Shale and Gas Shale in China

Zhang, Jinchuan¹
 Fan, Tailiang²
 Yu, Bingsong³

¹School of Energy Resources, China University of Geosciences, Beijing, China.
²School of Energy Resources, China University of Geosciences, Beijing, China.
³School of Earth Sciences, China University of Geosciences, Beijing, China.

Abstract Unlike conventional ones, gas shale is a kind of unconventional natural gas with the concurrence of free gas and adsorbed gas in source rocks for gas. There are at least 2 kinds of gas generating source rocks in China, one of which is so called mudstone from the lacustrine basins in East China and another is called shale from marine and transitional basins in Middle and West China. Researches on shale gas develops quickly in China recently, many basins in North China and Palaeozoic Yangtz regions in South China are of favorable geological settings for shale gas according to the investigateion progresses on shale gas from the year 2000. Based on geology analysis, logging data, seismic interpretation and well performance testing, favourable basins and profitable regions with shale gas potential can be made out. There are at least 3 kinds of reginal shale gas models as Cenozoic-Mesozoic lacustrine mudstone represented by Bohaibay or Turpan-Hami basin, Mesozoic-Palaeozoic transitional shale represented by Ordos basin, and Palaeozoic marine shale represented by Sichuan basin, Among which the resources of shale gas in Paleozoic is the largest, while that in Mesozoic and Cenozoic groups decreased in turn. It is demonstrated that there exist favorable geological settings and evidences for regional distribution of shale gas in Yangtz area, Southern China, which has ever been taken as one of the most difficult areas for hydrocarbon exploration. It is primarily assessed that the resources of shale gas in China is about 20-30 tcm.