页岩气藏地质资源量、可采资源量和井控可采储量的确定方法

Determination Methods of Geological Resources,Recoverable Resources and Well-Controlled Recoverable Reserves in Shale Gas Reservoir

页岩气的主要成分为甲烷(占98.5%以上),含少量和微量的乙烷、丙烷、氦气、氧气和二氧化碳气。页岩气藏是一种特殊的封闭性气藏,它的储集层由超致密的基质和微裂缝系统组成。基质中的天然气以饱和吸附状态储存于纳米(10-9m)到微米(10-6m)级的颗粒表面;微裂缝中的天然气以自由气状态存在于微裂缝之中,而且两者是一个压力平衡体系。由于页岩的密度较大,而裂缝的孔隙度很小,因此,吸附气为页岩气的主要储量。目前,由文献报导的评价页岩气资源量的方法是不正确的,所评价的结果也是不可靠的。提出了评价页岩气藏地质资源量的体积法、评价可采资源量的动态平衡法和评价井控可采储量的产量递减法。

The main component of shale gas is methane accounting for 98.5%,with minor amounts of ethane,propane,helium,oxygen and carbon dioxide gas.Shale gas reservoir is a kind of special closed gas reservoir,and it is composed of extra-dense matrix and micro-fracture system.Gas in matrix is stored in a state of saturated adsorption on the surface of particles ranging from nanometers （10^-9m） to micrometer （10^-6m）; natural gas in micro-fracture is existed in a free state into the micro-fractures,and they belong to one pressure-balanced system.Shale has larger density,while fracture has small porosity,therefore,adsorbed gas is the main reserves of shale gas.Currently,the evaluation methods for shale gas resources reported in the literatures are incorrect,hence the results are unreliable.This paper presents the volume method for geological resources,the dynamic balance method for recoverable resources and the production decline method for wellcontrolled recoverable reserves in shale gas reservoirs.