乐东—陵水凹陷梅山组海底扇储层物性与孔喉结构

Petrophysical Property and Pore-throat Structure of Submarine-fan Reservoirs in Meishan Formation, Ledong-Lingshui Sag

综合运用宏观物性、铸体薄片、扫描电镜、核磁共振、恒速压汞等技术手段,精细表征乐东—陵水凹陷不同类型海底扇储集空间、储集物性及微观孔喉结构,分析微观孔喉结构参数与储层物性间的相关关系。结果表明,研究区海底扇储层的储集空间主要以原生粒间孔和次生溶孔为主。孔喉结构主要为中—低孔微喉型,对渗透率起主要贡献的较大喉道比例小是该区低渗储层发育的主要原因。储层孔喉结构参数与储层孔隙度、渗透率、储层品质指数的相关性好,尤其与渗透率的相关性更为显著。分选差、粒度细、高泥质含量及较强压实作用是该区储层孔喉结构变差的主控因素。

Through analysis on macro petrophysical property, identification of casting thin-section, and some approaches of SEM,NMR, and constant-rate mercury injection, we implemented series researches on Ledong-Lingshui sag, containing(1) fine characterization on different submarine-fan reservoir space, petrophysical property, and micro pore-throat structure; and(2) analysis on the correlation between micro pore-throat structural parameters and petrophysical property. Results show that in this study area, reservoir space is dominated by primary intergranular pore and secondary dissolution pore; one type with medium to small pore and microthroat is the main pore-throat structure; a little bigger throat making major contribution to permeability is the main factor available for low-permeability reservoir development; the structural parameters have better correlation with porosity, permeability, quality index, especially obvious correlation with permeability; and poor sorting, fine grain size, higher shale content, and stronger compaction are the principal reasons making pore-throat structure worse.