海相和陆相页岩储层微观结构差异性分析

Analyses on differences of microstructure between marine and lacustrine facies shale reservoirs

为了深入分析海相和陆相页岩储层微观结构特征,探讨两者差异性及其影响因素,运用氩离子—抛光扫描电镜、低温氮气吸附实验、核磁共振和数理统计等技术和方法,对我国发育的海相和陆相页岩储层从定性和定量2个方面进行了实验研究。对比发现:1海相页岩储层基质孔隙主要发育粒间孔和有机质孔,陆相则以无机孔为主;2海相页岩储层孔径普遍小于陆相页岩储层,但比表面积和孔容却异常发育;3海相页岩储层发育的微裂缝主要为构造缝,而陆相则以黏土矿物层间缝为主。通过分析认为矿物组成、有机质类型、热演化成熟度和构造活动期次是影响两者微观结构特征差异性的主控因素。

In order to analyze microstructural characteristics of shale reservoirs from marine and lacustrine facies and discuss the differences and their influencing factors,Ar-ion milling-Scanning Electron Microscopy（Ar-SEM）,N2 adsorption test,nuclear magnetic resonance（NMR）and mathematical statistics are used to study two facies sediments from qualitative and quantitative aspects.Three obvious results are found：（1）Marine facies shale reservoirs mainly have developed inter-particle pores and organic matter pores in matrix-related pores,but lacustrine facies shale have more non-organic pores;（2）Pore size of marine facies shale reservoirs is smaller than the lacustrine ones,but they have more BET and BJH;（3）Geological microfractures are more developed in the marine facies shale reservoirs,the lacustrine ones mainly contain more micro-fractures between clay layers.Mineral constituents,organic matter types,thermal maturity and tectonic activity times are key factors to affect the differences on microstructural characteristics of two facies shale reservoirs.