Divisio Of Beier Depression Petroleum Systems

In this text we do researches in stratigraphic sequence、deposit feature、source bed、reservoir bed and capping formation of Beier Depression, combined geology survey and structural evolution process by the use of sedimentology, structural geology, petroleum geology, geochemistry and other theories as the guide, We believe Beier Depression main hydrocarbon source rocks in the main longitudinal group, secondery is Budate swarm and the important oil generation zone is sub-sag in Beixi.Longitudinal group, Damoguaihe group and Budate swarm are the main oil and gas province. Nantun2 group, South Sec reservoirs and Yinmin group are the main longitudinal group。The characteristics of the oil and gas accumulate control is:(1) The source rocks control the distribution of oil deposit.The main oil generation area is sub-sag in Beixi, forming four oil area around it.(2) The good condition of source bed、reservoir bed and capping formation control the formation of oil and gas accumulation。(3) Turbidite fan, delta fan and alluvial fan are enabling environment for hydrocarbon accumulation。They are always in deep subsag or at the fringe, sand body directly contact with hydrocarbon source rock, it is favorable for migration and accumulation of oil and gas, and they are the main reservoirs of oil and gas。(4) Hydrocarbon accumulation is in the control of development and formation of the effective traps。Beier depression develop many traps such as structure traps, strata traps, lithologic traps and compound traps, and these traps are formed more earlier than the main period of oil generation。(5) The reservoir is controlled by faults。The faults develop well in Beier depression, by analysis, the faults closed or not, the direction, fault throw, and the relationship between he fault and the thickness of the reservoir, are the major factors of oil and gas accumulation-Combined division trough theory and the result of oil source contrast, progress hydrocarbon system division according to the following principle:(1) Take oil-accumulation unit as the core, the migration pathway as the main line, and the source area as the boundary for oil and gas system division; (2) In the multiple oil and gas accumulation area where faults developed well, the hydrocarbon source rock distributes in the underlying formation and the oil gas mainly concentrates in different formation above the hydrocarbon source rock, so it is very difficult to divide oil and gas system clearly in longitudinal general. In general, take a migration and accumulation unit as a system。The result of hydrocarbon system division in this area is:Beier sag to Beixi depression for the oil source area, Sudeerte、Huoduomoer、Huhenuoren and Beixi slope are the oil and gas accumulation area belonged to petroleum system。And it can be further partitioned four petroleum systems:Sude erte, Huoduomoer、Huhenuoren and Beixi slope。...