IMMATURE CRUDE OILS POSSIBLY MAINLY ORIGINATING FROM PRIMARY SOLUBLE ORGANIC MATTER-I. DIRECT EVIDENCES FROM SATURATED HYDROCARBONS

Immature crude oils were found in many places of the world,but their formation mechanism has not been understood clearly.There are now more than five viewpoints on the origin of them.In face,most of immature oils have similar characters,so it is very possible that they were mainly formed by similar ways.In this paper,the results of simulation experiments on Jianghan calcareous mudstone,Green River shale,Fushun oil shale and Nanning lignite samples(collected from cores or orefields)were reported.Under the condition of lower temperature,the saturated hydrocarbons formed by kerogen from these samples are similar to mature oils,and those formed by bulk samples(including kerogen and soluble organic matter)are very similar to immature oils.This proved that immature crude oils possibly are mainly converted directly from primary souble organic matter in sediments.