Reverse-sequence traceability sampling method for helium exploration

Abstract

The invention discloses a reverse-sequence traceability sampling method for helium exploration. The method comprises the steps that BOG sampling is conducted on a selected LNG plant, the BOG helium content is determined, and whether the BOG helium content reaches the helium extraction lower limit or not is judged; if yes, reverse tracking is carried out, a gas supply reservoir of the LNG plant is determined, and helium content detection natural gas sampling preparation wells are screened from production wells of the gas reservoir; natural gas sampling is carried out on the selected preparation well, and natural gas components and helium content are detected and determined. According to the method, a real LNG plant is taken as an object, the helium content is detected through BOG sampling, natural gas resources with the helium extraction potential of BOG are determined, a target natural gas reservoir is determined through reverse tracing of an LNG gas source, a helium content detection natural gas sampling preparation well is screened from production wells of the gas reservoir, and the helium content detection natural gas sampling preparation well is selected from the production wells of the gas reservoir. A large amount of invalid sampling caused by one-by-one sampling from massive natural gas reservoir production wells is avoided, and the sampling and helium detection cost is saved.

Description

Technical Field

[0001] The present invention relates to the technical field of helium exploration, and in particular to a reverse tracing sampling method for helium exploration. Background Art

[0002] Helium is a strategic rare gas resource related to the development of high-tech industries and a key and basic resource for achieving high-quality development. China's proven helium resources are seriously insufficient, and its helium supply has long been highly dependent on foreign countries.

[0003] According to domestic and foreign literature research, the commercial helium extraction systems discovered so far are all accidental byproducts of oil exploration. According to the results of helium monitoring and detection in the atmosphere, the helium content in the natural gas that has been mined globally is only 0.03%, which does not have direct commercial helium extraction value, that is, most natural gas reservoirs do not have helium mining value. At present, there is still no special and mature exploration and evaluation technology for helium. The exploration of helium mainly uses the helium percentage method and the genesis method to calculate the helium resource volume. Among them, the key parameter of helium content is determined by sampling hydrocarbon natural gas and testing the helium content. Summary of the invention

[0004] The inventors found that because it is impossible to determine the possible helium content before sampling, even if the helium content data is detected after sampling, the helium resources cannot be converted into recoverable helium reserves for helium extraction because the helium content cannot meet the commercial helium extraction standards. Therefore, ineffective sampling causes a large amount of natural gas sampling and helium detection costs, and it is impossible to convert helium into the expected helium production through helium extraction.

[0005] During the development and use of natural gas, many oil and gas companies in the world usually directly discharge helium into the atmosphere together with exhaust gas, without considering the value of helium extraction and use. The main reasons are as follows: 1. They are unaware of the existence of commercially valuable helium in natural gas; 2. Helium is detected but is not commercially profitable and has no commercial value for helium extraction; 3. There is no need for helium in the region, and the actual demand and supply industry chain for helium cannot be realized; 4. There is a lack of helium extraction technology and equipment, and there is no ability to extract helium.

[0006] In order to enrich the process routes and increase the selection space, the present invention provides a reverse tracing sampling method for helium exploration based on the above situation, including:

[0007] Carry out BOG sampling at the selected LNG plant to determine the BOG helium content and judge whether the BOG helium content reaches the lower limit of helium extraction;

[0008] If yes, conduct reverse tracing to determine the gas reservoir that supplies the LNG plant, and screen the helium content in the production wells of the reservoir to test the natural gas sampling preparation wells.

[0009] In some embodiments, the determination of the selected LNG plant includes:

[0010] According to the set lower limit of helium content in natural gas and the lower limit of helium amount in helium extraction facilities, the lower limit of natural gas processing capacity screening of the LNG plant is determined, and based on the lower limit of natural gas processing capacity screening, multiple LNG plants are screened as BOG sampling targets;

[0011] According to the parameters related to helium extraction benefits and the principle of priority of LNG-BOG helium extraction benefit coverage area, the selected LNG plants are sorted to obtain the sampling sequence;

[0012] According to the sampling sequence, starting from the LNG plant with the highest sampling priority, the LNG plants are selected in turn as the selected LNG plants.

[0013] In some embodiments, the screening of multiple LNG plants as BOG sampling targets further includes:

[0014] The LNG plant with the largest production capacity on the same pipeline was selected as the BOG sampling target.

[0015] In some embodiments, it also includes:

[0016] Performing component analysis on the natural gas sample obtained from the prepared well to determine the matching relationship between the BOG helium content and the natural gas helium content;

[0017] Determining whether the helium content of the natural gas obtained from the preparation well and the helium content of the BOG of the corresponding LNG plant satisfy the matching relationship;

[0018] If so, it is determined that the helium content of the natural gas in the prepared well is reliable.

[0019] In some embodiments, the step of screening the helium content in the production wells of the gas reservoir to detect the natural gas sampling preparation wells comprises:

[0020] According to the production and location of the production wells of the gas reservoir, helium content detection natural gas sampling preparation wells are screened from the production wells of the gas reservoir. The distribution of the screened preparation wells has gas reservoir control capability and represents different production levels respectively.

[0021] In some embodiments, it also includes:

[0022] Determine the helium distribution characteristics of the gas reservoir based on the helium content of natural gas samples from each preparation well in the gas reservoir;

[0023] The helium content of the natural gas in the gas reservoir is determined according to the helium distribution characteristics.

[0024] In some embodiments, it also includes:

[0025] Determine the remaining recoverable helium resources in the gas reservoir based on the helium content of the natural gas in the gas reservoir and the recoverable natural gas reserves;

[0026] Determine the potential recoverable helium resources of the gas reservoir based on the remaining recoverable helium resources of the gas reservoir;

[0027] Determine the value of the extractable helium resources in the gas reservoir based on the potential extractable helium resources in the gas reservoir and the ex-factory price of helium;

[0028] The total revenue from helium extraction from the gas reservoir is determined based on the value of the extractable helium resources in the gas reservoir and the total cost of extracting helium.

[0029] In some embodiments, determining the remaining recoverable helium resources of the gas reservoir includes:

[0030] The remaining recoverable helium resources of the gas reservoir are determined by the following formula (1):

[0031] QRRHe=QRG× CHe (1)

[0032] In formula (1), QRRHe is the remaining recoverable helium resources, QRG is the recoverable natural gas reserves, and CHe is the helium content of natural gas.

[0033] In some embodiments, determining the potential helium resources of a gas reservoir includes:

[0034] The potential helium resources of the gas reservoir can be determined by the following formula (2):

[0035] HeeC=QRRHe-CYCL×PRG×CHe (2)

[0036] In formula (2), HeeC is the potential helium resources, QRRHe is the remaining recoverable helium resources, CYCL is the estimated time for the construction and commissioning of the helium extraction facilities, PRG is the actual annual natural gas production of the gas reservoir, and CHe is the helium content of the natural gas.

[0037] In some embodiments, determining the extractable helium resource value of the gas reservoir includes:

[0038] The extractable helium resource value of the gas reservoir is determined by the following formula (3):

[0039] VHE=PHe×HeeC×ROHe (3)

[0040] In formula (3), VHE is the value of helium resources that can be extracted from the gas reservoir, PHe is the ex-factory price of helium, HeeC is the potential helium resources that can be extracted, and ROHe is the helium recovery rate of the helium extraction equipment.

[0041] In some embodiments, determining the total yield of helium extraction from a gas reservoir includes:

[0042] The total helium extraction benefit of the gas reservoir is determined by the following formula (4):

[0043] TREV=VHE-TCOST (4)

[0044] In formula (4), TRE is the total revenue of helium extraction, VHE is the value of extractable helium resources in the gas reservoir, and TCOST is the total cost of helium extraction.

[0045] In some embodiments, it also includes:

[0046] Rank the gas reservoirs according to the total helium extraction revenue, select the LNG plants supplied by the gas reservoirs with the highest total helium extraction revenue, and formulate a helium extraction project construction plan.

[0047] The beneficial effects of the above technical solution provided by the embodiment of the present invention include at least:

[0048] (1) The reverse tracing sampling method for helium exploration provided by the embodiment of the present invention takes an actual LNG plant as the object, detects the helium content through BOG sampling, determines the natural gas resources with the potential for BOG helium extraction, and determines the target natural gas reservoir by reverse tracing the LNG gas source. The helium content is detected in the production wells of the gas reservoir to prepare the natural gas sampling wells, thereby avoiding a large amount of invalid sampling caused by sampling one by one from the production wells of a large number of natural gas reservoirs, and saving the sampling and helium detection costs.

[0049] (2) The reverse tracing sampling method for helium exploration provided in the embodiment of the present invention samples the target gas reservoir and detects the helium content, determines the helium content of natural gas in the helium-containing gas reservoir and its distribution characteristics, and conducts helium resource and value evaluation, which can effectively improve the efficiency of helium exploration, quickly determine the LNG plant with helium extraction conditions, and propose a supporting helium extraction project construction plan on the basis of reducing the investment in plant construction. It can not only solve the problem of LNG-BOG helium extraction gas source resources, but also reduce the cost of building a special LNG plant for helium extraction, maximize the use of helium-containing natural gas resources and existing LNG production capacity, and have significant economic benefits and the effect of quickly building a helium extraction demonstration project.

[0050] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings.

[0051] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0053] Figure 1 This is a flow chart of the reverse tracing sampling method for helium exploration in Example 1 of the present invention;

[0054] Figure 2 This is a technical flow chart for determining a selected LNG plant in Embodiment 1 of the present invention;

[0055] Figure 3 This is a specific implementation flow chart of the reverse tracing sampling method for helium exploration in an embodiment of the present invention. DETAILED DESCRIPTION

[0056] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0057] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0058] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which the invention belongs. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0059] In the description of the present invention, it should be noted that the terms "include", "including", "have", "contain" and the like are open terms, meaning including but not limited to.

[0060] The embodiment of the present invention provides a reverse tracing sampling method for helium exploration, which can avoid a large amount of invalid sampling caused by sampling one by one from production wells of massive natural gas reservoirs, thereby saving sampling and helium detection costs.

[0061] Embodiment 1

[0062] Embodiment 1 of the present invention provides a reverse tracing sampling method for helium exploration, see Figure 1 As shown, the following steps are included:

[0063] Step S11: sampling BOG from the selected LNG plant, determining the BOG helium content, and judging whether the BOG helium content reaches the lower limit of helium extraction.

[0064] LNG is the abbreviation of Liquefied Natural Gas, which refers to the liquefied natural gas that is cooled from gaseous natural gas, that is, liquefied natural gas; BOG is the abbreviation of boil off gas, which is the gas that evaporates from liquefied natural gas due to heat leakage in the system, also known as flash gas.

[0065] See also Figure 2 As shown, the determination of the selected LNG plant may include the following steps:

[0066] Step S21: Determine the natural gas processing capacity screening lower limit of the LNG plant according to the set natural gas helium content lower limit and the helium amount lower limit of the helium extraction facility, and select multiple LNG plants as BOG sampling targets based on the natural gas processing capacity screening lower limit.

[0067] According to the statistical analysis of helium detection results of natural gas sampling in China, the helium content is generally low, mainly less than 0.3%. If the helium content in natural gas is 0.1% as the lower limit of industrial helium extraction, the production rate is 90%, the natural gas helium extraction rate is 95%, and the annual extraction of high-purity helium is 5×10 4 Sm 3 In order to provide the lower limit of helium volume for the supporting helium supply facilities and considering the guarantee factor of 3.0, it can be inferred that the lower limit of the natural gas daily processing capacity screening of the LNG production plant is 50×10 4 Sm 3 The unit of gas volume in the embodiments of the present invention is Sm. 3 For example, it indicates the volume of gas under standard conditions. 3 .

[0068] On the premise of meeting the LNG natural gas processing capacity, considering the LNG liquefaction plants that have been built in the helium basin area and the surrounding areas, sort them from large to small according to the daily natural gas processing capacity, exclude the built LNG-BOG helium extraction plants, and select multiple LNG plants as BOG sampling targets. The LNG plant with the largest production capacity on the same pipeline is selected as the BOG sampling target.

[0069] Step S22: According to the helium extraction benefit-related parameters and the LNG-BOG helium extraction benefit coverage area priority principle, the selected LNG plants are sorted to obtain a sampling sequence.

[0070] According to the actual needs of domestic helium users, helium sales prices and other factors, and based on the principle of giving priority to the LNG-BOG helium benefit coverage area, the LNG-BOG sampling order is optimized and the sampling sequence is planned by comprehensively considering the above factors.

[0071] Step S23: According to the sampling sequence, starting from the LNG plant with the highest sampling priority, the LNG plants are selected in turn.

[0072] According to the temperature and pressure characteristics of BOG gas in the actual storage tanks of the LNG plant, a complete sampling plan that meets the safety of BOG sampling is designed, and sampling operations are carried out by professionals in strict accordance with the operating procedures; according to the needs of BOG sampling representativeness, direct sampling or indirect sampling is determined based on the on-site BOG sampling conditions and specific characteristics. Considering the representativeness and stability of the sampling, at least 3 samples need to be collected independently. Since different temperatures and pressures will have a certain impact on the detected helium content, the collection of each sample must be separated by a certain period of time; prepare sample labels that meet the gas sampling specifications, and send the collected samples to the helium content detection center in a timely manner for helium content testing and analysis to determine the helium content in BOG.

[0073] If the answer in step S11 is yes, execute step S12.

[0074] Step S12: Conduct reverse tracing to determine the gas reservoir of the LNG plant, and screen the helium content in the production wells of the gas reservoir to detect the natural gas sampling preparation wells.

[0075] After the BOG test analysis shows that the helium content reaches the lower limit of helium extraction, the LNG production plant is selected, and reverse tracing is carried out according to the source of raw gas to determine the gas source reservoir. Based on the production and location of the gas reservoir production wells, helium content detection natural gas sampling preparation wells are selected from the gas reservoir production wells. The distribution of the selected preparation wells has the ability to control the gas reservoir and can represent different production levels respectively.

[0076] Specifically, it can be that the proposed sampling wells are selected from the characteristics and distribution of gas reservoir production wells, and representative wells with relatively high, medium and low production in the gas reservoir are selected, and production wells with gas reservoir control capabilities and sampling conditions are distributed as natural gas sampling preparation wells for helium content detection.

[0077] According to the natural gas wellhead sampling specifications and helium detection requirements, strictly regulate the operation, collect natural gas samples from the wellheads of the screened helium content detection natural gas sampling preparation wells and send them to the helium detection unit for helium content testing.

[0078] At the same time, the components of the natural gas samples obtained from the reserve wells are analyzed to determine the matching relationship between the BOG helium content and the natural gas helium content; to determine whether the helium content of the natural gas obtained from the reserve wells satisfies the matching relationship with the BOG helium content of the corresponding LNG plant; if so, the natural gas helium content of the reserve wells is determined to be reliable; otherwise, it is necessary to analyze the reasons for the mismatch and confirm the reliability of the helium content in the gas reservoir.

[0079] The reverse tracing sampling method for helium exploration provided in the first embodiment of the present invention takes an actual LNG plant as the object, detects the helium content through BOG sampling, determines the natural gas resources with the potential for BOG helium extraction, determines the target natural gas reservoir through reverse tracing of the LNG gas source, and screens the helium content from the production wells of the gas reservoir to detect the natural gas sampling preparation wells, thereby avoiding a large amount of invalid sampling caused by sampling one by one from the production wells of massive natural gas reservoirs, and saving the sampling and helium detection costs.

[0080] In some embodiments, the helium distribution characteristics of the gas reservoir are determined based on the helium content of natural gas samples from each preparation well in the gas reservoir; and the helium content of the natural gas in the gas reservoir is determined based on the helium distribution characteristics.

[0081] Furthermore, if the distribution of helium content in natural gas is relatively uniform, the entire gas reservoir can be taken as an analysis unit; if the regional distribution of helium content in natural gas varies greatly, the gas reservoir can be divided into multiple analysis units, and subsequent analysis of the remaining recoverable helium resources, potential helium resources, extractable helium resource value, and total helium extraction revenue can be conducted for each analysis unit.

[0082] (1) Determine the remaining recoverable helium resources in the gas reservoir based on the helium content of the natural gas and the recoverable natural gas reserves in the gas reservoir.

[0083] The helium resources (reserves) can be assessed using the volume content method, and the remaining recoverable helium resources in the gas reservoir can be determined using the following formula (1):

[0084] QRRHe=QRG× CHe (1)

[0085] In formula (1):

[0086] QRRHe is the remaining recoverable helium resources, Sm 3 ;

[0087] QRG is recoverable natural gas reserves, Sm 3 ;

[0088] CHe is the helium content of natural gas, %.

[0089] The above-mentioned recoverable natural gas reserves adopt the evaluation results of natural gas reservoir reserves and development plans. The cumulative production of natural gas is calculated based on the natural gas production report. The recoverable natural gas reserves are the natural gas reserves minus the cumulative production of natural gas. When the remaining recoverable helium resources are converted into helium extraction resources, the recoverable helium resources are converted into recoverable helium reserves.

[0090] (2) Determine the potential helium resources of the gas reservoir based on the remaining recoverable helium resources of the gas reservoir.

[0091] The commercial value of recoverable helium resources is evaluated by determining the reasonable ex-factory sales price (PHe) of helium according to the helium market price in the helium extraction area, taking into account the cost factors such as the helium transportation cost, determining the potential helium resources (HeeC), estimating the helium price trend, and evaluating the value of helium resources. The potential helium resources of the gas reservoir can be determined by the following formula (2):

[0092] HeeC=QRRHe-CYCL×PRG×CHe (2)

[0093] In formula (2):

[0094] HeeC is the potential helium resource, Sm 3 ;

[0095] QRRHe is the remaining recoverable helium resources, Sm 3 ;

[0096] CYCL is the estimated time for the helium extraction facility to be completed and put into operation, a;

[0097] PRG is the actual annual natural gas production of the gas reservoir, Sm 3 / a;

[0098] CHe is the helium content of natural gas, %.

[0099] (3) Determine the value of the extractable helium resources in the gas reservoir based on the potential helium resources in the gas reservoir and the ex-factory price of helium.

[0100] The extractable helium resource value of a gas reservoir can be determined by the following formula (3):

[0101] VHE=PHe×HeeC×ROHe (3)

[0102] In formula (3):

[0103] VHE is the value of extractable helium resources in the gas reservoir, yuan;

[0104] PHe is the ex-factory price of helium, RMB / Sm 3 ;

[0105] HeeC is the potential helium resource, Sm3 ;

[0106] ROHe is the helium recovery rate of the helium extraction equipment, %.

[0107] (4) Determine the total revenue from helium extraction from the gas reservoir based on the value of the extractable helium resources in the gas reservoir and the total cost of extracting helium.

[0108] The total helium extraction revenue from the gas reservoir can be determined by the following formula (4):

[0109] TREV=VHE-TCOST (4)

[0110] In formula (4):

[0111] TRE is the total helium extraction revenue, yuan;

[0112] VHE is the value of extractable helium resources in the gas reservoir, yuan;

[0113] TCOST is the total cost of helium extraction, RMB.

[0114] (5) Sort the gas reservoirs according to their total helium extraction revenue, select the LNG plants supplied by the gas reservoirs with the highest total helium extraction revenue, and formulate a helium extraction project construction plan.

[0115] The embodiment of the present invention starts from the actual helium exploration in my country, considers the matching of helium resources and potential helium extraction facilities, and proposes a reverse tracing sampling and detection method for helium exploration based on the idea of ​​integrating helium resource utilization and helium production. While solving the problem of helium resource exploration and evaluation, it determines the priority direction of LNG production plants as the matching of helium extraction facilities, introduces helium demand areas and economic evaluation parameters, and optimizes the factory site selection of the helium extraction demonstration project.

[0116] The reverse tracing sampling method for helium exploration provided by the embodiment of the present invention has a specific technical process as shown in Figure 2 As shown, sampling and helium content detection of the target gas reservoir, determining the helium content and its distribution characteristics in the helium-containing gas reservoir, and conducting helium resource and value evaluation can effectively improve the efficiency of helium exploration, quickly determine the LNG plant with helium extraction conditions, and propose a supporting helium extraction project construction plan on the basis of reducing plant construction investment, which can not only solve the LNG-BOG helium extraction source resource problem, but also reduce the cost of building a special LNG plant for helium extraction, maximize the use of helium-containing natural gas resources and existing LNG production capacity, and have significant economic benefits and the effect of quickly building a helium extraction demonstration project.

[0117] Embodiment 2

[0118] Embodiment 2 of the present invention provides an application example of a reverse tracing sampling method for helium exploration.

[0119] xxLNG plant sampled and analyzed the LNG production tail gas (BOG), and detected a helium content of 15%, which is much higher than the lower limit of helium concentration for conventional economic helium extraction (0.3%). After reverse tracing the LNG gas source, it was determined to be xx shale gas. The helium extraction source resources are sufficient. According to calculations, the conditions for establishing a helium extraction demonstration project are met. The xxBOG helium extraction project team was established with the project approval, and now has built an annual production capacity of 20 tons (about 12.1×10 4 Sm 3 ) High-purity helium extraction plant.

[0120] Embodiment 3

[0121] Embodiment 3 of the present invention provides another application example of a reverse tracing sampling method for helium exploration.

[0122] In the xxLNG project, during the sampling and analysis of LNG production tail gas BOG, it was found that the helium content was 4.35%, which was higher than the lower limit of helium concentration for conventional economic helium extraction (0.3%). The LNG gas source was determined to be xx gas field gas and part of coalbed methane by reverse tracing. It was evaluated that the raw gas resources for helium extraction could meet the needs of establishing a helium extraction demonstration project. It was decided to build a BOG helium extraction plant, which is expected to achieve an annual helium production of 55×10 4 Sm 3 .

[0123] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process can be rearranged without departing from the scope of protection of the present disclosure. The attached method claims present the elements of the various steps in an exemplary order and are not intended to be limited to the specific order or hierarchy described.

[0124] In the above detailed description, various features are grouped together in a single embodiment to simplify the disclosure. This method of disclosure should not be interpreted as reflecting an intention that the embodiments of the claimed subject matter require more features than are clearly stated in each claim. On the contrary, as reflected in the appended claims, the invention is in a state of having less than all the features of the disclosed individual embodiments. Therefore, the appended claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the invention.

[0125] The above description includes examples of one or more embodiments. Of course, it is impossible to describe all possible combinations of components or methods for the purpose of describing the above embodiments, but it should be recognized by those skilled in the art that the various embodiments may be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications and variations that fall within the scope of protection of the appended claims. In addition, with respect to the term "comprising" used in the specification or claims, the word is covered in a manner similar to the term "including", just as "including," is explained as a transitional word in the claims. In addition, any term "or" used in the specification of the claims is intended to mean "non-exclusive or".

Claims

1. A reverse tracing sampling method for helium exploration, characterized in that: include: Carry out BOG sampling at the selected LNG plant to determine the BOG helium content and judge whether the BOG helium content reaches the lower limit of helium extraction; If yes, reverse tracing is carried out to determine the gas reservoir that supplies the LNG plant, and the helium content in the production wells of the gas reservoir is screened to detect the natural gas sampling preparation wells.

2. The method according to claim 1, characterized in that The determination of the selected LNG plant includes: According to the set lower limit of helium content in natural gas and the lower limit of helium amount in helium extraction facilities, the lower limit of natural gas processing capacity screening of the LNG plant is determined, and based on the lower limit of natural gas processing capacity screening, multiple LNG plants are screened as BOG sampling targets; According to the parameters related to helium extraction benefits and the principle of priority of LNG-BOG helium extraction benefit coverage area, the selected LNG plants are sorted to obtain the sampling sequence; According to the sampling sequence, starting from the LNG plant with the highest sampling priority, the LNG plants are selected in turn as the selected LNG plants.

3. The method according to claim 2, characterized in that The screening of multiple LNG plants as BOG sampling targets also includes: The LNG plant with the largest production capacity on the same pipeline was selected as the BOG sampling target.

4. The method according to claim 1, characterized in that Also includes: Performing component analysis on the natural gas sample obtained from the prepared well to determine the matching relationship between the BOG helium content and the natural gas helium content; Determining whether the helium content of the natural gas obtained from the preparation well and the helium content of the BOG of the corresponding LNG plant satisfy the matching relationship; If so, it is determined that the helium content of the natural gas in the prepared well is reliable.

5. The method according to claim 1, characterized in that The method of screening the helium content from the production wells of the gas reservoir to detect the natural gas sampling preparation wells comprises: According to the production and location of the production wells of the gas reservoir, helium content detection natural gas sampling preparation wells are screened from the production wells of the gas reservoir. The distribution of the screened preparation wells has gas reservoir control capability and represents different production levels respectively.

6. The method according to claim 5, characterized in that Also includes: Determine the helium distribution characteristics of the gas reservoir based on the helium content of natural gas samples from each preparation well in the gas reservoir; The helium content of the natural gas in the gas reservoir is determined according to the helium distribution characteristics.

7. The method according to claim 6, characterized in that Also includes: Determine the remaining recoverable helium resources in the gas reservoir based on the helium content of the natural gas in the gas reservoir and the recoverable natural gas reserves; Determine the potential recoverable helium resources of the gas reservoir based on the remaining recoverable helium resources of the gas reservoir; Determine the value of the extractable helium resources in the gas reservoir based on the potential extractable helium resources in the gas reservoir and the ex-factory price of helium; The total revenue from helium extraction from the gas reservoir is determined based on the value of the extractable helium resources in the gas reservoir and the total cost of extracting helium.

8. The method according to claim 7, characterized in that The method of determining the remaining recoverable helium resources of the gas reservoir comprises: The remaining recoverable helium resources of the gas reservoir are determined by the following formula (1): QRRHe=QRG× CHe (1) In formula (1), QRRHe is the remaining recoverable helium resources, QRG is the recoverable natural gas reserves, and CHe is the helium content of natural gas.

9. The method according to claim 7, characterized in that The potential helium resources of the identified gas reservoirs include: The potential helium resources of the gas reservoir can be determined by the following formula (2): HeeC=QRRHe-CYCL×PRG×CHe (2) In formula (2), HeeC is the potential helium resources, QRRHe is the remaining recoverable helium resources, CYCL is the estimated time for the construction and commissioning of the helium extraction facilities, PRG is the actual annual natural gas production of the gas reservoir, and CHe is the helium content of the natural gas.

10. The method according to claim 7, characterized in that Determining the extractable helium resource value of the gas reservoir includes: The extractable helium resource value of the gas reservoir is determined by the following formula (3): VHE=PHe×HeeC×ROHe (3) In formula (3), VHE is the value of helium resources that can be extracted from the gas reservoir, PHe is the ex-factory price of helium, HeeC is the potential helium resources that can be extracted, and ROHe is the helium recovery rate of the helium extraction equipment.

11. The method according to claim 7, characterized in that The total benefits of helium extraction from the identified gas reservoirs include: The total helium extraction benefit of the gas reservoir is determined by the following formula (4): TREV=VHE-TCOST (4) In formula (4), TRE is the total revenue of helium extraction, VHE is the value of extractable helium resources in the gas reservoir, and TCOST is the total cost of helium extraction.

12. The method according to any one of claims 7 to 11, characterized in that: Also includes: Rank the gas reservoirs according to the total helium extraction revenue, select the LNG plants supplied by the gas reservoirs with the highest total helium extraction revenue, and formulate a helium extraction project construction plan.

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