龙马溪组下部页岩储层孔隙结构特征与评价方案——以重庆南川三泉剖面泉浅1井为例

Characteristics and evaluation scheme of shales reservoir pores of the lower part of Longmaxi Formation: A case study at Chongqing Nanchuan Sanquan Quanqian Well one

运用场发射扫描电镜、高压压汞、低温氮吸附、薄片观察等实验技术手段,以重庆南川泉浅1井为例,探究了龙马溪组下部页岩储层的孔隙特征,结果表明:泉浅1井龙马溪组页岩孔隙度小、喉道细,孔隙较发育,类型多样,结构复杂,小孔和微孔是主要的孔隙,占据了主要的储集空间与比表面积;发育晶间孔、粒间孔、粒内孔、溶蚀孔隙、有机质纳米孔、微裂隙等孔隙,有机质纳米孔是气体吸附的主要场所。以TOC含量-孔径-脆性指数分别作为储层孔隙性、渗透性、脆性的评价指标,建立TOC含量-孔径-脆性指数评价方案,可以实现对储层基础物性经济有效、简便快捷的评价。

Using high-pressure mercury injection,nitrogen adsorption experiments,SEM and microscope observation,this study investigated the pore structure of the lower part shale reservoir of Longmaxi Formation in Quanqian Well one. The results show that the shale reservoir has the characteristics of small porosity,thin throat,various types and complicated structures. The micropores and mesopores are the main types of reservoir and occupy the main space and specific surface area. Intercrystal pore,intergranular pore,intragranular pore,dissolved pore,and organic nano-pore,microfissure were observed and the organic nano-pore contributes significantly for gas adsorption. Taking TOC-diameter-brittleness as the evaluation index for reservoir porosity-permeability-brittle respectively,the reservoir classification evaluation scheme based on TOC-diameter-brittleness can evaluate the physical and economical property of reservoir effectively and conveniently.