Shale Distribution and Favorable Area for Shale Gas Accumulation of Turpan-kumul Basin, Northwest of China

Abstract

Based on analyzing the spatial distribution, thickness, total organic carbon content, degree of organic metamorphism of shale in Turpan-kumul Basin, predicting the formation of fractures and the capability of gas adsorbing with the consideration of mineral composition, and studying the conditions of shale gas accumulation by analyzing the distribution of cap rocks, the quality of reservoir and the data of gas surveying, to totally evaluate the shale quality and shale gas prospecting for exploration. 1) The shale of Carboniferous, middle to lower Permian, middle to upper Triassic and Jurassic of the basin are is in wide distribution areas and large thickness. The shale is high in total organic carbon, high thermal evolution and good organic matter. 2) The contents such as pyrite and clay minerals of the shale are high, which shows the high adsorption capacity of the shale. 3) The content of brittle minerals such as quartz is high, and it is easy to be affected by external force to form natural cracks and induced fracture network, which is beneficial to the shale gas occurrence freely. 4) There are good cap rocks in or around the layer of organic-rich mud shale of the Basin, which provides favorable conditions for controlling the accumulation and distribution of shale gas reservoirs. 5) The shale gas measurement results of the Triassic Xiaoqungou Group and the Permian Taodonggou Group are significant and the resource potential is huge. The shale within Taodonggou Group of middle to lower Permian and Xiaoquangou Group of middle to upper Triassic have bigger thickness, higher brittle mineral content, higher degree of thermal evolution, and preferable assemblage of cap rock, thus probably being the potential horizons of shale gas exploration. The Taodonggou Group of Tainan depression, the north of Taibei depression and the northwest of Tuokexun depression and Xiaoquangou Group shale of Sanpu depression are favorable areas for shale gas.

AAPG Datapages/Search and Discovery Article #90333©2018 AAPG Middle East Region, Shale Gas Evolution Symposium, Manama, Bahrain, December 11-13, 2018