Liquid activator for improving the recovery rate of low-mature shale oil and gas and application thereof

Abstract

This invention relates to the field of in-situ extraction of unconventional oil and gas resources and in-situ pyrolysis conversion of medium- and low-maturity shale oil. The invention provides a liquid activator for improving the recovery rate of medium- and low-maturity shale oil and gas and its application. Medium- and low-maturity shale is pretreated by impregnation with a 1-10% (w / w) hydrogen peroxide solution, followed by freeze-drying to obtain a shale mixture. The resulting shale mixture is then subjected to pyrolysis under specific temperature, pressure, nitrogen atmosphere, and semi-closed conditions. After pyrolysis, the resulting oil and gas products are collected. This invention utilizes hydrogen peroxide for pre-oxidation etching of the organic matter structure and in-situ activation modification of minerals, effectively reducing the pyrolysis activation energy of organic matter and significantly improving the pyrolysis conversion efficiency of kerogen in medium- and low-maturity shale.

Description

Technical Field

[0001] This invention relates to the field of in-situ extraction of unconventional oil and gas resources and in-situ pyrolysis conversion of medium- and low-maturity shale oil, specifically to a liquid activator for improving the recovery rate of medium- and low-maturity shale oil and gas and its application. Background Technology

[0002] After years of intensive exploration and exploitation, the high-quality, shallow, and easily exploitable reserves of traditional conventional oil and gas resources have become increasingly depleted. The remaining recoverable resources are buried at increasingly deeper depths and the geological conditions are becoming more complex, which directly leads to a continuous increase in the difficulty of exploration and development, and a significant increase in extraction and operation and maintenance costs year by year. The structural gap between global oil and gas supply and demand continues to widen.

[0003] Medium- and low-maturity shale, as a high-quality unconventional oil and gas strategic replacement resource with extremely large global reserves, has an in-situ convertible oil and gas resource volume approaching the total recoverable conventional oil reserves. It is an ideal alternative to alleviate the current energy shortage and make up for the oil and gas supply gap. However, most of the shale currently under development belongs to medium- and low-maturity reservoirs, which generally suffer from inherent shortcomings such as overall dense formations, poor pore structure development, weak pore throat connectivity, high threshold for organic matter hydrocarbon generation and conversion, and great difficulty in deep in-situ quality improvement. Traditional surface dry distillation extraction technology is not only extremely energy-intensive, but also has many drawbacks such as large land area, difficulty in tailings disposal, and serious ecological damage. These problems seriously restrict the large-scale green commercialization and application of medium- and low-maturity shale resources. Therefore, developing low-energy-consumption, low-pollution, and high-efficiency in-situ conversion and extraction technology for medium- and low-maturity shale has become an urgent and pressing direction in the field of unconventional energy development worldwide.

[0004] In in-situ pyrolysis of medium- and low-maturity shale, highly efficient activation catalysts can further determine the reservoir stimulation effect, organic matter cracking efficiency, pyrolysis product quality, and ultimately, oil and gas recovery rate. Currently, most existing catalytic materials in the industry are solid powder catalysts. Common solid powder catalysts mainly cover three major systems: transition metal oxides and salts, acidic molecular sieves / zeolites, and alkali metal / alkaline earth metals. Transition metal systems, represented by nano-zero-valent iron, nickel oxide, cobalt oxide, ferric oxide, and nickel chloride, promote the conversion of heavy components to light hydrocarbons by lowering the activation energy of kerogen cracking. Acidic molecular sieve systems, represented by HZSM-5, ultrastable Y-type molecular sieves, and Beta molecular sieves, can significantly improve the yield of light hydrocarbons. Alkali metal / alkaline earth metal systems, represented by potassium carbonate, sodium carbonate, and calcium oxide, can promote the release of CO and H2, but at high temperatures, they are prone to sintering reactions with shale silicate minerals, leading to deactivation. However, existing solid powder catalysts generally have inherent defects such as high resistance to diffusion in deep formations, easy clogging of near-well throats, difficulty in uniformly spreading to deep reservoirs far from the well, and limited activation coverage. They can only produce quality improvement effects on a small area of ​​ore around the wellbore, and it is difficult to achieve uniform catalytic transformation over a large area and throughout the entire formation. As a result, the overall production increase and quality improvement effect is difficult to meet the expectations for industrialization. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a liquid activator and its application for improving the recovery rate of medium- and low-maturity shale oil and gas. This activator can diffuse and permeate uniformly over a long distance and over a wide area in porous formation media with low resistance, significantly reducing the pyrolysis activation energy of organic matter.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows.

[0007] The first aspect of this invention provides a method for improving the recovery rate of oil and gas in medium- and low-maturity shale, comprising the following steps: Liquid activator is injected into the medium-low maturity oil shale formation via continuous injection, allowing the liquid activator to penetrate into the shale pores and fractures. The organic matter is oxidized and activated at a temperature of 350℃~450℃. After removing the residual liquid activator by backflow or inert gas replacement, the activated low maturity oil shale formation is obtained. The activated low-maturity oil shale formation is heated and pyrolyzed under a protective atmosphere to convert organic matter into oil and gas products. The generated volatile products are extracted, condensed and separated to obtain liquid and gaseous products.

[0008] Specifically, the above-mentioned liquid activator is used to improve the recovery rate of medium- and low-maturity shale oil and gas in both experimental and actual mining environments.

[0009] Under experimental conditions, a liquid activator was injected into mined medium- to low-maturity shale samples for impregnation. A pyrolysis reaction was then carried out under a protective atmosphere. The pyrolysis products were condensed to obtain liquid products and uncondensed gaseous products. The mass-to-volume ratio of hydrogen peroxide in the medium- to low-maturity shale sample to that in the liquid activator was 30–100 g: 0.03–16.

[0010] In real-world environments, during the in-situ pyrolysis of oil shale underground, injection wells, production wells, and heating wells (electric / gas / steam) are arranged underground. The liquid activator is not injected all at once. In actual engineering, water is first pre-injected into the injection well at 1MPa–5MPa to open the channel, and then the liquid activator is continuously injected into the medium-to-low maturity oil shale formation, allowing it to fully penetrate the shale pores and fractures. It is important to note that the injection rate of the liquid activator is determined by reservoir permeability, fracture development, injection pressure, and target impregnation time. During continuous injection, the concentrations of key elements (Si, Al, Ca, Mg) in the return fluid samples from the production well outlet are collected and tested at the surface. When the ion concentration in the return fluid tends to stabilize, it indicates that the effect of the H2O2 activator on the reservoir has reached its limit, and injection can be stopped.

[0011] Organic matter is oxidized and activated at temperatures of 350℃ to 450℃ to promote kerogen structural fracture, improve reservoir permeability, and reduce the difficulty of subsequent pyrolysis. Specifically, actual underground engineering requires prolonged and continuous heating of the reservoir, with pyrolysis cycles typically lasting several months. On-site shutdown is not based on a predetermined timeframe. The pyrolysis reaction is considered complete only when the daily oil and gas production rate declines to below 5% to 10% of its peak value for several consecutive days, the convertible kerogen in the reservoir is essentially completely pyrolyzed, and the formation temperature remains consistently high with no signs of new oil and gas production. After the reaction, residual activators are removed through flowback or replacement with inert gas N2. The activated oil shale is then heated and pyrolyzed under a protective atmosphere to convert organic matter into oil and gas products. The generated volatile products are extracted, condensed, and separated to ultimately obtain liquid shale oil and uncondensed gas.

[0012] In another preferred embodiment, the hydrogen peroxide is a hydrogen peroxide solution with a mass percentage of 1% to 10%. The 1% to 10% hydrogen peroxide solution in this invention exhibits strong diffusion ability in deep underground environments, in-situ pore-forming and permeability-enhancing properties, and a self-feedback diffusion effect. It can also diffuse uniformly into deep reservoirs. Furthermore, at this concentration, it exhibits high autocatalytic activity, with no residue or harmful substances generated after the reaction. This effectively solves the problems of difficult diffusion, easy pore blockage, low activity, and high pollution associated with traditional solid catalysts.

[0013] In another preferred embodiment, the pressure of the pyrolysis reaction is 1 MPa to 5 MPa.

[0014] In another preferred embodiment, the temperature of the pyrolysis reaction is 350°C to 650°C, and the time is 2h to 4h.

[0015] In another preferred embodiment, the heating rate of the pyrolysis is 5°C / min to 10°C / min.

[0016] In another preferred embodiment, the protective atmosphere is at least one of nitrogen, helium, and argon.

[0017] In another preferred embodiment, the condensation temperature is -10°C to -60°C.

[0018] In another preferred embodiment, the liquid product is pyrolysis oil and the gaseous product is pyrolysis gas.

[0019] In another preferred embodiment, the pyrolysis oil includes gasoline, diesel, lubricating oil, and heavy oil; The pyrolysis gas includes hydrogen, carbon dioxide, methane, dienes, ethane, propane, and C4 components.

[0020] A second aspect of the present invention provides a liquid activator for improving the recovery rate of medium- and low-maturity shale oil and gas, wherein the liquid activator is the aforementioned hydrogen peroxide solution; The liquid activator is used for in-situ extraction of pyrolysis oil and gas products from medium- and low-maturity shale.

[0021] In another preferred embodiment, the medium-low maturity shale is shale with a vitrinite reflectance ≤1.0%.

[0022] Compared with the prior art, the present invention has the following beneficial effects: This invention selects hydrogen peroxide as a liquid activator and applies it to the extraction of oil and gas from medium- and low-maturity shale. It effectively solves the problems commonly found with solid powder catalysts, such as high resistance to deep formation seepage and diffusion, easy clogging of near-wellbore throats, difficulty in uniformly spreading to deeper reservoirs, and limited activation coverage. The choice of hydrogen peroxide to replace existing solid powder catalysts offers several advantages: firstly, this liquid activator possesses excellent deep formation seepage and diffusion capabilities, enabling uniform activation and coverage over a large area of ​​the reservoir; secondly, it can simultaneously dissolve the pore structure of shale, facilitating efficient pyrolysis oil and gas production; thirdly, it can in-situ activate and transform primary pyrite to generate iron-based active catalytic sites, constructing a free radical synergistic catalytic system, significantly reducing the activation energy of organic matter pyrolysis, and improving the yield and quality of light oil; and fourthly, the liquid activator offers a simple, environmentally friendly, and compliant process during extraction, making it suitable for large-scale, green in-situ extraction of medium- and low-maturity shale, possessing high theoretical value and promising industrial application prospects.

[0023] In this invention, a hydrogen peroxide solution with a mass percentage of 1% to 10% is selected as the liquid activator. This is because it has strong diffusion ability in deep underground areas, can create pores and enhance permeability in situ, forming a self-feedback diffusion effect, and can diffuse uniformly into deep reservoirs. Moreover, at this concentration, it has high autocatalytic activity, and there are no residues or harmful substances generated after the reaction. This can effectively solve the problems of difficult diffusion, easy pore blockage, low activity, and high pollution of traditional solid catalysts. Attached Figure Description

[0024] Figure 1 A comparison chart of pyrolysis oil and gas recovery rates from in-situ pyrolysis conversion in embodiments provided by the present invention.

[0025] Figure 2 A comparative diagram of simulated distillation of pyrolysis oil from in-situ pyrolysis conversion provided by the present invention.

[0026] Figure 3 The diagram shows the composition of the pyrolysis gas products of the in-situ pyrolysis conversion method provided by the present invention.

[0027] Figure 4 X-ray diffraction pattern of shale provided in the embodiments of the present invention.

[0028] Figure 5 Comparison of thermogravimetric and micro-thermogravimetric analyses of shale residue after in-situ pyrolysis and conversion reaction in embodiments provided by the present invention.

[0029] Figure 6 The following are electron paramagnetic resonance (EPR) images of shale rocks provided in the embodiments of the present invention; a is a magnetic field intensity image, and b is a g-value image. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0031] Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0032] Shale, as a key unconventional oil and gas resource with extremely abundant reserves, possesses enormous resource potential and strategic substitution value. However, shale resources with medium to low maturity (vitrinite reflectance Ro≤1.0%) generally suffer from inherent defects such as low organic matter evolution, stable and inert kerogen molecular structure, and poor reservoir porosity development. These defects result in high in-situ pyrolysis activation energy, extremely poor oil and gas flowability, and very low conventional pyrolysis conversion efficiency, severely restricting the economical and effective development of the resources. Therefore, developing efficient in-situ activation and upgrading technologies to break through the large molecular kerogen barrier and directionally convert heavy components into light, low molecular weight hydrocarbons, thereby optimizing deep reservoir porosity and efficiently releasing shale oil, is of crucial practical significance for promoting the green, efficient, and large-scale development and utilization of medium to low maturity shale resources.

[0033] The pyrolysis of shale mainly consists of three stages. Below 350℃, the weight of shale decreases slightly, primarily due to the reduction of moisture in the first stage. Between 350℃ and 550℃, shale experiences a significant weight loss, mainly attributed to the pyrolysis of kerogen, a large organic molecule in the shale. In this stage, kerogen molecules break down into asphaltenes, which further pyrolyze into shale oil. Above 550℃, the decomposition of inorganic materials, including clay minerals, carbonate minerals, and sulfide minerals, occurs.

[0034] This invention, through experimental analysis, reveals that the second stage is the crucial stage for the generation of shale oil and gas. However, existing in-situ pyrolysis catalysts for medium- and low-maturity shale generally suffer from bottlenecks due to weak formation diffusion capacity, limited penetration distance, insufficient catalytic efficiency, and difficulty in achieving both environmental protection and economic efficiency. These challenges make it difficult to meet the demands for efficient, green, and large-scale in-situ mining. Therefore, developing novel in-situ catalytic systems that can penetrate deeply, activate throughout the entire formation, are green and economical, and are highly compatible with the formation has become a key technological direction for the efficient development of medium- and low-maturity shale.

[0035] Based on this, the present invention proposes hydrogen peroxide as an in-situ pyrolysis liquid phase activation system for medium- and low-maturity shale. This liquid activator has outstanding advantages such as strong diffusion ability in deep underground, in-situ pore-forming and permeability enhancement, forming a self-feedback diffusion effect, promoting uniform diffusion of the activator into the deep reservoir, high autocatalytic activity, green and residue-free, safe and compliant, and simple process. It can effectively solve the bottlenecks of traditional solid catalysts such as difficult diffusion, easy pore blockage, low activity, and high pollution. It is particularly suitable for in-situ high-efficiency quality improvement mining of medium- and low-maturity shale, and has significant innovation and industrial application prospects.

[0036] Example 1: A method for improving the recovery rate of oil and gas in medium- and low-maturity shale. This method is conducted under laboratory conditions and includes the following steps: Step 1): Weigh 3g of hydrogen peroxide solution, impregnate 100g of shale, and then freeze-dry to obtain a mixture, denoted as OS0.03, where 0.03 is the mass ratio of H2O2 to shale. The mass percentage of hydrogen peroxide solution is 6%.

[0037] Step 2): Load the mixture into the semi-closed experimental apparatus reactor, introduce nitrogen into the reactor for 5 minutes to replace the air, and then continue to introduce nitrogen into the reactor until the initial pressure is 2.5 MPa. Use a heating mantle to control the temperature of the reactor to 450°C, and adjust the back pressure valve to stabilize the reaction pressure at 7 MPa. Carry out the pyrolysis reaction for 3 hours. After the reaction is completed, wait for the reactor to cool to room temperature and collect the pyrolysis oil and gas products.

[0038] Example 2: A method for improving the recovery rate of medium- and low-maturity shale oil and gas. This method is carried out in a laboratory environment. The operation steps of this example are basically the same as those of Example 1, except that the hydrogen peroxide content used in step 1 is 8g (OS 0.08).

[0039] Example 3: A method for improving the recovery rate of medium- and low-maturity shale oil and gas. This method is performed under laboratory conditions. The operation steps in this example are basically the same as those in Example 1, except that the hydrogen peroxide content used in step 1 is 12g (OS 0.12).

[0040] Example 4: A method for improving the recovery rate of medium- and low-maturity shale oil and gas. This method is performed under laboratory conditions. The operation steps in this example are basically the same as those in Example 1, except that the hydrogen peroxide content used in step 1 is 14g (OS 0.14).

[0041] Example 5: A method for improving the recovery rate of medium- and low-maturity shale oil and gas. This method is performed under laboratory conditions. The operation steps in this example are basically the same as those in Example 1, except that the hydrogen peroxide content used in step 1 is 16g (OS 0.16).

[0042] Comparative Example 1 The operation steps of this comparative example are basically the same as those of Example 1, except that in step 1, hydrogen peroxide is not used to impregnate the shale. Instead, the shale is directly loaded into the semi-closed experimental apparatus reactor, and nitrogen is introduced into the reactor for 5 minutes to replace the air. Then, nitrogen is continued to be introduced into the reactor until the initial pressure reaches 2.5 MPa. The temperature of the reactor is controlled to 450°C using a heating mantle, and the back pressure valve is adjusted to stabilize the reaction pressure at 7 MPa. The pyrolysis reaction is carried out for 3 hours. After the reaction is completed, the reactor is allowed to cool to room temperature, and the pyrolysis oil and gas products are collected.

[0043] Figure 1The figure shows the effect of different hydrogen peroxide contents on in-situ pyrolysis of medium and low maturity shale. Compared with the comparative example, the oil and gas recovery rate of the example with hydrogen peroxide content of 12g is the highest at 6.91%, of which the pyrolysis oil recovery rate is 1.49% and the pyrolysis gas recovery rate is 5.42%, which is 11.82% higher than that of the comparative example.

[0044] Figure 2 The results show the distillation range of the obtained pyrolysis oil products obtained by simulated distillation chromatography. Examples 1-5 and the comparative examples are as follows: gasoline (C5-C12) 47%, 47%, 45%, 47%, 48%, 38%; diesel (C12-C22) 34%, 37%, 36%, 35%, 38%; lubricating oil (C22-C30) 12%, 11%, 13%, 13%, 11%, 13%; heavy oil (C30 and above) 15%, 7%, 3%, 6%, 7%, 1%.

[0045] Figure 3 The figures show the gas components and contents detected by gas chromatography analysis of the pyrolysis gases of Examples 1-5 and the comparative examples.

[0046] Figure 4 The X-ray diffraction patterns of the shale before reaction in Example 3 and the comparative example are shown. After hydrogen peroxide treatment, the intensity of the pyrite standard characteristic diffraction peak of the shale was significantly reduced.

[0047] Figure 5 The results of thermogravimetric analysis (TGA) and micro-scale thermogravimetric analysis (DTG) of shale residues after the reactions in Examples 1-5 and the comparative examples are shown. In Example 1, the weight loss of the treated shale was 12.75%, which was slightly higher than the original 12.44%, indicating that during the organic matter pyrolysis stage (300-600℃), the content of unreacted organic matter in Example 1 was higher than that before treatment, and the shale pyrolysis in Example 1 had a slight inhibitory effect. In Examples 2-5, the weight loss of shale was reduced, indicating that hydrogen peroxide had played a role in the shale pyrolysis stage, promoting the decomposition of kerogen in the shale and converting more organic matter into oil and gas products during the pyrolysis process. Therefore, the content of residual pyrolytic organic matter / fixed carbon in the final semi-coke was significantly reduced, with the most significant reduction in shale weight loss observed in Example 3.

[0048] Figure 6The figure shows the electron paramagnetic resonance (EPR) spectra of the shale before reaction in Example 3 and the comparative example. As can be seen from the figure, the free radical signal intensity of the modified shale is significantly reduced. This is because a large number of hydroxyl radicals (·OH) are generated during the H2O2 activation process. These radicals preferentially act on the unpaired electrons on the aromatic rings and fused ring macromolecules of kerogen, selectively quenching inert free radicals that are stable at room temperature and hardly participate in pyrolysis to generate hydrocarbons. At the same time, ·OH can destroy the cross-linked framework of kerogen macromolecules, introducing oxygen-containing weak bond functional groups; and simultaneously etching pyrite crystals, optimizing the pore structure, and forming iron-based catalytic active sites in situ. The synergistic changes in the organic matter molecular structure, surface functional groups, and mineral microenvironment reduce the thermal stability and pyrolysis activation energy of kerogen, making it easier for chemical bonds to break during programmed temperature pyrolysis, generating a large number of new active free radicals, and thus significantly promoting the macromolecular cracking of oil shale and the generation of light oil and gas products.

[0049] Examples 1 to 5 above represent small-scale simulations of an underground in-situ pyrolysis process, i.e., processes under experimental conditions. Each step has a corresponding component in actual underground applications, but the implementation methods differ. The actual operation will be described step-by-step in accordance with Example 1 below. Specifically, the specific operation process under actual conditions is as follows:

[0050] Step 1) involves impregnating the shale with an H2O2 solution to allow the activator to penetrate the shale and contact the organic matter. In practical applications, a 6% (w / w) H2O2 solution is injected into the shale layer via an injection well. Formation pressure and fracture seepage allow the solution to penetrate the pores. The concentrations of key elements (Si, Al, Ca, Mg) in the return fluid from the production well are collected and monitored. When the ion concentrations in the return fluid stabilize, it indicates that the H2O2 solution has reached its limit for its effect on the reservoir, and injection can be stopped. In Example 1, step 1) involves freeze-drying the sample to obtain OS0.03 to remove moisture and fix the contact state between the activator and the shale. In actual underground environments, the sample is usually not dried but directly impregnated in a water-bearing environment. Subsequent flowback reduces the impact of residual liquid.

[0051] Step 2) In the actual corresponding underground closed / semi-closed reservoir area, a fracture network + caprock is used to form a confined space. Underground, nitrogen or inert gas is pre-injected / replaced to reduce oxygen content. Formation pressure or injection pressure is maintained through gas / liquid injection. Heating is performed using any of the following methods: heated wells, electric heating, or radio frequency heating, gradually raising the target area to 450°C. Caprock sealing and formation pressure control prevent premature product escape. When the daily oil and gas production rate continuously declines to below 5%~10% of its peak value for several days, the convertible kerogen in the reservoir is essentially completely pyrolyzed, and the formation temperature remains at a sustained low for an extended period without any new oil and gas production, the pyrolysis reaction can be considered terminated, and heating operations can be stopped. Oil and gas products are continuously produced through production wells and collected via surface condensation and separation. Through the above actual extraction process, large-scale, uniform catalytic conversion across the entire formation can be achieved, resulting in significant increases in production and quality.

[0052] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A method for improving the recovery rate of oil and gas in medium- and low-maturity shale, characterized in that, Includes the following steps: A liquid activator is continuously injected into medium- to low-maturity oil shale formations, allowing it to penetrate into the shale pores and fractures. The organic matter is then oxidized and activated at a temperature of 350℃ to 450℃. After removing the residual liquid activator through backflow or inert gas replacement, the activated low-maturity oil shale formation is obtained. The liquid activator is hydrogen peroxide. Under a protective atmosphere, the activated low-maturity oil shale formation is subjected to pyrolysis at 350℃~650℃, which transforms organic matter into oil and gas products. The generated volatile products are extracted, condensed and separated to obtain liquid and gaseous products.

2. The method for improving the recovery rate of medium- and low-maturity shale oil and gas according to claim 1, characterized in that, The hydrogen peroxide is a hydrogen peroxide solution with a mass percentage of 1% to 10%.

3. The method for improving the recovery rate of medium- and low-maturity shale oil and gas according to claim 1, characterized in that, The pressure of the pyrolysis reaction is 1 MPa to 5 MPa.

4. The method for improving the recovery rate of medium- and low-maturity shale oil and gas according to claim 3, characterized in that, The heating rate of the pyrolysis is 5℃ / min to 10℃ / min.

5. The method for improving the recovery rate of medium- and low-maturity shale oil and gas according to claim 1, characterized in that, The protective atmosphere is at least one of nitrogen, helium, and argon.

6. The method for improving the recovery rate of medium- and low-maturity shale oil and gas according to claim 1, characterized in that, The condensation temperature is -10℃ to -60℃.

7. The method for improving the recovery rate of medium- and low-maturity shale oil and gas according to claim 1, characterized in that, The liquid product is pyrolysis oil, and the gaseous product is pyrolysis gas.

8. The method for improving the recovery rate of medium- and low-maturity shale oil and gas according to claim 7, characterized in that, The pyrolysis oil includes gasoline, diesel, lubricating oil, and heavy oil; The pyrolysis gas includes hydrogen, carbon dioxide, methane, dienes, ethane, propane, and C4 components.

9. A liquid activator for improving the recovery rate of medium- and low-maturity shale oil and gas, characterized in that, The liquid activator is the hydrogen peroxide solution according to claim 2; The liquid activator is used for in-situ extraction of pyrolysis oil and gas products from medium- and low-maturity shale.

10. The liquid activator for improving the recovery rate of medium- and low-maturity shale oil and gas according to claim 9, characterized in that, The medium-low maturity shale refers to shale with a vitrinite reflectance of ≤1.0%.

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