Reservoir Characteristics and Controlling Factors of the Metamorphic Buried Hill of Bozhong Sag, Bohai Bay Basin

• Published in: Journal of earth science (Wuhan, China) Vol. 32; no. 4; pp. 919 - 926
• Main Authors: Xue, Yong’an, Zhao, Meng, Liu, Xiaojian
• Format: Journal Article
• Language: English
• Published: Wuhan China University of Geosciences 01.08.2021; Springer Nature B.V; China National Offshore Oil Corporation,Tianjin Branch,Tianjin 300459,China
• Subjects: Biogeosciences; Buried structures; Cores; Earth and Environmental Science; Earth Sciences; Fractures; Geochemistry; Geology; Geotechnical Engineering & Applied Earth Sciences; Gneiss; Granite; Lithology; Reservoirs; Sag; Tectonics; Weathering; Bohai Bay Basin; metamorphic rocks; buried hill; Bozhong sag
• ISSN: 1674-487X; 1867-111X
• DOI: 10.1007/s12583-021-1415-1

The burial depth of the metamorphic buried hill of the Bozhong sag is more than 4 500 m, however, the controlling factors of the reservoirs are not clear. Based on cores and sidewall cores obtained from 15 wells, this paper describes the reservoir characteristics and discussed their controlling factors. The metamorphic basement of the Bozhong sag consists of metamorphic granite, migmatitic granite and gneiss. These felsic rocks are more likely to develop fractures, thereby improving the reservoir properties. The Indosinian, Yanshanian and Himalayan tectonic events greatly reformed the Bozhong 19-6 metamorphic buried hill, forming a large scale fracture system. Weathering and deep thermal fluid contributed to the development of dissolved pores of the reservoirs. In general, controlled by lithology, tectonics, weathering and deep thermal fluid, the reservoir pattern of the metamorphic buried hill of the Bozhong 19-6 structure was established.