Font Size: a A A

Deep Gas Accumulation Formation Mechanism In Dongpu Depression

Posted on:2008-07-19Degree:DoctorType:Dissertation
Country:ChinaCandidate:Z H ChangFull Text:PDF
GTID:1100360245499590Subject:Geological Resources and Geological Engineering
Abstract/Summary:PDF Full Text Request
Based on exploration practice, hydrocarbon evolution of source rock and gas source correlation, taking dynamic process of reservoir formation for special gas field, together with applying reservoir formation theory of natural gas, inclusion analysis of fluids with high accuracy, natural gas genesis recognition, autogenic illite age dating, this paper has studied gas reservoir formation mechanism and analyzed principle factors controlling gas reservoir formation.Integrative applying of vitrinite reflectance and interval transit time method recovered denuded thickness of late Dongying formation of Baleaogene.By burial history and integrative thermal history simulation, thermal evolution and hydrocarbon generation of upper Paleozoic and Baleaogene source rock has been recovered in Dongpu depression. Study shows denudation of late Dongying formation is characteristic: thickness decreases along uplift-slope-center depression.As all the basin subsided and varying degrees sedimentary compensation since Eogene, source rock intake secondary oil generation. So source rock burial and hydrocarbon generation evolution of Baleaogene in Dongpu depression are of time space subsection and hydrocarbon generation peak is obviously of time space difference.Using components of natural gas, carbon and hydrogen isotope and inert gases isotope, air source correlation for natural gas has been carried out. Natural gas in Dongpu depression can be classified into coal bed gas, oil bed gas and mixed gas by its genesis. Coal bed gas mainly accumulates in the trap developed early in central uplift; condensate gas reservoir mainly surrounds 3 principle gas generation center including Pucheng-Qianliyuan sub-depression, Gegangji sub-depression and Liutun-Haitongji sub-depression; while mixed condensate gas reservoir are near the faults through the basement.Coal bed gas derived from kerogen cracking of source rock, main migrating in dissociated phase. Abnormal high pressure in the source rock is the main drive for gas accumulation and migration. Migration Pathways give priority to fractures,reservoir formating in denudation phase from Es1 to Ed. In the process of DongYing tectogenesis,gas dissipated when it's infusing, dynamic reservoir formatting is one serises infusing.Deep condensate gas involves primary type,crude oil cracking type, gas cutting enrichment type, inverse evaporation type and mixed type. Abnormal high pressure in the source rock liquid is the main original drive for oil and gas accumulation and migration, give priority to sand body migration Pathways and surrounding distributing, dividing into three reservoir formation:Es1-Ed, the time of DongYing tectogenesis and 7-5Ma since Neocene.There are mainly 3 factors controlling coal bed gas reservoir formation comprising of effective source rock, transport system and cap rock, among which gas generation center controls gas reservoir distribution, transport system constrains gas accumulation and migration and cap rock limits vertical enrichment of the gas. It is summed up that principle factors controlling condensate gas reservoir formation includes source rock, reservoir formation time, transport system and cap rock. Parent material of source rock controls condensate gas enrichment. Deep burial and late reservoir formation are favorable for development and preservation of deep condensate gas. Transport system controls condensate gas accumulation, migration and accumulation and cap rock controls vertical enrichment of natural gas.
Keywords/Search Tags:natural gas, transport system, formation mechanism, dominant control factors, Dongpu depression
PDF Full Text Request
Related items