A copper-based catalyst for in-situ exploitation of shale and its preparation method and application

Abstract

The present application relates to a kind of copper-based catalyst for in-situ exploitation of shale and its preparation method and application, the copper-based catalyst includes divalent copper ion and the amino-containing organic ligand complexed with the divalent copper ion;The amino-containing organic ligand includes at least four amino;The present application utilizes the copper-based catalyst in-situ exploitation of shale, solve the poor thermal stability of existing oil and gas exploitation catalyst, the problem of low shale pyrolysis efficiency, improve the yield of light oil, inhibit the generation of coke, wherein shale oil production efficiency is preferably up to 0.51% or more, shale gas production efficiency is preferably up to 7.35% or more, and heavy oil yield in the obtained shale oil is as low as 5.31% or less, the hydrocarbon content in the obtained shale gas is preferably up to 68.13% or more, realize the efficient conversion and utilization of shale resources.

Description

Technical Field

[0001] This invention relates to the field of oil and gas extraction technology, and in particular to a copper-based catalyst for in-situ shale extraction, its preparation method, and its application. Background Technology

[0002] The in-situ conversion of medium- and low-maturity shale oil and oil shale yields abundant resources, approximately twice that of conventional oil and gas resources. Organic matter in medium- and low-maturity shale oil and oil shale undergoes thermochemical reactions such as cracking, cyclization, and condensation through high-temperature heating, yielding light oil and shale gas. In-situ conversion technology is a novel, efficient, and environmentally friendly oil and gas extraction technology. Its main principle is to extract oil and gas by heating the organic matter in shale. However, it currently suffers from problems such as high in-situ conversion temperatures, low organic matter conversion efficiency, and poor stability of pyrolysis catalysts. Therefore, to achieve efficient in-situ conversion of organic matter in medium- and low-maturity shale oil and oil shale for efficient oil and gas extraction, researchers are dedicated to developing efficient, stable, and environmentally friendly in-situ conversion pyrolysis catalysts.

[0003] For example, CN108435154A discloses a catalyst for in-situ mining of oil shale and its application method. The catalyst includes magnesium sulfate and water in a mass ratio of 1:(100-1000). The concentration needs to be strictly controlled during use. If the concentration is too high, it can easily lead to crystallization during use, which can block the mining pipeline and the oil and gas seepage channels of the oil shale ore layer. Moreover, harmful gases such as H2S may be generated during the catalytic reaction, which requires additional treatment, thus resulting in higher mining costs.

[0004] For example, CN120054509A discloses an iron-based catalyst for in-situ exploitation of oil shale, its preparation method and application. This iron-based catalyst exists in emulsion form, which requires a long oil and gas recovery time and has a relatively low oil recovery rate under the same time conditions. Moreover, it has poor stability in high temperature and complex underground environments and is prone to deactivation under high temperature and high pressure, requiring regular replacement or regeneration.

[0005] Therefore, how to develop a new catalyst for in-situ shale mining to achieve efficient in-situ conversion of organic matter in shale resources and improve oil and gas recovery rate and quality is an urgent problem to be solved in this field. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a copper-based catalyst for in-situ shale mining, its preparation method, and its application. This solves the problems of poor thermal stability and low shale pyrolysis efficiency of existing oil and gas mining catalysts, improves the yield of light oil, inhibits coke formation, and promotes the efficient conversion and utilization of shale resources.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a copper-based catalyst for in-situ mining of shale, the copper-based catalyst comprising divalent copper ions and an amino-containing organic ligand complexed with the divalent copper ions;

[0009] The amino-containing organic ligand comprises at least four amino groups, for example, four, five, or six.

[0010] The copper-based catalyst of this invention has a layered structure with divalent copper ions as the core and amino-containing organic ligands as complexing agents. It has a high specific surface area, abundant catalytic active sites, and good thermal stability. By selecting organic ligands containing at least four amino groups to complex with divalent copper ions, the redox effect of the divalent copper ions and the directional adsorption of nitrogen atoms of the amino-containing organic ligands work synergistically to promote the efficient conversion of organic matter during the catalytic pyrolysis of shale resources. It also improves the yield of light oil and inhibits the formation of coke.

[0011] Preferably, the amino-containing organic ligand comprises triethylenetetramine and / or tetraethylenepentamine, more preferably tetraethylenepentamine.

[0012] The present invention further prefers that the amino-containing organic ligand be tetraethylenepentamine, because it has more amino groups, and the Cu-TEPA catalyst formed by complexing with divalent copper ions has better thermal stability and higher catalytic conversion efficiency.

[0013] Preferably, the copper-based catalyst has a layered structure.

[0014] Preferably, the porosity of the copper-based catalyst is 30% to 60%, for example, it can be 30%, 35%, 40%, 45%, 50%, 55% or 60%, etc.

[0015] Preferably, the specific surface area of ​​the copper-based catalyst is 50–300 cm². 2 / g, for example, could be 50cm 2 / g, 100cm 2 / g, 150cm 2 / g、200cm 2 / g、250cm 2 / g or 300cm 2 / g etc.

[0016] Preferably, the thermal decomposition temperature of the copper-based catalyst is 200-300°C, for example, it can be 200°C, 220°C, 250°C, 280°C or 300°C.

[0017] It is worth noting that the copper-based catalyst described in this invention has a higher thermal decomposition temperature in water as a medium.

[0018] Secondly, the present invention provides a method for preparing the copper-based catalyst described in the first aspect, the method comprising the following steps:

[0019] (1) Mix a copper source, an organic ligand containing at least four amino groups (e.g., four, five, or six, etc.) and a first solvent, and then proceed with a first reaction to obtain a precursor solution;

[0020] (2) The precursor solution in step (1) is dried first to obtain the copper-based catalyst.

[0021] The method for preparing the copper-based catalyst described in this invention has advantages such as inexpensive and readily available raw materials, no need for complex equipment, and simple and environmentally friendly operation.

[0022] Preferably, the copper source in step (1) includes any one or a combination of at least two of copper sulfate pentahydrate, copper nitrate trihydrate, or copper chloride dihydrate, wherein typical but non-limiting combinations include combinations of copper sulfate pentahydrate and copper nitrate trihydrate, combinations of copper sulfate pentahydrate and copper chloride dihydrate, or combinations of copper nitrate trihydrate and copper chloride dihydrate, etc.

[0023] Preferably, the organic ligand containing at least four amino groups in step (1) includes triethylenetetramine and / or tetraethylenepentamine, preferably tetraethylenepentamine.

[0024] Preferably, the molar ratio of the copper source to the organic ligand containing at least four amino groups is 1:(0.5-2), for example, it can be 1:0.5, 1:0.8, 1:1, 1:1.2, 1:1.5, 1:1.8 or 1:2, etc., preferably 1:(1-2).

[0025] The present invention further preferably uses a molar ratio of the copper source to the organic ligand containing at least four amino groups of 1:(1-2), which is beneficial for forming a highly active and structurally stable copper-amine complex and ensuring Cu2+ + Sufficient coordination; if the molar amount of the organic ligand containing at least four amino groups is relatively small, resulting in Cu2... + Insufficient coordination can easily lead to the formation of inactive species; if the molar amount of the organic ligand containing at least four amino groups is relatively large, it can result in excessive TEPA encapsulation of the active center, thus inhibiting the catalytic reaction activity.

[0026] Preferably, the mixing in step (1) includes first mixing the copper source and the first solvent to obtain a copper-containing solution, and then mixing the copper-containing solution with the organic ligand containing at least four amino groups.

[0027] Preferably, the second mixing includes adding the organic ligand containing at least four amino groups to the copper-containing solution.

[0028] Preferably, the organic ligand containing at least four amino groups is added to the copper-containing solution at a rate of 5 to 10 mL / min, for example, 5 mL / min, 6 mL / min, 7 mL / min, 8 mL / min, 9 mL / min or 10 mL / min, and more preferably 6 to 8 mL / min.

[0029] The present invention further preferably includes adding the organic ligand containing at least four amino groups to the copper-containing solution, and even more preferably, the rate at which the organic ligand containing at least four amino groups is added to the copper-containing solution is 6-8 mL / min, which is beneficial to the reaction of the ligand with Cu2+. + Sufficient coordination is crucial to avoid side reactions caused by local supersaturation or exothermic reactions; if the corresponding rate is too high, it will lead to Cu in the solution... 2+ If the saturation is too high, uncoordinated Cu(OH)2 precipitate or amorphous complex will be formed; if the corresponding rate is too low, it will lead to a longer catalyst preparation time, and some amino groups in tetraethylenepentamine will be easily oxidized.

[0030] Preferably, the second mixing is carried out under continuous stirring.

[0031] Preferably, the first reaction in step (1) is carried out in a protective gas atmosphere.

[0032] Preferably, the protective gas atmosphere includes nitrogen and / or argon.

[0033] Preferably, the temperature of the first reaction in step (1) is 20 to 30°C, for example, it can be 20°C, 22°C, 25°C, 28°C or 30°C.

[0034] Preferably, the reaction time in step (1) is 2 to 4 hours, for example, 2 hours, 2.5 hours, 3 hours, 3.5 hours or 4 hours.

[0035] Preferably, the first reaction in step (1) is carried out under continuous stirring.

[0036] Preferably, the first drying method in step (2) includes any one or a combination of at least two of freeze drying, electric heating drying, or vacuum drying, wherein typical but non-limiting combinations include a combination of freeze drying and electric heating drying, a combination of freeze drying and vacuum drying, or a combination of electric heating drying and vacuum drying, etc., preferably freeze drying.

[0037] Preferably, the freeze-drying temperature is -50 to -70°C, for example, it can be -50°C, -55°C, -60°C, -65°C or -70°C.

[0038] Preferably, the freeze-drying time is 24 to 48 hours, for example, it can be 24 hours, 28 hours, 30 hours, 32 hours, 34 hours, 36 hours, 38 hours, 40 hours, 42 hours, 45 hours or 48 hours.

[0039] Preferably, step (2) further includes grinding the dried solid phase to obtain the copper-based catalyst.

[0040] Preferably, the grinding process includes grinding the copper-based catalyst to an average particle size of 250–425 μm, such as 250 μm, 280 μm, 300 μm, 320 μm, 350 μm, 380 μm, 400 μm, or 425 μm.

[0041] As a further preferred embodiment of the present invention, the preparation method of the copper-based catalyst includes the following steps:

[0042] (1) First, the copper source and the first solvent are mixed to obtain a copper-containing solution. Then, under continuous stirring, an organic ligand containing at least four amino groups is slowly added to the copper-containing solution at a rate of 5-10 mL / min for a second mixing. Then, under a protective gas atmosphere, the solution is reacted for 2-4 hours at 20-30°C with continuous stirring to obtain a precursor solution.

[0043] (2) The precursor solution in step (1) is freeze-dried for 24 to 48 hours at -50 to -70°C and then ground to obtain the copper-based catalyst with an average particle size of 250 to 425 μm.

[0044] Wherein, the copper source in step (1) includes any one or a combination of at least two of copper sulfate pentahydrate, copper nitrate trihydrate or copper chloride dihydrate; the organic ligand containing at least four amino groups in step (1) includes triethylenetetramine and / or tetraethylenepentamine; the molar ratio of the copper source to the organic ligand containing at least four amino groups is 1:(0.5-2).

[0045] Thirdly, the present invention provides a method for in-situ mining of shale, the method employing the copper-based catalyst described in the first aspect, the method comprising the following steps:

[0046] S1: Mix shale powder, the copper-based catalyst, and the second solvent, and then dry them to obtain a solid mixture;

[0047] S2: The solid mixture described in step S1 undergoes a second reaction in a high-pressure closed environment to obtain shale oil and shale gas.

[0048] The in-situ shale extraction method of the present invention utilizes the copper-based catalyst described in the first aspect to carry out a second reaction in a high-pressure, closed environment, thereby realizing the extraction of shale oil and shale gas from shale. By leveraging the high specific surface area, abundant active sites, and excellent thermal stability of the copper-based catalyst, the in-situ conversion temperature of shale is reduced, promoting the efficient conversion of organic matter in shale resources. Furthermore, the electron transfer effect of divalent copper ions in the copper-based catalyst weakens the C-C bonds, and combined with the directional adsorption of nitrogen atoms in the organic ligands containing at least four amino groups, the yield of light oil is significantly improved, and the formation of coke is effectively suppressed.

[0049] Preferably, the shale powder in step S1 includes medium- to low-maturity shale powder.

[0050] Preferably, the vitrinite reflectance of the medium-low maturity shale powder is 0.6% to 1.1%, for example, it can be 0.6%, 0.7%, 0.8%, 0.9%, 1.0% or 1.1%.

[0051] Preferably, the shale powder in step S1 has a particle size of <60 mesh, for example, it can be 40 mesh, 42 mesh, 45 mesh, 48 mesh, 50 mesh, 52 mesh, 55 mesh or 58 mesh, etc.

[0052] Preferably, the amount of copper-based catalyst added in step S1 is 0.09% to 0.12% of the total mass of the shale powder, for example, it can be 0.09%, 0.1%, 0.11% or 0.12%, etc.

[0053] In a further preferred embodiment of the present invention, the amount of copper-based catalyst added in step S1 is 0.09% to 0.12% of the total mass of the shale powder. This is beneficial for the full in-situ conversion of shale resources, improving oil and gas recovery rate, and reducing extraction costs. If the amount of copper-based catalyst added in step S1 is too small, the shale resources will not be fully converted, the oil and gas recovery rate will decrease, and resources will be wasted. If the amount of copper-based catalyst added in step S1 is too large, it will not significantly improve the oil and gas recovery rate, but will instead cause waste and increase extraction costs.

[0054] Preferably, the mixing in step S1 includes first mixing the copper-based catalyst and the second solvent to obtain a copper-based catalyst solution, and then mixing the copper-based catalyst solution with the shale powder.

[0055] Preferably, the fourth mixing includes adding the copper-based catalyst solution dropwise into the shale powder.

[0056] Preferably, in step S1, the second solvent comprises any one or a combination of at least two of anhydrous ethanol, deionized water, or dichloromethane, wherein typical but non-limiting combinations include a combination of anhydrous ethanol and deionized water, a combination of anhydrous ethanol and dichloromethane, or a combination of deionized water and dichloromethane, preferably anhydrous ethanol.

[0057] Preferably, the temperature of the second drying step S1 is ≤60℃, for example, it can be 60℃, 58℃, 55℃, 53℃ or 50℃, and preferably 50~60℃.

[0058] Preferably, the pressure of the high-pressure sealed environment in step S2 is 0.5 to 5 MPa, for example, it can be 0.5 MPa, 1 MPa, 2 MPa, 3 MPa, 4 MPa or 5 MPa, etc.

[0059] Preferably, the second reaction in step S2 is carried out in a protective gas atmosphere.

[0060] Preferably, the temperature of the second reaction in step S2 is 350 to 550°C, for example, it can be 350°C, 400°C, 450°C, 500°C or 550°C.

[0061] Preferably, the reaction time in step S2 is 2 to 4 hours, for example, 2 hours, 2.5 hours, 3 hours, 3.5 hours or 4 hours.

[0062] In a further preferred embodiment of the present invention, the temperature of the second reaction in step S2 is 350-550°C, and the time of the second reaction is 2-4 hours. Compared with in-situ shale mining using catalysts in the prior art, the present invention achieves a higher oil and gas recovery rate in a shorter time at the same temperature. Under the same oil and gas recovery rate, the present invention only requires a lower temperature and a shorter time.

[0063] As a further preferred embodiment of the present invention, the method for in-situ shale mining includes the following steps:

[0064] S1: First, the copper-based catalyst and the second solvent are mixed to obtain a copper-based catalyst solution. Then, the copper-based catalyst solution is added dropwise to the shale powder. Finally, the mixture is dried at ≤60℃ to obtain a solid-phase mixture.

[0065] S2: The solid mixture described in step S1 undergoes a second reaction for 2 to 4 hours in a high-pressure closed environment at a pressure of 0.5 to 5 MPa and a temperature of 350 to 550°C to obtain shale oil and shale gas.

[0066] In step S1, the shale powder includes medium-low maturity shale powder; the vitrinite reflectance of the medium-low maturity shale powder is 0.6% to 1.1%; the particle size of the shale powder in step S1 is <60 mesh; and the amount of copper-based catalyst added in step S1 is 0.09% to 0.12% of the total mass of the shale powder.

[0067] Compared with the prior art, the present invention has at least the following beneficial effects:

[0068] (1) The copper-based catalyst for in-situ mining of shale provided by the present invention has a layered organic framework structure with divalent copper ions as the core and organic ligands containing at least four amino groups as complexing agents. It has a high specific surface area, abundant catalytic active sites and good thermal stability. Moreover, the redox effect of the divalent copper ions and the directional adsorption effect of nitrogen atoms of the amino-containing organic ligands work together to promote the efficient conversion of organic matter during the catalytic pyrolysis of shale resources, and also improve the yield of light oil and inhibit the formation of coke.

[0069] (2) The method for preparing copper-based catalysts provided by the present invention further improves the structural stability of the obtained copper-based catalysts by further optimizing parameters such as the raw material molar ratio, the mixing order of the raw materials and the addition rate, thereby further improving its catalytic performance. Moreover, it has the advantages of cheap and readily available raw materials, no need for complex equipment and simple and environmentally friendly operation.

[0070] (3) The in-situ shale extraction method provided by the present invention uses the copper-based catalyst described in the first aspect and reacts in a high-pressure closed environment to achieve efficient in-situ conversion of organic matter in shale. The shale oil recovery rate is preferably as high as 0.51% or more, the shale gas recovery rate is preferably as high as 7.35% or more, and the heavy oil yield in the obtained shale oil is as low as 5.31% or less, and the hydrocarbon content in the obtained shale gas is preferably as high as 68.13% or more, thus fully exploiting and utilizing shale resources. Attached Figure Description

[0071] Figure 1 This is the XRD pattern of tetraethylenepentamine copper described in Example 1 of the present invention;

[0072] Figure 2 This is the infrared spectrum of tetraethylenepentamine copper described in Example 1 of the present invention;

[0073] Figure 3 This is a comparison chart of the shale oil recovery rate and shale gas recovery rate obtained by the in-situ shale mining method described in Application Example 1 and Comparative Application Example 5 of the present invention;

[0074] Figure 4 This is a simulated distillation chromatogram of shale oil obtained by the in-situ shale extraction method described in Example 1 of this invention;

[0075] Figure 5 This is a gas chromatogram of shale gas obtained by the in-situ shale mining method described in Application Example 1 and Comparative Application Example 5 of the present invention. Detailed Implementation

[0076] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0077] I. Implementation Examples

[0078] Example 1

[0079] This embodiment provides a copper-based catalyst for in-situ shale mining. The copper-based catalyst comprises divalent copper ions and a tetraethylenepentamine organic ligand complexed with the divalent copper ions, i.e., the copper-based catalyst is copper-tetraethylenepentamine (Cu-TEPA) with a layered structure; the molar ratio of divalent copper ions to tetraethylenepentamine is 1:1; the porosity of the copper-based catalyst is 36%; and the specific surface area is 126 cm². 2 / g, thermal decomposition temperature is 280℃.

[0080] like Figure 1 As shown in the XRD pattern, the peaks are relatively sharp and there are no impurity peaks, which may indicate a layered structure, consistent with the characteristics of coordination polymers formed by tetraethylenepentamine ligands.

[0081] like Figure 2 As shown in the infrared spectrum, it can be seen that at 3342 cm⁻¹... -1 (NH stretching), 1645cm -1 (C=N expansion) and 456cm -1 The (Cu-N stretching) peaks indicate that tetraethylenepentamine forms a stable structure by coordinating with divalent copper ions through amino groups.

[0082] This embodiment also provides a method for preparing the above-mentioned copper-based catalyst, the preparation method comprising the following steps: (1) firstly mixing the copper sulfate pentahydrate and water to obtain a copper sulfate solution, and then, under continuous stirring, slowly adding the tetraethylenepentamine organic ligand at a rate of 6 mL / min to the copper sulfate solution for a second mixing; the molar ratio of the copper sulfate pentahydrate to the tetraethylenepentamine organic ligand is 1:1; and then, under a nitrogen atmosphere, at 25°C and under continuous stirring, undergoing a first reaction for 3 h to obtain a precursor solution;

[0083] (2) The precursor solution in step (1) was freeze-dried for 48 hours at -50°C and then ground to obtain the copper-based catalyst with an average particle size of 300 μm.

[0084] Example 2

[0085] This embodiment provides a copper-based catalyst for in-situ shale mining. The copper-based catalyst comprises divalent copper ions and a tetraethylenepentamine organic ligand complexed with the divalent copper ions, i.e., the copper-based catalyst is copper-tetraethylenepentamine (Cu-TEPA) with a layered structure; the molar ratio of the divalent copper ions to the tetraethylenepentamine is 1:1; the porosity of the copper-based catalyst is 45%; and the specific surface area is 190 g / cm³. 3 Its thermal decomposition temperature is 300℃.

[0086] This embodiment also provides a method for preparing the above-mentioned copper-based catalyst, the preparation method comprising the following steps: (1) firstly mixing the copper sulfate pentahydrate and water to obtain a copper sulfate solution, and then, under continuous stirring, slowly adding the tetraethylenepentamine organic ligand at a rate of 8 mL / min to the copper sulfate solution for a second mixing; the molar ratio of the copper sulfate pentahydrate to the tetraethylenepentamine organic ligand is 1:1; and then, under an argon atmosphere, at 30°C and under continuous stirring, undergoing a first reaction for 2 hours to obtain a precursor solution;

[0087] (2) The precursor solution in step (1) was freeze-dried for 24 hours at -70°C and then ground to obtain the copper-based catalyst with an average particle size of 400 μm.

[0088] Example 3

[0089] This embodiment provides a copper-based catalyst for in-situ shale mining. Except that the organic ligand of the copper-based catalyst is triethylenetetramine and its preparation method is adjusted accordingly, the rest is the same as in Example 1.

[0090] Example 4

[0091] This embodiment provides a method for preparing a copper-based catalyst for in-situ shale mining. The preparation method is the same as in Example 1, except that the molar ratio of copper sulfate pentahydrate to tetraethylenepentamine organic ligand is 1:0.5.

[0092] Example 5

[0093] This embodiment provides a method for preparing a copper-based catalyst for in-situ shale mining. The preparation method is the same as in Example 1, except that the molar ratio of copper sulfate pentahydrate to tetraethylenepentamine organic ligand is 1:2.2.

[0094] Example 6

[0095] This embodiment provides a method for preparing a copper-based catalyst for in-situ shale mining. The preparation method is the same as in Example 1, except that the tetraethylenepentamine organic ligand is slowly added to the copper sulfate solution at a rate of 10 mL / min for a second mixing.

[0096] II. Comparative Example

[0097] Comparative Example 1

[0098] This comparative example provides a copper-based catalyst for in-situ shale mining. The copper-based catalyst is the same as in Example 1 except that the tetraethylenepentamine organic ligand is replaced with 1,3,5-triaminobenzene and the preparation method is adjusted accordingly.

[0099] Comparative Example 2

[0100] This comparative example provides a copper-based catalyst for in-situ shale mining. Except for replacing the tetraethylenepentamine organic ligand with ethylenediamine, and adjusting the preparation method accordingly, the copper-based catalyst is the same as in Example 1.

[0101] Comparative Example 3

[0102] This comparative example provides an iron-based catalyst for in-situ shale mining. The iron-based catalyst is the same as in Example 1, except that the divalent copper ions are replaced with trivalent iron ions and the preparation method is adjusted accordingly to change copper sulfate pentahydrate to ferric sulfate nonahydrate.

[0103] III. Application Examples

[0104] Application Example 1

[0105] This application example provides a method for in-situ mining of shale, using the copper-based catalyst Cu-TEPA described in Example 1. The method includes the following steps:

[0106] S1: First, the copper-based catalyst Cu-TEPA and anhydrous ethanol are mixed to obtain a Cu-TEPA ethanol solution. Then, the Cu-TEPA ethanol solution is added dropwise to the shale powder. Finally, the mixture is dried at 50°C to obtain a solid mixture.

[0107] S2: The solid mixture described in step S1 undergoes a second reaction for 3 hours in a high-pressure closed environment at a pressure of 2 MPa and a temperature of 450°C to obtain shale oil and shale gas.

[0108] In step S1, the shale powder includes medium-low maturity shale powder; the vitrinite reflectance of the medium-low maturity shale powder is 0.8%; the particle size of the shale powder in step S1 is <60 mesh; and the amount of copper-based catalyst added in step S1 is 0.1% of the total mass of the shale powder.

[0109] The evaluation results of shale catalytic pyrolysis in this application example are as follows: After catalytic pyrolysis of shale with the addition of 0.1% tetraethylenepentamine copper, the shale mass loss was 2.5043 g, the collected oil mass was 0.1584 g, and the gas mass was 2.3459 g. Figure 3 As shown, compared to Comparative Application Example 5, the oil and gas recovery rate of this application example reached 9.17%, which means that the copper-based catalyst described in Example 1 exhibits excellent catalytic effect.

[0110] like Figure 4 As shown, the simulated distillation data results are as follows: after catalytic pyrolysis of shale with the addition of 0.1% tetraethylenepentamine copper, the collected crude oil contained 67.7% gasoline and diesel fractions, of which only 5.2% was heavy oil fraction. This indicates that tetraethylenepentamine copper, as a highly efficient in-situ conversion pyrolysis catalyst for medium and low maturity shale oil and oil shale, can significantly promote the cracking of macromolecular organic matter and improve the yield of light oil.

[0111] like Figure 5 As shown, the gas chromatography data results are as follows: after catalytic pyrolysis of shale with 0.1% tetraethylenepentamine copper, the shale gas collected contained 8.8178% methane, 0.0475% dienes, 1.8346% ethane and propane, and 0.0366% C4 components, all of which were higher than those in comparative application example 5. This indicates that tetraethylenepentamine copper has a good catalytic effect and meets the needs of efficient catalytic pyrolysis for in-situ conversion of medium- and low-maturity shale oil and oil shale.

[0112] Application Example 2

[0113] This application example provides a method for in-situ mining of shale, using the copper-based catalyst Cu-TEPA described in Example 2. The method includes the following steps:

[0114] S1: First, the copper-based catalyst Cu-TEPA and anhydrous ethanol are mixed to obtain a Cu-TEPA ethanol solution. Then, the Cu-TEPA ethanol solution is added dropwise to the shale powder. Finally, the mixture is dried at 55°C to obtain a solid mixture.

[0115] S2: The solid mixture described in step S1 undergoes a second reaction for 2 hours in a high-pressure closed environment at a pressure of 4 MPa and a temperature of 550°C to obtain shale oil and shale gas.

[0116] In step S1, the shale powder includes medium-low maturity shale powder; the vitrinite reflectance of the medium-low maturity shale powder is 0.6%; the particle size of the shale powder in step S1 is <60 mesh; and the amount of copper-based catalyst added in step S1 is 0.12% of the total mass of the shale powder.

[0117] Application Examples 3 to 6

[0118] The in-situ shale mining methods provided in Application Examples 3 to 6 are the same as those in Application Example 1, except that they use the copper-based catalysts provided in Examples 3, 4, 5 and 6 respectively.

[0119] Application Example 7

[0120] This application example provides a method for in-situ mining of shale. The method is the same as that in Application Example 1, except that the amount of copper-based catalyst added in step S1 is 0.15% of the total mass of the shale powder.

[0121] IV. Comparative Application Examples

[0122] Comparative Application Examples 1 to 3

[0123] The methods for in-situ shale mining provided in Comparative Application Examples 1 to 3 are the same as those in Application Example 1, except that they use the catalysts provided in Comparative Examples 1, 2 and 3 respectively.

[0124] Comparative Application Example 4

[0125] This comparative application example provides a method for in-situ mining of shale. The method is the same as that in application example 1, except that step S1 does not involve a second drying, i.e., step S2 is performed directly after mixing in step S1.

[0126] Comparative Application Example 5

[0127] This comparative application example provides a method for in-situ mining of shale, which is the same as application example 1 except that step S1 does not use the copper-based catalyst Cu-TEPA.

[0128] V. Tests and Results

[0129] The quality of shale oil and shale gas obtained by the in-situ shale extraction method provided in the above application examples or comparative application examples was tested, and the shale oil recovery rate and shale gas recovery rate were calculated. The composition and corresponding content of the obtained shale oil and shale gas were analyzed, and the heavy oil yield in shale oil and the hydrocarbon content in shale gas were calculated. The results are shown in Table 1.

[0130] Table 1

[0131]

[0132]

[0133] The data in Table 1 shows that:

[0134] (1) As can be seen from the comprehensive application examples 1 to 2, the copper-based catalyst for in-situ shale mining provided by the present invention, its preparation method and application, realize the efficient in-situ conversion of shale resources. The shale oil recovery rate is as high as 0.51% or more, the shale gas recovery rate is as high as 7.35% or more, and the heavy oil yield in the shale oil is as low as 5.31% or less, and the hydrocarbon content in the shale gas is as high as 68.13% or more.

[0135] (2) Combining Application Examples 1 and 3 to 6, it can be seen that in Application Example 3, the copper-based catalyst using triethylenetetramine as the organic ligand resulted in a decrease in shale oil and gas recovery rate; in Application Example 4, the molar ratio of copper sulfate pentahydrate to the tetraethylenepentamine organic ligand was too low, and it did not significantly improve the recovery rate of the obtained shale oil and the shale gas; in Application Example 5, the molar ratio of copper sulfate pentahydrate to the tetraethylenepentamine organic ligand was too high, resulting in a decrease in the recovery rate of the obtained shale oil and the shale gas, and an increase in the heavy oil yield in the shale oil and a further increase in the hydrocarbon content in the shale gas. The recovery rate of shale oil and gas was further reduced due to the relatively fast addition rate in Application Example 6. This indicates that the present invention further preferably uses tetraethylenepentamine as the organic ligand containing at least four amino groups, and further preferably uses a molar ratio of 1:(1-2) between the copper source and the organic ligand containing at least four amino groups, or further preferably uses a rate of 6-8 mL / min for adding the amino-containing organic ligand to the copper-containing solution. This further improves the conversion efficiency of organic matter in shale, thereby further increasing the recovery rate of oil and gas, and further improving the quality of the obtained shale oil and shale gas.

[0136] (3) Combining Application Example 1, Application Example 7, and Comparative Application Example 4, it can be seen that although the amount of copper-based catalyst Cu-TEPA added in step S1 of Application Example 7 is relatively high, i.e., the amount of Cu-TEPA used, it does not significantly improve the in-situ conversion effect. In Comparative Application Example 4, step S1 does not involve a second drying, but instead proceeds directly to step S2 after mixing in step S1, resulting in the thermal decomposition of residual ethanol to produce short-chain alkanes and olefins, affecting the analysis results of shale gas. Therefore, it is indicated that the present invention further preferably adds copper-based catalyst in step S1 at 0.09% to 0.12% of the total mass of the shale powder, selects the second drying after mixing in step S1 before proceeding to step S2, and further preferably uses a second drying temperature of ≤60℃ in step S1, which further improves the in-situ conversion efficiency of the shale.

[0137] (4) It can be seen from the comprehensive application example 1 and comparative application examples 1 to 3 that, since the organic ligands used in comparative application example 1 or comparative application example 2 contain only 3 or 2 amino groups, their complexation ability with divalent copper ions is weak, resulting in poor structural stability of the catalyst complex. Since the metal ion used in comparative application example 3 is a trivalent iron ion, the recovery rate of shale oil and gas decreases. Since no catalyst is used in comparative application example 5, the conversion of organic matter in shale relies solely on high-temperature pyrolysis, resulting in a decrease in the recovery rate of shale oil and gas. This shows that the in-situ shale extraction method of the present invention selects the copper-based catalyst, and selects the copper-based catalyst to include divalent copper ions and amino-containing organic ligands complexed with the divalent copper ions, so that its in-situ conversion efficiency is higher, the recovery rate of the obtained shale oil and shale gas is improved, and the quality of the obtained shale oil and shale gas is improved.

[0138] 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 copper-based catalyst for in-situ shale mining, characterized in that, The copper-based catalyst comprises divalent copper ions and an amino-containing organic ligand complexed with the divalent copper ions; The amino-containing organic ligand comprises at least four amino groups.

2. The copper-based catalyst according to claim 1, characterized in that, The amino-containing organic ligands include triethylenetetramine and / or tetraethylenepentamine, preferably tetraethylenepentamine; Preferably, the copper-based catalyst has a layered structure.

3. The copper-based catalyst according to claim 1 or 2, characterized in that, The porosity of the copper-based catalyst is 30% to 60%; Preferably, the specific surface area of ​​the copper-based catalyst is 50–300 cm². 2 / g; Preferably, the thermal decomposition temperature of the copper-based catalyst is 200–300°C.

4. A method for preparing a copper-based catalyst according to any one of claims 1 to 3, characterized in that, The preparation method includes the following steps: (1) A copper source, an organic ligand containing at least four amino groups and a first solvent are mixed and then subjected to a first reaction to obtain a precursor solution; (2) The precursor solution in step (1) is dried first to obtain the copper-based catalyst.

5. The preparation method according to claim 4, characterized in that, The copper source in step (1) includes any one or a combination of at least two of copper sulfate pentahydrate, copper nitrate trihydrate, or copper chloride dihydrate; Preferably, the organic ligand containing at least four amino groups in step (1) includes triethylenetetramine and / or tetraethylenepentamine, preferably tetraethylenepentamine; Preferably, the molar ratio of the copper source to the organic ligand containing at least four amino groups is 1:(0.5-2), more preferably 1:(1-2); Preferably, the mixing in step (1) includes first mixing the copper source and the first solvent to obtain a copper-containing solution, and then mixing the copper-containing solution with the organic ligand containing at least four amino groups. Preferably, the second mixing includes adding the organic ligand containing at least four amino groups to the copper-containing solution; Preferably, the organic ligand containing at least four amino groups is added to the copper-containing solution at a rate of 5–10 mL / min, more preferably 6–8 mL / min; Preferably, the second mixing is carried out under continuous stirring; Preferably, the first reaction in step (1) is carried out in a protective gas atmosphere; Preferably, the temperature of the first reaction in step (1) is 20–30°C; Preferably, the reaction time in step (1) is 2 to 4 hours; Preferably, the first reaction in step (1) is carried out under continuous stirring.

6. The preparation method according to claim 4 or 5, characterized in that, Step (2) The first drying method includes any one or a combination of at least two of freeze drying, electric heating drying, or vacuum drying, preferably freeze drying; Preferably, step (2) further includes grinding the dried solid phase to obtain the copper-based catalyst after drying; Preferably, the grinding process includes grinding the copper-based catalyst until the average particle size is 250–425 μm.

7. A method for in-situ mining of shale, characterized in that, The method is carried out using the copper-based catalyst according to any one of claims 1 to 3, and the method includes the following steps: S1: Mix shale powder, the copper-based catalyst, and the second solvent, and then dry them to obtain a solid mixture; S2: The solid mixture described in step S1 undergoes a second reaction in a high-pressure closed environment to obtain shale oil and shale gas.

8. The method according to claim 7, characterized in that, The shale powder mentioned in step S1 includes medium- to low-maturity shale powder; Preferably, the vitrinite reflectance of the medium-to-low maturity shale powder is 0.6% to 1.1%. Preferably, the particle size of the shale powder in step S1 is <60 mesh; Preferably, the amount of copper-based catalyst added in step S1 is 0.09% to 0.12% of the total mass of the shale powder.

9. The method according to claim 7 or 8, characterized in that, The mixing in step S1 includes first mixing the copper-based catalyst and the second solvent to obtain a copper-based catalyst solution, and then mixing the copper-based catalyst solution with the shale powder. Preferably, the fourth mixing includes adding the copper-based catalyst solution dropwise into the shale powder; Preferably, the temperature of the second drying step S1 is ≤60℃, and more preferably 50~60℃.

10. The method according to any one of claims 7 to 9, characterized in that, The pressure of the high-pressure sealed environment described in step S2 is 0.5–5 MPa; Preferably, the second reaction in step S2 is carried out in a protective gas atmosphere; Preferably, the temperature of the second reaction in step S2 is 350–550°C; Preferably, the reaction time in step S2 is 2 to 4 hours.

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