Study of Fluid-Rock Interactions in Eogene Formation in Dongying Depression,Bohai Gulf Basin

Key words: 
• Dongying Depression /
• Eogene formation /
• pore-fluid /
• fluid-rock interaction /

Abstract: Fluid rock interactions in sedimentary basin plays an important role in changing characteristics of reservoir rocks and properties of pore fluid,and then affects accumulation and distribution of oil and gas in reservoir.This paper has analyzed formation temperature,pressure condition and the geochemical feature of pore fluid in Eogene,Dongying Depression,Bohai Gulf Basin.The systems of fluid dynamics have been divided.The fluid dynamics characteristics and its distribution feature in defferent system of fluid dynamics are discussed.Base on the analytical result of composition and structural feature of mineral in mudstone which sampling from 4 section of Shahejie Formation in typical well of Niuzhuang Sag,Dongying Depression.The environment medium condition (including salinity,pH value and Eh value)in rock diagenetic process and geochemical characteristics of the pore fluid in rock are supposed.According to the combination feature of the major mineral in mud rock stratum and sandstone layer and its distribution law on stratigraphic profile of typical oil field,fluid rock interaction process would also been divided three stages,which is similar to fluid pressure and chemical characteristics.This paper summarizes the basic characteristics of fluid rock interaction of different stage in Eogene reservoir,Dongying Depression.The physicochemical factors affecting rock fluid interaction have been discussed,which include formation temperature,pore fluid nature and underground fluid dynamics feature and unusual formation pressure tape and so on.Based on the discussion above,a general geological/geochemical model of fluid rock interaction is established.This research shows the distribution feature,the evolution law of diagenetic mineral,the environment and fashion of fluid rock interaction are all different in different fluid dynamics system,which is to say that the geological/geochemical model of fluid rock interaction are different in different fluid dynamics system.