Step 3: After freeze drying the rock sample residue after extraction, weigh it and place it in a beaker, slowly add 50% hydrochloric acid (volume ratio 1:1) and heat it in a 70℃ water bath for 3h, stir it to make it fully react, and ensure that the carbonate minerals are fully dissolved; after cooling, transfer it to a plastic centrifuge bottle, centrifuge to remove the aqueous solution, add ultrapure water and rinse it repeatedly until the solution is neutral. After freeze drying the residue after acid hydrolysis of the sample, use Soxhlet extraction with a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7 for 72h. The soluble organic matter obtained is called chloroform asphalt "C", and the content of chloroform asphalt "C" is calculated.

[0097] Step 4. Weigh the remaining rock sample again and place it in a PE plastic bottle. Repeatedly treat it with a mixed solution of hydrofluoric acid and hydrochloric acid (the volume ratio of pure hydrofluoric acid to 50% hydrochloric acid is 1:2) and heat it in a 70°C water bath for 3 hours to completely dissolve the silicate minerals in the rock sample. After freeze-drying the sample residue after acid hydrolysis, Soxhlet extraction is performed for 72 hours using a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7. The soluble organic matter obtained is called chloroform asphalt "D", and the content of chloroform asphalt "D" is calculated.

[0098] Step 5: Take another 100 mg of rock sample powder ground to about 100 mesh and conduct a multi-step pyrolysis experiment at 200°C for 2 min to obtain S 1-1 Then the temperature was raised to 350℃ at 25℃ / min and kept at this temperature for 1min to test S 1-2Then, the temperature was raised to 450℃ at 30℃ / min and kept at this temperature for 3min to test S 2-1 Finally, the temperature was raised to 600℃ at 25℃ / min to test S 2-2 , S 1-1 , S 1-2 , S 2-1 and S 2-2 The four parameters represent non-polar free hydrocarbons, weakly polar free hydrocarbons, strongly polar adsorbed hydrocarbons and kerogen pyrolysis hydrocarbons.

[0099] Example 8

[0100] In this example, silt-containing dolomitic mudstone is used as the rock sample.

[0101] A method for quantitatively characterizing the occurrence state of mixed rock type shale oil comprises the following steps:

[0102] Step 1. Dry 50g of rock sample at 50℃ and crush it into 5-10mm particle size. Use Soxhlet extraction with a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7 for 72h. The soluble organic matter obtained is called chloroform asphalt "A". Calculate the content of chloroform asphalt "A".

[0103] Step 2: freeze-dry the rock sample residue after extraction, weigh it and grind it to 150 mesh by gentle manual method, extract it with a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7 in a Soxhlet extractor for 72 hours to obtain chloroform asphalt "B", and calculate the content of chloroform asphalt "B".

[0104] Step 3: After freeze-drying the rock sample residue after extraction, weigh it and place it in a beaker, slowly add 50% hydrochloric acid (volume ratio 1:1) and heat it in an 80℃ water bath for 3h, stir it to make it fully react, and ensure that the carbonate minerals are fully dissolved; after cooling, transfer it to a plastic centrifuge bottle, centrifuge to remove the aqueous solution, add ultrapure water and rinse it repeatedly until the solution is neutral. After freeze-drying the residue after acid hydrolysis of the sample, use Soxhlet extraction with a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7 for 72h. The soluble organic matter obtained is called chloroform asphalt "C", and the content of chloroform asphalt "C" is calculated.

[0105] Step 4. Weigh the remaining rock sample again and place it in a PE plastic bottle. Repeatedly treat it with a mixed solution of hydrofluoric acid and hydrochloric acid (the volume ratio of pure hydrofluoric acid to 50% hydrochloric acid is 1:2) and heat it in an 80°C water bath for 3 hours to completely dissolve the silicate minerals in the rock sample. After freeze-drying the sample residue after acid hydrolysis, Soxhlet extraction is performed for 72 hours using a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7. The soluble organic matter obtained is called chloroform asphalt "D", and the content of chloroform asphalt "D" is calculated.

[0106] Step 5: Take another 100 mg of rock sample powder ground to about 100 mesh and conduct a multi-step pyrolysis experiment at 200 °C for 1 min to obtain S 1-1 Then the temperature was raised to 350℃ at 25℃ / min and kept at this temperature for 1min to test S 1-2 Then, the temperature was raised to 450℃ at 25℃ / min and kept at this temperature for 1min to test S 2-1 Finally, the temperature was raised to 600℃ at 25℃ / min to test S 2-2 , S 1-1 , S 1-2 , S 2-1 and S 2-2 The four parameters represent non-polar free hydrocarbons, weakly polar free hydrocarbons, strongly polar adsorbed hydrocarbons and kerogen pyrolysis hydrocarbons.

[0107] Example 9

[0108] In this example, dolomitized silty mudstone is used as the rock sample.

[0109] A method for quantitatively characterizing the occurrence state of mixed rock type shale oil comprises the following steps:

[0110] Step 1. Dry 50g of rock sample at 50℃ and crush it into 5-10mm particle size. Use Soxhlet extraction with a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7 for 72h. The soluble organic matter obtained is called chloroform asphalt "A". Calculate the content of chloroform asphalt "A".

[0111] Step 2: freeze-dry the rock sample residue after extraction, weigh it and grind it to 150 mesh by gentle manual method, extract it with a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7 in a Soxhlet extractor for 72 hours to obtain chloroform asphalt "B", and calculate the content of chloroform asphalt "B".

[0112] Step 3: After freeze drying the rock sample residue after extraction, weigh it and place it in a beaker, slowly add 50% hydrochloric acid (volume ratio 1:1) and heat it in a water bath at 85°C for 3 hours, stir it to make it fully react, and ensure that the carbonate minerals are fully dissolved; after cooling, transfer it to a plastic centrifuge bottle, centrifuge to remove the aqueous solution, add ultrapure water and rinse it repeatedly until the solution is neutral. After freeze drying the residue after acid hydrolysis of the sample, use Soxhlet extraction with a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7 for 72 hours. The soluble organic matter obtained is called chloroform asphalt "C", and the content of chloroform asphalt "C" is calculated.

[0113] Step 4. Weigh the remaining rock sample again and place it in a PE plastic bottle. Repeatedly treat it with a mixed solution of hydrofluoric acid and hydrochloric acid (the volume ratio of pure hydrofluoric acid to 50% hydrochloric acid is 1:2) and heat it in an 85°C water bath for 3 hours to completely dissolve the silicate minerals in the rock sample. After freeze-drying the sample residue after acid hydrolysis, Soxhlet extraction is performed for 72 hours using a mixed reagent of dichloromethane and methanol in a volume ratio of 93:7. The soluble organic matter obtained is called chloroform asphalt "D", and the content of chloroform asphalt "D" is calculated.

[0114] Step 5: Take another 100 mg of rock sample powder ground to about 100 mesh and conduct a multi-step pyrolysis experiment at 200 °C for 1 min to obtain S 1-1 Then the temperature was raised to 350℃ at 25℃ / min and kept at this temperature for 1min to test S 1-2 Then, the temperature was raised to 450℃ at 25℃ / min and kept at this temperature for 1min to test S 2-1 Finally, the temperature was raised to 600℃ at 25℃ / min to test S 2-2 , S 1-1 , S 1-2 , S 2-1 and S 2-2 The four parameters represent non-polar free hydrocarbons, weakly polar free hydrocarbons, strongly polar adsorbed hydrocarbons and kerogen pyrolysis hydrocarbons.

[0115] The above embodiment takes the mixed sedimentary rock shale oil of the Lucaogou Formation in the Jimusar Sag as an example, and selects 9 samples of different lithofacies for multi-solvent step-by-step extraction experiments, which can intuitively obtain the proportion of hydrocarbons in different occurrence states in different lithofacies samples (Figure 2), so as to intuitively reflect the favorable lithofacies in the mixed sedimentary rock shale oil formation that are more conducive to production and utilization. For example, the content of chloroform asphalt "A" in silty mud limestone (sample number J-127), calcite dolomite (sample number J-138), and dolomitic siltstone (sample number J-140) is greater than 70%, indicating that the free oil content in the large pores and fractures of carbonate rocks and siltstones is high, higher than that of mudstone, and is the main lithofacies of the high-quality sweet spot section of the Lucaogou Formation.

[0116] The present invention takes the mixed sedimentary shale oil of Lucaogou Formation in Jimusar Depression as an example, and compares the ratio of free oil to total oil obtained from 9 samples of different lithofacies, and finds that they have good synergy ( Figure 3 ; Table 1), which verifies the reliability of this method.

[0117] Table 1

[0118]

[0119] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for quantitatively characterizing the occurrence state of mixed rock type shale oil, characterized in that: The following steps are involved: Step 1: crush the rock sample after drying, and use reagents to perform Soxhlet extraction. The soluble organic matter obtained is called chloroform asphalt "A" and the primary rock sample residue. Calculate the content of chloroform asphalt "A"; Step 2: freeze-dry the primary rock sample residue, weigh and grind it, and then use a reagent to perform Soxhlet extraction to obtain chloroform asphalt "B" and secondary rock sample residue, and calculate the content of chloroform asphalt "B"; Step 3, freeze-dry the secondary rock sample residue after extraction, weigh it and place it in a container for acid hydrolysis; freeze-dry the residue after acid hydrolysis of the sample, extract it with a reagent Soxhlet, and the soluble organic matter obtained is called chloroform asphalt "C" and the residual rock sample, and calculate the content of chloroform asphalt "C"; Step 4: Weigh the remaining rock sample again and place it in a container, and hydrolyze it with a mixed solution of hydrofluoric acid and hydrochloric acid. After freeze-drying the sample residue after acid hydrolysis, extract it with a Soxhlet reagent. The soluble organic matter obtained is called chloroform asphalt "D". Calculate the content of chloroform asphalt "D".

2. The method for quantitatively characterizing the occurrence state of mixed rock type shale oil according to claim 1, characterized in that: In the step 1, the reagent is a mixed reagent of dichloromethane and methanol in a volume ratio of 93:

7.

3. The method for quantitatively characterizing the occurrence state of mixed rock type shale oil according to claim 1, characterized in that: In the step 1, the Soxhlet extraction time is 36h-72h.

4. The method for quantitatively characterizing the occurrence state of mixed rock type shale oil according to claim 1, characterized in that: In the step 2, the primary rock sample residue is ground manually.

5. The method for quantitatively characterizing the occurrence state of mixed rock type shale oil according to claim 1, characterized in that: In step 3, the acid hydrolysis process is as follows: adding hydrochloric acid to a container and heating it in a water bath at 70° C.-90° C., stirring to fully dissolve the carbonate minerals; centrifuging to remove the aqueous solution after cooling, and repeatedly rinsing until the solution is neutral.

6. A method for quantitatively characterizing the occurrence state of mixed rock type shale oil according to claim 6, characterized in that: In the step 3, the hydrochloric acid is 50% hydrochloric acid.

7. The method for quantitatively characterizing the occurrence state of mixed rock type shale oil according to claim 1, characterized in that: In step 4, the acidolysis process is: repeatedly treating with a mixed solution of hydrofluoric acid and hydrochloric acid, and heating in a water bath at 70° C.-90° C. to completely dissolve the silicate minerals in the rock sample.

8. The method for quantitatively characterizing the occurrence state of mixed rock type shale oil according to claim 7, characterized in that: In step 4, in the mixed solution of hydrofluoric acid and hydrochloric acid, the volume ratio of pure hydrofluoric acid to 50% hydrochloric acid is 1:

2.

9. The method for quantitatively characterizing the occurrence state of mixed rock type shale oil according to claim 1, characterized in that: After step 4 is completed, another rock sample powder is taken for multi-step pyrolysis to obtain non-polar free hydrocarbons, weakly polar free hydrocarbons, strongly polar adsorbed hydrocarbons and kerogen pyrolysis hydrocarbons. The ratio of free hydrocarbons to total retained hydrocarbons obtained by multi-step pyrolysis is compared with the step-by-step extraction results to determine whether the change trends of the two are the same; The ratio of free hydrocarbons to total retained hydrocarbons obtained by multi-stage pyrolysis is: (S 1-1 +S 1-2 ) / (S 1-1 +S 1-2 +S 2-1 ); The step-by-step extraction results are: (A+B) / (A+B+C+D); Among them, S 1-1 is the content of non-polar free hydrocarbons, S 1-2 is the content of weakly polar free hydrocarbons, S 2-1 is the content of adsorbed hydrocarbons with strong polarity, S 2-1 is the content of hydrocarbons generated by kerogen pyrolysis; A is the content of chloroform asphalt "A", B is the content of chloroform asphalt "B", C is the content of chloroform asphalt "C", and D is the content of chloroform asphalt "D".

10. A method for quantitatively characterizing the occurrence state of mixed rock type shale oil according to claim 9, characterized in that: Keep the temperature at 200℃ for 1min-5min to obtain non-polar free hydrocarbons, then increase the temperature to 350℃ at 25℃ / min-30℃ / min and keep the temperature at 1min-5min to obtain weak polar free hydrocarbons, then increase the temperature to 450℃ at 25℃ / min-30℃ / min and keep the temperature at 1min-5min to obtain strongly polar adsorbed hydrocarbons S 2-1 Finally, the temperature is raised to 600°C at a rate of 25°C / min-30°C / min to obtain kerogen pyrolysis and hydrocarbon generation.

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