关键词: 中国, 陆相盆地, 原油, 油气运移, 生物标记化合物, 珠江口盆地

Abstract: Based on the study of biomarkers,the oil from L-oil field located on Dongs-ha aplift of pearl River Mouth Basin in China Most of oils from the margins and the surrounding sags of this aplift have similar maturity,same terpenoid distribution,and contain high abundance of 4-methyl-C₃₀ sterane.These oils are derived from Eocene lacustrine source rocks of Wenchang formation in these sags.The migration parameters of L-oil are much larger than those of the oils discovered in the margins of this aplift,and the carbon isotopes of the saturated alkanes and the aromatics of the L-oil are also lighter than that of the others,these geochemical characteristics indicate that the L-oil underwent a long distance migration.Dongsha aplift is a long time paleo-uplift,having developed basal faults and fractures surrounding the aplift,having an extensive distribution of high porosity marine sandstone and bioherm limestone,and having stable thick regional capping beds.These special geological conditions make the oilstomigrate for a long distance and accumulate enormously in the highs of the basin and form the big L-oil field with a considerable amount of reserve.