CN-122016989-A - Natural hydrogen cause identification method based on cluster isotopes

CN122016989ACN 122016989 ACN122016989 ACN 122016989ACN-122016989-A

Abstract

The invention discloses a natural hydrogen cause judgment method based on cluster isotopes, which comprises the following steps of obtaining a purified hydrogen sample to be detected through separation and purification treatment, carrying out cluster isotope measurement on the purified hydrogen sample to obtain cluster isotope values representing the degree of deviation of double deuterium molecule abundance from random distribution, when the cluster isotope values are judged to be in an original thermodynamic equilibrium state, reversing the formation temperature of the purified hydrogen sample according to a theoretical function relation between the cluster isotope values and the thermodynamic equilibrium temperature, and comparing the formation temperature with the formation temperature ranges of different cause types of natural hydrogen established in advance to determine the cause types of the purified hydrogen sample. The invention realizes the radical breakthrough from qualitative speculation to accurate quantitative judgement of the natural hydrogen cause by introducing the cluster isotope delta DD as an anti-interference core index and combining multi-source information verification and temperature quantitative inversion.

Inventors

YANG CHENG
LI QIAN
ZHU GUANGYOU
DONG MINGYI
SUN HEZHONG
ZHAO RONGSHENG

Assignees

长江大学

Dates

Publication Date: 20260512
Application Date: 20260226

Claims (10)

1. A natural hydrogen cause identification method based on cluster isotopes, which is characterized by comprising the following steps: obtaining a purified hydrogen sample to be detected through separation and purification treatment; performing cluster isotope measurement on the purified hydrogen sample to obtain cluster isotope values representing the degree of deviation of the abundance of the double deuterium molecules from random distribution; when the cluster isotope value is judged to be in an original thermodynamic equilibrium state, according to a theoretical functional relation between the cluster isotope value and the thermodynamic equilibrium temperature, the formation temperature of the purified hydrogen sample is inverted; Comparing the formation temperature with the formation temperature ranges of the natural hydrogen with different pre-established cause types, and determining the cause type of the purified hydrogen sample.
2. The method for identifying natural hydrogen causes based on cluster isotopes of claim 1, wherein the purified hydrogen sample to be measured is obtained by separation and purification treatment, comprising: And (3) processing a natural hydrogen sample containing impurities by adopting a liquid nitrogen freezing enrichment method, and condensing and intercepting the impurity gas under a low-temperature condition by utilizing the difference of boiling points of the hydrogen and the impurity gas so as to keep a hydrogen component in a gaseous state and flow out through a carrier gas to realize physical separation and purification of the hydrogen, wherein the impurity gas comprises methane, nitrogen and helium.
3. The method for identifying natural hydrogen causes based on cluster isotopes of claim 1, wherein the method for measuring the cluster isotopes of the purified hydrogen sample to obtain cluster isotope values representing the degree of deviation of the abundance of the double deuterium molecules from random distribution comprises the following steps: Sequentially measuring signal intensities of a common hydrogen molecular ion beam, a hydrogen deuterium molecular ion beam and a double deuterium molecular ion beam in the purified hydrogen sample by using a high-resolution stable isotope mass spectrometer by using a peak jump method, and subtracting background signals; Calculating to obtain a hydrogen isotope delta D value of the sample based on the measured signal intensity ratio of the hydrogen deuterium molecule to the common hydrogen molecule; Calculating to obtain a double deuterium molecule delta DD value of the sample based on the measured signal intensity ratio of the double deuterium molecule to the common hydrogen molecule; And calculating and obtaining the cluster isotope delta DD value of the purified hydrogen sample by using the reference gas subjected to the thermodynamic equilibrium treatment based on a reference measurement method established by a heating equilibrium experiment.
4. The method for determining the natural hydrogen cause of a hydrogen sample based on cluster isotopes of claim 1, wherein determining whether the cluster isotope values of the purified hydrogen sample are in an original thermodynamic equilibrium state comprises performing a comprehensive determination using at least one of: based on the combined analysis of the cluster isotope values and the hydrogen isotope values, judging whether the cluster isotope values and the hydrogen isotope values are positioned in a theoretical equilibrium relation curve or an error range of the theoretical equilibrium relation curve; judging whether the hydrogen isotope values of different samples in the same geological unit undergo an isotope homogenization process or not based on the consistency characteristics of the hydrogen isotope values and the cluster isotope values of the different samples; Indirectly inferring based on geochemical characteristics of the associated gas, including determining a gas source depth from a helium isotope ratio of the associated helium gas, or inferring whether the hydrogen gas undergoes a late reset by analyzing a cluster isotope equilibrium state of the associated methane gas; and comprehensively analyzing the geological background of the region and the reservoir temperature information, and judging whether the temperature indicated by the cluster isotopes is consistent with the current geothermal temperature or the ancient hydrothermal activity temperature of the reservoir.
5. The method for identifying natural hydrogen causes based on cluster isotopes of claim 1, characterized in that the method for identifying the formation temperature of the purified hydrogen sample is performed according to a theoretical functional relationship between the value of cluster isotopes and the thermodynamic equilibrium temperature, and comprises: The theoretical functional relation is pre-established by obtaining energy level data of hydrogen molecules, deuterium molecules and hydrogen deuterium molecules through quantum chemical calculation, further calculating thermodynamic equilibrium constants of isotope exchange reactions at different temperatures, and converting the equilibrium constants into functional relations between cluster isotope values and temperatures.
6. The method for judging the natural hydrogen causes based on the cluster isotopes according to claim 1, wherein the pre-established formation temperature ranges of the natural hydrogen of different causes comprise a temperature range corresponding to hydrogen production by microorganisms, a temperature range corresponding to hydrogen production by organic matter thermal evolution, a temperature range corresponding to hydrogen production by water rock reaction of iron-containing minerals, a temperature condition corresponding to hydrogen production by radiation decomposition of water and a temperature range corresponding to hydrogen production by water free radical decomposition related to rock breaking.
7. The cluster isotope-based natural hydrogen cause judgment method according to claim 1, wherein after determining the primary cause type of the purified hydrogen sample, further combining the hydrogen isotope data of the purified hydrogen sample and the component characteristics of associated gas thereof, and performing multi-dimensional comprehensive research to finally lock the cause type.
8. A computer device comprising a memory, a processor and a computer program stored on the memory, characterized in that the processor executes the computer program to carry out the steps of the method according to any one of claims 1-7.
9. A computer readable storage medium, on which a computer program is stored, characterized in that the computer program, when being executed by a processor, implements the steps of the method according to any of claims 1-7.
10. A computer program product comprising a computer program, characterized in that the computer program, when being executed by a processor, realizes the steps of the method according to any one of claims 1-7.

Description

Natural hydrogen cause identification method based on cluster isotopes Technical Field The invention belongs to the technical field of geochemistry and isotope geology, and particularly relates to a natural hydrogen cause identification method based on cluster isotopes. Background Natural hydrogen is considered as an important potential energy source to replace traditional fossil fuels due to its clean, high energy density characteristics. However, achieving its large scale exploration and efficient development, first has to solve the underlying geological problem of causative judgment. The source and the formation mechanism of the hydrogen are accurately identified, so that the hydrogen is not only a precondition for understanding the distribution rule of the hydrogen, but also a scientific basis for evaluating the potential of resources and guiding exploration deployment. At present, natural hydrogen cause discrimination mainly depends on two types of prior art methods. The first category is hydrogen isotope composition analysis, i.e., the derivation of the cause of deuterium (D) and hydrogen (H) by determining their relative abundance in hydrogen (typically expressed as δd values). Different causative processes (e.g., microbiological action, water rock reaction, deep degassing, etc.) theoretically produce hydrogen with a specific range of delta D values. However, hydrogen is highly chemically active and undergoes extensive isotopic exchange reactions with formation water, mineral surfaces and microorganisms during migration from the formation site to the reservoir, and even later storage. This process results in significant fractionation of the hydrogen isotope, so that the measured δd value often cannot represent the characteristics of the original δd value when it is formed, but reflects the result of post-reconstruction superposition, thereby seriously impairing the reliability and accuracy of the discrimination of the method. The second type of method is an indirect inference of the constituent characteristics of associated gas. The method indirectly presumes the source and environment of hydrogen by analyzing the chemical and isotopic composition of other gases (e.g., methane, helium, nitrogen, etc.) that are co-located with the hydrogen. For example, an indication of veil source helium may be associated with deep inorganic-derived hydrogen, while the presence of biogenic methane may suggest that the associated hydrogen has an organic source. While this approach can provide some degree of complementary causal clues and is used for cross-validation, it is an indirect evidence in nature that accounts for the existence of multiple solutions. Different causative processes may produce similar combinations of associated gas, and the same causative process may also cause changes in the composition of the associated gas due to environmental differences. Furthermore, the discrimination capability of this approach is particularly limited for some reservoirs lacking characteristic associated gas or experiencing complex mixing. In summary, the prior art methods, either direct but susceptible to modification of the hydrogen isotope method or indirect and polynosic associated gas composition method, suffer from significant drawbacks. They are difficult to effectively resist the physicochemical modifications that hydrogen undergoes in the late geological history, and do not provide a direct, robust and unique causative judgment index. This technical bottleneck restricts the accurate knowledge of the formation mechanism of natural hydrogen, especially deep inorganic causative hydrogen with complex sources, and also hinders the breakthrough of related exploration technologies. Therefore, there is an urgent need in the art to develop a novel cause judgment technology that can more directly record the original formation conditions, is less interfered by the later stage, and can improve the judgment accuracy. Disclosure of Invention In order to solve the technical problems, the invention provides a natural hydrogen cause identification method based on cluster isotopes, which comprises the following steps: obtaining a purified hydrogen sample to be detected through separation and purification treatment; performing cluster isotope measurement on the purified hydrogen sample to obtain cluster isotope values representing the degree of deviation of the abundance of the double deuterium molecules from random distribution; when the cluster isotope value is judged to be in an original thermodynamic equilibrium state, according to a theoretical functional relation between the cluster isotope value and the thermodynamic equilibrium temperature, the formation temperature of the purified hydrogen sample is inverted; Comparing the formation temperature with the formation temperature ranges of the natural hydrogen with different pre-established cause types, and determining the cause type of the purified hydrogen sample. Optionally,