The method is suitable for in-situ catalytic combustion mining method of low-permeability heavy oil, super heavy oil and complex lithology oil reservoirs

Abstract

The present application relates to oil and gas exploitation technology field, it is a kind of underground in-situ catalytic combustion mining method suitable for low-permeability heavy oil, super heavy oil and complex lithology reservoir, preparation catalyst precursor;Catalyst precursor is injected into reservoir layer, chemical autogenous heat system is injected into the reservoir layer dispersed with catalyst precursor, oxidation-reduction exothermic reaction occurs and heat is released to heat reservoir layer;Said reservoir layer is continuously injected with air or oxygen, and autogenous heat combustion reaction is carried out, and the gas generated drives crude oil to production well.The present application not only utilizes the heat released by the autogenous heat reaction of the reservoir in-situ, drives the catalyst precursor to directly synthesize the composite catalyst with high activity and high stability, but also utilizes the in-situ synthesized catalyst to reduce the activation energy of crude oil cracking and the ignition temperature of the reservoir, and simultaneously reduces the equipment investment and heat loss through autogenous heat reaction, thereby meeting the mining needs of low-permeability heavy oil, super heavy oil and complex lithology reservoir.

Description

Technical Field

[0001] This invention relates to the field of oil and gas extraction technology, and is an underground in-situ catalytic combustion extraction method suitable for low-permeability heavy oil, extra-heavy oil and complex lithological reservoirs. Background Technology

[0002] With the depletion of readily exploitable light crude oil resources globally, the efficient development of unconventional oil and gas resources such as heavy oil, extra-heavy oil, and complex lithological reservoirs has become a core challenge in the energy sector. These reservoirs generally exhibit high viscosity, low permeability, and small porosity, leading to bottlenecks in reservoir development such as low thermal energy utilization, formation blockage, poor crude oil flowability, and difficulty in ignition and start-up, resulting in an overall recovery rate that has long been below 30%.

[0003] To overcome this bottleneck, in-situ catalytic cracking and underground in-situ combustion (IOC) technologies have been extensively studied. However, existing technologies still have key limitations: Currently, reservoir in-situ catalysis technologies mainly rely on externally injected water-soluble metal salt-solid catalyst composite systems or supported catalysts. The former requires the delivery of solid particles to the formation through the wellbore, which can easily lead to pore throat blockage and uneven catalyst distribution during the injection process. The latter is limited by the high-temperature stability of the support material, and is prone to loss of active sites or structural collapse under the complex temperature and pressure environment of the reservoir, making it difficult to continuously exert its catalytic viscosity reduction and ignition temperature lowering effects. More importantly, existing technologies lack a synergistic control mechanism for the catalyst synthesis process and the reservoir combustion temperature field, making it impossible to dynamically optimize the catalytic reaction and combustion process according to the actual temperature and pressure conditions of the formation.

[0004] In-situ combustion technology achieves thermal oil recovery by inducing combustion in the reservoir, but its core bottleneck lies in ignition temperature control and combustion front stability regulation. For low-temperature, high-viscosity reservoirs, traditional external heating methods such as electric ignition and steam preheating suffer from high equipment costs, large heat loss, and uneven ignition areas. Although chemical ignition releases heat to raise formation temperature through oxidant-reducant reactions, current technologies only use chemical exothermics as a single ignition method, without coupling it with the in-situ catalyst generation process. This makes the combustion reaction prone to "flameout" or "deflagration" due to discontinuous heat supply or insufficient catalyst activity, making it difficult to accurately control the combustion front propagation speed and temperature distribution, resulting in low thermal energy utilization (<40%) and incomplete crude oil cracking.

[0005] Chinese patent document CN116378615A discloses an experimental apparatus and method for achieving uniform ignition and catalyst injection in fire-driven oil reservoirs, belonging to the field of experimental technology for burning oil reservoirs. The apparatus includes a gas injection system, a uniform ignition and catalyst injection device, a burner, a separation device, and a detection device; the uniform ignition and catalyst injection device includes an acceleration tube, a heating device, an atomizing device, a monitoring device, and a diffuser.

[0006] Chinese patent document CN116927736A discloses a method and apparatus for achieving a high success rate of fire-flooding ignition in light oil reservoirs. The apparatus includes an insulation layer, a heating rod, and a multi-stage metal cartridge. The heating rod penetrates the insulation layer and forms a heat-insulating cavity with the insulation layer. The multi-stage metal cartridge includes a primary metal cartridge and a secondary metal cartridge. The primary and secondary metal cartridges are fixed to the outside of the heating rod and located inside the heat-insulating cavity.

[0007] Chinese patent document CN108361009A discloses a catalyst for effectively improving the oxidation behavior of crude oil and its fire-driven oil recovery method. The main component is an oil-soluble metal salt, specifically at least one selected from copper stearate, iron stearate, cobalt stearate, copper oleate, and copper octoate. The catalyst system is simple in composition, preparation, and application; the components can be mixed in any way without special treatment. Compared to widely reported and used metal or metal oxide nanoparticles, this significantly reduces construction difficulty and costs. The oil-soluble catalyst system disperses well in crude oil, exhibits good contact with crude oil, and demonstrates high catalytic efficiency.

[0008] Chinese patent document CN104314525B discloses a fire-flooding oil recovery method using oleic acid for in-situ upgrading. The method includes the following steps: screening heavy oil reservoirs; continuously injecting oleic acid slugs into the oil layer through a gas injection well in the screened heavy oil reservoir; closing the injection well after injection and allowing it to stand for 4-7 days to allow the oleic acid and crude oil to undergo a cracking and upgrading reaction underground; performing fire-flooding of the oil layer; monitoring the produced gas to ensure that the oxygen content in the produced gas is within a safe range; simultaneously, conducting chemical analysis on the produced oil; and ending the fire-flooding operation when the combustion front reaches the vicinity of the production well, and the oxygen content in the produced gas (by volume fraction) is greater than 5%, or the wellhead temperature of the production well is greater than 200°C. This fire-flooding oil recovery method utilizes oleic acid for in-situ upgrading, which can improve the oil properties of heavy oil reservoirs, reduce crude oil viscosity, and increase the final recovery rate of fire-flooding.

[0009] The above four patents have the following shortcomings: ① Regarding catalysts, the injection method is prone to pore throat blockage and uneven distribution, the type is singular or the activity decays at high temperatures, and the stability is insufficient. Moreover, they mostly rely on external one-time injection, making it difficult to dynamically replenish or generate according to reservoir progress, thus limiting the contact efficiency with crude oil and catalytic efficiency; ② Regarding ignition and combustion control, they mostly rely on external heating or single ignition methods, lacking a coordinated control mechanism for reservoir temperature and pressure conditions and combustion temperature field, resulting in poor stability of the combustion front and problems such as "flameout," "deflagration," or low thermal energy utilization; ③ Regarding the scope of application, they are not adaptable enough to low-permeability heavy oil, extra-heavy oil, and complex lithological reservoirs, thus limiting their universality.

[0010] Therefore, there is an urgent need to develop an underground in-situ catalytic combustion extraction method suitable for low-permeability heavy oil, extra-heavy oil, and complex lithological reservoirs to achieve efficient ignition and enhanced oil recovery. Summary of the Invention

[0011] This invention provides an underground in-situ catalytic combustion extraction method suitable for low-permeability heavy oil, extra-heavy oil, and complex lithological reservoirs. It overcomes the shortcomings of the existing technology and can effectively solve the problems of catalyst injection clogging the formation, high-temperature activity decay, and uncontrolled combustion temperature field in the extraction of low-permeability heavy oil, extra-heavy oil, and complex lithological temperature-controlled reservoirs.

[0012] One of the technical solutions of this invention is achieved through the following measures: an underground in-situ catalytic combustion extraction method suitable for low-permeability heavy oil, extra-heavy oil, and complex lithological reservoirs, comprising:

[0013] S1, anionic metal complexes and cationic metal complexes are dissolved in a polymeric electrolyte solution to prepare a catalyst precursor, wherein the anions in the anionic metal complexes include [AlCl4]. - and [ZnCl4] 2- One or more of the following, [AuCl4] - and [PtCl4] 2- One or more of the following, as well as iron-based transition metal coordination anions, and the cations in the cationic metal complex include alkali metal ions and transition metal ions;

[0014] S2, the catalyst precursor is injected into the reservoir to uniformly disperse it in the reservoir, wherein the amount of catalyst precursor injected is 0.5 wt% of the crude oil mass in the reservoir;

[0015] S3, injecting a chemically self-heating system into the reservoir containing a catalyst precursor, causing an exothermic redox reaction and releasing heat to heat the reservoir;

[0016] S4, continuously inject air or oxygen into the reservoir, and synthesize composite catalysts in situ in the reservoir from catalyst precursors, thereby reducing the cracking activation energy of crude oil and the ignition temperature of the reservoir, so that the crude oil in the reservoir undergoes autogenous combustion reaction.

[0017] S5, the gas generated in the autogenous combustion reaction drives crude oil to the production well, enabling the exploitation of low-permeability heavy oil, extra-heavy oil and complex lithology temperature-controlled reservoirs.

[0018] The following are further optimizations and / or improvements to one of the above-mentioned technical solutions:

[0019] In step S1 above, the specific process for preparing the catalyst precursor includes:

[0020] S01, dissolve the anionic metal complex in a polymeric electrolyte solution to obtain an anionic catalyst precursor;

[0021] SO2 is used to dissolve cationic metal complexes in a polymeric electrolyte solution to obtain a cationic catalyst precursor.

[0022] S03, anionic catalyst precursor and cationic catalyst precursor are mixed at a mass ratio of 1:1 to obtain catalyst precursor.

[0023] In step S1 above, the iron-based transition metal coordination anion is [NiCl4]. 2- [FeCl4] - [CoCl4] 2- One or more of them.

[0024] In step S1 above, the alkali metal ions include one or more of Li, Na, and K, and the transition metal ions include iron-based transition metals and platinum-based transition metals. The iron-based transition metals include one or more of Ni, Fe, and Co, and the platinum-based transition metals include one or more of Pt, Ir, and Ru.

[0025] In step S3 above, the chemical self-generating heat system, by mass percentage, includes 30% to 35% reducing agent, 15% to 20% oxidant, 15% to 20% fuel additive, 10% to 15% emulsifier, and 10% to 15% hydrogen donor.

[0026] The reducing agent is obtained by mixing carbon powder, magnesium powder, aluminum powder, zinc powder and iron powder in any proportion; the oxidizing agent is obtained by mixing potassium permanganate, potassium chlorate, potassium nitrate, potassium dichromate and sodium bismuthate in any proportion; the fuel additive is obtained by mixing ethanol, CS2, gasoline, glycerol, benzoyl peroxide and citric acid in any proportion; the emulsifier is obtained by mixing sodium dodecyl sulfate, sodium alkylbenzene sulfonate, polyethylene glycol, sodium oleate and sodium benzoate magnesium stearate in any proportion; and the hydrogen donor is obtained by mixing lithium aluminum hydride, sodium borohydride, formic acid, hydrazine and calcium hydride in any proportion.

[0027] In step S3 above, the injection of the chemically self-heating system into the reservoir containing the catalyst precursor includes:

[0028] S11, a gelatin capsule is coated on the outer layer of the oxidant to obtain an oxidant capsule;

[0029] S12, oxidant capsules are injected into the reservoir layer containing dispersed catalyst precursors via a polymer solution;

[0030] S13, the reducing agent, fuel additive, emulsifier and hydrogen donor are mixed to obtain a mixture;

[0031] S14, after flushing the well with foam fluid, inject the mixture into the reservoir layer containing the catalyst precursor.

[0032] In step S3 above, the exothermic redox reaction temperature is between 150°C and 500°C.

[0033] In step S4 above, the injection rate of air or oxygen is 6000 Nm. 3 / d to 8000Nm 3 / d.

[0034] In step S5 above, during the self-heating combustion reaction, the injection volume of air or oxygen is adjusted so that the temperature of the combustion front is 500℃ to 700℃ and the advancing speed of the combustion front is 0.04m / d to 0.16m / d.

[0035] This invention not only utilizes the heat released by in-situ chemical autogenous thermal reaction in the reservoir to drive the direct synthesis of a composite catalyst with high activity and high stability from the catalyst precursor, but also uses the in-situ synthesis of catalyst to reduce the activation energy of crude oil cracking and the ignition temperature of the reservoir. At the same time, the autogenous thermal reaction reduces equipment investment and heat energy loss, thereby meeting the exploitation needs of low-permeability heavy oil, extra-heavy oil and complex lithology reservoirs. Attached Figure Description

[0036] Appendix Figure 1 This is a schematic diagram of the in-situ synthesis process of the composite catalyst in this invention.

[0037] The codes in the attached diagram are as follows: 1 for injection well, 2 for production well, 3 for reservoir top plate, 4 for reservoir layer, 5 for reservoir bottom plate, 6 for oxidant, 7 for reducing agent, 8 for fuel additive, 9 for emulsifier, 10 for composite catalyst, 11 for heavy oil macromolecules, 12 for anionic metal complex, 13 for cationic metal complex, and 14 for heavy oil small molecules. Detailed Implementation

[0038] This invention is not limited to the following embodiments, and specific implementation methods can be determined according to the technical solutions and actual conditions of this invention. Unless otherwise specified, all chemical reagents and chemicals mentioned in this invention are well-known and commonly used chemical reagents and chemicals in the prior art; unless otherwise specified, all percentages in this invention are mass percentages; unless otherwise specified, all solutions in this invention are aqueous solutions with water as the solvent, for example, hydrochloric acid solution is an aqueous solution of hydrochloric acid; room temperature in this invention generally refers to a temperature between 15°C and 25°C, generally defined as 25°C.

[0039] The present invention will be further described below with reference to embodiments:

[0040] Example 1: This underground in-situ catalytic combustion extraction method, applicable to low-permeability heavy oil, extra-heavy oil, and complex lithological reservoirs, includes:

[0041] S1, anionic and cationic metal complexes are dissolved in a polymeric electrolyte solution to prepare a catalyst precursor, which reduces reservoir ignition temperature and crude oil viscosity. The anionic metal complex contains [AlCl4] anions. - and [ZnCl4] 2- One or more of the following, [AuCl4] - and [PtCl4] 2- One or more of the following, as well as iron-based transition metal coordination anions, and the cations in the cationic metal complex include alkali metal ions and transition metal ions;

[0042] S2, the catalyst precursor is injected into the reservoir to ensure uniform dispersion of the catalyst precursor within the reservoir and to exert its catalytic effect. The amount of catalyst precursor injected is 0.5 wt% of the crude oil mass in the reservoir.

[0043] S3 involves injecting a chemically self-heating system into an oil reservoir containing a dispersed catalyst precursor. This process generates an exothermic redox reaction, releasing heat to heat the reservoir and bring it to its auto-ignition temperature, thus creating a stable combustion reaction.

[0044] S4, continuously inject air or oxygen into the reservoir, and synthesize composite catalysts in situ in the reservoir from catalyst precursors, thereby reducing the cracking activation energy of crude oil and the ignition temperature of the reservoir, promoting the combustion reaction of the reservoir, and enabling the crude oil in the reservoir to undergo autogenous combustion reaction.

[0045] S5, the gas generated in the autogenous combustion reaction plays the role of driving oil and promoting the flow of catalyst (the heat generated by the autogenous combustion reaction further reduces the viscosity of crude oil, making it easier to flow), driving crude oil to production wells, realizing the exploitation of low-permeability heavy oil, extra-heavy oil and complex lithology temperature-controlled reservoirs.

[0046] This invention utilizes the spontaneous chemical reaction between specific chemical reagents to trigger an exothermic reaction in underground oil reservoirs. By controlling the injection ratio, the heat in the reservoir is brought to its auto-ignition temperature, forming a stable combustion reaction. The high temperature generated by combustion creates conditions for the in-situ synthesis of a catalyst. The resulting in-situ synthesized catalyst can significantly reduce the reservoir ignition temperature and crude oil viscosity. Simultaneously, the gases released by the combustion reaction act as oil displacement agents and promote catalyst flow, causing the in-situ synthesized catalyst to disperse throughout the reservoir, exerting its catalytic efficiency and pushing the remaining oil and gas in the reservoir towards the production well, ultimately achieving efficient exploitation of complex oil reservoirs.

[0047] Example 2: As an optimization of the above example, in step S1, the specific process for preparing the catalyst precursor includes:

[0048] S01, dissolve the anionic metal complex in a polymeric electrolyte solution to obtain an anionic catalyst precursor;

[0049] SO2 is used to dissolve cationic metal complexes in a polymeric electrolyte solution to obtain a cationic catalyst precursor.

[0050] S03, anionic catalyst precursor and cationic catalyst precursor are mixed at a mass ratio of 1:1 to obtain catalyst precursor.

[0051] Example 3: As an optimization of the above example, in step S1, the iron-based transition metal coordination anion is [NiCl4]. 2- [FeCl4] - [CoCl4] 2- One or more of them.

[0052] Example 4: As an optimization of the above example, in step S1, the alkali metal ion is one or more of Li, Na, and K, and the transition metal ion includes iron-based transition metals and platinum-based transition metals. The iron-based transition metal is one or more of Ni, Fe, and Co, and the platinum-based transition metal is one or more of Pt, Ir, and Ru.

[0053] Example 5: As an optimization of the above example, in step S3, the chemical self-generating heat system includes, by mass percentage, 30% to 35% reducing agent, 15% to 20% oxidant, 15% to 20% fuel additive, 10% to 15% emulsifier, and 10% to 15% hydrogen donor.

[0054] Example 6: As an optimization of the above examples, the reducing agent is obtained by mixing carbon powder, magnesium powder, aluminum powder, zinc powder and iron powder in any proportion; the oxidizing agent is obtained by mixing potassium permanganate, potassium chlorate, potassium nitrate, potassium dichromate and sodium bismuthate in any proportion; the fuel additive is obtained by mixing ethanol, CS2, gasoline, glycerol, benzoyl peroxide and citric acid in any proportion; the emulsifier is obtained by mixing sodium dodecyl sulfate, sodium alkylbenzene sulfonate, polyethylene glycol, sodium oleate and sodium benzoate magnesium stearate in any proportion; and the hydrogen donor is obtained by mixing lithium aluminum hydride, sodium borohydride, formic acid, hydrazine and calcium hydride in any proportion.

[0055] Example 7: As an optimization of the above example, in step S3, the chemical self-heating system is injected into the reservoir containing the catalyst precursor, including:

[0056] S11, a gelatin capsule is coated on the outer layer of the oxidant to obtain an oxidant capsule;

[0057] S12, oxidant capsules are injected into the reservoir layer containing dispersed catalyst precursors via a polymer solution;

[0058] S13, the reducing agent, fuel additive, emulsifier and hydrogen donor are mixed to obtain a mixture;

[0059] S14, after flushing the well with foam fluid, inject the mixture into the reservoir layer containing the catalyst precursor.

[0060] Example 8: As an optimization of the above example, in step S3, the redox exothermic reaction temperature is 150°C to 500°C.

[0061] Example 9: As an optimization of the above embodiment, in step S4, the injection rate of air or oxygen is 6000 Nm. 3 / d to 8000Nm 3 / d.

[0062] Example 10: As an optimization of the above embodiment, in step S5, during the self-generated combustion reaction, the injection volume of air or oxygen is adjusted so that the temperature of the combustion front is 500°C to 700°C and the advancing speed of the combustion front is 0.04 m / d to 0.16 m / d.

[0063] This invention constructs a synergistic extraction technology of "chemical autogenous thermal reaction - in-situ catalyst synthesis - dynamic control of combustion parameters". On the one hand, it uses the heat released by the in-situ chemical autogenous thermal reaction in the reservoir to drive the direct synthesis of a composite catalyst with high activity and high stability from the catalyst precursor in the underground reservoir. On the other hand, it uses the in-situ synthesized composite catalyst to reduce the activation energy of crude oil cracking and the reservoir ignition temperature (50°C to 100°C lower than the traditional ignition method), thereby enhancing the low-temperature catalytic viscosity reduction and lightening reaction of heavy oil.

[0064] Among them, the in-situ synthesis process of the composite catalyst is as follows: Figure 1 As shown, this invention involves injecting a polymeric electrolyte solution containing anionic and cationic catalyst precursors into the ground via injection well 1 using a high-pressure pump. The reservoir layer 4 lies between the reservoir top plate 3 and the reservoir bottom plate 5, and injection well 1 and production well 2 penetrate and extend into the reservoir layer 4.

[0065] In this invention, a catalyst precursor formed by a portion of the anionic metal complex 12 and the cationic metal complex 13 in the polymeric electrolyte solution comes into contact with the heavy oil macromolecules 11 in the reservoir layer 4, thereby reducing the viscosity of the underground crude oil.

[0066] Simultaneously, a self-generating chemical heating system composed of oxidant 6, reducing agent 7, fuel additive 8, and emulsifier 9 is injected underground. This system reacts with the catalyst precursor in an exothermic redox reaction, releasing heat and allowing the metal ions at the injection end to synthesize composite catalyst 10 in situ (i.e., after the catalyst precursor is injected underground, it undergoes a chemical reaction and transforms into another form of catalyst). The synthesized composite catalyst 10 can lower the ignition point of crude oil. After igniting the oil reservoir, the generated gas will push the heavy oil small molecules 14 towards the production well 2. At the same time, the heat transported will cause the downstream metal ions to synthesize composite catalyst 10 in situ, further lowering the ignition point of the downstream crude oil, thereby realizing the underground in-situ catalytic combustion extraction of low-permeability heavy oil, extra-heavy oil, and complex lithological reservoirs.

[0067] Meanwhile, by replacing external heating methods such as electric heating and steam preheating with self-generated heat reaction, equipment investment and heat energy loss are reduced, which is especially suitable for deep oil reservoirs. The heat energy utilization rate is increased from less than 40% to more than 60%, and the recovery rate of complex oil reservoirs can be increased from less than 30% to more than 45%, ultimately achieving a significant improvement in the efficiency and economic benefits of complex oil reservoir development.

[0068] Subsequent oil recovery operations using the conventional fire-burning method can also efficiently extract remaining oil and gas from the reservoir.

[0069] Example 11: A typical oil reservoir development area was selected, characterized by high viscosity and low permeability, making traditional development methods inefficient. An injection well (1) and a production well (2) were drilled in this area to ensure both wells reach the target reservoir, preparing for subsequent chemical reagent injection and oil and gas extraction.

[0070] The typical underground in-situ catalytic combustion extraction method in this oil reservoir development area includes:

[0071] S1, dissolving anionic metal complex 12 and cationic metal complex 13 in a polymeric electrolyte solution to prepare a catalyst precursor, comprising:

[0072] [NiCl4] 2- [AlCl4] - [AuCl4] - Dissolving in a polyelectrolyte solution yields an anionic catalyst precursor, in which [NiCl4] is present. 2- [AlCl4] - [AuCl4] - The mass ratio is 1:1:1;

[0073] Alkali metal ions, iron-based transition metal ions, and platinum-based transition metal ions are dissolved in a polymer electrolyte solution to obtain a cationic catalyst precursor. The mass ratio of alkali metal ions, iron-based transition metal ions, and platinum-based transition metal ions in the obtained cationic catalyst precursor is 1:1.5:2. Among them, the alkali metal ions are Li, the iron-based transition metal ions are Ni and Fe, and the platinum-based transition metal ions are Pt and Ir.

[0074] Anionic catalyst precursor and cationic catalyst precursor are mixed at a mass ratio of 1:1 to obtain catalyst precursor;

[0075] S2, inject 0.5 wt% of the catalyst precursor of the crude oil in the reservoir into the reservoir to make the catalyst precursor uniformly dispersed in the reservoir.

[0076] S3 involves injecting a chemically self-heating system into the reservoir containing a dispersed catalyst precursor, causing an exothermic redox reaction that releases heat to heat the reservoir (the specific process is as follows). Figure 1 (as shown), including:

[0077] An oxidizing agent capsule is obtained by coating a gelatin capsule with 20% of an oxidizing agent (a mixture of potassium permanganate, potassium chlorate, potassium nitrate, potassium dichromate, and sodium bismuthate in a mass ratio of 5:3:2:3:1).

[0078] Oxidant capsules are injected into oil reservoirs containing dispersed catalyst precursors via polymer solutions.

[0079] A mixture is prepared by mixing 30% of a reducing agent (a mixture of carbon powder, magnesium powder, aluminum powder, zinc powder, and iron powder in a mass ratio of 2:3:3:3:2), 20% of a fuel additive (a mixture of ethanol, CS2, gasoline, glycerol, benzoyl peroxide, and citric acid in a mass ratio of 1:1:1:2:1:1), 15% of an emulsifier (a mixture of sodium dodecyl sulfate, sodium alkylbenzene sulfonate, polyethylene glycol, sodium oleate, sodium benzoate, and magnesium stearate in a mass ratio of 2:1.5:1:1.5:3), and 10% of a hydrogen donor (a mixture of lithium aluminum hydride, sodium borohydride, formic acid, hydrazine, and calcium hydride in a mass ratio of 1:3:2:1.5:2).

[0080] After flushing the well with foaming fluid, the mixture is then injected into the reservoir containing the catalyst precursor.

[0081] S4, continuously inject air (7000 Nm³) into the reservoir. 3 / d), the crude oil in the reservoir undergoes an autogenous combustion reaction;

[0082] S5, the gas generated in the autogenous combustion reaction drives crude oil to the production well, enabling the exploitation of low-permeability heavy oil, extra-heavy oil and complex lithology temperature-controlled reservoirs.

[0083] Real-time monitoring of the combustion front temperature at the bottom of the well (target 500℃ to 700℃) is conducted. If the temperature exceeds 700℃, the air injection rate is reduced, and the combustion front advance speed is maintained at 0.1 m / d to prevent fracture blockage or flameout. Products are collected from the production well, and the produced oil is analyzed to determine its viscosity, composition, and other indicators, evaluating the effectiveness of the composite catalyst in reducing crude oil viscosity and promoting crude oil cracking. Simultaneously, the concentrations of CO2 and O2 in the produced gas are monitored to assess the combustion status of the reservoir.

[0084] In Embodiment 11 of the present invention, compared with the traditional ignition method, the activation energy of crude oil cracking and the reservoir ignition temperature are reduced (the reservoir ignition temperature is reduced by 75°C), the thermal energy utilization rate is increased to 80%, and the reservoir recovery rate is increased to 47%.

[0085] Example 12:

[0086] The difference from Example 11 is as follows:

[0087] In step S1, the obtained anionic catalyst precursor contains [FeCl4]. - [ZnCl4] 2- [PtCl4] 2- The mass ratio is 1:1:1;

[0088] A cationic catalyst precursor was obtained, wherein the mass ratio of alkali metal ions, iron-based transition metal ions, and platinum-based transition metal ions in the cationic catalyst precursor was 1:1.5:2. Among them, the alkali metal ion was Na, the iron-based transition metal ion was Ni, and the platinum-based transition metal ion was Pt.

[0089] In step S3, the following mixtures are used: 15% oxidant (a mixture of potassium permanganate, potassium chlorate, potassium nitrate, potassium dichromate, and sodium bismuthate in a mass ratio of 1:5:3:2:3), 35% reducing agent (a mixture of carbon powder, magnesium powder, aluminum powder, zinc powder, and iron powder in a mass ratio of 3:2:2:3:3), 15% fuel additive (a mixture of ethanol, CS2, gasoline, glycerol, benzoyl peroxide, and citric acid in a mass ratio of 2:1:1:2:2:1), 10% emulsifier (a mixture of sodium dodecyl sulfate, sodium alkylbenzene sulfonate, polyethylene glycol, sodium oleate, sodium benzoate, and magnesium stearate in a mass ratio of 1.5:1:2:3:1.5), and 15% hydrogen donor (a mixture of lithium aluminum hydride, sodium borohydride, formic acid, hydrazine, and calcium hydride in a mass ratio of 2:1:1.5:2:3).

[0090] The remaining steps and processes are the same as in Example 11.

[0091] In Embodiment 12 of the present invention, compared with the traditional ignition method, the activation energy of crude oil cracking and the reservoir ignition temperature are reduced (the reservoir ignition temperature is reduced by 75°C), the thermal energy utilization rate is increased to 76%, and the reservoir recovery rate is increased to 45%.

[0092] Example 13:

[0093] The difference from Example 11 is that in the obtained anionic catalyst precursor, [CoCl4] 2- [AlCl4] - [PtCl4] 2- The mass ratio is 1:1:1;

[0094] In the obtained cationic catalyst precursor, the mass ratio of alkali metal ions, iron-based transition metal ions, and platinum-based transition metal ions is 1:1.5:2. Among them, the alkali metal ions are K, the iron-based transition metal ions are Fe, and the platinum-based transition metal ions are Ru.

[0095] The remaining steps and processes are the same as in Example 11.

[0096] In Embodiment 13 of the present invention, compared with the traditional ignition method, the activation energy of crude oil cracking and the reservoir ignition temperature are reduced (the reservoir ignition temperature is reduced by 75°C), the thermal energy utilization rate is increased to 78%, and the reservoir recovery rate is increased to 46%.

[0097] In summary, this invention not only utilizes the heat released by in-situ chemical autogenous thermal reaction in the reservoir to drive the direct synthesis of a composite catalyst with high activity and high stability from the catalyst precursor, but also uses in-situ catalyst synthesis to reduce the activation energy of crude oil cracking and the ignition temperature of the reservoir. At the same time, the autogenous thermal reaction reduces equipment investment and heat energy loss, thereby meeting the exploitation needs of low-permeability heavy oil, extra-heavy oil and complex lithology reservoirs.

[0098] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. A method for in-situ underground catalytic combustion extraction of low-permeability heavy oil, extra-heavy oil, and complex lithological reservoirs, characterized in that... include: S1, anionic metal complexes and cationic metal complexes are dissolved in a polymeric electrolyte solution to prepare a catalyst precursor, wherein the anions in the anionic metal complexes include [AlCl4]. - and [ZnCl4] 2- One or more of the following, [AuCl4] - and [PtCl4] 2- One or more of the following, as well as iron-based transition metal coordination anions, and the cations in the cationic metal complex include alkali metal ions and transition metal ions; S2, the catalyst precursor is injected into the reservoir to uniformly disperse it in the reservoir, wherein the amount of catalyst precursor injected is 0.5 wt% of the crude oil mass in the reservoir; S3, injecting a chemically self-heating system into the reservoir containing a catalyst precursor, causing an exothermic redox reaction and releasing heat to heat the reservoir; S4, continuously inject air or oxygen into the reservoir, and synthesize composite catalysts in situ in the reservoir from catalyst precursors, thereby reducing the cracking activation energy of crude oil and the ignition temperature of the reservoir, so that the crude oil in the reservoir undergoes autogenous combustion reaction. S5, the gas generated in the autogenous combustion reaction drives crude oil to the production well, enabling the exploitation of low-permeability heavy oil, extra-heavy oil and complex lithology temperature-controlled reservoirs.

2. The underground in-situ catalytic combustion extraction method for low-permeability heavy oil, extra-heavy oil, and complex lithological reservoirs according to claim 1, characterized in that... In step S1, the specific process for preparing the catalyst precursor includes: S01, dissolve the anionic metal complex in a polymeric electrolyte solution to obtain an anionic catalyst precursor; SO2 is used to dissolve cationic metal complexes in a polymeric electrolyte solution to obtain a cationic catalyst precursor. S03, anionic catalyst precursor and cationic catalyst precursor are mixed at a mass ratio of 1:1 to obtain catalyst precursor.

3. The underground in-situ catalytic combustion extraction method for low-permeability heavy oil, extra-heavy oil, and complex lithological reservoirs according to claim 2, characterized in that... In step S1, the iron-based transition metal coordination anion is [NiCl4]. 2- [FeCl4] - [CoCl4] 2- One or more of them.

4. The underground in-situ catalytic combustion extraction method for low-permeability heavy oil, extra-heavy oil, and complex lithological reservoirs according to claim 2 or 3, characterized in that... In step S1, the alkali metal ions include one or more of Li, Na, and K, and the transition metal ions include iron-based transition metals and platinum-based transition metals. The iron-based transition metals include one or more of Ni, Fe, and Co, and the platinum-based transition metals include one or more of Pt, Ir, and Ru.

5. The underground in-situ catalytic combustion extraction method for low-permeability heavy oil, extra-heavy oil, and complex lithological reservoirs according to claim 4, characterized in that... In step S3, the chemically self-generating heat system comprises, by mass percentage, 30% to 35% of reducing agent, 15% to 20% of oxidant, 15% to 20% of fuel additive, 10% to 15% of emulsifier, and 10% to 15% of hydrogen donor.

6. The underground in-situ catalytic combustion extraction method for low-permeability heavy oil, extra-heavy oil, and complex lithological reservoirs according to claim 5, characterized in that... The reducing agent is obtained by mixing carbon powder, magnesium powder, aluminum powder, zinc powder and iron powder in any proportion; the oxidizing agent is obtained by mixing potassium permanganate, potassium chlorate, potassium nitrate, potassium dichromate and sodium bismuthate in any proportion; the fuel additive is obtained by mixing ethanol, CS2, gasoline, glycerol, benzoyl peroxide and citric acid in any proportion; the emulsifier is obtained by mixing sodium dodecyl sulfate, sodium alkylbenzene sulfonate, polyethylene glycol, sodium oleate and sodium benzoate magnesium stearate in any proportion; and the hydrogen donor is obtained by mixing lithium aluminum hydride, sodium borohydride, formic acid, hydrazine and calcium hydride in any proportion.

7. The underground in-situ catalytic combustion extraction method for low-permeability heavy oil, extra-heavy oil, and complex lithological reservoirs according to claim 1, 2, 3, 5, or 6, characterized in that... In step S3, the chemical self-heating system is injected into the reservoir containing the catalyst precursor, including: S11, a gelatin capsule is coated on the outer layer of the oxidant to obtain an oxidant capsule; S12, oxidant capsules are injected into the reservoir layer containing dispersed catalyst precursors via a polymer solution; S13, the reducing agent, fuel additive, emulsifier and hydrogen donor are mixed to obtain a mixture; S14, after flushing the well with foam fluid, inject the mixture into the reservoir layer containing the catalyst precursor.

8. The underground in-situ catalytic combustion extraction method for low-permeability heavy oil, extra-heavy oil, and complex lithological reservoirs according to claim 7, characterized in that... In step S3, the exothermic redox reaction temperature is between 150°C and 500°C.

9. The underground in-situ catalytic combustion extraction method for low-permeability heavy oil, extra-heavy oil, and complex lithological reservoirs according to claim 1, 2, 3, 5, 6, or 8, characterized in that... In step S4, the injection rate of air or oxygen is 6000 Nm. 3 / d to 8000Nm 3 / d.

10. The underground in-situ catalytic combustion extraction method for low-permeability heavy oil, extra-heavy oil, and complex lithological reservoirs according to claim 9, characterized in that... In step S5, during the self-generated combustion reaction, the injection volume of air or oxygen is adjusted so that the temperature of the combustion front is 500℃ to 700℃ and the advancing speed of the combustion front is 0.04m / d to 0.16m / d.

Images