基于CT扫描的天然气水合物储层微观孔隙结构定量表征及特征分析

基于X射线CT技术对祁连山木里研究区水合物储层岩心样品进行扫描与成像,进而构建数字岩心三维模型,并将最大球算法应用于相应孔隙网络模型的提取,实现岩心孔隙结构的三维显示,应用数值模拟方法获取孔喉尺寸分布、配位数等岩心孔隙结构参数,最终实现水合物储层微观孔隙结构的定量表征。此外,对不同微观孔隙结构参数与储层物性的相关关系进行分析。结果表明:研究区水合物储层物性差、孔喉半径小;储集空间主要以粒内溶蚀孔隙、粒间溶蚀孔隙与微裂缝为主,以原生孔隙为辅;微观孔喉结构参数主要影响储层的渗透率,对孔隙度的影响相对较小。
The core samples of a hydrate reservoir in Muli area, Qilian Mountain were scanned and imaged using CT technology to construct a three dimensional digital core model. The corresponding pore network model was extracted and dimensional display was realized by using the maximum sphere algorithm. Numerical simulationswere applied to the acquisition of pore structure parameters toquantify the characteristics of reservoir microscopic pore structure. In addition, we analyzed the correlation between the parameters of different pore throats and the physical properties of the reservoir. The results show that, the physical properties of the hydrate reservoirs in the study area are poor with small pore throat radius; the reservoir space is mainly composed of intra-particles, inter-particle dissolved pores and micro-cracks with some primary pores;micro pore throat parameters have controls on permeability, but have less effect on porosity