Pesented by Dr. Yong Li, China University of Mining and Technology
The Ordos Basin, China's second-largest sedimentary basin, boasts widespread resources in an area of 370, 000km2. It contributes most to the reserves of natural gas, coalbed methane (CBM), and coal already proven in China, accounting for nearly 6%, 13%, and 20%, respectively. Ordos Basin contains about 11 trillion m3 natural gas and 19 trillion m3 CBM. Upper Paleozoic sequence is an independent petroleum system separated from the Mesozoic and the lower Paleozoic strata. In this petroleum system, the source rocks are widely distributed coals and dark mudstones occurring in the Carboniferous–lower Permian coal measures. Continuous hydrocarbon accumulation units were identified within the Upper Paleozoic, including the Permian Taiyuan, Shanxi and Xiashihezi formations with great tight gas potential, and the Taiyuan and Shanxi formations also containing shale gas and coalbed methane. To clearly know the super gas bearing section, a few main questions require answers: (1) the capability of gas supplement from shale, and if there is development potential of the widely deposited transitional shales; (2) the temporal and spatial evolution of hydrocarbon accumulations in the vast area (500 km length); and (3) the accumulation mechanism of different types of natural gases, and if there is any favorable strata combinations.