Multiple hydrocarbon generation of marine strata and its tracer technique in China

China's marine strata are characterized by the old age,large time-space span,many types of hydrocarbon sources,etc.Most of the hydrocarbon sources are in the highly mature-overmature stage and experience multiple hydrocarbon generation conversion process,resulting in a number of difficulties on correlation study of oil and gas accumulation and oil and gas source.According to the characteristics of China's marine hydrocarbon source,the variety of hydrocarbon sources is divided into three major types: insoluble,soluble and acid-soluble organic matte in terms of solubility,and into original hydrocarbon source(rocks),regeneration hydrocarbon source and chemical hydrocarbon source in terms of forming process.Marine original hydrocarbon source organic matter has its unique microorganism combination and occurrence form.The simulation of hydrocarbon generation reveals the variation of hydrocarbon production rate for different types of hydrocarbon sources,in particular,production rate of different types of soluble organic matters(paleo-reservoir,dispersed soluble organic matter,and asphalt,etc.) is closely related to the original state.In view of complexity and evolution particularity of different hydrocarbon sources,the genetic relationship between secondary hydrocarbon source and kerogen in the hydrocarbon source rock is effectively revealed from biomarker compound,isotopic composition and trace element characteristics of different hydrocarbon sources.Tracer indicator technology is integrated by effective combination of material sources,critical time and accumulation process with the elements,biomarker compound,stable isotope and rare gas isotopes,and further develops organic-inorganic tracking system of oil and gas formation and accumulation in China's marine strata.