Abstract:

Being controlled by Lanliao fault on the margin, Qianliyuan depression continues developing to provide the necessary foundation of the formation of deep basin gas accumulations. Well-developed hydrocarbon source rocks occur in Lower Tertiary in the depression, which has high evolution degree and abundant gas source.Tight sand reservoirs with low-porosity and low-permeability develop in the 3rd and 4th sub-members of the third members, Shahejie Formation,which are favorable for the formation of deep basin gas accumulations.Gas accumulations, characterized by “inverted gas and water”, anomalous high-pressure, long gas-bearing interval and low production,as well as unrelated with structure,etc.,have been discovered around Qianliyuan depression. Dongpu depression is a typical “fault-sag” type deep basin gas among the non-marine fault-depression basins, and the slope zone surrounding the depression will be favorable target for exploration in the future.

Key words: deep basin gas, inverted gas and water, tight reservoir, Qianliyuan depression