A sustained response method for enhanced in situ oil and gas recovery

Abstract

The application provides a method for improving in-situ conversion of oil and gas recovery, which comprises the following steps: impregnating shale with a ferrous sulfate catalyst solution, drying to obtain a mixture, and performing a pyrolysis reaction under a hydrogen condition with hydrogen, and collecting pyrolysis products after the reaction is completed. The method provided by the application utilizes the coupling of a water-soluble ferrous sulfate catalyst and a hydrogen condition to catalyze pyrolysis of shale, reduce the pyrolysis activation energy and pyrolysis temperature of organic matter, and improve the pyrolysis efficiency and oil and gas recovery of shale.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas extraction technology, specifically relating to a sustained-effective method for improving in-situ conversion oil and gas recovery rate. Background Technology

[0002] Oil shale refers to shale buried at depths ranging from several hundred to several thousand meters, rich in thickened liquid petroleum hydrocarbons and unconverted organic matter. The organic matter in the shale has undergone burial and heating (thermal evolution), reaching a medium-to-low maturity stage. At this stage, the organic matter (kerogen) has generated a considerable amount of liquid hydrocarbons (petroleum), but due to the shale's density and extremely low permeability, the generated oil is not fully discharged or migrated to other, more porous reservoirs, but remains trapped in the tiny pores and fractures within the oil-generating shale layer. Oil shale refers to sedimentary rocks (mainly shale or marl) rich in organic matter (primarily kerogen), with the organic matter in oil shale at a very low maturity (immature) stage. The solid kerogen in oil shale contains a large amount of organic matter, which can be converted into oil and gas through processes such as pyrolysis. Medium-to-low maturity shale oil or oil shale resources are vast in scale and are considered a potentially huge unconventional energy resource. However, the extraction of medium-to-low maturity shale oil and the development of oil shale face a series of technical challenges. Due to the poor fluidity of medium- and low-maturity shale oil and the low content of petroleum hydrocarbons in oil shale, it cannot be developed directly using existing extraction technologies like traditional oil and gas resources. Against this backdrop, in-situ pyrolysis technology has become an important research direction in the extraction of medium- and low-maturity shale oil and the development of oil shale.

[0003] CN117358284A discloses a catalyst for reducing the oil production temperature of oil shale pyrolysis, its preparation method, and its application. This pyrolysis method uses Chlorella as a catalyst carrier, loading zinc chloride as the active ingredient, and then mixes the catalyst with oil shale for pyrolysis, thereby improving the pyrolysis efficiency of oil shale. CN118956441A discloses a catalytic pyrolysis method for small-particle oil shale, which involves coating the surface of oil shale powder with a catalyst, performing low-temperature drying, and then fluidized bed roasting to obtain oil shale oil products.

[0004] Introducing in-situ catalytic pyrolysis technology can significantly reduce the activation energy required for the conversion of medium- to low-maturity shale oil shale and oil shale at the thermodynamic level, and promote the directional cracking of kerogen macromolecules at the kinetic level, thereby improving oil and gas recovery rates. However, the application of existing catalyst systems still faces many technical bottlenecks, particularly the poor dispersibility of the catalyst in medium- to low-maturity shale oil shale and oil shale and insufficient contact with kerogen, which seriously affects the efficiency of catalytic cracking reactions and oil and gas recovery. Therefore, developing novel catalyst systems and pyrolysis methods, and optimizing pyrolysis, are key to improving the efficiency of pyrolysis technology. Summary of the Invention

[0005] The purpose of this invention is to provide a sustainable method for improving the recovery rate of oil and gas in situ conversion, thereby enhancing the efficiency of pyrolysis and increasing the recovery rate of shale pyrolysis.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] This invention provides a sustained-effect method for improving in-situ conversion oil and gas recovery, the sustained-effect method comprising the following steps:

[0008] Shale was impregnated with a ferrous sulfate catalyst solution and dried to obtain a mixture. The mixture was then subjected to a pyrolysis reaction with hydrogen under hydrogen conditions. After the reaction was completed, the pyrolysis products were collected.

[0009] This invention develops ferrous sulfate as an active catalyst for shale pyrolysis. Water-soluble ferrous sulfate can penetrate deep into the porous structure of shale, directly contacting the large molecular organic matter kerogen within the shale. Ferrous sulfate exhibits excellent catalytic decomposition activity, accelerating kerogen pyrolysis and reducing the reaction time and temperature. The catalytic activity of ferrous sulfate synergistically works with hydrogen-exposed conditions to promote the conversion of organic kerogen into low-carbon hydrocarbons, thereby improving oil and gas recovery. Furthermore, under hydrogen-exposed conditions, ferrous sulfate demonstrates good stability and long service life, allowing for repeated use and sustained effectiveness.

[0010] Preferably, the vitrinite reflectance Ro of the shale is ≤1.0%, for example, it can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9% or 1.0%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0011] Preferably, the total organic carbon content of the shale is 12-20%, for example, it can be 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0012] Preferably, the hydrocarbon production potential of the shale is ≥65mg / g, for example, it can be 65mg / g, 70mg / g, 75mg / g, 80mg / g, 90mg / g, 100mg / g, 150mg / g, 200mg / g, 250mg / g, 300mg / g, 400mg / g or 500mg / g, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0013] Preferably, the shale has a hydrogen content index ≥450, for example, it can be 450, 480, 500, 550, 600, 700, 800 or 1000, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0014] Preferably, the shale grain size is ≤0.25mm, for example, it can be 0.01mm, 0.03mm, 0.05mm, 0.1mm, 0.15mm, 0.2mm or 0.25mm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0015] Preferably, the shale is crushed and screened.

[0016] Preferably, the mass ratio of ferrous sulfate to shale in the ferrous sulfate catalyst is 1:(20-10000), for example, it can be 1:20, 1:50, 1:100, 1:300, 1:500, 1:800, 1:1000, 1:3000, 1:5000, 1:8000 or 1:10000, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0017] Preferably, the drying method includes freeze drying.

[0018] Preferably, the pyrolysis temperature is 250-650℃, for example, it can be 250℃, 300℃, 350℃, 400℃, 450℃, 500℃, 550℃, 600℃ or 650℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0019] Preferably, the initial pressure of the hydrogen gas is 0.1-5 MPa, for example, it can be 0.1 MPa, 0.5 MPa, 1 MPa, 2 MPa, 3 MPa, 4 MPa or 5 MPa, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0020] Preferably, the pressure of the pyrolysis reaction is 0.1-15 MPa, for example, it can be 0.1 MPa, 0.5 MPa, 1 MPa, 3 MPa, 5 MPa, 8 MPa, 10 MPa, 12 MPa or 15 MPa, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0021] Preferably, the pyrolysis reaction time is 1-3 hours, for example, 1 hour, 1.5 hours, 2 hours, 2.5 hours or 3 hours, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The method provided by this invention utilizes the coupling effect of water-soluble ferrous sulfate catalyst and hydrogen-bearing conditions to catalytically pyrolyze low-maturity shale and oil shale, thereby reducing the pyrolysis activation energy and pyrolysis temperature of organic matter, and improving shale pyrolysis efficiency and oil and gas recovery rate. Attached Figure Description

[0024] Figure 1 This is the X-ray diffraction pattern of the ferrous sulfate catalyst in Example 1;

[0025] Figure 2 This is the Fourier transform infrared spectrum of the ferrous sulfate catalyst in Example 1;

[0026] Figure 3 This is a comparison chart of the pyrolysis oil and gas recovery rates of the sustained-effect methods provided in Example 1 and Comparative Examples 1-2;

[0027] Figure 4 This is a simulated distillation comparison diagram of the pyrolysis oil products of the sustained-effect method provided in Example 1 and Comparative Example 1;

[0028] Figure 5 This is a composition diagram of the pyrolysis gas products of the sustained-effect method provided in Example 1;

[0029] Figure 6 This is a comparison chart of thermogravimetric and micro-thermogravimetric analyses of medium- to low-maturity shale oil shale and oil shale in Example 1 and Comparative Example 1. Detailed Implementation

[0030] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0031] To clearly illustrate the technical solution of the present invention, in a specific embodiment, a shale sample from a certain region was selected, and its vitrinite reflectance (Ro) was measured to be 0.6%, total organic carbon content was 17.3%, hydrocarbon production potential was 69.17 mg / g, and hydrogen index was 467.85.

[0032] Example 1

[0033] This embodiment provides a sustained-effect method for improving in-situ conversion oil and gas recovery, the sustained-effect method comprising the following steps:

[0034] (1) Shale is crushed and sieved using a crusher to obtain shale powder with a particle size of less than 60 mesh (0.25 mm);

[0035] (2) Dissolve 0.03g of ferrous sulfate in water to form a ferrous sulfate catalyst solution, impregnate 30g of shale powder with the ferrous sulfate catalyst solution, and then freeze dry to obtain a mixture, wherein the mass ratio of ferrous sulfate to shale powder is 1:1000;

[0036] (3) Place the obtained mixture into a sealed reactor, introduce hydrogen into the reactor for 5 minutes to replace the air, and then continue to introduce hydrogen until the initial pressure is 2 MPa. Use a heating jacket to control the temperature of the reactor to 450°C, and increase the hydrogen pressure to 5 MPa to carry out the pyrolysis reaction for 3 hours. After the reaction is completed, the reactor is cooled and the pyrolysis oil and gas products are collected.

[0037] In this embodiment, X-ray diffraction analysis was performed on ferrous sulfate, and the obtained X-ray diffraction pattern is shown below. Figure 1 As shown, this indicates that ferrous sulfate is a monoclinic crystal material. The Fourier transform infrared spectrum of ferrous sulfate is as follows: Figure 2 As shown, it includes the characteristic vibrational modes of metal and oxygen, the vibrational mode of anionic sulfate, and the vibrational mode of structural water, indicating that the molecular vibrational modes are consistent with the crystal structure.

[0038] In this embodiment, the pyrolysis oil and gas recovery rate was calculated to be 13.36% based on the collected pyrolysis oil and gas products. Figure 3 As shown, the pyrolysis oil recovery rate was 1.47%, and the pyrolysis gas recovery rate was 11.90%.

[0039] The obtained pyrolysis oil products were analyzed by simulated distillation chromatography, such as... Figure 4 As shown, the distillation range of the pyrolysis oil is obtained: gasoline (C5-C5). 12 24.6%, diesel (C 12 -C 22 30.8%, lubricating oil (C 22 -C 30 33.3%, heavy oil (C 30 above) 11.3%.

[0040] The obtained pyrolysis gas products were analyzed by gas chromatography to determine the gas composition and content, such as... Figure 5 As shown: hydrogen 54.90%, carbon dioxide 3.89%, methane 25.14%, dienes 0.13%, ethane and propane 15.84%, C4 components 0.10%. It can be seen that the pyrolysis gas products are mainly composed of low-carbon alkanes.

[0041] Example 2

[0042] This embodiment provides a sustained-effect method for improving in-situ conversion oil and gas recovery, the sustained-effect method comprising the following steps:

[0043] (1) Shale is crushed and sieved using a crusher to obtain shale powder with a particle size of less than 60 mesh (0.25 mm);

[0044] (2) Dissolve 0.03g of ferrous sulfate in water to form a ferrous sulfate catalyst solution, impregnate 60g of shale powder with the ferrous sulfate catalyst solution, and then freeze dry to obtain a mixture, wherein the mass ratio of ferrous sulfate to shale powder is 1:2000;

[0045] (3) Place the obtained mixture into a sealed reactor, introduce hydrogen into the reactor for 5 minutes to replace the air in it, and then continue to introduce hydrogen until the initial pressure is 5 MPa. Use a heating mantle to control the temperature of the reactor to 350°C, and increase the hydrogen pressure to 15 MPa to carry out the pyrolysis reaction for 2 hours. After the reaction is completed, cool the reactor and collect the pyrolysis oil and gas products.

[0046] In this embodiment, the pyrolysis oil and gas recovery rate was calculated to be 7.28% based on the collected pyrolysis oil and gas products, of which the pyrolysis oil recovery rate was 0.77% and the pyrolysis gas recovery rate was 6.51%.

[0047] The obtained pyrolysis oil products were analyzed by simulated distillation chromatography to obtain the distillation range of the pyrolysis oil: gasoline (C5-C5). 12 26.2%, diesel (C 12 -C 22 33.6%, lubricating oil (C 22 -C 30 32.5%, heavy oil (C 30 above) 7.7%.

[0048] The obtained pyrolysis gas products were analyzed by gas chromatography to determine the gas composition and content: hydrogen 68.06%, carbon dioxide 3.97%, methane 18.27%, dienes 0.05%, ethane and propane 9.62%, and C4 components 0.03%.

[0049] Example 3

[0050] This embodiment provides a sustained-effect method for improving in-situ conversion oil and gas recovery, the sustained-effect method comprising the following steps:

[0051] (1) Shale is crushed and sieved using a crusher to obtain shale powder with a particle size of less than 60 mesh (0.25 mm);

[0052] (2) Dissolve 0.3g of ferrous sulfate in water to form a ferrous sulfate catalyst solution, impregnate 30g of shale powder with the ferrous sulfate catalyst solution, and then freeze dry to obtain a mixture, wherein the mass ratio of ferrous sulfate to shale powder is 1:100;

[0053] (3) Place the obtained mixture into a sealed reactor, introduce hydrogen into the reactor for 5 minutes to replace the air, and then continue to introduce hydrogen until the initial pressure is 1 MPa. Use a heating jacket to control the temperature of the reactor to 650°C, and increase the hydrogen pressure to 2 MPa to carry out the pyrolysis reaction for 1 hour. After the reaction is completed, the reactor is cooled and the pyrolysis oil and gas products are collected.

[0054] In this embodiment, the pyrolysis oil and gas recovery rate was calculated to be 14.83% based on the collected pyrolysis oil and gas products, of which the pyrolysis oil recovery rate was 0.51% and the pyrolysis gas recovery rate was 14.32%.

[0055] The obtained pyrolysis oil products were analyzed by simulated distillation chromatography to obtain the distillation range of the pyrolysis oil: gasoline (C5-C5). 12 25.3%, diesel (C 12 -C 22 32.6%, lubricating oil (C 22 -C 30 31.7%, heavy oil (C 30 above) 10.4%.

[0056] The obtained pyrolysis gas products were analyzed by gas chromatography to determine the gas composition and content: hydrogen 45.1%, carbon dioxide 5.01%, methane 31.36%, dienes 0.09%, ethane and propane 18.37%, and C4 components 0.07%.

[0057] Comparative Example 1

[0058] This comparative example provides a sustained method for improving in-situ conversion oil and gas recovery. Compared with Example 1, the catalyst impregnation in step (2) is not performed, and the shale powder is directly subjected to the pyrolysis reaction in step (3). The rest is the same as Example 1.

[0059] In this comparative example, the recovery rate of pyrolysis oil and gas was calculated to be 10.74% based on the collected pyrolysis oil and gas products. Figure 3 As shown, the pyrolysis oil recovery rate was 1.07%, and the pyrolysis gas recovery rate was 9.67%.

[0060] The obtained pyrolysis oil products were analyzed by simulated distillation chromatography, such as... Figure 4 As shown, the distillation range of the pyrolysis oil is obtained: gasoline (C5-C5). 12 13.6% for diesel (C) 12 -C 22 34.7%, lubricating oil (C 22 -C 30 36.9%, heavy oil (C 30 above) 14.8%.

[0061] The obtained pyrolysis gas products were analyzed by gas chromatography to determine the gas composition and content: hydrogen 63.34%, carbon dioxide 2.07%, methane 19.10%, dienes 0.06%, ethane and propane 12.74%, and C4 components 2.69%.

[0062] Compared to Example 1, in this comparative example, no catalyst impregnation was used, resulting in a significant decrease in pyrolysis efficiency, a decrease in oil and gas recovery rate, an increase in the proportion of heavy oil components such as diesel, and a decrease in oil quality.

[0063] Comparative Example 2

[0064] This comparative example provides a method for improving the sustained effectiveness of in-situ conversion oil and gas recovery. Compared with Example 1, hydrogen is not introduced in step (3), and nitrogen is replaced with hydrogen at the same pressure. All other steps are the same as in Example 1.

[0065] In this comparative example, the collected pyrolysis oil and gas products, such as Figure 3 As shown, the calculated pyrolysis oil and gas recovery rate is 7.65%, of which the pyrolysis oil recovery rate is 0.34% and the pyrolysis gas recovery rate is 7.31%.

[0066] The obtained pyrolysis oil products were analyzed by simulated distillation chromatography to obtain the distillation range of the pyrolysis oil: gasoline (C5-C5). 12 20.6%, diesel (C 12 -C 22 43.6%, lubricating oil (C 22 -C 30 28.9%, heavy oil (C 30 above) 6.9%.

[0067] The obtained pyrolysis gas products were analyzed by gas chromatography to determine the gas composition and content: hydrogen 19.06%, carbon dioxide 17.88%, methane 52.58%, dienes 0.15%, ethane and propane 10.20%, and C4 components 0.11%.

[0068] Compared to Example 1, in this comparative example, pyrolysis was not carried out under hydrogen conditions, resulting in a significant decrease in pyrolysis efficiency and oil and gas recovery rate. At the same time, the proportion of heavy oil components increased, leading to a decrease in oil quality.

[0069] Comparative Example 3

[0070] This comparative example provides a method for improving the sustained effectiveness of in-situ conversion oil and gas recovery. Compared with Example 1, the ferrous sulfate catalyst is replaced with copper oxide powder at the same mass as the ferrous sulfate, and all other aspects are the same as in Example 1.

[0071] In this comparative example, the pyrolysis oil and gas recovery rate was calculated to be 12.24% based on the collected pyrolysis oil and gas products, of which the pyrolysis oil recovery rate was 1.23% and the pyrolysis gas recovery rate was 11.01%.

[0072] The obtained pyrolysis oil products were analyzed by simulated distillation chromatography to obtain the distillation range of the pyrolysis oil: gasoline (C5-C5). 12 20.7%, diesel (C 12 -C 22 28.6%, lubricating oil (C 22 -C 30 35.2%, heavy oil (C 30 above) 15.5%.

[0073] The obtained pyrolysis gas products were analyzed by gas chromatography to determine the gas composition and content: hydrogen 57.20%, carbon dioxide 5.03%, methane 20.86%, dienes 0.08%, ethane and propane 16.76%, and C4 components 0.07%.

[0074] Compared to Example 1, copper oxide was used as a catalyst in this comparative example, and its catalytic pyrolysis effect was far inferior to that of ferrous sulfate catalyst.

[0075] The mixture obtained by impregnating shale with the ferrous sulfate catalyst provided in Example 1 and the shale powder without catalyst provided in Comparative Example 1 were subjected to thermogravimetric analysis (TGA) and derivative thermogravimetric analysis. The results are as follows: Figure 6 As shown, in the first stage of shale pyrolysis (300-480℃), which is mainly the process of kerogen thermally decomposing into asphaltene, the weight loss rate of shale significantly increases after the addition of ferrous sulfate catalyst. Similarly, in the second stage of pyrolysis (480-600℃), which is mainly the process of asphaltene decomposing into oil and gas, the addition of ferrous sulfate catalyst not only increases the weight loss rate but also advances the maximum decomposition temperature by about 10-50℃; furthermore, the total weight loss of shale during the entire pyrolysis process (100-900℃) is further increased.

[0076] The results above demonstrate that ferrous sulfate catalysts significantly promote shale pyrolysis under hydrogen-exposed conditions, effectively improving oil and gas recovery. Under hydrogen-exposed conditions, the ferrous sulfate catalyst significantly enhances mass transfer and reaction kinetics in shale pyrolysis through the synergistic effect of its active sites and hydrogen. Its acidic surface sites effectively adsorb kerogen macromolecules, reducing the activation energy for cracking into asphaltenes; simultaneously, hydrogen participates in the hydrogenation reaction, reducing the formation of heavy coke.

[0077] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for sustained effectiveness in improving in-situ conversion oil and gas recovery, characterized in that, The method for sustained effectiveness includes the following steps: Shale was impregnated with a ferrous sulfate catalyst solution and dried to obtain a mixture. The mixture was then subjected to a pyrolysis reaction with hydrogen under hydrogen conditions. After the reaction was completed, the pyrolysis products were collected.

2. The method for sustained effectiveness according to claim 1, characterized in that, The vitrinite reflectance Ro of the shale is ≤1.0%.

3. The method for sustained effectiveness according to claim 1 or 2, characterized in that, The total organic carbon content of the shale is 12-20%; Preferably, the hydrocarbon production potential of the shale is ≥65mg / g; Preferably, the shale has a hydrogen content index ≥450.

4. The method for sustained effectiveness according to any one of claims 1-3, characterized in that, The shale grain size is ≤0.25mm; Preferably, the shale is crushed and screened.

5. The method for sustained effectiveness according to any one of claims 1-4, characterized in that, The mass ratio of ferrous sulfate to shale in the ferrous sulfate catalyst is 1:(20-10000).

6. The method for sustained effectiveness according to any one of claims 1-5, characterized in that, The drying method includes freeze drying.

7. The method for sustained effectiveness according to any one of claims 1-6, characterized in that, The pyrolysis temperature is 250-650℃.

8. The method for sustained effectiveness according to any one of claims 1-7, characterized in that, The initial pressure of the hydrogen gas is 0.1-5 MPa.

9. The method for sustained effectiveness according to any one of claims 1-8, characterized in that, The pressure of the pyrolysis reaction is 0.1-15 MPa.

10. The method for sustained effectiveness according to any one of claims 1-9, characterized in that, The pyrolysis reaction takes 1-3 hours.

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