青海祁连山冻土区天然气水合物资源量的估算方法——以钻探区为例

Estimation method of gas hydrate resource in the Qilian Mountain permafrost area,Qinghai,China—a case of the drilling area

祁连山冻土区天然气水合物DK-1、DK-2、DK-3、DK-4号钻孔揭示,该区天然气水合物及其异常主要产出于破碎岩层裂隙中和砂岩孔隙中,根据不同的赋存类型分别赋予具体地质含义,并运用体积法建立了2种产状天然气水合物资源量的计算方法。基于野外地质观测统计数据和室内分析测试结果,在钻探区约40×104m2的范围内,计算得到砂岩孔隙中的天然气水合物资源量约为6.24×104m3天然气,破碎岩层裂隙中的天然气水合物资源量约为88×104m3天然气,总的资源量约为94.2×104m3天然气。可以看出,钻探区中产于破碎岩层裂隙中的天然气水合物资源量是主体,这与钻探中肉眼观察的结果一致。

Based on various kinds of occurrence that gas hydrate and its related anomalies exist in the fissure of fractured rocks and in the pore space of sandstones which are revealed from the holes of DK-1,DK-2,DK-3,DK-4 in the Qilian Mountain permafrost,estimation methods for gas hydrate resource in two types of gas hydrate occurrence are established respectively after different parameters are presented with detailed geological meanings in the utilization of volumetric estimation in this paper.According to field-based observed data and indoor analyzed results,gas hydrate resource in the pore space of sandstones and that of the fissure of rocks are preliminarily estimated to be about 6.24×104m3 and 88×104m3 gas in the drilling area of 40×104m2 respectively,with the total of about 94.2× 104m3 gas.These estimations indicate that the major part of gas hydrate resources lies in the fissure of rocks in the drilling area,which is consistent with what is observed with the naked eye in the field.