关键词: 物性特征, 粘土矿物, 黑色页岩, 龙马溪组, 鹿角剖面, 渝东南地区

Abstract:

In order to search after clay minerals of black shale and their effects on physical properties of shale gas reservoirs in the southeast of Chongqing, combination and distribution characteristic, formation mechanism and controlling factors of clay minerals and their effect on porosity and permeability are discussed in detail based on the knowledge of previous studies on clay minerals in petroliferous basins and taking Lujiao outcrop section in Pengshui County for example. Then it draws a conclusion that the combination of clay minerals in Lujiao section is I+C+I/S and the formation is controlled by palaeoenvironment and diagenesis which on one hand, the palaeosalinity is higher in the bottom and becomes lower in the up part, on the other hand, the black shale is in the B stage of late diagenesis. It has been discovered that type, quantity and distribution character of clay minerals are closely related to porosity and permeability of shale gas reservoirs. Exactly speaking, the growth of illite in the diagenesis can increase the porosity in some extent but will lose some permeability; chlorite has a positive correlation with porosity and permeability, which may be resulted from the detrital feldspars.

Key words: physical property, clay mineral, black shale, Longmaxi Formation, Lujiao section；southeast of Chongqing