Abstract:

In order to evaluate and recognize the exploration potential of fault depressions except for the middle part fault depression where had a great breakthrough,the geological and geochemical data from the risk exploration well-Longshen 1, qualitative appraisement and quantitative calculation method are used to study gas source conditions and the exploration potential of Yingtai fault depression. This research indicates that dark mudstones of K₁yc and K₁sh layers are relatively development and the residual organic carbon content is relatively higher, and the organic matter is mainly at high-to over-mature evolution stage, especially with type Ⅱ₁ and Ⅱ₂ organic matter which have a higher gas generation potential, other than the type III organic matter accepted by predecessor. All above evidence hints there is a better exploration potential in deep fault depression. Meanwhile, the original carbon content and hydrocarbon potential of organic matter are much higher than present values, which indicate the signification of restitution for the objective appraisement of high-over-mature source rock. Quantitative appraisement preliminarily reveals that the gas resource of Yingtai fault depression is ranger from 93.8 to 375.8 billion cubic meters, where has a gas source condition for forming medium to large-sized gas fields or groups. It also means that some fault depressions have important and exploratory exploration potential, besides Xujiaweizi and Changling fault depression.

Key words: Yingtai fault depression, gas source conditions, exploration potential, original abundance of organic carbon, original hydrocarbon potential