Evaluation method for contribution of bauxite rock to helium reservoir forming

Abstract

The invention belongs to the technical field of resource exploration, and particularly discloses a method for evaluating helium reservoir forming contribution of alumina rock, which comprises the following steps: selecting an alumina rock stratum of a research block, collecting an alumina rock sample, calculating abundance of U and Th radioactive elements, and calculating the helium reservoir forming contribution of the alumina rock. The method comprises the following steps: firstly, calculating the total volume of helium released by decay of U and Th radioactive elements in an alumina rock stratum from a diagenesis period to the current alumina rock stratum by utilizing a cause method, subtracting the volume of helium dissolved in alumina rock stratum water from a calculation result to obtain a difference which is the reservoir forming contribution of the helium released by decay of the U and Th radioactive elements in the alumina rock stratum, and outputting an evaluation result through the contribution. The method is high in practicability, reliability and operability, and provides technical and theoretical support for establishment of a helium reservoir forming main control factor evaluation technology, optimization of an exploration target area and acceleration of helium exploration and development.

Description

Technical Field

[0001] The invention belongs to the technical field of resource exploration, and in particular relates to a method for evaluating the contribution of bauxite to helium accumulation. Background Art

[0002] Helium has special physical and chemical properties, especially its characteristics of being liquid at ultra-low temperatures and chemical inertness, making it an irreplaceable, important and scarce strategic resource related to national security and the development of high-tech industries. At present, extracting helium from helium-containing and helium-rich natural gas reservoirs is still the only way to produce helium industrially. The study of helium sources is one of the key research contents in helium resource exploration. It can not only provide a theoretical basis and support for the establishment of helium accumulation mechanism, but also provide key evidence and understanding for the prediction of helium-rich natural gas reservoirs. Generally, the sources of helium include crustal helium, mantle helium and atmospheric helium. Most of the helium in helium-rich natural gas reservoirs is mainly crustal helium, and the ancient basin basement granite is the main helium source rock. However, in recent years, it has been found that compared with the basement granite, the geological age of bauxite is relatively young, but its uranium and thorium concentration is several to dozens of times that of granite. Therefore, the helium formed by their decay can also form a beneficial supplement to the helium reservoir. Therefore, how to judge the contribution of bauxite to helium accumulation is an urgent problem to be solved.

[0003] Up to now, the previous research results are mainly the judgment method of Paleozoic basement granite and granite gneiss to helium-rich natural gas reservoirs, which determines that basement granite is an effective source rock of helium, including: Qinghai Fourth Geological Exploration Institute "A method for judging whether basement granite supplies helium to helium-rich natural gas reservoirs" application number: 202310071311.6; China University of Petroleum (Beijing) "A method for judging whether basement granite supplies helium to helium-rich natural gas reservoirs" application number: 202211010422.8; The contribution of helium released by the decay of U and Th elements in the granite and granite gneiss in the base to its diagenesis is quantitatively evaluated by the natural gamma ray spectroscopy logging method and the component method, including: Peking University "Quantitative Characterization Method of Contribution of Helium Source Rocks in Helium-Rich Gas Fields in Stable Craton Basins" Application No.: 202310342322.3; Chen Xinjun 2023, BROWNAA 2019, He Yanxin 2023, but there is a lack of research and calculation methods on the contribution of helium released by the decay of U and Th elements in bauxite formations to its reservoir formation. Summary of the invention

[0004] The purpose of the present invention is to provide a method for evaluating the contribution of bauxite to helium accumulation, so as to solve the problem of lack of research and calculation methods on the contribution of helium released by the decay of U and Th elements in bauxite formations to its accumulation.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a method for evaluating the contribution of bauxite to helium accumulation, comprising:

[0007] Select the bauxite strata in the study area, collect bauxite samples, and calculate the abundance of U and Th radioactive elements;

[0008] Based on the abundance of U and Th radioactive elements and combined with historical data, the total volume of helium released by the decay of U and Th radioactive elements in bauxite strata from the diagenesis period to the present is calculated using the genetic method.

[0009] Obtain various parameters of the bauxite formation in the study area and calculate the volume of helium dissolved in the bauxite formation water;

[0010] Based on the total volume of helium released by the decay of U and Th radioactive elements in the bauxite formation from the diagenesis period to the present, and the volume of helium dissolved in the water of the bauxite formation, the contribution of helium released by the decay of U and Th radioactive elements in the bauxite formation to its accumulation is calculated;

[0011] The evaluation results are output based on the contribution of helium released by the decay of U and Th radioactive elements in bauxite formations to their reservoir formation.

[0012] Furthermore, the bauxite formation in the study area has a thickness of h, an area of ​​s, and a density of ρ 铝土岩 The abundance of U and Th radioactive elements in each gram of bauxite sample was measured experimentally, and they were c 1、 c2.

[0013] Furthermore, the decay constant of U is 12.06×10 -14 m 3 / ng, the decay constant of Th is 2.87×10 -14 m 3 / ng.

[0014] Furthermore, the calculation formula for the total volume of helium released by the decay of U and Th radioactive elements in the bauxite strata from the diagenesis period to the present is:

[0015] V1=shρ 铝土岩 *(12.06×10 -14 c1+2.87×10 -14 c2)n

[0016] Where V1 is the total volume of helium released by the decay of U and Th radioactive elements in the bauxite strata from the diagenesis period to the present, m 3 ; s is the area of ​​bauxite, m 2 ; h is the thickness of bauxite, m; ρ 铝土岩 is the density of bauxite, g / m 3; c1 is the abundance percentage of U in bauxite, g / g; c2 is the abundance percentage of Th in bauxite, g / g; n is the diagenetic age of bauxite, years.

[0017] Furthermore, the parameters of the bauxite formation in the study area specifically include:

[0018] Average porosity φ of bauxite gas reservoir, water saturation w of bauxite, solubility r of helium in formation water and density ρ of formation water 水 .

[0019] Furthermore, the calculation formula for the volume of helium dissolved in the bauxite formation water is:

[0020] V2=shφwρ 水 r / ρ 氦

[0021] Where V2 is the volume of helium dissolved in the bauxite formation water, m 3 ; s is the area of ​​bauxite, m 2 ; h is the thickness of bauxite, m; φ is the average porosity of bauxite gas reservoir, %; w is the water saturation of bauxite, %; ρ 水 is the density of formation water, g / m 3 ; r is the solubility percentage of helium in bauxite formation water, g / g; ρ 氦 is the density of helium, g / m 3 .

[0022] Furthermore, the calculation formula for the contribution of helium released by the decay of U and Th radioactive elements in the bauxite formation to its accumulation is:

[0023] V=V1-V2

[0024] Where V is the contribution of helium released by the decay of U and Th radioactive elements in bauxite formation to its accumulation, m 3 .

[0025] Furthermore, the smaller the calculated contribution of helium released by the decay of U and Th radioactive elements in bauxite formations to its reservoir formation, the smaller the contribution of helium released by the decay of U and Th radioactive elements in bauxite formations to its reservoir formation; the larger the calculated contribution of helium released by the decay of U and Th radioactive elements in bauxite formations to its reservoir formation, the greater the contribution of helium released by the decay of U and Th radioactive elements in bauxite formations to its reservoir formation.

[0026] In a second aspect, an electronic device includes a processor and a memory, wherein the processor is used to execute a computer program stored in the memory to implement a method for evaluating the contribution of bauxite to helium accumulation as described in any one of the above.

[0027] In a third aspect, a computer-readable storage medium stores at least one instruction, and when the at least one instruction is executed by a processor, a method for evaluating the contribution of bauxite to helium accumulation as described in any one of the above is implemented.

[0028] The present invention has at least the following beneficial effects:

[0029] 1. The present invention selects the bauxite formation in the research area, collects bauxite samples, calculates the abundance of U and Th radioactive elements, first uses the genetic method to calculate the total volume of helium released by the decay of U and Th radioactive elements in the bauxite formation from the diagenesis period to the present, subtracts the volume of helium dissolved in the water of the bauxite formation from the calculated result, and the difference obtained is the contribution of helium released by the decay of U and Th radioactive elements in the bauxite formation to its reservoir formation, and outputs the evaluation result through the contribution. It has strong practicality, reliability, and operability, and provides technical and theoretical support for establishing the evaluation technology of the main controlling factors of helium reservoir formation, optimizing the exploration target area, and accelerating the exploration and development of helium.

[0030] 2. The present invention establishes quantitative evaluation indicators and methods for the helium generation potential of bauxite helium source rocks and their contribution to helium accumulation, and establishes a new approach to helium resource evaluation from the perspective of helium source rocks and the process of helium migration and accumulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0032] In the attached picture:

[0033] Figure 1 A schematic diagram of a flow chart of a method for evaluating the contribution of bauxite to helium accumulation;

[0034] Figure 2 This is the distribution map of bauxite in the Taiyuan Formation in a gas field in a certain basin. DETAILED DESCRIPTION

[0035] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other without conflict.

[0036] The following detailed description is an exemplary description, which is intended to provide further detailed description of the present invention. Unless otherwise specified, all technical terms used in the present invention have the same meaning as those generally understood by those skilled in the art to which the present invention belongs. The terms used in the present invention are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present invention.

[0037] like Figure 1As shown, a method for evaluating the contribution of bauxite to helium accumulation includes:

[0038] S1: Select a relatively uniform bauxite formation in the study area, with a thickness of h, an area of ​​s, and a density of ρ 铝土岩 , collect bauxite samples, and use experiments to measure the abundance of U and Th radioactive elements in each gram of bauxite samples, which are c 1、 c2.

[0039] S2: Based on the abundance of U and Th radioactive elements and combined with historical data, the total volume of helium released by the decay of U and Th radioactive elements in the bauxite strata from the diagenesis period to the present is calculated using the genetic method;

[0040] Specifically, it includes: searching the literature to obtain how many cubic meters of helium are produced per gram of radioactive elements U and Th per year, i.e., the decay constants of U and Th;

[0041] The decay constant of U is 12.06×10 -14 m 3 / ng, the decay constant of Th is 2.87×10 -14 m 3 / ng, the diagenetic age n of the bauxite sample was measured by the zircon dating method, and the total volume V1 of helium released by the decay of U and Th radioactive elements in the bauxite strata from the diagenesis period to the present was obtained by the calculation formula:

[0042] V1=shρ 铝土岩 *(12.06×10 -14 c1+2.87×10 -14 c2)n

[0043] Where V1 is the total volume of helium released by the decay of U and Th radioactive elements in the bauxite strata from the diagenesis period to the present, m 3 ; s is the area of ​​bauxite, m 2 ; h is the thickness of bauxite, m; ρ 铝土岩 is the density of bauxite, g / m 3 ; c1 is the abundance percentage of U in bauxite, g / g; c2 is the abundance percentage of Th in bauxite, g / g; n is the diagenetic age of bauxite, years.

[0044] S3: Obtain various parameters of the bauxite formation in the study area and calculate the volume of helium dissolved in the water of the bauxite formation;

[0045] Specifically, the average porosity data of the bauxite gas reservoir in the study block determined in S1 is obtained as φ, the water saturation of the bauxite is w, the bauxite formation water in the study block is collected, the solubility r of helium in the formation water is measured by experiment, and the volume of helium dissolved in the bauxite formation water V2 is calculated by the formula:

[0046] V2=shφwρ 水 r / ρ 氦

[0047] Where V2 is the volume of helium dissolved in the bauxite formation water, m 3 ; s is the area of ​​bauxite, m 2 ; h is the thickness of bauxite, m; φ is the average porosity of bauxite gas reservoir, %; w is the water saturation of bauxite, %; ρ 水 is the density of formation water, g / m 3 ; r is the solubility percentage of helium in bauxite formation water, g / g; ρ 氦 is the density of helium, g / m 3 .

[0048] S4: Based on the total volume of helium released by the decay of U and Th radioactive elements in the bauxite formation from the diagenesis period to the present, and the volume of helium dissolved in the water of the bauxite formation, calculate the contribution of helium released by the decay of U and Th radioactive elements in the bauxite formation to its accumulation;

[0049] Specifically, the total volume of helium released by the decay of U and Th radioactive elements in the bauxite formation from the diagenesis period to the present is subtracted from the volume of helium dissolved in the water of the bauxite formation V2 to calculate the contribution of helium released by the decay of U and Th radioactive elements in the bauxite formation to its accumulation. The calculation formula is:

[0050] V=V1-V2

[0051] Where V is the contribution of helium released by the decay of U and Th radioactive elements in bauxite formation to its accumulation, m 3 .

[0052] S5: Output the evaluation results according to the contribution of helium released by the decay of U and Th radioactive elements in the bauxite formation to its reservoir formation;

[0053] According to the calculated contribution V of helium released by the decay of U and Th radioactive elements in bauxite formations to their reservoir formation, the smaller the calculated value is, the smaller the contribution V of helium released by the decay of U and Th radioactive elements in bauxite to their reservoir formation is; the larger the value is, the greater the contribution V of helium released by the decay of U and Th radioactive elements in bauxite to their reservoir formation is.

[0054] Example 1

[0055] This is further explained through a specific example of a gas field in a certain basin.

[0056] like Figure 2As shown, the Taiyuan Formation of the gas field has a relatively uniform bauxite stratum of thin thickness. After sampling experiments, the uranium and thorium content in the bauxite is relatively high, and the helium content is relatively high. Therefore, the helium released by the decay of U and Th radioactive elements in the bauxite of the Taiyuan Formation has a certain contribution to the formation of helium reservoirs. The calculation method of the present invention can be used to calculate the contribution of helium released by the decay of U and Th radioactive elements in the bauxite stratum of the Taiyuan Formation of the gas field to the helium reservoir, including the following specific steps:

[0057] Step 1: The average thickness of the bauxite formation of the Taiyuan Group in a gas field in a basin is 6.1m, the area is 20018.7 square kilometers, and the density is 3.9X10 6 g / m 3 , bauxite samples were collected, and the average abundance of U and Th radioactive elements in each gram of bauxite samples was measured experimentally to be 16.8×10 -6 (g / g), 56.71×10 -6 (g / g).

[0058] Step 2: Search the literature to obtain the number of cubic meters of helium produced per gram of radioactive elements U and Th per year, i.e., the decay constants of U and Th. The decay constant of U is 12.06×10 -14 m 3 / ng, the Th decay constant is 2.87×10 -14 m 3 / ng, the diagenesis age of the bauxite sample measured by the zircon dating method is about 290 million years, and the calculation formula is:

[0059] V1=shρ 铝土岩 *(12.06×10 -14 c1+2.87×10 -14 c2)n

[0060] The total volume of helium released by the decay of U and Th radioactive elements in bauxite strata from the diagenesis period to the present is 505 million cubic meters.

[0061] Step 3: The average porosity φ of the gas reservoir in the bauxite of the Taiyuan Formation of the gas field was measured to be 3.1%, and the water saturation w was 79.8%. The bauxite formation water in the study area was collected, and the solubility of helium in the formation water was measured to be 0.55×10 -5 g / g, calculated as follows:

[0062] V2=shφwρ 水 r / ρ 氦

[0063] The volume of helium dissolved in the bauxite formation water is calculated to be 151 million cubic meters.

[0064] Step 4: Use the total volume of helium released by the decay of U and Th radioactive elements in the bauxite formation from the diagenesis period to the present V1, minus the volume of helium dissolved in the water of the bauxite formation V2, to calculate the contribution of helium released by the decay of U and Th radioactive elements in the bauxite formation to its accumulation V. The calculation formula is:

[0065] V=V1-V2

[0066] It was found that the contribution of helium released by the decay of U and Th radioactive elements in the bauxite strata of a gas field in a certain basin to its reservoir formation was 354 million cubic meters.

[0067] Example 2

[0068] An electronic device comprises a processor and a memory, wherein the processor is used to execute a computer program stored in the memory to implement a method for evaluating the contribution of bauxite to helium accumulation as described above.

[0069] Example 3

[0070] A computer-readable storage medium stores at least one instruction, and when the at least one instruction is executed by a processor, a method for evaluating the contribution of bauxite to helium accumulation as described above is implemented.

[0071] It is known from common technical knowledge that the present invention can be implemented by other embodiments that do not deviate from its spirit or essential features. Therefore, the above disclosed embodiments are only illustrative in all respects and are not exclusive. All changes within the scope of the present invention or within the scope equivalent to the present invention are included in the present invention.

[0072] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented 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.

[0073] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0074] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0075] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for evaluating the contribution of bauxite to helium accumulation, characterized in that: include: Select the bauxite strata in the study area, collect bauxite samples, and calculate the abundance of U and Th radioactive elements; Based on the abundance of radioactive elements U and Th, combined with historical data, the total volume of helium released by the decay of radioactive elements U and Th in the bauxite strata from the diagenesis period to the present is calculated using the genetic method. Obtain various parameters of the bauxite formation in the study area and calculate the volume of helium dissolved in the bauxite formation water; Based on the total volume of helium released by the decay of U and Th radioactive elements in the bauxite formation from the diagenesis period to the present, and the volume of helium dissolved in the water of the bauxite formation, the contribution of helium released by the decay of U and Th radioactive elements in the bauxite formation to its accumulation is calculated; The evaluation results are output based on the contribution of helium released by the decay of U and Th radioactive elements in bauxite formations to their reservoir formation.

2. The method for evaluating the contribution of bauxite to helium accumulation according to claim 1, characterized in that: The thickness of the bauxite formation in the study area is h, the area is s, and the density is ρ 铝土岩 , the abundance of U and Th radioactive elements in each gram of bauxite sample was measured experimentally, which were c1 and c2 respectively.

3. The method for evaluating the contribution of bauxite to helium accumulation according to claim 1, characterized in that: The decay constant of U is 12.06×10 -14 m 3 / ng, the decay constant of Th is 2.87×10 -14 m 3 / ng.

4. The method for evaluating the contribution of bauxite to helium accumulation according to claim 3, characterized in that: The calculation formula for the total volume of helium released by the decay of U and Th radioactive elements in the bauxite strata from the diagenesis period to the present is: V1=shρ 铝土岩 *(12.06×10 -14 c1+2.87×10 -14 c2)n Where V1 is the total volume of helium released by the decay of U and Th radioactive elements in the bauxite strata from the diagenesis period to the present, m 3 ; s is the area of ​​bauxite, m 2 ; h is the thickness of bauxite, m; ρ 铝土岩 is the density of bauxite, g / m 3 ; c1 is the abundance percentage of U in bauxite, g / g; c2 is the abundance percentage of Th in bauxite, g / g; n is the diagenetic age of bauxite, years.

5. The method for evaluating the contribution of bauxite to helium accumulation according to claim 4, characterized in that: The parameters of the bauxite formation in the study area specifically include: Average porosity φ of bauxite gas reservoir, water saturation w of bauxite, solubility r of helium in formation water and density ρ of formation water 水 .

6. The method for evaluating the contribution of bauxite to helium accumulation according to claim 5, characterized in that: The calculation formula for the volume of helium dissolved in the bauxite formation water is: V2=shφwρ 水 r / r 氦 Where V2 is the volume of helium dissolved in the bauxite formation water, m 3 ; s is the area of ​​bauxite, m 2 ; h is the thickness of bauxite, m; φ is the average porosity of bauxite gas reservoir, %; w is the water saturation of bauxite, %; ρ 水 is the density of formation water, g / m 3 ; r is the solubility percentage of helium in bauxite formation water, g / g; ρ 氦 is the density of helium, g / m 3 .

7. The method for evaluating the contribution of bauxite to helium accumulation according to claim 6, characterized in that: The calculation formula for the contribution of helium released by the decay of U and Th radioactive elements in the bauxite formation to its accumulation is: V=V1-V2 Where V is the contribution of helium released by the decay of U and Th radioactive elements in bauxite formation to its accumulation, m 3 .

8. The method for evaluating the contribution of bauxite to helium accumulation according to claim 1, characterized in that: The smaller the calculated contribution of helium released by the decay of U and Th radioactive elements in bauxite formations to their reservoir formation, the smaller the contribution of helium released by the decay of U and Th radioactive elements in bauxite formations to their reservoir formation; the larger the calculated contribution of helium released by the decay of U and Th radioactive elements in bauxite formations to their reservoir formation, the greater the contribution of helium released by the decay of U and Th radioactive elements in bauxite formations to their reservoir formation.

9. An electronic device, characterized in that: It comprises a processor and a memory, wherein the processor is used to execute a computer program stored in the memory to implement a method for evaluating the contribution of bauxite to helium accumulation as claimed in any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores at least one instruction, and when the at least one instruction is executed by the processor, the method for evaluating the contribution of bauxite to helium accumulation as described in any one of claims 1 to 8 is implemented.

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