Abstract:

 Shale gas is the natural gas existing in mudstone/shale or their interlayers, being adsorbed or free. The Eastern Region of Liaohe Depression consists of the Eastern Sag and Eastern Uplift and it is a typical transformation superimposed basin which had undergone the stages of the base and land mass formation, of the floor development, of the rift development and of the depression development. The Eastern Region is not only rich in conventional oil and gas but also in unconventional oil and gas because of having deposited multiple sets of hydrocarbon source rocks. Now, to some extent, it has made some important progress in the exploration of shale gas. Basically, the three main sets of shale formations in the Eastern Region of Liaohe Depression meet the demands of shale gas accumulation: favorable conditions of hydrocarbon generation, a certain thickness, and abundance of organic matter. Shale in the Eastern Region of Liaohe Depression has favorable conditions of gas accumulation, and at the same time, a huge number of micropores and microfractures and high fragile mineral content make it conducive to the postfracturing. By studying and analyzing a large number of data, the shale gas in the Paleogene is mainly composed of free gas, while adsorbed gas accounts for a large amount of shale gas in Eastern Uplift whose condition of structure preservation can be slightly loose. The Eastern Sag has lower maturity and better preservation conditions in the Paleogene and free gas accounts for more in its shale; meanwhile, there are shale gas and shale oil symbiosis in shale formations. There are some favorable areas for shale gas exploration, such as Well Jie3 area, Qinglongtai area, Taoyuan area, Huangyure area in the Eastern Region, and Well Tong3, south of Well Wangcan1 are good choice for shale gas exploration currently.

Key words: shale gas, shale gas accumulation conditions, prospective, Eastern Region of Liaohe Depression