摘要： 全球天然气水合物(NGH)调查研究工作取得了飞速发展,自 1973 年到现在至少有 30 组科学家开展过NGH资源潜力定量评价.前人基于全油气系统的学术思想,将天然气水合物与常规油气和非常规油气的形成分布结合起来展开研究,并基于物质平衡的思想建立了它们之间的定量关系模式,在主控因素和实际试采资料约束下模拟计算出全球天然气水合物可采资源量众数值为41.46×1012 m3.基于物质平衡原理模拟计算全球天然气水合物可采资源量的主控因素包括自由碳氢化合物动态场的面积(AF-HDF)、自由碳氢化合物动态场的厚度(HF-HDF)、水合物稳定带的面积(AGHSZ)、水合物稳定带的厚度(HGHSZ)、常规油气资源量(Qc1)、稠油沥青资源量(Qc2)和可采系数(RGH),同时考虑到水合物的生物降解和热降解两种成因机制,引入源岩供气比率(g);考虑到水合物与常规油气相态的差异,引入各自的体积系数Bgh和Bg.考虑到影响因素较多且各自变化范围较大,数值模拟结果的敏感性和可信度需进行分析,本文首先就物质平衡原理获得全球NGH可采资源量评估结果的敏感性进行了研究.结果表明:可采系数的敏感性最高(31.13%),其后依次为Qc1、Qc2、AF-HDF、AGHSZ、HGHSZ和HF-HDF,数值分别为22.70%、13.38%、12.44%、8.89%、6.12%和 5.34%;然后在各要素联合控制下应用蒙特卡洛模拟评估可信度,全球水合物可采资源量众数值和平均值分别为 78.09×1012 m3 和 86.06×1012 m3,处于众数值前后±50%区间的置信度为 88.95%,可信度较高,同时基于前人的评估结果进行了验证.进一步提高全球水合物可采资源量评价结果精度的有效方法是获得更多数量的实际试采开采资料,降低它们之间的不确定性.

关键词: 天然气水合物, 全球水合物资源潜力, 敏感性分析, 物质平衡法, 资源勘查

Abstract: The global investigation of natural gas hyate(NGH)has made rapid progress,and at least 30 groups of scientists have carried out quantitative evaluation of NGH resource potential since 1973.Based on the academic thought of Whole Petroleum System,Professor Pang Xiongqi and others combined the formation and distribution of natural gas hydrate with conventional oil and gas and unconventional oil and gas,and established a quantitative relationship model between them based on the idea of mass balance.Under the constraints of the main control factors and the actual test data,the global natural gas hydrate recoverable resources quantity is calculated as 41.46×1012 m3.Based on the principle of mass balance,there are seven main controlling factors to calculate the recoverable resources of global natural gas hydrate.It includes the area of the free hydrocarbon dynamic field(AF-HDF),the thickness of the free hydrocarbon dynamic field(HF-HDF),the area of the hydrate stability zone(AGHSZ),the thickness of the hydrate stability zone(HGHSZ),the amount of conventional oil and gas resources(Qc1),the amount of heavy oil asphalt resources(Qc2)and the recovery coefficient(RGH).Taking into account both the biological degradation and thermal degradation mechanisms of hydrates,the source rock gas supply ratio(g)is introduced considering the difference in volume coefficients between hydrates and conventional oil and gas,their respective volume coefficients Bgh and Bg are introduced.In the case that the principle of the method is completely correct,the sensitivity and reliability of the numerical simulation results need to be analyzed considering that there are many influencing factors and their respective variation ranges are large.In this paper,the sensitivity of the mass balance method to obtain the assessment results of global NGH recoverable resources are studied.The results showed that the recoverable coefficient exhibits the highest sensitivity(31.13%),followed by Qc1,Qc2,AF-HDF,AGHSZ,HGHSZ and HF-HDF,with values of 22.70%,13.38%,12.44%,8.89%,6.12%and 5.34%,respectively.Then under the joint control of all factors,applying Monte Carlo simulation to assess credibility.The global mode and mean values of recoverable hydrate resources are 78.09×1012 m3 and 86.06×1012 m3 respectively,and the confidence of±50%before and after the key value is 88.95%,indicating a high reliability.Simultaneously,validation was conducted based on the assessment results of previous researchers.The effective method to further improve the accuracy of global hydrate recoverable resources evaluation is to obtain more actual test production data and reduce the uncertainty between them.

Key words: natural gas hydrate, global hydrate resource potential, sensitivity analysis, mass balance method, resource explora-tion

中图分类号: 

• TE122.3 P618.13