Accumulation Characteristics and Charging Process of Heterogeneous Mixed Reservoir in Bozhong 26-6 Buried Hill Oilfield,Bohai Bay Basin
Guan Dayong
Shi Wenlong
Zhao Dijiang
Zhang Xingqiang
An Junrui
Abstract：Bozhong 26-6 Oilfield is located in the west section of Bonan Low Uplift,Bozhong Depression,Bohai Bay Basin.It is an another buried hill oil field newly discovered in Bohai Sea area with 100 million ton reserves after the exploration breakthrough of Bozhong 19-6 buried hill condensate gas field,is also the largest oil and gas discovery in China's offshore waters in recent years.In response to solve unclear reservoir formation laws in the research area,especially the unclear source and accumulation process of oil and gas,this paper comprehensively uses the methods of crude oil physical property analysis,biomarkers,inclusion Petrography,homogenization temperature-paleosalinity and hydrocarbon generation simulation of source rocks,a systematic analysis was conducted,the results have shown that:(1)Bozhong 26-6 structure has different oil and gas sources,the characteristics of biomarker compounds indicate that crude oil mainly comes from the third member of the Shahejie Formation in the Huanghekou sag,however,condensate gas mainly comes from the third member of the Shahejie Formation in the southern subsag of the Bozhong Depression;(2)The Bozhong 26-6 oilfield has gone through three stages of oil and gas injection:early normal mature crude oil,middle condensate oil and gas(natural gas),and late light oil,The large scale of fluid filling in the middle and late stages plays a decisive role in the formation of reservoirs in the Bozhong 26-6 oilfield;(3)There are differences in hydrocarbon generation evolution between the source rocks in the Small sub depression in the southern part of Bozhong Depression and the Huanghekou Depression,and the contact relationship between the source rocks and the Bozhong 26-6 buried hill is different.therefore,this leads to differences in reservoir formation patterns and fluid phase states between different blocks in Bozhong 26-6.The above understanding and inspiration are of great significance for enriching the rules of buried hill oil and gas accumulation and guiding oil and gas exploration.
Keywords：Bozhong 26-6buried hill oil-gas reserviormixed accumulationreservoir characteristicsfilling processpetroleum geology
Publication Date：2025-02-14
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：16( 478-493 )