Font Size: a A A

Accumulation History And Formation Mechanism Of Petroleum Pools In Wenchang A Sag, Western Pearl River Mouth Basin

Posted on:2008-06-30Degree:DoctorType:Dissertation
Country:ChinaCandidate:H J GanFull Text:PDF
GTID:1100360215450799Subject:Institute of Geochemistry
Abstract/Summary:PDF Full Text Request
The paper preformed high temperature and high pressure pyrolysis experiments on the source rock with closed system in Wenchang A sag, and studied the kinetic of hydrocarbon generation and gaseous carbon isotopic fractionation based on the data of pyrolysis components and gaseous carbon isotopic value. Taking WC9-2 condensate gas pool in the centre of the sag and WC10-3 oil and gas pool nearby the southern boundary fault for example, coupled with fluid inclusion data and PVT model, the paper investigated the stages and time of oil charge in the pools. The source of oil and gas in the pools were also distinguished by GC-MS analysis and kinetic of carbon isotopic fractionation. Based on the study above, Combined with the structural model, the paper analyzed the spatio-temporal relationship between the trap and oil generation and charge, and concluded the formation mechanism of petroleum pool in Wenchang A sag. The main conclusions and achievements are listed below.1. Hydrocarbon was generated early, which keeps very long. The source rock around WC9-2 condensate gas pool enters into oil and gas generation threshold at 30Ma and 22Ma respectively; and the source rock around the WC10-3 oil and gas pool reaches oil and gas generation threshold at 23Ma and 16Ma respectively. There are two main hydrocarbon generation stages at different structural zone in the sag.2. Two stages of oil charge were found and oil charge time was different in different parts of the sag. The oil charge time is 17.8-17.5Ma and 14.8-11Ma respectively in WC9-2 oil and gas pool, and the oil charge time was 18.5-18.3 and 15-8.3Ma respectively in WC10-3 oil and gas pool.3. The source of oil and gas was different between WC9-2 and WC10-3 oil and gas pool. The origin of oil and gas in WC9-2 oil and gas pool are both from the source rock in Enping formation, and oil in WC10-3 oil and gas pool is not only from Enping formation but also from Wenchang formation, but the gas mainly originated from Wenchang formation.4. The formation of petroleum pool is controlled not only by time of hydrocarbon generation, but also by the shaped time of traps. Only the trap forms before the end of hydrocarbon generation in Wenchang formation can capture the oil and gas from it, but most discovered traps shape later than that, so the oil and gas in the pool is mainly from the source rock in Enping formation.All the conclusions and achievements are important guidances on petreoleum evaluation and prospecting in Wenchang A sag.
Keywords/Search Tags:Wenchang A sag, Kinetics, Petroleum accumulation history, Source of oil and gas, Formation pattern of petroleum pool
PDF Full Text Request
Related items