Analysis of Diagenetic Facies in Deep Secondary Denudation Zone of G Structure,Xihu Sag

The hydrocarbon exploration in deep zone of Xihu sag is facing great challenge in reservoir optimization and forecasting.How to find favorable reservoirs in extremely low porosity and permeability formation has become the key to the success of exploration.In this article,taking the deep secondary denudation zone in G structure as an example,the idea that diagenetic facies is determined by compaction and denudation in the study area has been put forward based on analysis on sedimentary evolution,detrital components,porosity and permeability characteristics.In addition,the internal structure,vertical evolution,and spacial distribution of secondary denudation zone were also discussed in this article.Moreover,deep understanding about the petroleum geological significance of deep acid secondary dissolution and the development conditions have been made,which not only provides a powerful evidence for understanding the geologic conditions for hydrocarbon accumulation in deep reservoirs in G structure,but also provides new ideas on the deep hydrocarbon exploration in the whole Xihu depression.