川南观音场-瓦市地区须家河组六段储层特征及其控制因素

Reservoir characteristics and controlling factors of the 6th member of the Xujiahe Formation in the Guanyinchang-Washi region,southern Sichuan

通过对4条野外剖面、40口并岩心样品及84张薄片的观察和测井等资料的分析,对川南观音场-瓦市地区须六段的岩石学特征、孔隙类型、孔隙结构及孔渗特征等进行了深入研究。结果表明:川南地区须六段岩性主要为中-细粒长石岩屑砂岩和岩屑石英砂岩,孔隙度在6%～10%之间,平均孔隙度为7.3%。渗透率为0.03×10-3μm2～0.9×10-3μm2,平均渗透率为0.177×10-3μm2。储层属于典型的低孔低渗储层,储集空间主要为粒间孔和粒内溶孔。在平面上,储层物性受沉积相带的控制;在垂向上,随深度的增加,压实作用和胶结作用使物性急剧变差。绿泥石的环边胶结作用、长石的溶蚀作用对储层物性起建设性作用,构造作用极大地改善了储层的物性。

Abstract： The petrology, porosity, permeability and controlling factors are explored on the basis of the field investigation, core observation, microscopic examination and well logs from the 6th member of the Xujiahe Formation in the Guanyinchang-Washi region, southern Sichuan. The lithology in the study area mainly consists of medium- to fine-grained feldspathic litharenite and lithic quartz sandstone, with the porosity ranging between 6% and 10% and an average of 7.3%, and with the permeability ranging between 0.03 x 10^-3μm^2and O. 9 x10^-3μm^2and an average of 0. 177 x 10^-3μm^2The reservoirs cited above belong to the typical low-porosity and low- permeability reservoirs with intergranular and intragranular solution openings. In a planar view, the physical properties of the reservoirs tend to be controlled by sedimentary facies, and vertically, they become sharply poorer due to compaction and cementation with the increase of depths. On the whole, the physical properties of the reservoirs tend to be improved by the rim cementation of chlorite, dissolution of feldspar and tectonism in the study area.