CN115964842A

CN115964842A - Method and system for determining natural gas hydrate resource amount

Info

Publication number: CN115964842A
Application number: CN202211278774.1A
Authority: CN
Inventors: 胡涛; 刘远; 庞雄奇; 吴冠昀; 周阔; 马龙; 马明明; 肖惠译; 胡耀
Original assignee: China University of Petroleum Beijing
Current assignee: China University of Petroleum Beijing
Priority date: 2022-10-19
Filing date: 2022-10-19
Publication date: 2023-04-14

Abstract

The invention provides a method and a system for determining natural gas hydrate resource amount. The method comprises the following steps: obtaining the thickness and the area of a sedimentary rock stratum of a natural gas hydrate stability zone of a target area, the volume factor of the natural gas hydrate, the thickness and the area of the sedimentary rock stratum where a conventional oil and gas resource is located and the volume factor of the natural gas; acquiring the proportion of gaseous hydrocarbons in a target area; determining the proportion of the natural gas hydrate in the conventional oil and gas resources in a target region based on the thickness and the area of the sedimentary rock formation of the natural gas hydrate stability zone, the volume factor of the natural gas hydrate, the thickness and the area of the sedimentary rock formation where the conventional oil and gas resources are located, the volume factor of the natural gas and the proportion of gaseous hydrocarbon; acquiring the conventional petroleum and natural gas resource quantity and the conventional heavy oil and asphalt resource quantity of a target area; and determining the natural gas hydrate resource amount of the target region based on the conventional petroleum and natural gas resource amount, the conventional heavy oil and asphalt resource amount and the ratio of the natural gas hydrate in the conventional oil gas resource of the target region.

Description

Method and system for determining natural gas hydrate resource amount

Technical Field

The invention relates to the technical field of natural gas hydrate exploration, in particular to a method and a system for determining natural gas hydrate resource amount.

Background

Natural Gas Hydrates (NGH) are considered as a new resource to replace traditional oil and gas resources in the future. The evaluation of its global resource potential has been a concern. Due to the uncertainty of a natural Gas Hydrate Stability Zone (GHSZ) and other evaluation resource parameters, the global natural gas hydrate resource quantity evaluation research is slow in progress, and a difficult problem to be solved urgently is formed. The former people have made at least 29 published evaluation results of the global natural gas hydrate resource based on different research areas and evaluation methods, and the difference between the evaluation results is up to 10000 times. Aiming at the problem of further reducing the uncertainty of the estimation of the global natural gas hydrate resource amount, the preschool researchers successively put forward different methods, and great progress is made from the analysis of the main control factors of the hydrate stability zone distribution to the accurate observation model and function calculation so as to reduce the uncertainty of the estimation of the global hydrate resource amount.

From 1973 to 1981, based on very few real data and imaginary parameters, the maximum value of the global natural gas hydrate resource amount is estimated to exceed 1.67 × 10 by scholars ¹⁸ m ³ The scholars are in an optimistic attitude towards the resource potential of the natural gas hydrate. In 1982, scholars began to live around the ocean in the worldThe resource amount of the natural gas hydrate is researched in the environment, and the fact that the hydrate does not exist in an area with the water depth of less than 500m is determined, so that the global natural gas hydrate resource amount analogizing result is reduced to half of the original result. In 1991, researchers began to apply geological research and prospecting to the prediction of favorable regions of natural gas hydrates in marine environments. The seabed simulated reflection layer (BSR) represents the abnormity reflected by the seismic profile between the stratum containing the natural gas hydrate and the underlying stratum not containing the natural gas hydrate in the seabed stratum and is used for determining the existence area of the natural gas hydrate, so that the global natural gas hydrate resource quantity analogy result is reduced to 1/4 of the original result again. In 1999, scholars revealed that the degradation of organic matters in sedimentary formations is the source of gas in natural gas hydrate reservoirs, the gas and water form solid combustible ice with a cage-shaped structure, and the solid combustible ice is stable only under specific conditions of high pressure and low temperature, so that the natural gas hydrate stability zone is limited to be in the hydrate stability zone (GHSZ) in two poles of the earth, plateau frozen earth and sedimentary basins in deep sea, and the global natural gas hydrate resource quantity evaluation result is further reduced to 1/3 of the original value. In 2009 to 2016, researchers proposed the amount of recoverable hydrate resource, and limited the hydrate accumulated in the high-porosity and high-permeability stratum to the amount of recoverable resource, such as sandstone, conglomerate and mudstone with fracture development, and further evaluation showed that the amount of recoverable resource was only 18% or less of the total hydrate resource in the world. In recent years, with the advance of physical simulation experiments and field pilot production, the technical recovery rate of the natural gas hydrate is determined to be 15-70%, the average value is 30%, and the recoverable resource amount of the global natural gas hydrate is further reduced to 1/3 of the original recoverable resource amount.

In the above evaluations, it can be found that, over time, advances in scientific and technical research and improvements in methodology appear to result in diminishing results in the evaluation of NGH potential resources. In evaluating the quantity of NGH resources, it is inevitable to determine the area and thickness of the ghz, and the porosity, permeability and hydrate saturation of the ghz formation, due to its distribution characteristics of high pressure and low temperature. In general, the previous research is based on actual measurement or simulation data of a certain region, the potential resource amount of the natural gas hydrate in the region is calculated through data such as the volume, porosity, permeability and hydrate saturation of a GHSZ rock stratum in the research region, and evaluation of the potential resource of the global natural gas hydrate is realized through a field data extrapolation method or a model function building calculation method. The variability of the data results in inaccurate evaluation results, great differences among the evaluation results, and difficulty in improving the precision of the evaluation results with the existing technical level and exploration degree. In addition, in the previous research, all hydrates in the GHSZ are considered as potential resources, and dispersed hydrates in mudstone are not distinguished from enriched hydrate resources in a high-permeability reservoir, so that the evaluation result is larger.

Under the existing technical level and exploration degree, the accurate evaluation of the global natural gas hydrate resource amount is basically impossible. Researchers find that organic matter degradation gas generation in a stratum below GHSZ is an important source of gas in hydrate in GHSZ, reflecting that after gas generation of deep hydrocarbon source rocks in an oil-rich gas basin is discharged, the gas can be transported to a hydrate stability zone to form cage-shaped hydrate with water, 1/3 of 13 hydrate exploratory wells in the world prove that the gas in the hydrate is derived from organic matter degradation in the deep hydrocarbon source rocks, and the natural gas hydrate is proved to be the same as conventional oil and gas resources and is a special type in a global oil and gas system. Because natural gas hydrate has common characteristics with conventional oil and gas resources in many aspects, for example, the natural gas hydrate and the conventional oil and gas resources are both formed in a free power field, buoyancy driving is used as power for migration and aggregation, hydrocarbons in the two resources are all derived from degradation of organic matters in hydrocarbon source rocks, and a reservoir stratum is required to have the basic characteristics of high porosity and high permeability, the resource evaluation of the natural gas hydrate can be similar to the evaluation method and thought of the conventional oil and gas resources. Based on the method, the invention provides a method for evaluating the natural gas hydrate resource quantity based on the conventional oil and gas resource analogy.

Disclosure of Invention

The invention aims to provide a method and a system capable of determining the natural gas hydrate resource quantity, which solve the problems of difficult evaluation and low precision of the natural gas hydrate resource quantity and provide important technical support for evaluation of hydrate resource potential and energy prospect.

In order to achieve the above object, the present invention provides the following four aspects of technical solutions.

In a first aspect, the present invention provides a method for determining the amount of a natural gas hydrate resource, wherein the method comprises:

obtaining the thickness and the area of a sedimentary rock stratum of a natural gas hydrate stability zone of a target area and a natural gas hydrate volume factor;

obtaining the thickness and the area of a sedimentary rock stratum where the conventional oil and gas resources of a target area are located and a natural gas volume factor; the conventional oil gas resource is generated by organic matters, distributed in a free power field and taking buoyancy as migration power;

acquiring the proportion of gaseous hydrocarbons in a target area; wherein the gaseous hydrocarbon ratio refers to the ratio of gaseous hydrocarbons in the discharged hydrocarbon;

determining the occupation ratio of the natural gas hydrate in the target region in the conventional oil and gas resources based on the thickness and the area of the sedimentary rock stratum of the natural gas hydrate stability zone in the target region, the volume factor of the natural gas hydrate, the thickness and the area of the sedimentary rock stratum where the conventional oil and gas resources in the target region are located, the volume factor of the natural gas and the occupation ratio of the gaseous hydrocarbon in the target region;

acquiring the conventional petroleum and natural gas resource quantity and the conventional heavy oil and asphalt resource quantity of a target area; the conventional petroleum and natural gas resources are petroleum and natural gas resources which are generated by organic matters, distributed in a free power field, taking buoyancy as migration power and are not biodegraded, and the conventional heavy oil and asphalt resources are heavy oil and asphalt resources which are generated by organic matters, distributed in the free power field, taking buoyancy as migration power and are biodegraded;

and determining the natural gas hydrate resource amount of the target area based on the conventional petroleum and natural gas resource amount of the target area, the conventional heavy oil and asphalt resource amount and the ratio of natural gas hydrates in the conventional oil and gas resources.

According to a preferred embodiment of the first aspect, wherein obtaining the target zone gaseous hydrocarbon fraction comprises:

acquiring the ratio of the gas quantity generated by the hydrocarbon source rock with the organic matter type III in the biochemical gas generation stage (Ro < 0.5%) to the total hydrocarbon quantity generated by the hydrocarbon source rock in the target area, namely a first ratio; acquiring a second ratio which is the ratio of the gas quantity to the total hydrocarbon quantity in the conventional petroleum and natural gas reservoir which is proved to be in the target area;

acquiring a weighted average value of ratios of gaseous hydrocarbons and total hydrocarbons generated by hydrocarbon source rocks of which the organic matter types are I type, II type and III type in a free power field of a target area in a biological gas generation stage and a thermal gas generation stage, wherein the ratio is a third ratio;

determining the gaseous hydrocarbon proportion of the target area based on the first ratio, the second ratio and the third ratio; wherein the ratio of the gaseous hydrocarbons in the target region is less than or equal to a first ratio and greater than or equal to a second ratio;

preferably, the third ratio is used as an initial value of the gaseous hydrocarbon ratio of the target area, and the initial value of the gaseous hydrocarbon ratio of the target area is corrected by using the first ratio and the second ratio to obtain the gaseous hydrocarbon ratio of the target area; when the initial value of the gaseous hydrocarbon proportion of the target area is less than or equal to a first ratio and greater than or equal to a second ratio, the initial value of the gaseous hydrocarbon proportion of the target area is the initial value of the gaseous hydrocarbon proportion of the target area; when the initial value of the gaseous hydrocarbon proportion of the target area is greater than the first ratio, the gaseous hydrocarbon proportion of the target area is the first ratio; and when the initial value of the gaseous hydrocarbon proportion of the target area is smaller than the second ratio, the gaseous hydrocarbon proportion of the target area is the second ratio.

According to a preferred embodiment of the first aspect, wherein the ratio of natural gas hydrates in conventional oil and gas resources is determined by the following formula:

in the formula, f is the proportion of the natural gas hydrate in the conventional oil gas resource, and the unit percent; b is _gh The volume factor of the natural gas hydrate is a unit dimensionless unit, and represents the ratio of the volume of the methane hydrate under the standard surface condition to the volume of the natural gas hydrate under the reservoir layer condition; b is _g Is a natural gas volume factor, and represents the natural gas volume and the reservoir under the standard surface conditionThe volume ratio of natural gas under the stratum condition, the unit is dimensionless; a. The _GHSZ Area of sedimentary rock formation as gas hydrate stability zone, unit 10 ⁶ km ² ；H _GHSZ The thickness of the sedimentary rock formation in m, which is the natural gas hydrate stability zone; a. The _conv The unit of the area of the sedimentary rock stratum where the conventional oil and gas resources are located is 10 ⁶ km ² ；H _conv The thickness of the sedimentary rock stratum where the conventional oil and gas resources are located is m; g is the proportion of gaseous hydrocarbon in unit percent.

According to a preferred embodiment of the first aspect, the natural gas hydrate resource amount is determined by a natural gas hydrate resource amount determination model; the natural gas hydrate resource quantity determination model is a calculation model of the natural gas hydrate resource quantity related to the proportion of the natural gas hydrate in conventional oil and gas resources, the conventional petroleum and natural gas resource quantity and the conventional heavy oil and asphalt resource quantity;

preferably, the natural gas hydrate resource amount determination model is:

in the formula, f is the proportion of the natural gas hydrate in the conventional oil gas resource, and the unit percent; q _C1 Is the natural gas hydrate resource amount (in gas equivalent), and has the unit of 10 ¹² m ³ ；Q _C2 For the amount of conventional petroleum and natural gas resources (in gas equivalent), the unit: 10 ¹² m ³ ；Q _C3 Is the amount of conventional heavy oil and bitumen resources (in gas equivalents), the unit: 10 ¹² m ³ 。

In a second aspect, the present invention provides a system for determining an amount of a natural gas hydrate resource, wherein the system comprises:

a natural gas hydrate parameter acquisition module: the method is used for obtaining the thickness and the area of a sedimentary rock stratum of a natural gas hydrate stability zone of a target area and a natural gas hydrate volume factor;

an oil and gas resource parameter acquisition module: the method is used for obtaining the thickness and the area of a sedimentary rock stratum where the conventional oil and gas resources of a target area are located and the natural gas volume factor; the conventional oil-gas resource is generated by organic matters, distributed in a free power field and taking buoyancy as migration power;

the gaseous hydrocarbon proportion obtaining module: the method is used for acquiring the gaseous hydrocarbon ratio of a target area; wherein the gaseous hydrocarbon ratio refers to the ratio of gaseous hydrocarbons in the discharged hydrocarbon;

the natural gas hydrate proportion obtaining module: the method comprises the steps of determining the occupation ratio of natural gas hydrates in a target region in conventional oil and gas resources based on the thickness and the area of a sedimentary rock stratum of a natural gas hydrate stability zone of the target region, the volume factor of the natural gas hydrates, the thickness and the area of the sedimentary rock stratum where the conventional oil and gas resources of the target region are located, the volume factor of the natural gas and the occupation ratio of gaseous hydrocarbons of the target region;

conventional energy amount acquisition module: the method is used for acquiring the conventional petroleum and natural gas resource quantity and the conventional heavy oil and asphalt resource quantity of a target area; the conventional petroleum and natural gas resources are petroleum and natural gas resources which are generated by organic matters, distributed in a free power field, taking buoyancy as migration power and are not biodegraded, and the conventional heavy oil and asphalt resources are heavy oil and asphalt resources which are generated by organic matters, distributed in the free power field, taking buoyancy as migration power and are biodegraded;

the natural gas hydrate resource amount acquisition module: the method is used for determining the natural gas hydrate resource amount of the target area based on the conventional petroleum and natural gas resource amount, the conventional heavy oil and asphalt resource amount and the ratio of natural gas hydrate in the conventional oil gas resource of the target area.

According to a preferred embodiment of the second aspect, the gaseous hydrocarbon fraction obtaining module includes:

a first ratio acquisition submodule: the method is used for obtaining the ratio of the gas quantity generated by the hydrocarbon source rock with the organic matter type III in the biochemical gas generation stage (Ro < 0.5%) to the total hydrocarbon quantity generated in the target area, namely the first ratio;

a second ratio acquisition submodule: the method is used for acquiring a second ratio which is the ratio of the gas quantity to the total hydrocarbon quantity in the conventional petroleum and natural gas reservoir which is proved to be in a target area;

a third ratio acquisition submodule: the weighted average value of the ratios of gaseous hydrocarbons generated by hydrocarbon source rocks of which the organic matter types are I type, II type and III type in the free power field of the target area in the biological gas generation stage and the thermal gas generation stage to the total hydrocarbons generated is a third ratio;

a gaseous hydrocarbon ratio determination submodule: for determining a target zone gaseous hydrocarbon fraction based on the first ratio, the second ratio, and the third ratio; wherein the ratio of the gaseous hydrocarbons in the target area is less than or equal to a first ratio and greater than or equal to a second ratio;

preferably, the gaseous hydrocarbon ratio determining submodule is used for taking the third ratio as an initial gaseous hydrocarbon ratio value of the target area, and correcting the initial gaseous hydrocarbon ratio value of the target area by using the first ratio and the second ratio to obtain the gaseous hydrocarbon ratio of the target area; when the initial value of the gaseous hydrocarbon proportion of the target area is less than or equal to a first ratio and is greater than or equal to a second ratio, the initial value of the gaseous hydrocarbon proportion of the target area is the initial value of the gaseous hydrocarbon proportion of the target area; when the initial value of the gaseous hydrocarbon proportion of the target area is greater than the first ratio, the gaseous hydrocarbon proportion of the target area is the first ratio; and when the initial value of the gaseous hydrocarbon proportion of the target area is smaller than the second ratio, the gaseous hydrocarbon proportion of the target area is the second ratio.

According to a preferred embodiment of the second aspect, the natural gas hydrate proportion obtaining module determines the proportion of the natural gas hydrate in the conventional oil and gas resources by the following formula:

in the formula, f is the proportion of natural gas hydrate in conventional oil gas resources, and the unit percent; b is _gh The volume factor of the natural gas hydrate is a unit dimensionless unit, and represents the ratio of the volume of the methane hydrate under the standard surface condition to the volume of the natural gas hydrate under the reservoir layer condition; b is _g The natural gas volume factor is a natural gas volume factor and represents the ratio of the natural gas volume under the standard surface condition to the natural gas volume under the reservoir layer condition, and the unit is dimensionless; a. The _GHSZ Area of sedimentary rock formation as gas hydrate stability zone, unit 10 ⁶ km ² ；H _GHSZ Thickness in m of sedimentary rock formation of the natural gas hydrate stability zone; a. The _conv The unit is 10 of the area of a sedimentary rock stratum where conventional oil and gas resources are located ⁶ km ² ；H _conv The thickness of the sedimentary rock stratum where the conventional oil and gas resources are located is m; g is the proportion of gaseous hydrocarbon in unit percent.

According to a preferred embodiment of the second aspect, the natural gas hydrate resource amount obtaining module determines the natural gas hydrate resource amount by using the natural gas hydrate resource amount determination model; the natural gas hydrate resource quantity determination model is a calculation model of the natural gas hydrate resource quantity related to the proportion of the natural gas hydrate in conventional oil and gas resources, the conventional petroleum and natural gas resource quantity and the conventional heavy oil and asphalt resource quantity;

preferably, the natural gas hydrate resource amount determination model is as follows:

in the formula, f is the proportion of natural gas hydrate in conventional oil gas resources, and the unit percent; q _C1 Is the natural gas hydrate resource amount (in gas equivalent), and has the unit of 10 ¹² m ³ ；Q _C2 The unit is 10 for the conventional petroleum and natural gas resource amount (in gas equivalent) ¹² m ³ ；Q _C3 The unit is 10 for the amount of conventional heavy oil and bitumen resources (in gas equivalent) ¹² m ³ 。

In a third aspect, the present invention provides an electronic device, comprising a processor, a memory, and a computer program stored on the memory and executable on the processor, wherein the processor executes the computer program to perform the steps of determining natural gas hydrate resource measure.

In a fourth aspect, the present invention provides a computer readable storage medium having stored thereon a computer program which, when executed by a processor, performs the steps of determining a natural gas hydrate resource quantity method.

The technical scheme provided by the invention effectively solves the problem of evaluating the natural gas hydrate resource amount, solves the problem of low reliability of natural gas hydrate resource amount evaluation caused by low exploration degree, low exploration technology and lack of exploration data in the past, can obtain the natural gas hydrate resource amount more objectively and accurately, and has great guiding significance for the research on the resource potential and the energy prospect of the natural gas hydrate.

Drawings

FIG. 1 is a flow diagram of a method for determining an amount of a natural gas hydrate resource in one embodiment.

FIG. 2 is a block diagram of a system for determining the amount of a natural gas hydrate resource in one embodiment.

FIG. 3 is an area A of a sedimentary rock formation of the global gas hydrate stability zone in example 1 _GHSZ And (5) a distribution statistical chart.

FIG. 4 is a thickness H of a sedimentary rock formation of the global gas hydrate stability zone in example 1 _GHSZ And (5) a distribution statistical chart.

Fig. 5 is a statistical graph of the distribution of the global natural gas hydrate gaseous hydrocarbon ratio g in example 1.

Fig. 6 is a graph of gas to total hydrocarbon ratio of different organic matter type source rocks during the biochemical gassing phase (Ro < 0.5%) in example 1.

Figure 7 is a graph of the gas to total hydrocarbon ratio in the world identified for the conventional reservoir in example 1.

FIG. 8 is a graph of the ratio of gaseous hydrocarbons to total hydrocarbons in the amount of hydrocarbons produced in biogenic and thermogenic stages from hydrocarbon source rocks having kerogen type I, II and III in a free power field.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be described in detail and completely with reference to the drawings in the embodiments of the present invention. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The inventor brings natural gas hydrate resources into a global oil and gas system, carries out unified analysis and research, establishes a unified model and a mass balance equation between NGH resource quantity and conventional oil and gas resource quantity, synthesizes and analogizes conventional oil and gas evaluation parameters and 29 groups of former people natural gas hydrate evaluation results, and provides a method for evaluating the natural gas hydrate resource quantity based on conventional oil and gas resource analogy, so as to solve the problems of difficult evaluation and low precision of the global natural gas hydrate resource quantity and provide a new idea for evaluating hydrate resource potential and energy prospect. The technical solution provided by the present invention is explained by listing some specific examples.

Referring to fig. 1, an embodiment of the present invention provides a method for determining the amount of natural gas hydrate resources, wherein the method includes:

step S1: obtaining the thickness and the area of a sedimentary rock stratum of a natural gas hydrate stability zone of a target area and a natural gas hydrate volume factor;

step S2: obtaining the thickness and the area of a sedimentary rock stratum where conventional oil and gas resources in a target area are located and a natural gas volume factor; the conventional oil-gas resource is generated by organic matters, distributed in a free power field and taking buoyancy as migration power;

and step S3: acquiring the gaseous hydrocarbon ratio of a target area; wherein the gaseous hydrocarbon proportion refers to the proportion of gaseous hydrocarbons in the discharged hydrocarbon;

and step S4: determining the occupation ratio of the natural gas hydrate in the target region in the conventional oil and gas resources based on the thickness and the area of the sedimentary rock stratum of the natural gas hydrate stability zone in the target region, the volume factor of the natural gas hydrate, the thickness and the area of the sedimentary rock stratum where the conventional oil and gas resources in the target region are located, the volume factor of the natural gas and the occupation ratio of the gaseous hydrocarbon in the target region;

step S5: acquiring the conventional petroleum and natural gas resource quantity and the conventional heavy oil and asphalt resource quantity of a target area; the conventional petroleum and natural gas resources are petroleum and natural gas resources which are generated by organic matters, distributed in a free power field, taking buoyancy as migration power and are not biodegraded, and the conventional heavy oil and asphalt resources are heavy oil and asphalt resources which are generated by organic matters, distributed in the free power field, taking buoyancy as migration power and are biodegraded;

step S6: and determining the natural gas hydrate resource amount of the target area based on the conventional petroleum and natural gas resource amount of the target area, the conventional heavy oil and asphalt resource amount and the ratio of natural gas hydrates in the conventional oil and gas resources.

The method for the natural gas hydrate resource amount overcomes the defects of insufficient geological theory and large error of the evaluation method in the prior art, realizes the prediction of geological basis and has high reliability; the prediction has advanced technology and high accuracy; the prediction has a brand new idea and strong innovation; in addition, the method only utilizes common evaluation parameters in conventional oil gas evaluation, and data information is obtained, so that the operation process is simple and rapid. Overall, the method has the following advantages: the geological basis is sufficient, and the reliability is high; (2) the technical characteristics are distinct and the accuracy is high; (3) the thought is complete and clear, and the innovation is strong; and (4) the data are simple and easy to obtain, and the operability is strong.

In one embodiment, step S3, obtaining the ratio of gaseous hydrocarbons in the target area comprises:

step S31: obtaining the ratio of the gas quantity generated by the hydrocarbon source rock with the organic matter type III in the biochemical gas generation stage (Ro < 0.5%) to the total hydrocarbon quantity generated in the target area, namely the first ratio; the first ratio is a possible upper limit value of the parameter gaseous hydrocarbon ratio;

step S32: acquiring a second ratio which is the ratio of the gas quantity to the total hydrocarbon quantity in the conventional petroleum and natural gas reservoir which is proved to be in the target area; the second ratio is a possible lower limit value of the parameter gaseous hydrocarbon ratio;

step S33: acquiring a weighted average value of ratios of gaseous hydrocarbons and total hydrocarbons generated by hydrocarbon source rocks of which the organic matter types are I type, II type and III type in a free power field of a target area in a biological gas generation stage and a thermal gas generation stage, wherein the weighted average value is a third ratio;

step S34: determining the gaseous hydrocarbon ratio of the target area based on the first ratio, the second ratio and the third ratio; wherein the ratio of the gaseous hydrocarbons in the target region is less than or equal to a first ratio and greater than or equal to a second ratio;

for example, the third ratio is used as an initial value of the gaseous hydrocarbon ratio of the target area, and the initial value of the gaseous hydrocarbon ratio of the target area is corrected by using the first ratio and the second ratio to obtain the gaseous hydrocarbon ratio of the target area; when the initial value of the gaseous hydrocarbon proportion of the target area is less than or equal to a first ratio and greater than or equal to a second ratio, the initial value of the gaseous hydrocarbon proportion of the target area is the initial value of the gaseous hydrocarbon proportion of the target area; when the initial value of the gaseous hydrocarbon proportion of the target area is greater than the first ratio, the gaseous hydrocarbon proportion of the target area is the first ratio; when the initial value of the gaseous hydrocarbon proportion of the target area is smaller than the second ratio, the gaseous hydrocarbon proportion of the target area is the second ratio;

for example, the ratio of gaseous hydrocarbons generated by the source rocks with the organic matter type I in the biological gas generation stage to total hydrocarbons generated by the source rocks with the organic matter type I in the free power field of the target area, the ratio of gaseous hydrocarbons generated by the source rocks with the organic matter type I in the thermal gas generation stage to total hydrocarbons generated by the source rocks with the organic matter type II in the biological gas generation stage, the ratio of gaseous hydrocarbons generated by the source rocks with the organic matter type II in the thermal gas generation stage to total hydrocarbons generated by the source rocks with the organic matter type II, the ratio of gaseous hydrocarbons generated by the source rocks with the organic matter type III in the biological gas generation stage to total hydrocarbons generated by the source rocks with the organic matter type III in the thermal gas generation stage, and the ratios are weighted and averaged to obtain a third ratio.

In one embodiment, step S4, the ratio of the natural gas hydrate in the conventional oil and gas resources is determined by the following formula:

in the formula, f is the proportion of natural gas hydrate in conventional oil gas resources, and the unit percent; b is _gh Is a natural gas hydrate volume factor representing the methane hydrate volume and reservoir bar under standard surface conditionsThe volume ratio of the natural gas hydrate under the part is in unit dimensionless; b is _g The natural gas volume factor is a natural gas volume factor and represents the ratio of the natural gas volume under the standard surface condition to the natural gas volume under the reservoir layer condition, and the unit is dimensionless; a. The _GHSZ Area of sedimentary rock formation as gas hydrate stability zone, unit 10 ⁶ km ² ；H _GHSZ The thickness of the sedimentary rock formation in m, which is the natural gas hydrate stability zone; a. The _conv The unit is 10 of the area of a sedimentary rock stratum where conventional oil and gas resources are located ⁶ km ² ；H _conv The thickness of the sedimentary rock stratum where the conventional oil and gas resources are located is m; g is the proportion of gaseous hydrocarbon in unit percent.

In one embodiment, step S6, determining the natural gas hydrate resource amount by using a natural gas hydrate resource amount determination model; the natural gas hydrate resource quantity determination model is a calculation model of the natural gas hydrate resource quantity related to the ratio of natural gas hydrate in conventional oil and gas resources, conventional petroleum and natural gas resource quantity and conventional heavy oil and asphalt resource quantity;

further, the natural gas hydrate resource amount determination model is as follows:

in the formula, f is the proportion of natural gas hydrate in conventional oil gas resources, and the unit percent; q _C1 Is the natural gas hydrate resource amount (in gas equivalent), and the unit is 10 ¹² m ³ ；Q _C2 The unit is 10 for the conventional petroleum and natural gas resource amount (in gas equivalent) ¹² m ³ ；Q _C3 The unit is 10 for the amount of conventional heavy oil and bitumen resources (in gas equivalent) ¹² m ³ ；

The natural gas hydrate resource amount determination model is preferably established in the following manner:

the natural gas hydrate is the same as other oil gas resources, and hydrocarbons of the natural gas hydrate come from degradation of deep organic matters, so that the natural gas hydrate resources are brought into an oil gas system; the oil-gas system comprises all hydrocarbon source rocks on the earth surface and related hydrocarbon migration and aggregation processes, and the types of oil-gas resources contained in the oil-gas system comprise conventional oil-gas resources, unconventional oil-gas resources and shale oil-gas resources; according to the mass balance principle, establishing a correlation model of the oil and gas resources generated by the conventional oil and gas resources, the unconventional oil and gas resources, the shale oil and gas resources and the hydrocarbon source rocks in the oil and gas system in total:

Q _C +Q _U +Q _S ≤≤Q _P

in the formula, Q _C The amount of conventional oil and gas resources; q _U Is unconventional oil and gas resource amount; q _S Is shale oil and gas resource quantity, Q _P The total generated oil and gas resource amount;

the natural gas hydrate has the same characteristics with the conventional petroleum and natural gas resource quantity and the conventional heavy oil and asphalt resource quantity in the aspects of hydrocarbon substance sources, migration aggregation power and processes, reservoir stratum characteristics and the like, and in addition, the natural gas hydrate is only stored in a high-pressure low-temperature stable band, so the natural gas hydrate can be regarded as a special conventional oil and gas resource aggregated in a reservoir stratum under the high-pressure low-temperature condition; based on the method, the correlation models of natural gas hydrate resources, conventional petroleum and natural gas resources and conventional heavy oil and asphalt resources are established:

Q _C ＝Q _C1 +Q _C2 +Q _C3 ≤Q _EC

in the formula, Q _C1 Is the natural gas hydrate resource amount (in gas equivalent), and the unit is 10 ¹² m ³ ；Q _C2 The unit is 10 for the conventional petroleum and natural gas resource amount (in gas equivalent) ¹² m ³ ；Q _C3 The unit is 10 for the amount of conventional heavy oil and bitumen resources (in gas equivalent) ¹² m ³ ；Q _EC The amount of hydrocarbon resources (in gas equivalent) exhausted from the source rock above the lower limit of buoyancy sequestration and within the free kinetic field is 10 ¹² m ³ ；Q _C Is the conventional oil gas resource amount (in gas equivalent), and the unit is 10 ¹² m ³ ；

Based on the related models of natural gas hydrate resources, conventional petroleum and natural gas resources and conventional heavy oil and asphalt resources, a unified model and a mass balance equation between the natural gas hydrate resource amount and the conventional oil and gas resources are established:

Q _C1 ＝Q _C -Q _C2 -Q _C3 ＝f×Q _C

in the formula, Q _C1 Is the natural gas hydrate resource amount (in gas equivalent), and has the unit of 10 ¹² m ³ ；Q _C2 The unit is 10 for the conventional petroleum and natural gas resource amount (in gas equivalent) ¹² m ³ ；Q _C3 The unit is 10 for the amount of conventional heavy oil and bitumen resources (in gas equivalent) ¹² m ³ ；Q _EC The amount of hydrocarbon resources (in gas equivalent) discharged by the source rock above the lower limit of buoyancy buildup and within the free dynamic field is 10 ¹² m ³ ；Q _C Is the conventional oil gas resource amount (in gas equivalent), and has the unit of 10 ¹² m ³ (ii) a f is the ratio of the natural gas hydrate in the conventional oil gas resource, unit%;

establishing a natural gas hydrate resource quantity determination model based on a unified model and a mass balance equation between the natural gas hydrate resource quantity and the conventional oil gas resource, wherein the natural gas hydrate resource quantity determination model comprises the following steps:

in the formula, f is the proportion of natural gas hydrate in conventional oil gas resources, and the unit percent; q _C1 Is the natural gas hydrate resource amount (in gas equivalent), and has the unit of 10 ¹² m ³ ；Q _C2 The unit is 10 for the conventional petroleum and natural gas resource amount (in gas equivalent) ¹² m ³ ；Q _C3 The unit is 10 for the amount of conventional heavy oil and asphalt resources (in gas equivalent) ¹² m ³ ；

In short, the natural gas hydrate resource amount determination model is established by starting from an oil-gas system, performing unified analysis and model construction on three types of conventional oil-gas resources (natural gas hydrate resources, conventional petroleum and natural gas resource amounts and conventional heavy oil and asphalt resources) which are generated by organic matters and take the buoyancy effect as the migration driving force in a free power field, and based on a substance balance principle; the natural gas hydrate resource quantity determination model can reflect the mass balance relationship between the natural gas hydrate resource quantity and the conventional petroleum and natural gas resource quantity and between the conventional heavy oil and the asphalt resource, and can realize the reliable evaluation of the target regional natural gas hydrate resource quantity (including the global regional natural gas hydrate resource quantity).

In one embodiment, step S5, obtaining the amount of the conventional petroleum and natural gas resources and the amount of the conventional heavy oil and bitumen resources in the target area is implemented by:

and determining the conventional petroleum and natural gas resource quantity and the conventional heavy oil and asphalt resource quantity of the target area according to expert evaluation in the petroleum geology and exploration fields and the data of the world authoritative petroleum institution.

In one embodiment, in step S1, obtaining the thickness and area of the sedimentary rock formation of the natural gas hydrate stability zone of the target region and the natural gas hydrate volume factor is implemented by:

and determining the thickness and the area of the sedimentary rock stratum of the natural gas hydrate stability zone of the target region and the volume factor of the natural gas hydrate by a mathematical statistic analysis method according to published evaluation results about the natural gas hydrate resources of the target region.

In one embodiment, step S2, obtaining the thickness and area of the sedimentary rock formation where the conventional hydrocarbon resources in the target area are located and the volume factor of the natural gas is implemented by:

and determining the thickness and the area of the sedimentary rock stratum where the conventional oil and gas resources of the target area are located and the volume factor of the natural gas through a mathematical statistical analysis method according to the authoritative data of the oil and gas industry of the target area.

The embodiment of the invention also provides a specific implementation mode of the system for determining the natural gas hydrate resource amount, and the system is used for realizing the embodiment of the method for determining the natural gas hydrate resource amount. Referring to fig. 2, the system includes:

the natural gas hydrate parameter acquisition module 21: the method is used for obtaining the thickness and the area of a sedimentary rock stratum of a natural gas hydrate stability zone of a target area and a natural gas hydrate volume factor;

oil and gas resource parameter acquisition module 22: the method is used for obtaining the thickness and the area of a sedimentary rock stratum where the conventional oil and gas resources of a target area are located and the natural gas volume factor; the conventional oil gas resource is generated by organic matters, distributed in a free power field and taking buoyancy as migration power;

the gaseous hydrocarbon ratio acquisition module 23: the method is used for acquiring the gaseous hydrocarbon ratio of a target area; wherein the gaseous hydrocarbon ratio refers to the ratio of gaseous hydrocarbons in the discharged hydrocarbon;

the natural gas hydrate ratio obtaining module 24: the method comprises the steps of determining the occupation ratio of natural gas hydrates in a target region in conventional oil and gas resources based on the thickness and the area of a sedimentary rock stratum of a natural gas hydrate stability zone of the target region, the volume factor of the natural gas hydrates, the thickness and the area of the sedimentary rock stratum where the conventional oil and gas resources of the target region are located, the volume factor of the natural gas and the occupation ratio of gaseous hydrocarbons of the target region;

the conventional energy amount acquisition module 25: the method is used for acquiring the conventional petroleum and natural gas resource quantity and the conventional heavy oil and asphalt resource quantity of a target area; the conventional petroleum and natural gas resources are petroleum and natural gas resources which are generated by organic matters, distributed in a free power field, taking buoyancy as migration power and are not biodegraded, and the conventional heavy oil and asphalt resources are heavy oil and asphalt resources which are generated by organic matters, distributed in the free power field, taking buoyancy as migration power and are biodegraded;

the natural gas hydrate resource amount acquisition module 26: the method is used for determining the natural gas hydrate resource amount of the target area based on the conventional petroleum and natural gas resource amount of the target area, the conventional heavy oil and asphalt resource amount and the ratio of natural gas hydrate in the conventional oil and gas resource.

In one embodiment, the gaseous hydrocarbon ratio obtaining module 23 includes:

the first ratio obtaining sub-module 231: the method is used for acquiring the ratio of the gas quantity generated by the hydrocarbon source rock with the organic matter type III in the biochemical gas generation stage (Ro < 0.5%) to the total hydrocarbon quantity generated by the hydrocarbon source rock in the target area, namely a first ratio; the first ratio is a possible upper limit value of the parameter gaseous hydrocarbon ratio;

the second ratio obtaining sub-module 232: the method is used for acquiring a second ratio which is the ratio of the gas quantity to the total hydrocarbon quantity in the conventional petroleum and natural gas reservoir which is proved to be in a target area; the second ratio is a possible lower limit value of the parameter gaseous hydrocarbon ratio;

the third ratio acquisition sub-module 233: the weighted average value of the ratios of the gaseous hydrocarbons generated by the hydrocarbon source rocks of which the organic matter types are I type, II type and III type in the free power field of the target area in the biological gas generation stage and the thermal gas generation stage to the total hydrocarbons generated is a third ratio;

the gaseous hydrocarbon fraction determination submodule 234: determining a target zone gaseous hydrocarbon fraction based on the first ratio, the second ratio, and the third ratio; wherein the ratio of the gaseous hydrocarbons in the target area is less than or equal to a first ratio and greater than or equal to a second ratio;

further, the gaseous hydrocarbon ratio determining submodule 234 is specifically configured to use the third ratio as an initial gaseous hydrocarbon ratio value of the target area, and correct the initial gaseous hydrocarbon ratio value of the target area by using the first ratio and the second ratio to obtain the gaseous hydrocarbon ratio of the target area; when the initial value of the gaseous hydrocarbon proportion of the target area is less than or equal to a first ratio and is greater than or equal to a second ratio, the initial value of the gaseous hydrocarbon proportion of the target area is the initial value of the gaseous hydrocarbon proportion of the target area; when the initial value of the gaseous hydrocarbon proportion of the target area is greater than the first ratio, the gaseous hydrocarbon proportion of the target area is the first ratio; and when the initial value of the gaseous hydrocarbon proportion of the target area is smaller than the second ratio, the gaseous hydrocarbon proportion of the target area is the second ratio.

In one embodiment, the natural gas hydrate proportion obtaining module 24 determines the proportion of the natural gas hydrate in the conventional oil and gas resources according to the following formula:

in the formula, f is the proportion of natural gas hydrate in conventional oil gas resources, and the unit percent; b is _gh Is a natural gas hydrate volume factor, and represents the methane hydrate volume and the reservoir stratum under the standard surface conditionThe volume ratio of the natural gas hydrate under the condition has unit dimensionless; b is _g The natural gas volume factor is a natural gas volume factor and represents the ratio of the natural gas volume under the standard surface condition to the natural gas volume under the reservoir layer condition, and the unit is dimensionless; a. The _GHSZ Area of sedimentary rock formation as gas hydrate stability zone, unit 10 ⁶ km ² ；H _GHSZ Thickness in m of sedimentary rock formation of the natural gas hydrate stability zone; a. The _conv The unit is 10 of the area of a sedimentary rock stratum where conventional oil and gas resources are located ⁶ km ² ；H _conv The thickness of the sedimentary rock stratum where the conventional oil and gas resources are located is m; g is the proportion of gaseous hydrocarbon in unit percent.

In one embodiment, the natural gas hydrate resource amount obtaining module 26 determines the natural gas hydrate resource amount by using the natural gas hydrate resource amount determination model; the natural gas hydrate resource quantity determination model is a calculation model of the natural gas hydrate resource quantity related to the proportion of the natural gas hydrate in conventional oil and gas resources, the conventional petroleum and natural gas resource quantity and the conventional heavy oil and asphalt resource quantity;

in the formula, f is the proportion of natural gas hydrate in conventional oil gas resources, and the unit percent; q _C1 Is the natural gas hydrate resource amount (in gas equivalent), and the unit is 10 ¹² m ³ ；Q _C2 The unit is 10 for the conventional petroleum and natural gas resource amount (in gas equivalent) ¹² m ³ ；Q _C3 The unit is 10 for the amount of conventional heavy oil and asphalt resources (in gas equivalent) ¹² m ³ ；

the natural gas hydrate is the same as other oil gas resources, hydrocarbons of the natural gas hydrate are all derived from degradation of deep organic matters, and the natural gas hydrate resources are brought into an oil gas system; the oil gas system comprises all hydrocarbon source rocks on the earth surface and related hydrocarbon migration and aggregation processes, and the types of oil gas resources contained in the oil gas system comprise conventional oil gas resources, unconventional oil gas resources and shale oil gas resources; according to the mass balance principle, establishing a correlation model of the oil and gas resources generated by the conventional oil and gas resources, the unconventional oil and gas resources, the shale oil and gas resources and the hydrocarbon source rocks in the oil and gas system in total:

Q _C +Q _U +Q _S ≤Q _P

in the formula, Q _C Is the conventional oil gas resource amount (in gas equivalent), and the unit is 10 ¹² m ³ ；Q _U For unconventional oil and gas resource amount (in gas equivalent), the unit is 10 ¹² m ³ ；Q _S Is shale oil and gas resource amount (in gas equivalent) with the unit of 10 ¹² m ³ ；Q _P For the total amount of hydrocarbon resources produced (in gas equivalent), unit 10 ¹² m ³ ；

Q _C ＝Q _C1 +Q _C2 +Q _C3 ≤Q _EC

in the formula, Q _C1 Is the natural gas hydrate resource amount (in gas equivalent), and the unit: 10 ¹² m ³ ；Q _C2 The unit is 10 for the conventional petroleum and natural gas resource amount (in gas equivalent) ¹² m；Q _C3 The unit is 10 for the amount of conventional heavy oil and asphalt resources (in gas equivalent) ¹² m ³ ；Q _EC The amount of hydrocarbon resources (in gas equivalent) exhausted from the source rock above the lower limit of buoyancy sequestration and within the free kinetic field is 10 units ¹² m ³ ；Q _C Is the conventional oil gas resource amount (in gas equivalent), and has the unit of 10 ¹² m ³ ；

Based on the correlation models of the natural gas hydrate resource, the conventional petroleum and natural gas resource and the conventional heavy oil and asphalt resource, establishing a unified model and a mass balance equation between the natural gas hydrate resource amount and the conventional oil and gas resource:

Q _C1 ＝Q _C -Q _C2 -Q _C3 ＝f×Q _C

in the formula, Q _C1 Is the natural gas hydrate resource amount (in gas equivalent), and the unit: x 10 ¹² m ³ ；Q _C2 The unit is 10 for the amount of conventional petroleum and natural gas resources (in gas equivalent) ¹² m ³ ；Q _C3 The unit is 10 for the amount of conventional heavy oil and bitumen resources (in gas equivalent) ¹² m ³ ；Q _EC The amount of hydrocarbon resources (in gas equivalent) exhausted from the source rock above the lower limit of buoyancy sequestration and within the free kinetic field is 10 units ¹² m ³ ；Q _C Is the conventional oil and gas resource quantity with the unit of 10 ¹² m ³ (ii) a f is the ratio of the natural gas hydrate in the conventional oil gas resource, unit%;

in the formula, f is the proportion of natural gas hydrate in conventional oil gas resources, and the unit percent; q _C1 Is the natural gas hydrate resource amount (in gas equivalent), and the unit is 10 ¹² m ³ ；Q _C2 The unit is 10 for the amount of conventional petroleum and natural gas resources (in gas equivalent) ¹² m ³ ；Q _C3 The unit is 10 for the amount of conventional heavy oil and asphalt resources (in gas equivalent) ¹² m ³ ；

In short, the natural gas hydrate resource quantity determination model is established by starting from an oil-gas system, performing unified analysis and model construction on three types of conventional oil-gas resources (natural gas hydrate resources, conventional petroleum and natural gas resource quantity and conventional heavy oil and asphalt resources) which are generated by organic matters and take buoyancy action as migration driving force in a free power field, and establishing based on a substance balance principle; the natural gas hydrate resource quantity determination model can reflect the mass balance relationship between the natural gas hydrate resource quantity and the conventional petroleum and natural gas resource quantity and between the conventional heavy oil and the asphalt resource, and can realize the reliable evaluation of the target regional natural gas hydrate resource quantity (including the global regional natural gas hydrate resource quantity).

In one embodiment, the conventional energy obtaining module 25 obtains the amount of the conventional petroleum and natural gas resources and the amount of the conventional heavy oil and asphalt resources in the target area by:

In an embodiment, the natural gas hydrate parameter obtaining module 21 obtains the thickness and the area of the sedimentary rock formation of the natural gas hydrate stability zone of the target area and the natural gas hydrate volume factor by:

according to published evaluation results about the natural gas hydrate resource of the target region, the thickness and the area of the sedimentary rock stratum of the natural gas hydrate stability zone of the target region and the volume factor of the natural gas hydrate are determined by a mathematical statistics analysis method.

In one embodiment, the hydrocarbon resource parameter obtaining module 22 obtains the thickness and area of the sedimentary rock formation where the conventional hydrocarbon resource of the target area is located and the natural gas volume factor by:

according to authoritative data of the target region petroleum and gas industry, the thickness and the area of a sedimentary rock stratum where conventional oil and gas resources of the target region are located and a natural gas volume factor are determined through a mathematical statistics analysis method.

The embodiment of the present invention further provides a specific implementation manner of an electronic device, which is capable of implementing all steps in the method for determining the natural gas hydrate resource amount in the above embodiment, where the electronic device specifically includes the following contents:

a processor, a memory, a communication interface, and a bus;

the processor, the memory and the communication interface complete mutual communication through a bus; the communication interface is used for realizing information transmission between related equipment such as server-side equipment, client-side equipment and the like; the processor is configured to invoke a computer program in the memory, and the processor executes the computer program to implement all the steps of the method for determining the amount of natural gas hydrate resources in the above embodiments, for example, the processor executes the computer program to implement the following steps:

step S2: obtaining the thickness and the area of a sedimentary rock stratum where the conventional oil and gas resources of a target area are located and a natural gas volume factor; the conventional oil gas resource is generated by organic matters, distributed in a free power field and taking buoyancy as migration power;

and step S4: determining the proportion of the target region natural gas hydrates in the conventional oil and gas resources based on the thickness and the area of the sedimentary rock formations of the target region natural gas hydrate stability zone, the volume factor of the natural gas hydrates, the thickness and the area of the sedimentary rock formations where the target region conventional oil and gas resources are located, the volume factor of the natural gas and the proportion of the target region gaseous hydrocarbons;

step S6: and determining the natural gas hydrate resource amount of the target region based on the conventional petroleum and natural gas resource amount, the conventional heavy oil and asphalt resource amount and the ratio of the natural gas hydrate in the conventional oil gas resource of the target region.

Embodiments of the present invention also provide a computer readable storage medium capable of implementing all the steps in the method for determining an amount of a natural gas hydrate resource in the above embodiments, the computer readable storage medium having stored thereon a computer program, which when executed by a processor implements all the steps of the method for determining an amount of a natural gas hydrate resource in the above embodiments, for example, the processor implements the following steps when executing the computer program:

step S2: obtaining the thickness and the area of a sedimentary rock stratum where the conventional oil and gas resources of a target area are located and a natural gas volume factor; the conventional oil-gas resource is generated by organic matters, distributed in a free power field and taking buoyancy as migration power;

and step S3: acquiring the gaseous hydrocarbon ratio of a target area; wherein the gaseous hydrocarbon ratio refers to the ratio of gaseous hydrocarbons in the discharged hydrocarbon;

Example 1

The following describes a method for determining the natural gas hydrate resource amount provided by the present invention by determining the global natural gas hydrate resource amount by using the method for determining the natural gas hydrate resource amount provided by the present invention, with the global as a target area.

In the embodiment, from the angle of the forward edge geological theory, aiming at the problems that the evaluation of the global natural gas hydrate resource amount is difficult and the precision is low, especially the problem that the evaluation reliability of the global natural gas hydrate resource amount is low due to low exploration degree, low exploration technology and lack of exploration data, the comprehensive analysis utilizes the results of the previous research and key parameters, and the natural gas hydrate resource is brought into a global oil and gas system based on the mass balance principle, so that a corresponding unified model and a mass balance equation are established, and the global natural gas hydrate resource amount is finally determined.

The method adopted by the embodiment specifically comprises the following steps:

1. a natural gas hydrate resource amount determination model; the method specifically comprises the following steps:

1.1, the hydrocarbons of the natural gas hydrate are from the degradation of deep organic matters as other oil gas resources, and the natural gas hydrate resources are brought into an oil gas system; the global oil-gas system comprises all hydrocarbon source rocks on the earth surface and related hydrocarbon migration and aggregation processes, and the types of oil-gas resources contained in the global oil-gas system comprise conventional oil-gas resources, unconventional oil-gas resources and shale oil-gas resources; according to the mass balance principle, a correlation model of conventional oil and gas resources (the conventional oil and gas resources refer to oil and gas resources which are generated by organic matters, distributed in a free power field and taking buoyancy as migration power), unconventional oil and gas resources and oil and gas resources generated by shale oil and gas resources and hydrocarbon source rocks in an oil and gas system in total is established:

Q _C +Q _U +Q _S ≤Q _P

in the formula, Q _C Is the conventional oil gas resource amount (in gas equivalent), and has the unit of 10 ¹² m ³ ；Q _U For unconventional oil and gas resource amount (in gas equivalent), the unit is 10 ¹² m ³ ；Q _S Is shale oil and gas resource amount (in gas equivalent) and has the unit of 10 ¹² m ³ ，Q _P For the total amount of hydrocarbon resources produced (in gas equivalent), unit 10 ¹² m ³ ；

1.2, the natural gas hydrate has the same characteristics with the conventional petroleum and natural gas resource quantity and the conventional heavy oil and asphalt resource quantity in the aspects of hydrocarbon substance sources, migration aggregation power and processes, reservoir characteristics and the like, and besides, the natural gas hydrate is only stored in a high-pressure low-temperature stable band, so that the natural gas hydrate can be regarded as a special conventional oil and gas resource aggregated in a reservoir under high-pressure low-temperature conditions; based on the above, a correlation model of natural gas hydrate resources, conventional petroleum and natural gas resources (conventional petroleum and natural gas resources refer to petroleum and natural gas resources which are generated by organic matters, distributed in a free power field, using buoyancy as migration power and are not biodegraded) and conventional heavy oil and asphalt resources (conventional heavy oil and asphalt resources refer to heavy oil and asphalt resources which are generated by organic matters, distributed in the free power field, using buoyancy as migration power and are biodegraded) is established:

Q _C ＝Q _C1 +Q _C2 +Q _C3 ≤Q _EC

in the formula, Q _C1 Is the natural gas hydrate resource amount (in gas equivalent), and has the unit of 10 ¹² m ³ ；Q _C2 The unit is 10 for the amount of conventional petroleum and natural gas resources (in gas equivalent) ¹² m ³ ；Q _C3 The unit is 10 for the amount of conventional heavy oil and bitumen resources (in gas equivalent) ¹² m ³ ；Q _EC The amount of hydrocarbon resources (in gas equivalent) exhausted from the source rock above the lower limit of buoyancy sequestration and within the free kinetic field is 10 units ¹² m ³ ；Q _C Is a constantOil and gas resource amount (in gas equivalent) of unit 10 ¹² m ³ ；

1.3, establishing a unified model and a mass balance equation between the natural gas hydrate resource amount and the conventional oil gas resource based on the related models of the natural gas hydrate resource, the conventional petroleum and natural gas resource and the conventional heavy oil and asphalt resource:

Q _C1 ＝Q _C -Q _C2 -Q _C3 ＝f×Q _C

in the formula, Q _C1 Is the natural gas hydrate resource amount (in gas equivalent), and the unit is 10 ¹² m ³ ；Q _C2 The unit is 10 for the conventional petroleum and natural gas resource amount (in gas equivalent) ¹² m ³ ；Q _C3 The unit is 10 for the amount of conventional heavy oil and asphalt resources (in gas equivalent) ¹² m ³ ；Q _EC The amount of hydrocarbon resources (in gas equivalent) discharged by the source rock above the lower limit of buoyancy buildup and within the free dynamic field is 10 ¹² m ³ ；Q _C Is the conventional oil gas resource amount (in gas equivalent), and has the unit of 10 ¹² m ³ (ii) a f is the proportion of the natural gas hydrate in the conventional oil gas resource, and the unit percent is;

1.4, establishing a natural gas hydrate resource quantity determination model based on a unified model and a mass balance equation between the natural gas hydrate resource quantity and the conventional oil and gas resource, wherein the natural gas hydrate resource quantity determination model comprises the following steps:

2. Obtaining the thickness and the area of a sedimentary rock stratum of a global natural gas hydrate stability zone and a natural gas hydrate volume factor, and obtaining the thickness and the area of the sedimentary rock stratum of global conventional oil and gas resources and the natural gas volume factor;

in this example, 29 globally published evaluation results of global natural gas hydrate resources and global oil and gas industry authority data were selected, and key parameters required for evaluating the natural gas hydrate resource amount based on a conventional oil and gas resource analogy were obtained by a mathematical statistical analysis method, including a parameter of the sedimentary rock area a of the natural gas hydrate stability zone reflecting the sedimentary rock area in the natural gas stability zone _GHSZ Thickness H _GHSZ And gas hydrate volume factor B _gh Data reflecting the area A of the sedimentary rock stratum where the conventional oil and gas resources are located according to the parameters of the sedimentary rock stratum volume of the conventional oil and gas reservoir in the free dynamic field _conv Thickness H _conv And natural gas volume factor B _g See table 1, fig. 3, and fig. 4 for data.

3. Acquiring the proportion of gaseous hydrocarbon; the method specifically comprises the following steps:

3.1, obtaining a first ratio of the gas quantity generated by the global source rock with the organic matter type III in a biochemical gas generation stage (Ro < 0.5%) to the total hydrocarbon quantity;

the gas to total hydrocarbon ratios of different organic matter type source rocks during the biochemical gassing phase (Ro < 0.5%) for different organic matter type source rocks during the biochemical gassing phase (Ro < 0.5%) are shown in fig. 6;

3.2, obtaining a second ratio of the gas quantity to the total hydrocarbon quantity in the globally proven conventional petroleum and natural gas reservoir;

world has ascertained in conventional reservoirs the world has ascertained that the ratio of gas to total hydrocarbons in conventional reservoirs is shown in figure 7;

3.3, obtaining a weighted average value of ratios of gaseous hydrocarbons generated by hydrocarbon source rocks with organic matter types of I type, II type and III type in a free power field of the whole world to total generated hydrocarbons in a biological gas generation stage and a thermal gas generation stage, namely a third ratio; specifically, the method comprises the following steps:

respectively obtaining the ratio of gaseous hydrocarbon generated by a hydrocarbon source rock with an organic matter type I in a biological gas generation stage to total hydrocarbon generated, the ratio of gaseous hydrocarbon generated by the hydrocarbon source rock with an organic matter type I in a thermal gas generation stage to total hydrocarbon generated, the ratio of gaseous hydrocarbon generated by the hydrocarbon source rock with an organic matter type II in the biological gas generation stage to total hydrocarbon generated, the ratio of gaseous hydrocarbon generated by the hydrocarbon source rock with an organic matter type II in the thermal gas generation stage to total hydrocarbon generated, the ratio of gaseous hydrocarbon generated by the hydrocarbon source rock with an organic matter type III in the biological gas generation stage to total hydrocarbon generated, and the ratio of gaseous hydrocarbon generated by the hydrocarbon source rock with an organic matter type III in the thermal gas generation stage to total hydrocarbon generated in the free power field, and weighting and averaging the ratios to obtain a third ratio;

the ratio of gaseous hydrocarbons to total hydrocarbons produced in hydrocarbon source rocks with kerogen types I, II and III in the free power field during the biogenic and thermogenic stages is shown in FIG. 8;

step S34: determining a gaseous hydrocarbon fraction g based on the first ratio, the second ratio, and the third ratio; specifically, the method comprises the following steps:

taking the third ratio as an initial value of the gaseous hydrocarbon ratio, and correcting the initial value of the gaseous hydrocarbon ratio by using the first ratio and the second ratio to obtain a gaseous hydrocarbon ratio g; when the initial value of the gaseous hydrocarbon ratio is less than or equal to a first ratio and greater than or equal to a second ratio, the gaseous hydrocarbon ratio g is the initial value of the gaseous hydrocarbon ratio; when the initial value of the gaseous hydrocarbon ratio is greater than the first ratio, the gaseous hydrocarbon ratio g is the first ratio; when the initial value of the gaseous hydrocarbon proportion is smaller than the second ratio, the gaseous hydrocarbon proportion g is the second ratio;

the global gaseous hydrocarbon ratio g distribution is shown in fig. 5.

TABLE 1

Parameter(s)	Minimum value	Optimum value	Maximum value
				A _GHSZ (10 ⁶ km ² )	5.0	50-30	150
H _GHSZ (m)	10	500-400	1200
				A _conv (10 ⁶ km ² )	162	180	240
H _conv (m)	300	2600-3500	7000
				B _gh	160	164	168
B _g	35	210	360
				g	0.379	0.715-0.67	0.907

4. Based on the thickness and the area of the sedimentary rock stratum of the natural gas hydrate stability zone and the volume factor of the natural gas hydrate, the thickness and the area of the sedimentary rock stratum where the conventional oil and gas resource is located and the volume factor of the natural gas hydrate, the proportion of the natural gas hydrate in the conventional oil and gas resource is determined by the following formula:

in the formula, f is the proportion of the natural gas hydrate in the conventional oil gas resource, and the unit percent; b is _gh The volume factor of the natural gas hydrate represents the ratio of the volume of the methane hydrate under the standard surface condition to the volume of the natural gas hydrate under the reservoir stratum condition, and the unit is dimensionless; b is _g The natural gas volume factor is a natural gas volume factor and represents the ratio of the natural gas volume under the standard surface condition to the natural gas volume under the reservoir stratum condition, and the unit is dimensionless; a. The _GHSZ Area of sedimentary rock formation of gas hydrate stability zone, unit 10 ⁶ km ² ；H _GHSZ The thickness of the sedimentary rock formation in m, which is the natural gas hydrate stability zone; a. The _conv The unit is 10 of the area of a sedimentary rock stratum where conventional oil and gas resources are located ⁶ km ² ；H _conv The thickness of the sedimentary rock stratum where the conventional oil and gas resources are located is m; g is the proportion of gaseous hydrocarbon in unit percent.

5. Acquiring the resource quantity of conventional petroleum and natural gas and the resource quantity of conventional heavy oil and asphalt; specifically, the method comprises the following steps:

determining the global conventional petroleum and natural gas resource quantity Q according to the expert evaluation and the world authoritative petroleum institution data in the petroleum geology and exploration field _C2 Data and conventional heavy oil and bitumen resource quantity Q _C3 And (4) data.

6. And determining the global natural gas hydrate resource amount through a natural gas hydrate resource amount determination model based on the conventional petroleum and natural gas resource amount, the conventional heavy oil and asphalt resource amount and the ratio of natural gas hydrates in the conventional oil and gas resources.

In the embodiment, the optimal value of the proportion f of the natural gas hydrate in the conventional oil and gas resources is 0.01-0.03; the global conventional petroleum resource amount is 1983.3 multiplied by 10 ⁹ m ³ Global conventional natural gas resource amount: 672.1 × 10 ¹² m ³ The two are added to form the global conventional petroleum and natural gas resource quantity Q _C2 (ii) a Global conventional heavy oil and asphaltene resources Q _C3 Is 1438.0 is multiplied by 10 ¹² m ³ . Finally determining the optimal value of the global natural gas hydrate resource amount to be 84 multiplied by 10 ¹² m ³ Average value of 179X 10 ¹² m ³ And the final result is as follows: 84-179X 10 ¹² m ³ 。

The method for determining the natural gas hydrate resource amount provided by the embodiment starts from a leading-edge geological theory, brings natural gas hydrate resources into a global oil-gas system to construct a unified model and a mass balance equation, finds out similar points of the natural gas hydrate resources and conventional oil-gas resources on resource types, and performs reliable evaluation work on the global natural gas hydrate resource amount by comparing with a conventional oil-gas resource evaluation method. By the method, the defects of insufficient geological theory and large error of an evaluation method in the prior art are overcome, geological basis is predicted, and the reliability is high; the prediction has advanced technology and high accuracy; a brand-new thought is provided for prediction, and the innovation is strong; in addition, the method only utilizes common evaluation parameters in conventional oil gas evaluation, integrates evaluation results and parameters of predecessors on the hydrate, and is simple and easy to obtain in data type and simple and quick in operation process. In general, after practical application verification, the method has the following advantages: the geological basis is sufficient, and the reliability is high; (2) the technical characteristics are distinct and the accuracy is high; (3) the thought is complete and clear, and the innovation is strong; and (4) the data are simple and easy to obtain, and the operability is strong.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. A method of determining an amount of a natural gas hydrate resource, wherein the method comprises:

obtaining the thickness and the area of a sedimentary rock stratum where the conventional oil and gas resources of a target area are located and a natural gas volume factor; the conventional oil-gas resource is generated by organic matters, distributed in a free power field and taking buoyancy as migration power;

acquiring the gaseous hydrocarbon ratio of a target area; wherein the gaseous hydrocarbon ratio refers to the ratio of gaseous hydrocarbons in the discharged hydrocarbon;

determining the proportion of the target region natural gas hydrates in the conventional oil and gas resources based on the thickness and the area of the sedimentary rock formations of the target region natural gas hydrate stability zone, the volume factor of the natural gas hydrates, the thickness and the area of the sedimentary rock formations where the target region conventional oil and gas resources are located, the volume factor of the natural gas and the proportion of the target region gaseous hydrocarbons;

and determining the natural gas hydrate resource amount of the target region based on the conventional petroleum and natural gas resource amount, the conventional heavy oil and asphalt resource amount and the ratio of the natural gas hydrate in the conventional oil gas resource of the target region.

2. The method of claim 1, wherein obtaining a target zone gaseous hydrocarbon fraction comprises:

acquiring a first ratio of the gas quantity generated by the hydrocarbon source rock with the organic matter type III in the biochemical gas generation stage to the total hydrocarbon quantity generated by the hydrocarbon source rock in the target area; acquiring a second ratio which is the ratio of the gas quantity to the total hydrocarbon quantity in the conventional petroleum and natural gas reservoir which is proved to be in the target area;

acquiring a weighted average value of ratios of gaseous hydrocarbons and total hydrocarbons generated by hydrocarbon source rocks of which the organic matter types are I type, II type and III type in a free power field of a target area in a biological gas generation stage and a thermal gas generation stage, wherein the weighted average value is a third ratio;

determining the gaseous hydrocarbon ratio of the target area based on the first ratio, the second ratio and the third ratio; wherein the ratio of the gaseous hydrocarbons in the target area is less than or equal to a first ratio and greater than or equal to a second ratio;

preferably, the third ratio is used as an initial value of the gaseous hydrocarbon ratio of the target area, and the initial value of the gaseous hydrocarbon ratio of the target area is corrected by using the first ratio and the second ratio to obtain the gaseous hydrocarbon ratio of the target area; when the initial value of the gaseous hydrocarbon proportion of the target area is less than or equal to a first ratio and is greater than or equal to a second ratio, the initial value of the gaseous hydrocarbon proportion of the target area is the initial value of the gaseous hydrocarbon proportion of the target area; when the initial value of the gaseous hydrocarbon proportion of the target area is greater than the first ratio, the gaseous hydrocarbon proportion of the target area is the first ratio; and when the initial value of the gaseous hydrocarbon proportion of the target area is smaller than the second ratio, the gaseous hydrocarbon proportion of the target area is the second ratio.

3. The method of claim 1, wherein the natural gas hydrate is determined in the conventional oil and gas resource by the following formula:

in the formula, f is the proportion of natural gas hydrate in conventional oil gas resources, and the unit percent; b _gh Is a natural gas hydrate volume factor with unit dimensionless; b is _g Is a natural gas volume factor, and the unit is dimensionless; a. The _GHSZ Area of sedimentary rock formation of gas hydrate stability zone, singlyBit 10 ⁶ km ² ；H _GHSZ The thickness of the sedimentary rock formation in m, which is the natural gas hydrate stability zone; a. The _conv The unit of the area of the sedimentary rock stratum where the conventional oil and gas resources are located is 10 ⁶ km ² ；H _conv The thickness of the sedimentary rock stratum where the conventional oil and gas resources are located is m; g is the proportion of gaseous hydrocarbon in unit percent.

4. The method of claim 1, wherein the natural gas hydrate resource amount is determined using a natural gas hydrate resource amount determination model; the natural gas hydrate resource quantity determination model is a calculation model of the natural gas hydrate resource quantity related to the proportion of the natural gas hydrate in conventional oil and gas resources, the conventional petroleum and natural gas resource quantity and the conventional heavy oil and asphalt resource quantity;

preferably, the natural gas hydrate resource amount determination model is:

in the formula, f is the proportion of natural gas hydrate in conventional oil gas resources, and the unit percent; q _C1 Is the natural gas hydrate resource amount with the unit of 10 ¹² m ³ ；Q _C2 The unit is 10 for the conventional petroleum and natural gas resource quantity ¹² m ³ ；Q _C3 Is the resource quantity of conventional heavy oil and asphalt, and has a unit of 10 ¹² m ³ 。

5. A system for determining an amount of a natural gas hydrate resource, wherein the system comprises:

an oil and gas resource parameter acquisition module: the method is used for obtaining the thickness and the area of a sedimentary rock stratum where the conventional oil and gas resources of a target area are located and the natural gas volume factor; the conventional oil gas resource is generated by organic matters, distributed in a free power field and taking buoyancy as migration power;

the conventional energy quantity acquisition module: the method is used for acquiring the conventional petroleum and natural gas resource quantity and the conventional heavy oil and asphalt resource quantity of a target area; the conventional petroleum and natural gas resources are petroleum and natural gas resources which are generated by organic matters, distributed in a free power field, taking buoyancy as migration power and are not biodegraded, and the conventional heavy oil and asphalt resources are heavy oil and asphalt resources which are generated by organic matters, distributed in the free power field, taking buoyancy as migration power and are biodegraded;

the natural gas hydrate resource quantity acquisition module: the method is used for determining the natural gas hydrate resource amount of the target area based on the conventional petroleum and natural gas resource amount, the conventional heavy oil and asphalt resource amount and the ratio of natural gas hydrate in the conventional oil gas resource of the target area.

6. The system of claim 5, wherein the gaseous hydrocarbon fraction obtaining module comprises:

a first ratio acquisition submodule: the method is used for obtaining the ratio of the gas quantity generated by the hydrocarbon source rock with the organic matter type III in the biochemical gas generation stage to the total hydrocarbon quantity generated in the target area, namely the first ratio;

a second ratio acquisition submodule: the second ratio is used for acquiring the ratio of the gas quantity to the total hydrocarbon quantity in the conventional petroleum and natural gas reservoir which is already detected in the target area;

a third ratio acquisition submodule: the weighted average value of the ratios of the gaseous hydrocarbons generated by the hydrocarbon source rocks of which the organic matter types are I type, II type and III type in the free power field of the target area in the biological gas generation stage and the thermal gas generation stage to the total hydrocarbons generated is a third ratio;

a gaseous hydrocarbon ratio determination submodule: determining a target zone gaseous hydrocarbon fraction based on the first ratio, the second ratio, and the third ratio; wherein the ratio of the gaseous hydrocarbons in the target area is less than or equal to a first ratio and greater than or equal to a second ratio;

preferably, the gaseous hydrocarbon ratio determination submodule is used for taking the third ratio as an initial gaseous hydrocarbon ratio value of the target area, and correcting the initial gaseous hydrocarbon ratio value of the target area by using the first ratio and the second ratio to obtain the gaseous hydrocarbon ratio of the target area; when the initial value of the gaseous hydrocarbon proportion of the target area is less than or equal to a first ratio and is greater than or equal to a second ratio, the initial value of the gaseous hydrocarbon proportion of the target area is the initial value of the gaseous hydrocarbon proportion of the target area; when the initial value of the gaseous hydrocarbon proportion of the target area is greater than the first ratio, the gaseous hydrocarbon proportion of the target area is the first ratio; and when the initial value of the gaseous hydrocarbon proportion of the target area is smaller than the second ratio, the gaseous hydrocarbon proportion of the target area is the second ratio.

7. The system of claim 5, wherein the natural gas hydrate fraction acquisition module determines the natural gas hydrate fraction in the conventional oil and gas resource by the following formula:

in the formula, f is the proportion of natural gas hydrate in conventional oil gas resources, and the unit percent; b is _gh Is a natural gas hydrate volume factor with unit dimensionless; b is _g Is a natural gas volume factor, and the unit is dimensionless; a. The _GHSZ Area of sedimentary rock formation as gas hydrate stability zone, unit 10 ⁶ km ² ；H _GHSZ The thickness of the sedimentary rock formation in m, which is the natural gas hydrate stability zone; a. The _conv Sedimentary rock for conventional oil and gas resourcesArea of layer, unit 10 ⁶ km ² ；H _conv The thickness of the sedimentary rock stratum where the conventional oil and gas resources are located is m; g is the proportion of gaseous hydrocarbon in unit percent.

8. The system of claim 5, wherein the natural gas hydrate resource amount acquisition module determines the natural gas hydrate resource amount using a natural gas hydrate resource amount determination model; the natural gas hydrate resource quantity determination model is a calculation model of the natural gas hydrate resource quantity related to the proportion of the natural gas hydrate in conventional oil and gas resources, the conventional petroleum and natural gas resource quantity and the conventional heavy oil and asphalt resource quantity;

in the formula, f is the proportion of natural gas hydrate in conventional oil gas resources, and the unit percent; q _C1 Is the natural gas hydrate resource amount with the unit of 10 ¹² m ³ ；Q _C2 The unit is 10 for the conventional petroleum and natural gas resource quantity ¹² m ³ ；Q _C3 The unit is 10 for the amount of conventional heavy oil and asphalt resources ¹² m ³ 。

9. An electronic device comprising a processor, a memory, and a computer program stored on the memory and executable on the processor, the processor when executing the program implementing the steps of determining a natural gas hydrate resource quantity method according to any one of claims 1-4.

10. A computer readable storage medium having stored thereon a computer program which, when executed by a processor, carries out the steps of any of claims 1-4 of determining a natural gas hydrate resource quantity method.