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Hydrocarbon Accumulation Of The Deep Reservoir In Huimin Depression

Posted on:2009-01-22Degree:DoctorType:Dissertation
Country:ChinaCandidate:Z C YangFull Text:PDF
GTID:1100360245987536Subject:Marine Geology
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Huimin depression is located in JiYang depression.It is a half-graben depression by faulting in the north and overlaping in the south.It is bounded by the Chengning High in the north,Luxi High in the south,Dongying depression in the east and Linqing depression in the west.Since there have been lack of detailed research on petroleum generation and accumulation patterns of the depression for a long period, there is now no a clear idea for its potential and further exploration.The article based on the petroleum geology,geochemistry,and geophysics to discuss the hydrocarbon accumulation and occurrence of the deep zone.The beach bar of the Es4s member developed in the central uplift belt.The fan deltas of the Es4s member developed at the edge of Yangxin sag.Deltaic deposition occurred in Zizhen sag,the south slope and the south of the Yucheng zone.The braided river of the Es4x member developed in the south slope and fan deltas of the Es4x member developed at the border of Yangxin sag.The source rock of the fourth member of Shahejie Formation in YangXin sag is the deepest,which is 500m at depth.The source rock depth of Linnan sag could be 150m.There is abundant organic matter within the Es4s member of Linnan and Yangxin sag.The source rocks are moderate to good types.The petroleum potential of Yangxin sag is more than Linnan sag.The organic matter of Linnan sag is dominated byⅡkerogen type and secondly by kerogenⅢtype.The organic matter of Yangxin sag is dominated byⅠkerogen type and secondly by kerogen type.The dark mudstones of Zizhen sag were formed under weak reducing and fresh water environments.The source rocks developed in the reducing and fresh water environment.The salinity of Es4 member in Yangxin sag is very high,and its ratios of Gammacerane/C30 hopane is 0.8.The Es4 member of Linnan sag has low salinity and both lower hydrobiont and terrigenous higher plants inputs.The dark mudstone in the Huimin depression has high content of phenanthrene compound and the predominance of dibenzothiophen.There have been great differences in biomarker and carbon isotope for the oils from the deep zone.These oils can be divided into three family groups,Es3x type, mature Es4 type and immature Es4 type.The oils of the Es3x member have dominant algae inputs.The ratios of Pr/Ph for Es3x oils are more than 1.The parent material of Es3x oils were formed in weak reducing and fresh water environment.The ratios of Gammacerane/C30 hopane range from 0.04 to 0.14.The maturity parameters C29S/S+R range from 0.52~0.60.The oils of the Es3x have accessed the high mature phase.There are much content of tricyclic terpane in the Es3x member.The ratios of tricyclic terpane/pentacyclic terpane range from 0.69 to 1.23.The mature oils in Es4 member have abundant terrigenous higher plants and lower hydrobiont inputs.The ratios of Pr/Ph range from 0.53~1.23 and the content of tricyclic is lower.The maturity parameter C29S/S+R is over 0.4.The parameter of XX96,PS2,QX141,XX507,LS1,S52-2 is more than 0.5.It can indicate that the oils of Es4 member are over mature.The ratio of C29S/S+R for the immature oils is less than 1 and The ratios of Pr/Ph is less than 1.Source materials deposited in the reducing environment.The ratios of Gammacerane/C30 hopane are more than 0.1.The immature oils are rich in triaromatic steroid series.The immature oils often occur in the structural high,such as central uplift belt and the south slope.According to temperature histogram of oil-bearing inclusions,the accumulation phase of petroleum reservoirs in the south slope have been divided into two phases in combination with burial history curve,32Ma and 5Ma.The timing age is the Early Oligocene phase and the Miocene~Pliocene phase.During the Early Oligocene phase the source rocks reached mature.The reservoirs were charged by maure oils.The early filling oils experienced biodegradation.During the second phase,the mature oils and immature oils were injected into the adjacent reservoirs.The early filling oils and the late filling oils were commingled. The characteristic of the oils from the Kongdian formation and the oils from Es4 member are similar.It can indicate that the oils from the Kongdian formation came from Es4 member.The distribution of aromatic hydrocarbon in the Kongdian formation is alike the Es4 member.It is first that dibenzothiophene and nitrogen compounds are used to estimate the path of oil migration in the Huimin depression.The oils in Linnan sag migrated dominantly along the trend of fault.The hydrocarbon accumulation conditions are abundant petroleum resource,multiple source-reservoir-seal associations and favorable passage system.The model of hydrocarbon migration and accumulation has two models which include lateral migration sand control pattern and vertical migration fault control pattern.We analyzed six classical hydrocarbon accumulation model and forecasted four favorable prospect.
Keywords/Search Tags:Huimin depression, Paleogene, hydrocarbon accumulation, biomarker, source rock
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