Geochemical Characterization Of The Heavy Oils From Caoqiao Oilfield And West Slope Of Songliao Basin

Caoqiao oilfield and west slope of Songliao basin have rich resources of heavy oil,the formation of heavy oil related to the secondary action of crude oil,the secondary action including biodegradation migration,fractionation migmatization and water washing,biodegradation is the main influencing,the secondary action make the viscosity of crude oil increased and lead to the fluidity decreased,all of it make crude oil difficult to develop.In this paper,based on geochemical method,44 oil sand extracts from Caoqiao oilfiled and 23 oil sand extracts from Daqing oilfiled have been analysis,including crude oil group composition separation,gas chromatographic-mass spectrometry analysis of saturated hydrocarbon and aromatic hydrocarbon,combined with physical property the article discussed the impacts of biodegradation,investigating the characteristics of molecular geochemistry of heavy oil from Caoqiao oilfield and Songliao basin.The impacts of biodegradation on the physical property and component of oil have been studied,which geochemistry characteristics show: base lines are in bumps,n-alkanes are depleted,a large amount of 25-norhopanes exist,the number of triaromatic steroids and pregnanes is relatively high.These characteristics show crude oil experienced biodegradation.The paper mainly studies the effect of biodegradation on various molecular compound of crude oil,evaluates the effect of biodegradation on different reservoir with various geochemistry indicators.The heterogeneity of reservoir is very important to exploration engineering and oilfield development,the physical properties of reservoir is always good of heavy oil reservoir except for viscosity,in conventional reservoir the physical properties of reservoir control the viscosity of fluid,so study on reservoir fluid heterogeneity having important significance to develop heavy oil reservoir.In this paper,through calculation ratio of different sensitive compounds and making a fitting to viscosity then getting a fitting relation,using this relation to forecast viscosity of heavy oil reservoir,it is important to forecast viscosity of Caoqiao oilfield and Songliao basin.Through research geochemical characteristic and fluid heterogeneity provide evidence for exploration of heavy oli of Caoqiao oilfield and Songliao basin.