Overpressure Formation Mechanism in Xihu Depression of the East China Sea Shelf Basin
Duan Modong
Ye Jiaren
Wu Jingfu
Shan Chao
Lei Chuang
Abstract：Overpressure is widely developed in Xihu depression,which has complicated formation mechanism.However,there is no in-depth study on this topic at present.In this paper,starting from the main factors that produce overpressure,we use both the micro analysis and macro evidence to comprehensively analyze the mudstone overpressure formation mechanism in the Xihu depression of the East China sea shelf basin,based on the logging response characteristics of overpressure formation,as well as the relationship between speed and vertical effective stress,the relationship between the evolution history of deposition and porosity,the coupling of pressure evolution history and that of hydrocarbon-generated rate.It is concluded that overpressure formation in Baochu slope belt is mainly attributed to under-compaction,and its hydrocarbon generation contribution rate is estimated at 23％-57％ with an average of 41％.In the central anticlinal belt,overpressure formation mainly has the following two models:one is the model of hydrocarbon generation with a contribution rate of 51％-78％,and the other is the model of under-compaction interaction.Both the hydrocarbon generation and under-compaction have played an important role in the overpressure formation in Santan sag and the average contribution rate of hydrocarbon generation is about 60％.
Keywords：formation mechanismmudstone overpressureXihu depressionpetroleum geology
Publication Date：2017-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：11( 119-129 )