Method and device for determining multi-element mixed source ratio of natural gas reservoir

Abstract

The invention provides a method and a device for determining the multi-element mixed source ratio of a natural gas reservoir. The method comprises the steps that the methane content, the C2 + hydrocarbon component content and the methane carbon isotope value delta 13C1 of natural gas of a target natural gas reservoir are obtained; obtaining a heat cause gas drying coefficient, a methane carbon isotope value delta 13C1 heat, a primary biogas methane carbon isotope value delta 13C1 primary and a secondary biogas methane carbon isotope value delta 13C1 secondary; based on the methane content, the C2 + hydrocarbon component content and the methane carbon isotope value delta 13C1 of the natural gas of the target natural gas reservoir, the methane carbon isotope value delta 13C1 < heat > of the protogenetic gas, the methane carbon isotope value delta 13C1 < primary > of the protogenetic gas and the methane carbon isotope value delta 13C1 < secondary > of the secondary biogas are combined, and the methane carbon isotope value delta 13C1 < secondary > of the protogenetic gas is calculated. And determining the contribution ratio of the thermogenic gas, the primary biogas and the secondary biogas in the natural gas of the target natural gas reservoir. According to the technical scheme provided by the invention, the mixed source proportion of the ternary mixed natural gas reservoir can be quantitatively determined by using hydrocarbon composition and isotope distribution in the natural gas reservoir.

Description

Technical Field

[0001] The invention relates to a method and a device for determining a multi-source mixed ratio of a natural gas reservoir. Background Art

[0002] As a clean energy, natural gas is an important alternative energy source. Its sources or causes are complex and diverse, including mantle-derived gas, inorganic gas produced by water-rock reaction in the deep crust, coal-type gas, thermogenic gas formed by the evolution of source rocks under thermal action in oil and gas basins, methane gas (primary biogenic gas) produced by microbial transformation of organic matter in the early stage of diagenesis, and secondary biogenic gas generated by biodegradation of oil reservoirs.

[0003] Natural gas hydrates are widely distributed in offshore waters and permafrost zones. They are new types of deposits formed by natural gas and water from deep or different sources under low temperature and high pressure conditions. They are also called combustible ice and are very abundant. In these conventional or unconventional natural gas systems, the current quantitative analysis or calculation methods for the mixed source ratio are mainly based on binary mixed natural gas reservoirs. There is no effective technology or method for the quantitative analysis of the mixed source ratio of ternary or higher mixed natural gas reservoirs.

[0004] There are two main quantitative methods for the mixed source ratio of natural gas reservoirs: one is to conduct a binary mixing ratio experiment of natural gas (select end-gas samples, mix the end-gases in a certain proportion under isobaric conditions, let the gases stand in a constant temperature environment after mixing, and analyze the mixed source gas components, monomer hydrocarbon carbon and hydrogen isotopes, light hydrocarbon fingerprints, etc. after the natural gas is fully mixed), and then establish a mixed source ratio identification chart, and use the established mixed source ratio identification chart to quantitatively determine the mixed source ratio of natural gas reservoirs; the other is to establish a binary mixed source natural gas isotope model, and use the isotope model to quantitatively determine the mixed source ratio of natural gas reservoirs. However, both methods have many problems. Among them, the first method has a long cycle due to the experimental process, and there will be inevitable errors in the ratio experiment process, which will have a certain impact on the accuracy of the results. If this method is used to quantitatively identify the mixed source ratio of ternary or more, the experimental and analysis process will be more cumbersome, the cycle will be longer, and the error of the experimental results will also increase significantly. Among them, the second method is a feasible method for determining the mixing ratio of binary mixed source natural gas, but for ternary or higher mixed source natural gas, due to the addition of an unknown variable, the method of using the existing binary mixed source natural gas isotope model to determine the mixing ratio is not feasible. In general, the existing quantitative method for the mixing ratio of natural gas reservoirs is not suitable for the quantitative determination of the mixing ratio of ternary or higher mixed natural gas reservoirs.

[0005] In summary, it is still necessary to study new technical solutions for quantitatively determining the mixed source ratio of natural gas reservoirs in order to achieve quantitative determination of the mixed source ratio of ternary or higher mixed natural gas reservoirs. Summary of the invention

[0006] The object of the present invention is to provide a technical solution capable of quantitatively determining the mixing ratio of mixed sources in a ternary mixed natural gas reservoir.

[0007] To achieve the above object, the present invention provides a method for determining the multi-source mixing ratio of a natural gas reservoir, wherein the method includes:

[0008] Obtaining the methane content, C2+ hydrocarbon component (composed of hydrocarbon compounds containing two or more carbon atoms) content, and methane carbon isotope value δ 13 C1;

[0009] Obtaining the dry coefficient of thermogenic gas and the methane carbon isotope value δ 13 C 1热 , the methane carbon isotope value δ 13 C 1原生 of primary biogenic gas, and the methane carbon isotope value δ 13 C 1次生 ;

[0010] Based on the methane content, C2+ hydrocarbon component content, and methane carbon isotope value δ 13 C1 of the natural gas in the target natural gas reservoir, combined with the dry coefficient of thermogenic gas and the methane carbon isotope value δ 13 C 1热 , the methane carbon isotope value δ 13 C 1原生 of primary biogenic gas, and the methane carbon isotope value δ 13 C 1次生 , determining the contribution ratios of thermogenic gas, primary biogenic gas, and secondary biogenic gas in the natural gas of the target natural gas reservoir.

[0011] In a second aspect, the present invention provides a device for determining the multi-source mixing ratio of a natural gas reservoir, wherein the device includes:

[0012] The first data acquisition module: used to obtain the methane content, C2+ hydrocarbon component (composed of hydrocarbon compounds containing two or more carbon atoms) content, and methane carbon isotope value δ 13 C1;

[0013] The second data acquisition module: used to obtain the dry coefficient of thermogenic gas and the methane carbon isotope value δ 13 C 1热 , the methane carbon isotope value δ 13 C 1原生 , the methane carbon isotope value δ 13 C 1次生 ;

[0014] Contribution ratio determination module: used to determine the contribution ratios of thermogenic gas, primary biogenic gas, and secondary biogenic gas in the natural gas of the target gas reservoir based on the methane content, C2+ hydrocarbon component content, methane carbon isotope value δ 13 C1, in combination with the dry coefficient of thermogenic gas and the methane carbon isotope value δ 13 C 1热 , the methane carbon isotope value δ 13 C 1原生 of primary biogenic gas, and the methane carbon isotope value δ 13 C 1次生 of secondary biogenic gas

[0015] Thirdly, an embodiment of this specification also provides a computer device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, it implements the method for determining the multiple mixed-source ratio of a gas reservoir provided in the first aspect.

[0016] Fourthly, the present invention provides a computer-readable storage medium storing a computer program, and when the computer program is executed by a processor, it implements the method for determining the multiple mixed-source ratio of a gas reservoir provided in the first aspect.

[0017] Fifthly, the present invention provides a computer program product, which includes a computer program, and when the computer program is executed by a processor, it implements the method for determining the multiple mixed-source ratio of a gas reservoir provided in the first aspect.

[0018] In the areas where gas reservoirs and gas hydrates are distributed, the sources of natural gas are often very complex and multi-source. The technical solution provided by the present invention can quantitatively determine the mixed-source ratio of a ternary mixed gas reservoir by using the hydrocarbon composition and isotope distribution in the gas reservoir, without the need for possibly complex and cumbersome ratio experiments, processing and analysis, and drawing of charts, as well as possible experimental errors. The results are accurate and reliable, and can effectively serve the exploration, development, and resource evaluation of oil and gas-bearing basins and gas hydrates. Description of the Drawings

[0019] In order to more clearly illustrate the technical solutions in the embodiments of this specification or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. The drawings described below are only some embodiments recorded in this specification. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0020] Figure 1 It is a characteristic diagram of the natural gas components and carbon isotope distribution of the target gas reservoir in Embodiment 1.

[0021] Figure 2 It is a distribution characteristic diagram of the C1 hydrocarbon and C2+ hydrocarbon contents of the natural gas in the target natural gas reservoir of Example 1 and the standard natural gas.

[0022] Figure 3 It is a distribution characteristic diagram of the carbon isotopes δ 13 C of ethane and propane in the natural gas of the target natural gas reservoir of Example 1 and the standard natural gas.

[0023] Figure 4 It is a triangular diagram of the contribution ratios of thermogenic gas, primary biogenic gas, and secondary biogenic gas in the natural gas of the target natural gas reservoir of Example 1. Detailed implementation manners

[0024] Next, the technical solutions in the embodiments of this specification will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of this specification. Obviously, the described embodiments are only a part of the embodiments of this specification, rather than all the embodiments. The specific embodiments described herein are only used to explain the present disclosure, rather than limiting the present disclosure. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present disclosure belong to the scope of protection of the present disclosure. In addition, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0025] Natural gas: Generally refers to all natural gas-like gases existing in nature. In the present invention, it mainly refers to the natural gas produced from oil and gas fields or reservoirs, and gas reservoirs in oil and gas basins, usually mainly composed of hydrocarbon gases such as methane, ethane, propane, and butane, and may contain non-hydrocarbon gases such as carbon dioxide, nitrogen, helium, or argon.

[0026] Drying coefficient: Refers to the percentage of methane content in natural gas accounting for all hydrocarbon gases.

[0027] Natural gas hydrate: Refers to an ice-like solid formed by the combined action of natural gas and water under low temperature and high pressure conditions, also known as combustible ice, which is distributed on the surface of sediments in offshore waters and in frozen soil areas.

[0028] Thermogenic gas: As the degree of thermal evolution increases, natural gas generated by the cracking of liquid hydrocarbons and the thermal degradation of kerogen in the high maturity stage, including oil-type gas and coal-type gas, etc., generally contains C2+ hydrocarbons, and its stable carbon isotope δ 13 C is heavier, usually distributed between -55‰ and -30‰, and is usually distributed in deep oil and gas reservoirs in oil and gas basins.

[0029] Primary biogenic gas, or biogenic gas, is natural gas generated by the microbial degradation of organic matter in the early stage of diagenesis. The main component is methane, and its carbon isotope is light, that is, poor 13C, with a distribution range of -90‰ to -55‰.

[0030] Secondary biogas: Generated by the degradation of hydrocarbons due to the action of bacteria and other microorganisms under the condition that the formation temperature of the oil and gas reservoir does not exceed 80°C. It is mainly dry gas, without heavy hydrocarbons, with relatively light carbon isotopes, generally < -55‰.

[0031] The methane carbon isotope value refers to the abundance of stable carbon isotopes in methane, expressed as the ratio between the ratios of the two most abundant carbon isotopes in the methane sample and the corresponding ratio in the international standard, denoted by the symbol δ. Due to the small difference in the ratio between the sample and the standard reference, the stable isotope abundance is expressed as the per mille of the deviation between the sample and the standard. Taking carbon as an example: Internationally, the isotope standard of belemnite from the Cretaceous in South Carolina, USA, i.e., the PDB standard, is adopted. Its 13 C / 12 C = 0.0112372. The stable isotope abundance of the reference material is defined as 0‰. If the 13 C / 12 C ratio of a certain substance > 0.0112372, it has a positive value; if its 13 C / 12 C ratio < 0.0112372, it has a negative value.

[0032] In various oil and gas basins, oil and gas fields, oil and gas reservoirs, and gas reservoirs on land and in the sea, thermogenic gas provided by the thermal evolution of source rocks (or coal), methane gas (biogas) generated by the microbial transformation of immature source rocks in the early diagenetic stage, and secondary biogas generated by the biodegradation of oil and gas reservoirs are the most common sources of natural gas. The purpose of the present invention is to establish a technical solution that can quantitatively determine the mixing ratio of mixed-source natural gas reservoirs based on the origin and geochemical composition characteristics of natural gas and the principle of mass balance, scientifically understand and distinguish the supply sizes of natural gas with different origins, and serve oil and gas exploration and development and resource evaluation.

[0033] The embodiment of the present invention provides a method for determining the multi-source mixing ratio of a natural gas reservoir. Among them, the method includes:

[0034] Step S11: Obtain the methane content, C2+ hydrocarbon component (composed of hydrocarbon compounds containing two or more carbon atoms) content, and methane carbon isotope value δ 13 C1 of the natural gas in the target natural gas reservoir;

[0035] Step S12: Obtain the dry coefficient of thermogenic gas and the methane carbon isotope values δ 13 C 1热 , the methane carbon isotope value δ 13 C 1原生 of primary biogas, and the methane carbon isotope value δ of secondary biogas13 C 1次生 ;

[0036] Step S13: Based on the methane content, C2+ hydrocarbon component content, and methane carbon isotope value δ 13 C1 of the natural gas in the target gas reservoir, combined with the dry coefficient of thermogenic gas and the methane carbon isotope value δ 13 C 1热 , the methane carbon isotope value δ 13 C 1原生 of primary biogenic gas, and the methane carbon isotope value δ 13 C 1次生 of secondary biogenic gas, determine the contribution ratios of thermogenic gas, primary biogenic gas, and secondary biogenic gas in the natural gas of the target gas reservoir.

[0037] In some embodiments, the methane content, C2+ hydrocarbon component (composed of hydrocarbon compounds containing two or more carbon atoms) content, and methane carbon isotope value δ 13 C1 of the natural gas in the target gas reservoir can be measured by laboratory tests; the present invention does not limit this.

[0038] In some embodiments, the dry coefficient of thermogenic gas and the methane carbon isotope values δ 13 C 1热 , the methane carbon isotope value δ 13 C 1原生 of primary biogenic gas, and the methane carbon isotope value δ 13 C 1次生 of secondary biogenic gas can be determined by referring to data, or by referring to the methane carbon isotope value δ 13 C 1热 of thermogenic gas, the methane carbon isotope value δ 13 C 1原生 of primary biogenic gas, and the methane carbon isotope value δ 13 C 1次生 of secondary biogenic gas of gas reservoirs with similar C2+ hydrocarbon component content - methane content distribution characteristics and ethane carbon isotope - propane carbon isotope distribution characteristics; the present invention does not limit this.

[0039] In some embodiments, in step S13, based on the methane content, C2+ hydrocarbon component content, and methane carbon isotope value δ 13 C1 of the natural gas in the target gas reservoir, combined with the dry coefficient of thermogenic gas and the methane carbon isotope value δ 13 C 1热 , the methane carbon isotope value δ 13 C 1原生 , the methane carbon isotope value δ 13 C 1次生, determining the contribution ratios of thermogenic gas, primary biogenic gas, and secondary biogenic gas in the natural gas of the target gas reservoir includes:

[0040] Step S131: Based on the dry coefficient of thermogenic gas, the methane content, and the C2+ hydrocarbon component content of the natural gas in the target gas reservoir, determine the contribution ratio of thermogenic gas in the natural gas of the target gas reservoir;

[0041] Step S132: Based on the contribution ratio of thermogenic gas in the natural gas of the target gas reservoir, the C2+ hydrocarbon component content of the natural gas in the target gas reservoir, the methane carbon isotope value δ 13 C1 of the natural gas in the target gas reservoir, the methane carbon isotope value δ 13 C 1热 of thermogenic gas, the methane carbon isotope value δ 13 C 1原生 of primary biogenic gas, and the methane carbon isotope value δ 13 C 1次生 of secondary biogenic gas, determine the contribution ratios of primary biogenic gas and secondary biogenic gas in the natural gas of the target gas reservoir;

[0042] Further, in step S131, based on the dry coefficient of thermogenic gas, the methane content, and the C2+ hydrocarbon component content of the natural gas in the target gas reservoir, determining the contribution ratio of thermogenic gas in the natural gas of the target gas reservoir includes:

[0043] Based on the dry coefficient of thermogenic gas and the C2+ hydrocarbon component content of the natural gas in the target gas reservoir, determine the methane content of thermogenic gas in the natural gas of the target gas reservoir;

[0044] Based on the methane content of thermogenic gas in the natural gas of the target gas reservoir and the methane content of the natural gas in the target gas reservoir, determine the contribution ratio of thermogenic gas in the natural gas of the target gas reservoir;

[0045] Among them, the methane content of thermogenic gas in the natural gas of the target gas reservoir is preferably determined by the following formula:

[0046] C 热 = (A·B)÷(1 - A)

[0047] In the formula, A is the dry coefficient of thermogenic gas, with no unit; B is the C2+ hydrocarbon component content of the natural gas in the target gas reservoir, in %; C 热 is the methane content of thermogenic gas in the natural gas of the target gas reservoir, in %;

[0048] Among them, the contribution ratio of thermogenic gas in the natural gas of the target gas reservoir is preferably determined by the following formula:

[0049] X 热 = C 热 ÷ C

[0050] Wherein, C 热 is the methane content of thermogenic gas in the natural gas of the target gas reservoir, in %; C is the methane content of the natural gas of the target gas reservoir, in %; X 热 is the contribution ratio of thermogenic gas in the natural gas of the target gas reservoir, in %.

[0051] In some embodiments, in step S132, the contribution ratios of primary biogas and secondary biogas in the natural gas of the target gas reservoir are determined by the following formula:

[0052] δ 13 C 1热 ·X 热 +δ 13 C 1原生 ·X 原生 +δ 13 C 1次生 ·X 次生 =δ 13 C1

[0053] X 热 +X 原生 +X 次生 =1

[0054] Wherein, X 原生 is the contribution ratio of primary biogas in the natural gas of the target gas reservoir, in %; X 次生 is the contribution ratio of secondary biogas in the natural gas of the target gas reservoir, in %; X 热 is the contribution ratio of thermogenic gas in the natural gas of the target gas reservoir, in %.

[0055] The embodiments of the present specification provide a device for determining the multi-source mixing ratio of a gas reservoir, as described in the following embodiments. Since the principle of the device for solving the problem is similar to the method for determining the multi-source mixing ratio of a gas reservoir, the implementation of the device can refer to the implementation of the method for determining the multi-source mixing ratio of a gas reservoir, and the repeated parts will not be elaborated.

[0056] The device for determining the multi-source mixing ratio of a gas reservoir provided by the embodiments of the present invention includes:

[0057] The first data acquisition module 21: used to acquire the methane content, C2+ hydrocarbon component (composed of hydrocarbon compounds containing two or more carbon atoms) content, and methane carbon isotope value δ 13 C1 of the natural gas of the target gas reservoir;

[0058] The second data acquisition module 22: used to acquire the dry coefficient of thermogenic gas and the methane carbon isotope values δ 13 C 1热 and the methane carbon isotope value δ 13 C of primary biogas,1原生 and the methane carbon isotope value δ 13 C 1次生 of the secondary biogenic gas;

[0059] Contribution ratio determination module 23: used to determine the contribution ratios of thermogenic gas, primary biogenic gas, and secondary biogenic gas in the natural gas of the target gas reservoir based on the methane content, C2+ hydrocarbon component content, and methane carbon isotope value δ 13 C1 of the natural gas in the target gas reservoir, in combination with the dryness coefficient of thermogenic gas and the methane carbon isotope value δ 13 C 1热 of the primary biogenic gas methane, and the methane carbon isotope value δ 13 C 1原生 of the secondary biogenic gas methane, and the methane carbon isotope value δ 13 C 1次生 of the secondary biogenic gas methane.

[0060] In some embodiments, the contribution ratio determination module 23 includes:

[0061] First contribution ratio determination sub-module 231: used to determine the contribution ratio of thermogenic gas in the natural gas of the target gas reservoir based on the dryness coefficient of thermogenic gas, the methane content, and the C2+ hydrocarbon component content of the natural gas in the target gas reservoir;

[0062] Second contribution ratio determination sub-module 232: used to determine the contribution ratios of primary biogenic gas and secondary biogenic gas in the natural gas of the target gas reservoir based on the contribution ratio of thermogenic gas in the natural gas of the target gas reservoir, the C2+ hydrocarbon component content of the natural gas in the target gas reservoir, the methane carbon isotope value δ 13 C1 of the natural gas in the target gas reservoir, the methane carbon isotope value δ 13 C 1热 of the thermogenic gas methane, the methane carbon isotope value δ 13 C 1原生 of the primary biogenic gas methane, and the methane carbon isotope value δ 13 C 1次生 of the secondary biogenic gas methane.

[0063] Furthermore, the first contribution ratio determination sub-module 231 includes:

[0064] Methane content determination sub-unit 2311 of thermogenic gas: used to determine the methane content of thermogenic gas in the natural gas of the target gas reservoir based on the dryness coefficient of thermogenic gas and the C2+ hydrocarbon component content of the natural gas in the target gas reservoir;

[0065] First contribution ratio determination sub-unit 2312: used to determine the contribution ratio of thermogenic gas in the natural gas of the target gas reservoir based on the methane content of thermogenic gas in the natural gas of the target gas reservoir and the methane content of the natural gas in the target gas reservoir;

[0066] Among them, the methane content determination subunit 2311 of thermogenic gas preferably determines the contribution ratio of thermogenic gas in the natural gas of the target gas reservoir through the following formula:

[0067] C 热 =(A·B)÷(1 - A)

[0068] In the formula, A is the dry coefficient of thermogenic gas, unitless; B is the C2+ hydrocarbon component content of the natural gas in the target gas reservoir, unit %; C 热 is the methane content of thermogenic gas in the natural gas of the target gas reservoir, unit %;

[0069] Among them, the first contribution ratio determination subunit 2312 preferably determines the contribution ratio of thermogenic gas in the natural gas of the target gas reservoir through the following formula:

[0070] X 热 =C 热 ÷C

[0071] In the formula, C 热 is the methane content of thermogenic gas in the natural gas of the target gas reservoir, unit %; C is the methane content of the natural gas in the target gas reservoir, unit %; X 热 is the contribution ratio of thermogenic gas in the natural gas of the target gas reservoir, unit %.

[0072] Furthermore, the second contribution ratio determination sub-module 232 determines the contribution ratios of primary biogenic gas and secondary biogenic gas in the natural gas of the target gas reservoir through the following formula:

[0073] δ 13 C 1热 ·X 热 +δ 13 C 1原生 ·X 原生 +δ 13 C 1次生 ·X 次生 =δ 13 C1

[0074] X 热 +X 原生 +X 次生 =1

[0075] In the formula, X 原生 is the contribution ratio of primary biogenic gas in the natural gas of the target gas reservoir, unit %; X 次生 is the contribution ratio of secondary biogenic gas in the natural gas of the target gas reservoir, unit %; X 热 is the contribution ratio of thermogenic gas in the natural gas of the target gas reservoir, unit %.

[0076] An embodiment of this specification also provides a computer device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the method for determining the multi-source mixing ratio of natural gas reservoirs provided by the embodiments of the present invention is implemented.

[0077] An embodiment of this specification also provides a computer-readable storage medium. The computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the method for determining the multi-source mixing ratio of natural gas reservoirs provided by the embodiments of the present invention is implemented.

[0078] An embodiment of this specification also provides a computer program product. The computer program product includes a computer program. When the computer program is executed by a processor, the method for determining the multi-source mixing ratio of natural gas reservoirs provided by the embodiments of the present invention is implemented.

[0079] Embodiment 1

[0080] This embodiment provides a method for determining the multi-source mixing ratio of natural gas reservoirs.

[0081] This embodiment is used to determine the multi-source mixing ratio of the hydrate natural gas reservoir in Well A in Area A. Area A is a favorable area for the development of natural gas hydrates. The sources of natural gas include thermogenic gas generated from source rocks, primary biogenic gas produced by the microbial degradation of shallow organic matter, and secondary biogenic gas formed by the biodegradation of oil and gas reservoirs in the basin. This embodiment determines the contribution ratios of thermogenic gas, primary biogenic gas, and secondary biogenic gas in the hydrate natural gas reservoir of Well A through a method for determining the multi-source mixing ratio of natural gas reservoirs. The hydrate natural gas in the hydrate natural gas reservoir of Well A exhibits the characteristics of a mixed origin of biogenic gas and thermolytic gas, but mainly thermolytic gas.

[0082] The method includes:

[0083] 1. Obtain the methane content, C2+ hydrocarbon component content, and methane carbon isotope value δ 13 C1 of the hydrate natural gas in the hydrate natural gas reservoir of Well A. The results are shown in Table 1.

[0084] 2. Obtain the dry coefficient of thermogenic gas and the methane carbon isotope value δ 13 C 1热 , the methane carbon isotope value δ 13 C 1原生 of primary biogenic gas, and the methane carbon isotope value δ 13 C 1次生 .

[0085] The component and carbon isotope distribution characteristics of the hydrate natural gas in the hydrate natural gas reservoir of Well A are as Figure 1As shown (with the methane carbon isotope value on the abscissa and the methane content ÷ (C2 hydrocarbon content + C3 hydrocarbon content) on the ordinate).

[0086] The distribution characteristics of the C2+ hydrocarbon components and methane content in the hydrate natural gas in Well A hydrate natural gas reservoir are as Figure 2 shown (with the methane content on the abscissa and the C2+ hydrocarbon component content on the ordinate). The distribution characteristics of the ethane and propane carbon isotopes in the hydrate natural gas in Well A hydrate natural gas reservoir are as Figure 3 shown (with the ethane carbon isotope value on the abscissa and the propane carbon isotope value on the ordinate). From Figure 2 、 Figure 3 it can be seen that the hydrate natural gas in Well A hydrate natural gas reservoir as a whole shows the same characteristics as the natural gas standard samples of Well B and Well C, which are thermogenic natural gas wells in the deep part of the basin, and is more similar to the characteristics of the natural gas standard sample of Well C. Based on this, the dry coefficient of thermogenic gas and the methane carbon isotope value δ 13 C 1热 for the hydrocarbon-supplying thermogenic gas in the hydrate natural gas reservoir are taken with reference to Well C, where the methane carbon isotope value is taken as -39‰; further, with reference to relevant literature materials, the methane carbon isotope value δ 13 C 1原生 of primary biogenic gas is taken as -76.6‰, and the methane carbon isotope value δ 13 C 1次生 of secondary biogenic gas is taken as -55‰; for specific values, please refer to Table 1.

[0087] 3. Based on the methane content, C2+ hydrocarbon component content, and methane carbon isotope value δ 13 C1 of the hydrate natural gas in Well A hydrate natural gas reservoir, combined with the dry coefficient of thermogenic gas and the methane carbon isotope value δ 13 C 1热 , the methane carbon isotope value δ 13 C 1原生 of primary biogenic gas, and the methane carbon isotope value δ 13 C 1次生 of secondary biogenic gas, determine the contribution ratios of thermogenic gas, primary biogenic gas, and secondary biogenic gas in the hydrate natural gas in Well A hydrate natural gas reservoir. Specifically, it includes:

[0088] Based on the dry coefficient of thermogenic gas and the C2+ hydrocarbon component content of the natural gas in the target natural gas reservoir, determine the methane content of the thermogenic gas in the natural gas of the target natural gas reservoir; among them, the methane content of the thermogenic gas in the natural gas of the target natural gas reservoir is determined by the following formula:

[0089] C 热 =(A·B)÷(1 - A)

[0090] In the formula, A is the drying coefficient of thermogenic gas, dimensionless; B is the content of C2+ hydrocarbon components in the natural gas of the target gas reservoir, in %; C 热 is the methane content of thermogenic gas in the natural gas of the target gas reservoir, in %.

[0091] Based on the methane content of thermogenic gas in the natural gas of the target gas reservoir and the methane content of the natural gas of the target gas reservoir, determine the contribution ratio of thermogenic gas in the natural gas of the target gas reservoir; among them, the contribution ratio of thermogenic gas in the natural gas of the target gas reservoir is determined by the following formula:

[0092] X 热 = C 热 ÷ C

[0093] In the formula, C 热 is the methane content of thermogenic gas in the natural gas of the target gas reservoir, in %; C is the methane content of the natural gas of the target gas reservoir, in %; X 热 is the contribution ratio of thermogenic gas in the natural gas of the target gas reservoir, in %.

[0094] Based on the contribution ratio of thermogenic gas in the hydrate natural gas of Well A, the C2+ hydrocarbon component content of the hydrate natural gas in Well A, the methane carbon isotope value δ 13 C1 of the hydrate natural gas in Well A, the methane carbon isotope value δ 13 C 1热 of thermogenic gas, the methane carbon isotope value δ 13 C 1原生 of primary biogenic gas, and the methane carbon isotope value δ 13 C 1次生 of secondary biogenic gas, determine the contribution ratios of primary biogenic gas and secondary biogenic gas in the hydrate natural gas of Well A through the following formula;

[0095] δ 13 C 1热 · X 热 + δ 13 C 1原生 · X 原生 + δ 13 C 1次生 · X 次生 = δ 13 C1

[0096] X 热 + X 原生 + X 次生 = 1

[0097] In the formula, X 原生 is the contribution ratio of primary biogenic gas in the natural gas of the target gas reservoir, in %; X 次生is the contribution ratio of secondary biogas in the natural gas of the target gas reservoir, in %; X 热 is the contribution ratio of thermogenic gas in the natural gas of the target gas reservoir, in %.

[0098] The results are shown in Table 1 Figure 4 as follows.

[0099] Table 1

[0100]

[0101] Note: * If the calculated value exceeds 100%, it is counted as 100%, indicating a natural gas hydrate reservoir formed entirely by thermogenic gas, and the contribution of primary and secondary biogas is 0.

[0102] From Table 1 Figure 4 it can be seen that the natural gas hydrate in the natural gas hydrate reservoir of Well A shows a mixed origin of biogenic gas and thermogenic gas, but is mainly characterized by thermogenic gas, which is consistent with the actual situation.

[0103] Those skilled in the art can understand that this specification can be provided as a method, system, or computer program product. Therefore, this specification can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, this specification can 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.

[0104] This specification is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products of the embodiments of this specification. It should be understood that each process and / or block in the flowchart and / or block diagram can be implemented by computer program instructions, and the combination of the processes and / or blocks in the flowchart and / or block diagram can also be implemented by computer program instructions. The computer can be a personal computer, a laptop computer, a cellular phone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or any combination of these devices.

[0105] Each functional unit in the embodiments of this specification can be integrated into one processing unit, or each functional unit can exist physically alone, or two or more functional units can be integrated into one processing unit.

[0106] Those skilled in the art can understand that the descriptions of the embodiments in this specification each have their own focuses. For the parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments. Additionally, it can be understood that after reading this specification document, those skilled in the art can, without creative effort, think of arbitrarily combining some or all of the embodiments listed in this specification, and these combinations are also within the scope of disclosure and protection of this specification.

[0107] Although this specification is depicted through embodiments, those of ordinary skill in the art know that the above embodiments are only used to help understand the core idea of this specification. Those skilled in the art can understand that this specification has many variations and changes. It is hoped that the appended claims will cover these variations and changes without departing from the spirit of this specification.

Claims

1. A method for determining the multi-source mixing ratio of a natural gas reservoir, wherein, The method includes: Obtain the methane content, C2+ hydrocarbon component content, and methane carbon isotope value δ of the natural gas in the target natural gas reservoir 13 C1; Obtain the drying coefficient of thermogenic gas and the methane carbon isotope value δ 13 C 1热 , the methane carbon isotope value δ 13 C 1原生 of primary biogenic gas, and the methane carbon isotope value δ 13 C 1次生 ; Based on the methane content, C2+ hydrocarbon component content, and methane carbon isotope value δ 13 C1 of the natural gas in the target gas reservoir, combined with the dryness coefficient of thermogenic gas and the methane carbon isotope value δ 13 C 1热 , the methane carbon isotope value δ 13 C 1原生 of primary biogenic gas, and the methane carbon isotope value δ 13 C 1次生 of secondary biogenic gas, determine the contribution ratios of thermogenic gas, primary biogenic gas, and secondary biogenic gas in the natural gas of the target gas reservoir.

2. The method according to claim 1, wherein Based on the methane content, C2+ hydrocarbon component content, methane carbon isotope value δ 13 C1 of the natural gas in the target gas reservoir, combined with the dry coefficient of thermogenic gas and the methane carbon isotope value δ 13 C 1热 , the methane carbon isotope value δ 13 C 1原生 of primary biogenic gas, and the methane carbon isotope value δ 13 C 1次生 of secondary biogenic gas, determining the contribution ratios of thermogenic gas, primary biogenic gas, and secondary biogenic gas in the natural gas of the target gas reservoir includes: Determining the contribution ratio of thermogenic gas in the natural gas of the target gas reservoir based on the drying coefficient of thermogenic gas, the methane content of the natural gas in the target gas reservoir, and the C2+ hydrocarbon component content; Based on the contribution ratio of thermogenic gas in the natural gas of the target gas reservoir, the C2+ hydrocarbon component content of the natural gas in the target gas reservoir, and the methane carbon isotope value δ 13 C1 of the natural gas in the target gas reservoir and the methane carbon isotope value δ 13 C 1热 of thermogenic gas, and the methane carbon isotope value δ 13 C 1原生 of primary biogenic gas, and the methane carbon isotope value δ 13 C 1次生 of secondary biogenic gas, determine the contribution ratios of primary biogenic gas and secondary biogenic gas in the natural gas of the target gas reservoir.

3. The method according to claim 2, wherein Determining the contribution ratio of thermogenic gas in the natural gas of the target gas reservoir based on the drying coefficient of thermogenic gas, the methane content of the natural gas in the target gas reservoir, and the C2+ hydrocarbon component content includes: Determining the methane content of thermogenic gas in the natural gas of the target gas reservoir based on the drying coefficient of thermogenic gas and the C2+ hydrocarbon component content of the natural gas in the target gas reservoir; Determining the contribution ratio of thermogenic gas in the natural gas of the target gas reservoir based on the methane content of thermogenic gas in the natural gas of the target gas reservoir and the methane content of the natural gas in the target gas reservoir; Preferably, the methane content of thermogenic gas in the natural gas of the target gas reservoir is determined by the following formula: C 热 = (A·B) ÷ (1 - A) Wherein, A is the drying coefficient of thermogenic gas, dimensionless; B is the content of C2+ hydrocarbon components in the natural gas of the target gas reservoir, in %; C 热 is the methane content of thermogenic gas in the natural gas of the target gas reservoir, in %; Preferably, the contribution ratio of thermogenic gas in the natural gas of the target gas reservoir is determined by the following formula: X 热 = C 热 ÷ C In the formula, C 热 is the methane content of thermogenic gas in the natural gas of the target natural gas reservoir, in %; C is the methane content of the natural gas of the target natural gas reservoir, in %; X 热 is the contribution ratio of thermogenic gas in the natural gas of the target natural gas reservoir, in %.

4. The method according to claim 2, wherein The contribution ratios of primary biogenic gas and secondary biogenic gas in the natural gas of the target gas reservoir are determined by the following formula: δ 13 C 1热 ·X 热 +δ 13 C 1原生 ·X 原生 +δ 13 C 1次生 ·X 次生 =δ 13 C1 X 热 +X 原生 +X 次生 = 1 Wherein, X 原生 is the contribution ratio of primary biogas in the natural gas of the target gas reservoir, in %; X 次生 is the contribution ratio of secondary biogas in the natural gas of the target gas reservoir, in %; X 热 is the contribution ratio of thermogenic gas in the natural gas of the target gas reservoir, in %.

5. An apparatus for determining the multi-source mixing ratio of a natural gas reservoir, wherein, Including: First data acquisition module: used to acquire the methane content, C2+ hydrocarbon component content, and methane carbon isotope value δ of the natural gas in the target natural gas reservoir 13 C1; Second data acquisition module: used to acquire the drying coefficient of thermogenic gas and the methane carbon isotope value δ 13 C 1热 , the methane carbon isotope value δ 13 C 1原生 , the methane carbon isotope value δ 13 C 1次生 ; Contribution ratio determination module: used to determine the contribution ratios of thermogenic gas, primary biogenic gas, and secondary biogenic gas in the natural gas of the target gas reservoir based on the methane content, C2+ hydrocarbon component content, methane carbon isotope value δ 13 C1, in combination with the dry coefficient of thermogenic gas and the methane carbon isotope value δ 13 C 1热 , the methane carbon isotope value δ 13 C 1原生 of primary biogenic gas, the methane carbon isotope value δ 13 C 1次生 of secondary biogenic gas 6. The apparatus according to claim 5, wherein, The contribution ratio determination module includes: The first contribution ratio determination sub-module: used to determine the contribution ratio of thermogenic gas in the natural gas of the target gas reservoir based on the drying coefficient of thermogenic gas, the methane content of the natural gas in the target gas reservoir, and the C2+ hydrocarbon component content; The second contribution ratio determination sub-module: used to determine the contribution ratios of primary biogenic gas and secondary biogenic gas in the natural gas of the target gas reservoir based on the contribution ratio of thermogenic gas in the natural gas of the target gas reservoir, the C2+ hydrocarbon component content of the natural gas of the target gas reservoir, the methane carbon isotope value δ 13 C1 of the thermogenic gas methane carbon isotope value δ 13 C 1热 , the methane carbon isotope value δ 13 C 1原生 of the primary biogenic gas, and the methane carbon isotope value δ 13 C 1次生 of the secondary biogenic gas, and determine the contribution ratios of primary biogenic gas and secondary biogenic gas in the natural gas of the target gas reservoir.

7. The device according to claim 5, wherein The first contribution ratio determination sub-module includes: The methane content determination sub-unit of thermogenic gas: used to determine the methane content of thermogenic gas in the natural gas of the target gas reservoir based on the drying coefficient of thermogenic gas and the C2+ hydrocarbon component content of the natural gas in the target gas reservoir: The first contribution ratio determination sub-unit: used to determine the contribution ratio of thermogenic gas in the natural gas of the target gas reservoir based on the methane content of thermogenic gas in the natural gas of the target gas reservoir and the methane content of the natural gas in the target gas reservoir; Preferably, the methane content of thermogenic gas in the natural gas of the target gas reservoir is determined by the following formula: C 热 = (A·B) ÷ (1 - A) Wherein, A is the drying coefficient of thermogenic gas, dimensionless; B is the content of C2+ hydrocarbon components in the natural gas of the target gas reservoir, in %; C 热 is the methane content of thermogenic gas in the natural gas of the target gas reservoir, in %; Preferably, the contribution ratio of thermogenic gas in the natural gas of the target gas reservoir is determined by the following formula: X 热 = C 热 ÷ C where C 热 is the methane content of thermogenic gas in the natural gas of the target gas reservoir, in %; C is the methane content of the natural gas of the target gas reservoir, in %; X 热 is the contribution ratio of thermogenic gas in the natural gas of the target gas reservoir, in %; The second contribution ratio determination sub-module determines the contribution ratios of primary biogenic gas and secondary biogenic gas in the natural gas of the target gas reservoir by the following formula: δ 13 C 1热 ·X 热 +δ 13 C 1原生 ·X 原生 +δ 13 C 1次生 ·X 次生 =δ 13 C1 X 热 +X 原生 +X 次生 = 1 In the formula, X 原生 is the contribution ratio of primary biogas in the natural gas of the target gas reservoir, in %; X 次生 is the contribution ratio of secondary biogas in the natural gas of the target gas reservoir, in %; X 热 is the contribution ratio of thermogenic gas in the natural gas of the target gas reservoir, in %.

8. A computer device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein when the processor executes the computer program, the method for determining the multiple mixed-source ratio of a gas reservoir according to any one of claims 1-4 is implemented.

9. A computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the method for determining the multiple mixed-source ratio of a gas reservoir according to any one of claims 1-4 is implemented.

10. A computer program product comprising a computer program, wherein when the computer program is executed by a processor, the method for determining the multiple mixed-source ratio of a gas reservoir according to any one of claims 1-4 is implemented.

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