In Partial Fulfilment Of Requirements For Admittance To The Degree Of Doctor Of Philosophy

In this dissertation, hydrocarbons in reservoir rocks have been classified as "free oils","absorbed oils" and "oil-bearing fluid inclusions". The "absorbed oils" include thoseadsorbed by minerals and asphaltene networks. In order to obtain all these types of oilcomponents, a practicaI approach of sequential extraction has been developed and carriedout on reservoir rocks, such as sandstone, volcanic and carbonate reservoir rocks. Thevariant types of oil components extracted separately from a same reservoir rock samplewere fractionated to obtain aliphatic fractions which were further analyzed by GC andGC-MS. The geochemical behavior and significance of every type oil components hasbeen discussed in details based on molecular parameters.Molecular correlation indicates that striking differences exist among different types of oilcomponents obtained from a same reservoir rock sampIe, reflecting compositionalvariations of oil chaiges into this reservoir during oil filling process. The results of thisstudy demonstrate that oil reservoirs in Shixi Oilfield and Mosowan Uplift of JunggarBasin and in Northern Tarim Uplift and Kuche Depression of Tarim Basin formed withseveraI oil charging episodes and were derived from multipIe source rocks. According tothe GC-MS analysis of adsorbed oils in asphaltene networks, the primary oilcompositions have been reconstructed and multiple oil charging episodes have been alsodemonstrated in Silurian tar sands from TZII Well. Based on the correlation of free oilcomponents and adsorbed oil components by asphaltene networks of two crude oilsamples collected from Linnan region of the Jiyang Depression, gross and molecularcolnpositional Fractionations caused by oil migration have been re-evaluated.