Abstract:
Recent studies have shown that the black shale in Dawuba Formation of Lower Carboniferous is widely distributed in southern Guizhou Province. The formation with black shale has become an objective layer of shale gas exploration in this area. In this study, the black shale samples in Dawuba Formation of Daiye-1 well are analyzed to obtain some crucial parameters of shale gas and evaluate exploration potential. The results show that, firstly, the sedimentary environment of Dawuba Formation is mainly deep sea shelf and the thickness of black shale is 80 m;secondly, kerogen maceral is mainly sapropelinite, exinite and vitrinite. The kerogen type of Dawuba Formation is dominated by type Ⅰ to type Ⅲ. The TOC content of black shale in Dawuba Formation is 1.5%-3.3% and the
Ro ranges from 2.15% to 2.66%; thirdly, quartz and clay minerals are the dominant minerals in the black shale, and the content of brittle minerals (calcites not contained) ranges from 35% to 64%; finally, the shale gas content of field measurement is between 0.49 m
3/t and 4.97m
3/t with the average value of 2.20 m
3/t. Meanwhile, the Dawuba Formation with great thickness has good gas content, organic geochemical index and reservoir potentiality by field investigation and laboratory tests. Furthermore, the black shale of Dawuba formation has good exploration prospects, so it is significant to further investigate the basic geology, shale reservoir exploitation and shale gas regularity.