Method and apparatus for in-situ heating of oil and gas and uranium recovery

Abstract

The application provides a method and device for in-situ heating and simultaneous exploitation of oil and gas and uranium, comprising: based on the experimental measurement values of the original uranium content of the rock sample, the oil and gas production amount and the uranium extraction amount at different temperatures, calculating the oil and gas production abundance and the uranium extraction abundance of unit volume of rock in-situ heating, determining the target stratum section for simultaneous exploitation through threshold screening; carrying out in-situ heating exploitation of oil and gas generated by organic matter cracking, injection of displacement fluid to produce residual oil and gas in the stratum, back injection of purified produced gas to oxidize uranium in the stratum with air, injection of uranium dissolution solution to cyclically exploit uranium, and taking the uranium concentration of the produced liquid lower than the preset threshold as the exploitation termination condition. The application solves the problems of poor simultaneity of independent exploitation of oil and gas and uranium, lack of quantitative temperature standard for layer selection, low uranium extraction rate and low utilization rate of exploitation by-products, realizes the whole process simultaneity from resource evaluation to exploitation, improves the layer selection accuracy, the oil and gas recovery rate and the uranium extraction efficiency, and provides reliable technical support for efficient development of oil and gas and uranium co-associated resources.

Description

Technical Field

[0001] This invention belongs to the field of in-situ heating and co-extraction of oil, gas and uranium in oil and gas exploration and development, and particularly relates to a method and apparatus for in-situ heating and co-extraction of oil, gas and uranium. Background Technology

[0002] With the continuous advancement of deep energy exploration and development, the comprehensive development of resources in formations where oil, gas, and uranium coexist has gradually become a focus of industry attention. In existing technologies, oil and gas resources and uranium resources are generally extracted independently, with oil and gas extraction projects and uranium mining operations deployed separately. The two are independent in terms of formation evaluation, extraction process, and by-product utilization.

[0003] In the resource evaluation and formation selection stages, existing technologies lack a unified quantitative evaluation standard suitable for collaborative mining; the discrepancy between well logging data and the actual uranium content of the formation leads to insufficient accuracy in the selection of target mining formations, making it difficult to support precise decision-making for collaborative mining.

[0004] In the mining operation process, the existing independent mining mode is difficult to achieve synergistic efficiency of mining technology: the associated gases generated during the in-situ heating and extraction of oil and gas are usually only simply purified and transported or directly discharged, resulting in the waste of associated gas resources, increasing the difficulty of subsequent uranium dissolution and extraction, and the overall extraction efficiency of uranium resources is low.

[0005] In the management and control of uranium mining, existing technologies rely heavily on experience to determine the mining endpoint, which can easily lead to problems such as insufficient mining resulting in low resource recovery rates, or over-mining leading to increased operating costs. The control and control of the mining process lacks precision and economic efficiency.

[0006] In summary, existing technologies for the exploitation of associated oil and gas resources with uranium suffer from drawbacks such as low accuracy in target layer evaluation, poor coordination in the exploitation process, and insufficient uranium extraction efficiency, making it difficult to meet the actual needs for efficient and economically coordinated development of associated resources. Summary of the Invention

[0007] This invention provides a method for in-situ heating and co-development of oil, gas, and uranium. This method combines in-situ heating and co-development of oil and gas with the following steps: calculating abundance based on experimental measurements of rock samples and determining target formations using dual thresholds; in-situ heating and development of oil and gas; displacement extraction of residual oil and gas followed by reinjection to purify produced gas; and threshold control of uranium dissolution fluid circulation injection and production. This method effectively solves the problems of poor synergy in traditional independent oil, gas, and uranium resource development, lack of quantitative temperature-related evaluation standards for target formation selection, insufficient accuracy in uranium mining termination determination, and low utilization rate of mining by-products. It achieves coordinated operations from resource evaluation and formation selection to oil and gas development and uranium extraction, improving the accuracy of target formation selection, oil and gas recovery rate, and uranium extraction efficiency. This provides reliable technical support for the efficient co-development of associated oil, gas, and uranium resources. The method includes: Experimental measurements of the original uranium content of rock samples were obtained, as well as experimental measurements of the amount of oil and gas produced and the amount of uranium extracted from rock samples when heated in situ at different temperatures. Based on the experimental measurements of the original uranium content of the rock samples, as well as the experimental measurements of the amount of oil and gas produced and the amount of uranium extracted from the rock samples at different in-situ heating temperatures, the abundance of oil and gas produced and the abundance of uranium extracted per unit volume of rock by in-situ heating are calculated. The target stratigraphic interval for in-situ heating co-mining is determined based on the abundance of oil and gas produced by in-situ heating and the abundance of uranium extracted by in-situ heating per unit volume of rock. Controlled in-situ heating of the target formation section to extract oil and gas generated by the cracking of formation organic matter; After in-situ heating extraction or after heating is stopped, displacement fluid is injected into the target formation to extract residual oil and gas trapped in the formation; after the residual oil and gas extraction is completed, purified in-situ heated gas and air are reinjected into the target formation. The uranium dissolving solution is injected into the target formation section and uranium-containing solution is extracted; when the uranium concentration in the extracted uranium-containing solution is lower than a preset mining threshold, mining is stopped.

[0008] This invention provides an in-situ heated co-extraction device for oil, gas, and uranium. This method combines in-situ heated extraction of oil and gas with the following steps: calculating abundance based on experimental measurements of rock samples and determining target formations using dual thresholds; in-situ heated extraction of oil and gas; displacement extraction of residual oil and gas followed by reinjection to purify produced gas; and uranium dissolution fluid circulation injection-production threshold control. This effectively solves the problems of poor synergy in traditional independent oil, gas, and uranium resource extraction, lack of quantitative temperature-related evaluation standards for target formation selection, insufficient accuracy in uranium mining termination determination, and low utilization rate of mining by-products. It achieves coordinated operations from resource evaluation and formation selection to oil and gas extraction and uranium extraction, improving the accuracy of target formation selection, oil and gas recovery rate, and uranium extraction efficiency. This provides reliable technical support for the efficient co-extraction of associated oil, gas, and uranium resources. The in-situ heated co-extraction device for oil, gas, and uranium includes: The data acquisition module is used to acquire the original experimental measurement values ​​of uranium content in rock samples, as well as the experimental measurement values ​​of oil and gas production and uranium extraction from rock samples heated in situ at different temperatures. The abundance calculation module is used to calculate the abundance of oil and gas produced by in-situ heating and the abundance of uranium extracted by in-situ heating per unit volume of rock, based on the original experimental measurement of uranium content in rock samples, as well as the experimental measurement of oil and gas production and uranium extraction from rock samples at different in-situ heating temperatures. The target stratigraphic interval determination module is used to determine the target stratigraphic interval for in-situ heating co-mining based on the abundance of oil and gas produced by in-situ heating and the abundance of uranium extracted by in-situ heating per unit volume of rock. The in-situ heating module is used to control the in-situ heating of the target formation section to extract oil and gas generated by the cracking of formation organic matter; The oil and gas extraction module is used to control the injection of displacement fluid into the target formation after in-situ heating extraction or after heating is stopped, to extract the residual oil and gas remaining in the formation; after the residual oil and gas extraction is completed, it controls the reinjection of purified in-situ heated gas and air into the target formation. The uranium mining module is used to control the injection of uranium dissolving fluid into the target formation and to extract uranium-containing solution; when the uranium concentration in the extracted uranium-containing solution is lower than a preset mining threshold, mining is stopped.

[0009] In this embodiment of the invention, the original experimental measurement value of uranium content of rock samples, as well as the experimental measurement values ​​of oil and gas production and uranium extraction of rock samples under in-situ heating at different temperatures, are obtained. Based on the original experimental measurement value of uranium content of rock samples, and the experimental measurement values ​​of oil and gas production and uranium extraction of rock samples under in-situ heating at different temperatures, the abundance of oil and gas produced and the abundance of uranium extracted per unit volume of rock under in-situ heating are calculated. Based on the abundance of oil and gas produced and the abundance of uranium extracted per unit volume of rock under in-situ heating, the target formation for in-situ heating and co-mining are determined. In-situ heating of the target formation is controlled to extract oil and gas generated by the cracking of formation organic matter. Displacement fluid is injected into the target formation after in-situ heating or after heating is stopped to extract residual oil and gas remaining in the formation. After the residual oil and gas extraction is completed, purified oil and gas is reinjected into the target formation. In-situ heating produces gas and air; controlled injection of uranium dissolving solution into the target formation section to extract uranium-containing solution; when the uranium concentration in the extracted uranium-containing solution is lower than a preset mining threshold, mining is stopped; this embodiment of the invention effectively solves the problems of poor coordination between traditional independent oil and gas and uranium resource mining, lack of quantitative temperature correlation evaluation standards for target formation section selection, insufficient accuracy of uranium mining termination determination, and low utilization rate of mining by-products by means of uranium dissolving solution. It realizes coordinated operation from resource evaluation and selection, oil and gas extraction to uranium resource extraction, improves the accuracy of target formation section selection, oil and gas recovery rate and uranium resource extraction efficiency, and provides reliable technical support for the efficient coordinated mining of oil and gas and uranium co-existing resources. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 This is a flowchart of the in-situ heating and co-extraction method for oil, gas and uranium in an embodiment of the present invention; Figure 2 This is a specific example of calculating the abundance of oil and gas produced by in-situ heating of a unit volume of rock and the abundance of uranium extracted by in-situ heating in an embodiment of the present invention; Figure 3 This is a comparison chart of uranium content values ​​in embodiments of the present invention; Figure 4 This is a graph showing the uranium content extracted by in-situ heating at different temperatures in this embodiment of the invention. Figure 5 This is a specific example of in-situ heating of the target stratum in an embodiment of the present invention; Figure 6 This is a specific example of reinjecting purified in-situ heated gas and air into a target formation according to an embodiment of the present invention; Figure 7 This is a structural example diagram of an apparatus for in-situ heating and co-extraction of oil, gas and uranium in an embodiment of the present invention. Detailed Implementation

[0011] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0012] Figure 1 This is a flowchart of the in-situ heating and co-extraction method for oil, gas and uranium extraction in an embodiment of the present invention, as shown below. Figure 1 As shown, the method for in-situ heating and co-extraction of oil, gas, and uranium includes: Step 101: Obtain the original experimental measurement value of uranium content in the rock sample, as well as the experimental measurement value of oil and gas production and uranium extraction of the rock sample under in-situ heating at different temperatures; Step 102: Based on the experimentally measured values ​​of the original uranium content of the rock samples, as well as the experimentally measured values ​​of the amount of oil and gas produced and the amount of uranium extracted from the rock samples at different in-situ heating temperatures, calculate the abundance of oil and gas produced and the abundance of uranium extracted per unit volume of rock by in-situ heating. Step 103: Determine the target stratigraphic interval for in-situ heating co-mining based on the abundance of oil and gas produced by in-situ heating and the abundance of uranium extracted by in-situ heating per unit volume of rock. Step 104: Control the in-situ heating of the target formation section to extract oil and gas generated by the cracking of formation organic matter; Step 105: After in-situ heating extraction or after heating is stopped, inject displacement fluid into the target formation section to extract residual oil and gas trapped in the formation; after the residual oil and gas extraction is completed, reinject purified in-situ heated gas and air into the target formation section. Step 106: Control the injection of uranium dissolving fluid into the target formation section and extract uranium-containing solution; when the uranium concentration in the extracted uranium-containing solution is lower than the preset mining threshold, stop mining.

[0013] Depend on Figure 1 As shown in the flowchart, in this embodiment of the invention, the original experimental measurement value of uranium content of the rock sample is obtained, as well as the experimental measurement values ​​of oil and gas production and uranium extraction of the rock sample under in-situ heating at different temperatures. Based on the original experimental measurement value of uranium content of the rock sample, and the experimental measurement values ​​of oil and gas production and uranium extraction of the rock sample under in-situ heating at different temperatures, the abundance of oil and gas produced and the abundance of uranium extracted per unit volume of rock under in-situ heating are calculated. The process involves: determining the target formation for in-situ heating and co-mining; controlling in-situ heating of the target formation to extract oil and gas generated from the cracking of formation organic matter; controlling the injection of displacement fluid into the target formation after in-situ heating or after heating is stopped to extract residual oil and gas remaining in the formation; controlling the reinjection of purified in-situ heated gas and air into the target formation after the residual oil and gas extraction is completed; controlling the injection of uranium dissolving liquid into the target formation to extract uranium-containing solution; and stopping mining when the uranium concentration in the extracted uranium-containing solution is lower than a preset mining threshold.

[0014] Compared with existing technologies, this method calculates the abundance of oil and gas produced and the abundance of uranium extracted per unit volume of rock by using experimental measurements of the original uranium content of rock samples and experimental measurements of oil and gas production and uranium extraction at different in-situ heating temperatures. This helps determine the target formation for in-situ heating-assisted mining. First, in-situ heating is carried out on the target formation to extract oil and gas generated from the cracking of formation organic matter. Then, during the later stages of in-situ heating or after heating is stopped, displacement fluids are injected to extract residual oil and gas remaining in the formation. After the residual oil and gas extraction is completed, purified in-situ heated gas is reinjected along with air. The process involves injecting uranium dissolving solution into the target formation to extract uranium, stopping mining when the uranium concentration in the extracted uranium-containing solution falls below a preset mining threshold. This effectively solves the problems of poor coordination between traditional independent oil and gas and uranium resource extraction, lack of quantitative temperature correlation evaluation standards for target formation selection, insufficient accuracy in uranium mining termination determination, and low utilization rate of mining by-products. It realizes coordinated operations from resource evaluation and formation selection, oil and gas extraction to uranium resource extraction, improving the accuracy of target formation selection, oil and gas recovery rate, and uranium resource extraction efficiency, and providing reliable technical support for the efficient coordinated mining of oil, gas, and uranium co-existing resources.

[0015] In step 101, the experimental measurements of the original uranium content of the rock sample are obtained, as well as the experimental measurements of the amount of oil and gas produced and the amount of uranium extracted from the rock sample when heated in situ at different temperatures.

[0016] In a specific embodiment, the original uranium content of the rock sample was obtained through experiments, as well as the oil and gas production and uranium extraction quantities under different heating temperatures. This provides basic experimental data support for the subsequent calculation of oil and gas production and uranium extraction abundance per unit volume of rock and the selection of target layers.

[0017] The rock samples used in the experiment were collected from systematic core wells of the target strata in the study area. Rock samples from the same region, stratum, and depth were grouped and prepared into two types: pulverized samples and cylindrical samples. The particle size of the pulverized samples was controlled within the range of 0.2 mm to 0.5 mm, used to measure the original uranium content and maximum extractable uranium content of the rock. The cylindrical samples were processed into standard cylinders with a diameter of 8 cm and a length of 10 cm to simulate the uranium extraction effect under in-situ underground reservoir conditions. The sample collection density was set at 0.5 m / point to 2 m / point, covering the complete target stratum to ensure the stratigraphic representativeness of the experimental data.

[0018] The original uranium content experimental measurement value was obtained by full chemical extraction of crushed rock samples in their natural state. The samples were soaked and extracted twice using 6 mol / L HCl solution and 6 mol / L HF:HNO3=1:1 solution, with each soaking lasting 10 days. The sum of the uranium content obtained from the two extractions was taken as the total uranium content of the sample. The average value of the measurements of multiple parallel samples was taken as the original uranium content benchmark value of the rocks in this stratum, characterizing the uranium abundance in the natural state of the stratum.

[0019] The measured values ​​of oil and gas production under in-situ heating at different temperatures were obtained through multi-temperature gradient thermal simulation experiments conducted in a semi-open thermal simulation system. The experimental system was set with a hydrocarbon backpressure of 2 MPa and 11 preset heating temperatures: 100℃, 150℃, 200℃, 250℃, 300℃, 350℃, 400℃, 450℃, 500℃, 550℃, and 600℃. Each temperature group corresponded to an independent rock sample experimental group. A stepped heating process was adopted, with the time to rise from room temperature to the preset temperature taking 2 days, followed by a 90-hour constant-temperature holding period. During the heating process, light oil and natural gas products generated from the cracking of organic matter in the rock were continuously collected. The total oil and gas production per unit mass of rock under different temperature conditions was measured to obtain the experimental measured values ​​of oil and gas production at the corresponding temperature gradient.

[0020] The experimental measurements of uranium extraction yield under in-situ heating at different temperatures were conducted after the thermal simulation experiments at the corresponding temperatures were completed and the rock samples were allowed to cool naturally to room temperature. For both pulverized and cylindrical samples heated to different temperatures, extraction was performed twice using 6 mol / L HCl solution and 6 mol / L HF:HNO3 = 1:1 solution, with each soak lasting 10 days. The sum of the uranium extracted in both soaks was taken as the total uranium extraction yield under those temperature conditions. The extraction result for the pulverized sample corresponds to the maximum extractable uranium content of the rock, while the extraction result for the cylindrical sample closely approximates the actual uranium extraction effect from underground in-situ mining. Finally, two sets of experimental measurements were obtained for the uranium extraction yield per unit mass of rock at different heating temperatures: one for pulverized samples and one for cylindrical samples.

[0021] Figure 2 This is a specific example diagram illustrating the calculation of hydrocarbon abundance and uranium extraction abundance per unit volume of rock by in-situ heating, as described in this invention. Figure 2 As shown, based on the experimentally measured original uranium content of rock samples, and the experimentally measured oil and gas production and uranium extraction amounts of rock samples heated in situ at different temperatures, the in-situ heating oil and gas production abundance and in-situ heating uranium extraction abundance per unit volume of rock can be calculated, which may include: Step 201: Determine the uranium content distribution data based on the original experimental measurements of uranium content in the rock sample; Step 202: Calculate the oil and gas abundance per unit volume of rock produced by in-situ heating based on the experimental measurements of oil and gas production from rock samples at different in-situ heating temperatures. Step 203: Based on the experimental measurements of uranium extraction from rock samples at different in-situ heating temperatures, establish the correlation between in-situ heating temperature and uranium extraction rate. Step 204: Based on the uranium content distribution data and the correspondence between in-situ heating temperature and uranium extraction rate, calculate the uranium abundance extracted per unit volume of rock by in-situ heating.

[0022] In a specific embodiment, based on experimental measurement data, the spatial distribution of uranium content is calibrated, the oil and gas abundance per unit volume is converted, the temperature-uranium extraction rate relationship is modeled, and the uranium abundance per unit volume is calculated, forming a complete abundance quantification system. All parameters and calculation logic match the experimental results and geological reality, providing accurate quantitative basis for target layer selection and resource quantity accounting.

[0023] In step 201, uranium content distribution data are determined based on the original experimental measurements of uranium content in the rock samples. Using the experimental measurements of uranium content in the original formation rock samples as a calibration benchmark, a relationship model is established with the corresponding depth gamma-ray spectral logging uranium measurement values ​​to complete the calibration and correction of the gamma-ray spectral logging uranium content values. Figure 3 This is a comparison chart of uranium content values ​​in embodiments of the present invention, such as... Figure 3 As shown, the calibrated gamma spectroscopy logging uranium content values ​​are in good agreement with the experimentally measured uranium concentration, with a relative error of less than 5.3%. Under in-situ heating to 360℃, the uranium concentration extracted from the cylindrical sample is lower than that extracted from the crushed sample, with a ratio of approximately 56%. The uranium concentration obtained from the crushed sample is the maximum obtainable uranium concentration, used to calculate the total uranium resources. The conditions for extracting uranium from the cylindrical sample are closer to the conditions for in-situ underground mining, and the corresponding results are used to calculate the recoverable uranium resources.

[0024] Using calibrated gamma spectral logging data, continuous uranium content distribution data along the depth direction of the target layer can be obtained throughout the well. Combined with the rock density parameters of the target layer, the original uranium abundance per unit volume of rock can be further calculated, thus fully depicting the uranium occurrence and distribution characteristics under natural formation conditions.

[0025] In step 202, the in-situ heating hydrocarbon abundance per unit volume of rock is calculated based on experimental measurements of hydrocarbon production from rock samples at different in-situ heating temperatures. Based on the measured hydrocarbon production per unit mass of rock at each temperature gradient obtained from semi-open thermal simulation experiments, and combined with the rock density parameters of the target layer, the in-situ heating hydrocarbon abundance per unit volume of rock at the corresponding heating temperature is calculated. Besides the experimental conversion method, the in-situ heating hydrocarbon production per unit volume of rock can also be calculated based on the total organic carbon content, vitrinite reflectance, retained oil volume, and layer thickness parameters of the study layer. Furthermore, the in-situ heating hydrocarbon production per unit volume of the study layer can be determined by constructing a geological model and using numerical simulation methods. Multiple calculation methods can be cross-checked to ensure the accuracy of the hydrocarbon abundance data.

[0026] In step 203, based on the experimental measurements of uranium extraction from rock samples at different in-situ heating temperatures, a correlation between in-situ heating temperature and uranium extraction rate is established.

[0027] Figure 4 This is a graph showing the uranium content extracted by in-situ heating at different temperatures in embodiments of the present invention, such as... Figure 4 As shown, based on the original uranium content of the rock, the uranium extraction rate at each heating temperature was calculated, establishing a quantitative correlation between in-situ heating temperature and uranium extraction rate. Experimental results show that the uranium extraction rate generally increases with increasing heating temperature, reaching approximately 2.5% at room temperature and approximately 73.5% at 600℃. Specifically, the increase in uranium extraction is relatively small before 250℃, with a significant increase between 300℃ and 450℃, and a significant decrease in the increase after 450℃. This evolutionary pattern matches the characteristics of increased formation porosity and permeability during in-situ heating. Temperature-extraction rate relationships were established for both pulverized and cylindrical samples: the extraction results for pulverized samples corresponded to the maximum uranium extraction rate that can be extracted from the rock, used to calculate the total uranium resources; the extraction results for cylindrical samples closely approximate the in-situ reservoir conditions, corresponding to the actual uranium extraction rate under in-situ mining scenarios, used to calculate the amount of recoverable uranium resources; for example, when heated in-situ to 360℃, the uranium extraction amount of cylindrical samples is approximately 56% of that of pulverized samples; the uranium extraction amount when heated in-situ to 450℃ is approximately 69% of the extraction amount at 600℃.

[0028] In step 204, the in-situ uranium abundance extracted per unit volume of rock is calculated by combining uranium content distribution data and the correspondence between in-situ heating temperature and uranium extraction rate. Based on the original uranium abundance per unit volume of rock, the uranium extraction rate corresponding to the target heating temperature is matched to calculate the in-situ uranium abundance extracted per unit volume of rock under that temperature condition. The maximum extractable uranium abundance calculated using the maximum extraction rate of pulverized samples is the maximum extractable uranium abundance per unit volume of rock, which can be used to calculate the total uranium resource quantity of the target layer; the actual recoverable uranium abundance calculated using the in-situ extraction rate of cylindrical samples is the actual recoverable uranium abundance per unit volume of rock, which can be used to calculate the recoverable uranium resource quantity under collaborative mining scenarios. Based on this, combined with the temperature distribution, rock density, uranium density, layer thickness, and distribution area parameters of the target layer, the total uranium resource quantity and recoverable uranium resource quantity of the target layer can be further calculated, providing complete quantitative support for the economic evaluation of mining and development scheme design of the target layer.

[0029] In step 103, the target stratum for in-situ heating-assisted mining is determined based on the abundance of oil and gas produced by in-situ heating per unit volume of rock and the abundance of uranium extracted by in-situ heating.

[0030] In a specific embodiment, the abundance of oil and gas produced by in-situ heating of rock per unit volume and the abundance of uranium extracted by in-situ heating are used as the core judgment indicators. Combined with the mining threshold, target strata are screened to clarify the stratigraphic range in which in-situ heating of oil and gas and uranium can be carried out in tandem, thus ensuring the technical feasibility and rationality of the mining plan.

[0031] For target formations to be used for in-situ heated co-extraction of oil, gas, and uranium, two criteria must be met simultaneously: first, the convertible organic matter within the formation must meet the oil and gas abundance threshold for per unit volume of rock under in-situ heated conditions; second, the uranium abundance extracted per unit volume of rock under different in-situ heated temperatures must meet the corresponding extraction threshold. The oil and gas abundance threshold for per unit volume of rock under in-situ heated conditions is determined based on experimental measurements of the oil and gas abundance produced by in-situ heated conditions at different temperatures; the uranium abundance threshold for per unit volume of rock under in-situ heated conditions is determined based on experimental measurements of the uranium abundance extracted by in-situ heated conditions at different temperatures.

[0032] The threshold determination preferably adopts an economic evaluation standard: the threshold for the abundance of oil and gas in in-situ heating extraction is preferably set at a value greater than or equal to the cost of oil and gas extraction from the target layer's organic matter and the oil retained therein through in-situ heating and conversion; the threshold for the abundance of uranium extraction is preferably set at a value greater than or equal to the cost of uranium extraction per unit volume. The value of the extracted oil and gas is the sum of the products of the amount of oil and gas produced during the entire in-situ heating process and its corresponding price; the cost of oil and gas extraction is the total cost of the oil and gas produced during the entire in-situ heating process, or the total cost corresponding to the amount of oil and gas produced per unit volume during the entire in-situ heating process.

[0033] Differentiated mining criteria are applied to study sections with different abundance characteristics: when a study section simultaneously meets the unit volume oil and gas production abundance threshold and the unit volume uranium abundance threshold for in-situ heated oil and gas and uranium co-mining, it is identified as the target formation for in-situ heated oil and gas and uranium co-mining; when a study section meets the unit volume oil and gas production abundance threshold for in-situ conversion oil and gas mining, but does not meet the unit volume uranium abundance threshold for uranium mining, it is only designated as an in-situ heated oil and gas mining formation, and uranium co-mining is not carried out.

[0034] Figure 5 This is a specific example diagram of in-situ heating of the target stratum in an embodiment of the present invention, as shown in the figure. Figure 5 As shown, controlling in-situ heating of the target formation section to extract oil and gas generated from the cracking of formation organic matter may include: Step 501: Deploy heating wells and production wells in the target formation section according to the preset ratio; Step 502: Control the in-situ heating of the target formation section through the heating well, raise the temperature of the target formation section to the preset temperature, and then control the production well to extract the oil and gas generated by the cracking of formation organic matter.

[0035] In this embodiment, the heating well and the production well are one or more combinations of horizontal wells, vertical wells, and directional wells.

[0036] In a specific embodiment, by optimizing the well network deployment and controlling in-situ heating, the cracking and transformation of solid organic matter in the target formation and the efficient production of oil and gas are achieved. The well type configuration, well layout ratio, well completion method and heating parameters are all matched with the reservoir characteristics of the target formation, ensuring the technical feasibility of heating extraction.

[0037] In step 501, heating wells and production wells are deployed in the target formation according to a preset ratio. The heating wells and production wells can be one or more combinations of horizontal wells, vertical wells, and directional wells. Preferably, both heating wells and production wells are horizontal wells to expand the heating coverage and improve oil and gas seepage efficiency. The heating wells and production wells are deployed in a preset ratio ranging from 100:1 to 5:1, with a further preferred ratio of 20:1 to 10:1, balancing the uniformity of heating coverage and the overall efficiency of oil and gas production. The well completion method can be casing perforation completion, casing perforation fracturing completion, screen completion, or open hole completion. Preferably, both heating wells and production wells use screen completion or open hole completion, with open hole completion being further preferred to reduce the obstruction of the wellbore structure to heating heat transfer and fluid seepage, thereby improving overall production efficiency.

[0038] In step 502, the target formation is heated in situ via a heating well to raise its temperature to a preset level. Then, oil and gas generated from the cracking of formation organic matter are extracted through a production well. The in-situ heating can employ one or more combinations of conduction heating, radiation heating, and convection heating. Specifically, it can use one or more combinations of electric heating, fluid heating, gas convection heating, lava convection heating, and combustion heating, with electric heating being preferred to achieve precise and controllable temperature adjustment. During the heating process, the temperature of the target formation is raised to above 300°C, and the temperature near the production well is further controlled to be above 300°C, allowing the convertible organic matter in the formation to fully crack and convert into light oil and natural gas for production. Simultaneously, the in-situ heating process significantly increases the porosity and permeability of the target formation. Porosity can be increased tenfold, reaching 20%–40%, and permeability can be increased by 5–10 orders of magnitude, reaching 1 mD–10 mD, creating the necessary reservoir flow conditions for subsequent fluid displacement of residual oil and gas and uranium mining using uranium dissolution fluid. The oil and gas generated by the cracking of organic matter are continuously extracted to the surface through production wells, completing the in-situ heating stage of oil and gas extraction.

[0039] In step 105, after in-situ heating and extraction or after heating is stopped, displacement fluid is injected into the target formation section to extract residual oil and gas trapped in the formation; after the residual oil and gas extraction is completed, purified in-situ heated gas and air are reinjected into the target formation section.

[0040] Figure 6 This is a specific example illustration of reinjecting purified in-situ heated gas and air into the target formation section according to an embodiment of the present invention. Figure 6 As shown, after the residual oil and gas extraction is completed, the controlled reinjection of purified, in-situ heated produced gas and air into the target formation may include: Step 601: Obtain the gas produced during the in-situ heating mining process, and purify the gas produced during the in-situ heating mining process to obtain purified produced gas. Step 602: Mix the purified gas with air to obtain a mixed injection gas; Step 603: Control the injection of mixed injection gas into the target formation section.

[0041] In this embodiment, the purification process is a process to remove light hydrocarbons and hydrogen sulfide.

[0042] In a specific embodiment, fluid displacement operation is initiated after the in-situ heating and extraction stage of oil and gas. Displacement fluid is injected into the target formation in the later stage of in-situ heating and extraction or after heating is stopped. The residual oil and gas trapped in the formation is extracted through fluid displacement, thereby improving the overall recovery rate of oil and gas resources. After the extraction of residual oil and gas is completed, purified in-situ heating produced gas and air are reinjected into the target formation. The reinjected gas is used to oxidize uranium minerals in the formation, laying the foundation for improving the uranium extraction rate in the subsequent uranium mining stage.

[0043] The timing for initiating the injection of displacement fluid falls into two scenarios: First, in the later stages of in-situ heating and extraction, when the value of oil and gas produced per unit time is equal to or less than the operating cost per unit production time, injection is preferably initiated at the point where the value of oil and gas produced equals the operating cost per unit production time. Second, after the cessation of in-situ heating operations, fluid displacement extraction is preferably carried out after heating has stopped. The displacement fluid can be one or a combination of liquid and gas, with gas being the preferred displacement fluid. More preferably, gas produced in-situ heating is treated and reinjected as the displacement fluid; specifically, gas produced in-situ heating after the removal of light hydrocarbons and hydrogen sulfide is used as the displacement medium. Fluid injection employs a well network pattern of injection from heating wells or partially heated wells and extraction from production wells. During its seepage through the formation, the displacement fluid carries the residual oil and gas to the production wells, ultimately being extracted to the surface through the production wells. The decision point for stopping fluid injection is when the amount of fluid injected per unit time and the corresponding cost are greater than or equal to the value of the produced oil and gas. It is preferable to stop injection when the amount of fluid injected per unit time and the cost are equal to the value of the produced oil and gas, so as to ensure the economic benefits of the displacement and exploitation stage.

[0044] After the remaining oil and gas extraction is completed, gas reinjection operations will be carried out: In step 601, the gas produced during the in-situ heating mining process is obtained and purified to obtain purified produced gas. Specifically, the purification process involves removing light hydrocarbons and hydrogen sulfide, eliminating the light hydrocarbon components and corrosive hydrogen sulfide components from the produced gas, thus mitigating safety and equipment corrosion risks during reinjection, while retaining effective oxidizing components such as carbon dioxide to ensure effective oxidation of uranium ore after reinjection.

[0045] In step 602, the purified gas is mixed with air to obtain a mixed injection gas. The addition of air increases the oxygen content in the mixed gas, which, in synergy with the carbon dioxide in the purified gas, further enhances the oxidation effect on uranium in the formation, allowing the uranium in the formation to be fully converted into a soluble form, thereby improving the extraction efficiency of the subsequent uranium dissolution solution.

[0046] In step 603, a mixed injection gas is injected into the target formation section. The mixed injection gas is injected into the heated and modified area of ​​the target formation section through the existing well network. With the help of the increased porosity and permeability after in-situ heating, it diffuses fully in the formation, comes into full contact with uranium minerals, and completes the oxidation process, providing favorable mineral morphology conditions for subsequent uranium mining using uranium dissolution fluid.

[0047] In step 106, uranium dissolving fluid is injected into the target formation section to extract uranium-containing solution; when the uranium concentration in the extracted uranium-containing solution is lower than a preset mining threshold, mining is stopped.

[0048] In a specific embodiment, the process is carried out after all the steps of in-situ heating and extraction of oil and gas, injection of fluid to displace residual oil and gas, and reinjection of gas to oxidize uranium in the formation are completed. Uranium leaching is achieved by injecting uranium dissolving solution into the heated target formation section. Mining is terminated when the uranium concentration of the extracted uranium-containing solution is lower than the preset mining threshold. The entire process relies on the significantly increased formation porosity and permeability after in-situ heating to ensure effective injection of uranium dissolving solution and full contact with uranium minerals.

[0049] Before formally injecting uranium dissolving fluid, the wellbore adaptation modification must be completed: remove all heaters from the heated well, and lower the uranium dissolving fluid injection pipe to the target formation. The material of the injection pipe should not chemically react with the uranium dissolving fluid used. At the wellbore position above the target formation, a packer is installed between the uranium dissolving fluid injection pipe and the casing or formation to seal the annulus space, prevent the uranium dissolving fluid from flowing back up the wellbore to non-target formations, and ensure that the uranium dissolving fluid is used entirely for the target mining formation.

[0050] Uranium dissolution fluid mining can be carried out using either the injection-stop-mining method or the injection-mining method.

[0051] The specific process of the injection-stop-production method is as follows: Uranium dissolving fluid is injected simultaneously from one or both of the heating wells or production wells. After injection, the well is shut in and left to stand for a period of time to allow the uranium dissolving fluid to fully react with the uranium minerals in the formation. Subsequently, while injecting uranium dissolving fluid from the heating well, the mixture of uranium dissolving fluid and uranium is extracted from the production well. The amount of uranium dissolving fluid injected in the second injection is greater than or equal to the amount injected in the first injection, preferably the two injection amounts are equal. The above injection-stop-production process is repeated until the uranium concentration in the extracted mixture of uranium dissolving fluid and uranium is lower than the preset mining threshold, at which point the cyclic injection and extraction operations are stopped.

[0052] The specific process of the injection-production method is as follows: a continuous displacement mode of injection from heated wells and production wells is adopted. Uranium dissolution fluid is continuously injected from heated wells into the target formation. After seeping into the formation and dissolving uranium minerals, it is extracted from the production wells carrying uranium components. The injection volume and injection rate of uranium dissolution fluid are controlled according to the principle of fully extracting uranium from the formation. The injection operation is stopped when the uranium content in the mixture of uranium dissolution fluid and uranium extracted from the production well is lower than the preset mining threshold.

[0053] Uranium dissolving fluid can be an acidic or alkaline solution system. Acidic solutions include H₂SO₄, HF + HNO₃, etc.; alkaline solutions include NaOH, Na₂CO₃, NaHCO₃, (NH₄)₂CO₃, NH₄HCO₃, etc., with Na₂CO₃ solution being preferred. The concentration of the uranium dissolving fluid is greater than 2 mol / L, preferably greater than 6 mol / L. When open-hole completion is used for heating wells and production wells, and a uranium dissolving fluid string that does not react with HCl is run into the well and a packer is installed below the metal casing, an HCl solution can also be used as the uranium dissolving fluid.

[0054] The preset mining threshold is based on economic considerations. Specifically, it is determined that the value of uranium in the extracted uranium solution is less than the cost of injecting the uranium solution, corresponding to a critical value for the uranium concentration in the extracted solution. When the uranium concentration in the extracted uranium-containing solution is lower than this threshold, it is determined that the economic benefits of continuing mining do not meet the requirements, and uranium mining operations are stopped.

[0055] This invention also provides an apparatus for in-situ heating and co-extraction of oil, gas, and uranium, as described in the following embodiments. Since the principle behind this apparatus is similar to that of the method for in-situ heating and co-extraction of oil, gas, and uranium, its implementation can be referenced from the implementation of the method for in-situ heating and co-extraction of oil, gas, and uranium; repeated details will not be elaborated further.

[0056] Figure 7 This is a structural example diagram of an apparatus for in-situ heating and co-extraction of oil, gas and uranium in an embodiment of the present invention, as shown below. Figure 7 As shown, the device for in-situ heating and co-extraction of oil, gas, and uranium includes: The data acquisition module 701 is used to acquire the original experimental measurement value of uranium content of rock samples, as well as the experimental measurement value of oil and gas production and uranium extraction of rock samples under in-situ heating at different temperatures. The abundance calculation module 702 is used to calculate the abundance of oil and gas produced by in-situ heating and the abundance of uranium extracted by in-situ heating per unit volume of rock based on the original experimental measurement value of uranium content of rock samples, as well as the experimental measurement value of oil and gas produced and the experimental measurement value of uranium extracted from rock samples at different in-situ heating temperatures. The target stratigraphic unit 703 is used to determine the target stratigraphic unit for in-situ heating co-mining based on the abundance of oil and gas produced by in-situ heating and the abundance of uranium extracted by in-situ heating per unit volume of rock. The in-situ heating module 704 is used to control the in-situ heating of the target formation section to extract oil and gas generated by the cracking of formation organic matter. The oil and gas extraction module 705 is used to control the injection of displacement fluid into the target formation after in-situ heating extraction or after heating is stopped, to extract the residual oil and gas remaining in the formation; after the residual oil and gas extraction is completed, it controls the reinjection of purified in-situ heated gas and air into the target formation. The uranium mining module 706 is used to control the injection of uranium dissolving fluid into the target formation and to extract uranium-containing solution; when the uranium concentration in the extracted uranium-containing solution is lower than a preset mining threshold, mining is stopped.

[0057] In one embodiment, the abundance calculation module 702 is specifically used for: Based on the original experimental measurements of uranium content in the rock samples, determine the uranium content distribution data; Based on experimental measurements of the amount of oil and gas produced from rock samples at different in-situ heating temperatures, the abundance of oil and gas produced per unit volume of rock by in-situ heating is calculated. Based on experimental measurements of uranium extraction from rock samples at different in-situ heating temperatures, a correlation between in-situ heating temperature and uranium extraction rate was established. By combining uranium content distribution data and the correlation between in-situ heating temperature and uranium extraction rate, the uranium abundance extracted per unit volume of rock by in-situ heating is calculated.

[0058] In one embodiment, the in-situ heating module 704 is specifically used for: According to the preset ratio, heating wells and production wells are deployed in the target formation section; The target formation section is heated in situ through a heating well to raise its temperature to a preset temperature, and then the oil and gas generated by the cracking of formation organic matter is extracted through a production well.

[0059] In one embodiment, the heating well and the production well are one or more combinations of horizontal wells, vertical wells, and directional wells.

[0060] In one embodiment, the oil and gas extraction module 705 is specifically used for: The gas produced during the in-situ heating mining process is obtained, and the gas produced during the in-situ heating mining process is purified to obtain purified produced gas. The purified gas is mixed with air to obtain a mixed injection gas; The injection of mixed injection gas into the target formation section is controlled.

[0061] In one embodiment, the purification process is a removal of light hydrocarbons and hydrogen sulfide.

[0062] In this embodiment of the invention, the original experimental measurement value of uranium content of rock samples, as well as the experimental measurement values ​​of oil and gas production and uranium extraction of rock samples under in-situ heating at different temperatures, are obtained. Based on the original experimental measurement value of uranium content of rock samples, and the experimental measurement values ​​of oil and gas production and uranium extraction of rock samples under in-situ heating at different temperatures, the abundance of oil and gas produced and the abundance of uranium extracted per unit volume of rock under in-situ heating are calculated. Based on the abundance of oil and gas produced and the abundance of uranium extracted per unit volume of rock under in-situ heating, the target formation for in-situ heating and co-mining are determined. In-situ heating of the target formation is controlled to extract oil and gas generated by the cracking of formation organic matter. Displacement fluid is injected into the target formation after in-situ heating or after heating is stopped to extract residual oil and gas remaining in the formation. After the residual oil and gas extraction is completed, purified oil and gas is reinjected into the target formation. In-situ heating produces gas and air; controlled injection of uranium dissolving solution into the target formation section to extract uranium-containing solution; when the uranium concentration in the extracted uranium-containing solution is lower than a preset mining threshold, mining is stopped; this embodiment of the invention effectively solves the problems of poor coordination between traditional independent oil and gas and uranium resource mining, lack of quantitative temperature correlation evaluation standards for target formation section selection, insufficient accuracy of uranium mining termination determination, and low utilization rate of mining by-products by means of uranium dissolving solution. It realizes coordinated operation from resource evaluation and selection, oil and gas extraction to uranium resource extraction, improves the accuracy of target formation section selection, oil and gas recovery rate and uranium resource extraction efficiency, and provides reliable technical support for the efficient coordinated mining of oil and gas and uranium co-existing resources.

[0063] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0064] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for in-situ heating and co-extraction of oil, gas, and uranium, characterized in that, include: Experimental measurements of the original uranium content of rock samples were obtained, as well as experimental measurements of the amount of oil and gas produced and the amount of uranium extracted from rock samples after in-situ heating at different temperatures. Based on the experimental measurements of the original uranium content of the rock samples, as well as the experimental measurements of the amount of oil and gas produced and the amount of uranium extracted from the rock samples at different in-situ heating temperatures, the abundance of oil and gas produced and the abundance of uranium extracted per unit volume of rock by in-situ heating are calculated. The target stratigraphic interval for in-situ heating-assisted mining is determined based on the abundance of oil and gas produced by in-situ heating and the abundance of uranium extracted by in-situ heating per unit volume of rock. Controlled in-situ heating of the target formation section to extract oil and gas generated by the cracking of formation organic matter; After in-situ heating extraction or after heating is stopped, displacement fluid is injected into the target formation to extract residual oil and gas trapped in the formation; after the residual oil and gas extraction is completed, purified in-situ heated gas and air are reinjected into the target formation. The uranium dissolving solution is injected into the target formation section and uranium-containing solution is extracted; when the uranium concentration in the extracted uranium-containing solution is lower than a preset mining threshold, mining is stopped.

2. The method as described in claim 1, characterized in that, Based on the experimentally measured original uranium content of the rock samples, and the experimentally measured oil and gas production and uranium extraction yield of the rock samples at different in-situ heating temperatures, the in-situ heating oil and gas production abundance and in-situ heating uranium extraction abundance per unit volume of rock were calculated, including: Based on the original experimental measurements of uranium content in the rock samples, determine the uranium content distribution data; Based on experimental measurements of the amount of oil and gas produced from rock samples at different in-situ heating temperatures, the abundance of oil and gas produced per unit volume of rock by in-situ heating is calculated. Based on experimental measurements of uranium extraction from rock samples at different in-situ heating temperatures, a correlation between in-situ heating temperature and uranium extraction rate was established. By combining uranium content distribution data and the correlation between in-situ heating temperature and uranium extraction rate, the uranium abundance extracted per unit volume of rock by in-situ heating is calculated.

3. The method as described in claim 1, characterized in that, Controlled in-situ heating of the target formation section to extract oil and gas generated from the cracking of formation organic matter includes: According to the preset ratio, heating wells and production wells are deployed in the target formation section; The target formation section is heated in situ through a heating well to raise its temperature to a preset temperature, and then the oil and gas generated by the cracking of formation organic matter is extracted through a production well.

4. The method as described in claim 3, characterized in that, The heating well and the production well are one or more combinations of horizontal wells, vertical wells, and directional wells.

5. The method as described in claim 1, characterized in that, After residual oil and gas extraction is completed, the purified in-situ heated produced gas and air are reinjected into the target formation in a controlled manner, including: The gas produced during the in-situ heating mining process is obtained, and the gas produced during the in-situ heating mining process is purified to obtain purified produced gas. The purified gas is mixed with air to obtain a mixed injection gas; The injection of mixed injection gas into the target formation section is controlled.

6. The method as described in claim 5, characterized in that, The purification process involves the removal of light hydrocarbons and hydrogen sulfide.

7. An apparatus for in-situ heating and synergistic extraction of oil, gas, and uranium, characterized in that, include: The data acquisition module is used to acquire the original experimental measurement values ​​of uranium content in rock samples, as well as the experimental measurement values ​​of oil and gas production and uranium extraction from rock samples heated in situ at different temperatures. The abundance calculation module is used to calculate the abundance of oil and gas produced by in-situ heating and the abundance of uranium extracted by in-situ heating per unit volume of rock, based on the original experimental measurement of uranium content in rock samples, as well as the experimental measurement of oil and gas production and uranium extraction from rock samples at different in-situ heating temperatures. The target stratigraphic unit is used to determine the target stratigraphic unit for in-situ heating co-mining based on the abundance of oil and gas produced by in-situ heating and the abundance of uranium extracted by in-situ heating per unit volume of rock. The in-situ heating module is used to control the in-situ heating of the target formation section to extract oil and gas generated by the cracking of formation organic matter; The oil and gas extraction module is used to control the injection of displacement fluid into the target formation after in-situ heating extraction or after heating is stopped, to extract the residual oil and gas remaining in the formation; after the residual oil and gas extraction is completed, the module controls the reinjection of purified in-situ heated gas and air into the target formation. The uranium mining module is used to control the injection of uranium dissolving fluid into the target formation and to extract uranium-containing solution; when the uranium concentration in the extracted uranium-containing solution is lower than a preset mining threshold, mining is stopped.

8. The apparatus as claimed in claim 7, characterized in that, The abundance calculation module is specifically used for: Based on the original experimental measurements of uranium content in the rock samples, determine the uranium content distribution data; Based on experimental measurements of the amount of oil and gas produced from rock samples at different in-situ heating temperatures, the abundance of oil and gas produced per unit volume of rock by in-situ heating is calculated. Based on experimental measurements of uranium extraction from rock samples at different in-situ heating temperatures, a correlation between in-situ heating temperature and uranium extraction rate was established. By combining uranium content distribution data and the correlation between in-situ heating temperature and uranium extraction rate, the uranium abundance extracted per unit volume of rock by in-situ heating is calculated.

9. The apparatus as claimed in claim 7, characterized in that, In-situ heating module, specifically used for: According to the preset ratio, heating wells and production wells are deployed in the target formation section; The target formation section is heated in situ through a heating well to raise its temperature to a preset temperature, and then the oil and gas generated by the cracking of formation organic matter is extracted through a production well.

10. The apparatus as claimed in claim 7, characterized in that, Oil and gas extraction module, specifically used for: The gas produced during the in-situ heating mining process is obtained, and the gas produced during the in-situ heating mining process is purified to obtain purified produced gas. The purified gas is mixed with air to obtain a mixed injection gas; The injection of mixed injection gas into the target formation section is controlled.

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