渝东北下寒武统页岩气储层特征研究

The Research on Reservoir Characteristics of Lower Cambrian Shale Gas in Northeast Chongqing

渝东北地区位于扬子克拉通北缘的大巴山弧形构造带,为多期构造叠加所形成的冲断褶皱带。该区内下寒武统为一套广海陆棚相沉积,发育富有机质的黑色碳质、硅质泥页岩,该套页岩气目的层具有多种类型储集空间,通过对区域58个样品点统计显示,孔隙直径分布于3.1~5.6nm,BET比表面积平均为8.26m^2/g,为典型低孔低渗特征储层,暗色泥页岩矿物成分以石英、长石等脆性矿物为主,黏土矿物次之,碳酸盐岩矿物普遍偏低,具有较好页岩气吸附能力及含气显示,是该区内页岩气勘探评价的主要层系位。

The Dabashan arcuate tectonic belt in Northeast Chongqing is located at the northern margin of the Yangtze Craton,which is a thrust belt formed by the multi stage superposition. In the area, the Lower Cambrian is a set of open marine shelf sediments, where developed the organic carbon black and siliceous shale. The set of shale gas has various types of reservoir space, their pore diameters are 3 1~5 6 nm, their BET specific surface area is 8 26 m2/g, which is typical low porosity and low permeability. The dark shale is mainly composed of quartz and feldspar, and the clay minerals take second place, and the carbonate minerals are generally low. This set of reservoir has a good capacity of shale gas adsorption and gas bearing shows, which an important layer for the exploration and evaluation of shale gas in this region.