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A Study On The Reservoir Characteristics And Dominated Factors Of Chang4+5Oil Layers Of Yanchang Formation In LongDong Area

Posted on:2014-02-12Degree:MasterType:Thesis
Country:ChinaCandidate:M T ChenFull Text:PDF
GTID:2230330398994019Subject:Geology
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Guided by sedimentology and reservoir geology theorys,this Master’s degreespaper takes the chang4+5oil-bearing Intervals of the Triassic Yanchang formation inLongDong area as research subject and discussed it from five aspects,Such as fieldprofiles, well core, log informations and sample tests. It focus on the combination ofmacro-observation and micro-analysis, qualitative description and quantitativelycompute, systematically arranged and comprehensive improvement, mainly studiedthe provenance analysis and parent rocks properties, sedimentary system, sand bodycharacters, governing factor of sand body development and reservoir characters ofexploration layers in the sudy area. Based on the above jobs, this paper made thefollowing results and understanding:This paper discusses its provenance characteristics from analyzing the clasticrock components characteristics, the heavy mineral features and ancient flowcharacteristics, then ensured that the provenance was from the northeast andsouthwest, followed by the south and southwest during the deposition of6thoil-bearing member of Yanchang Formation.The types of developed sedimentary facies in this area include Lacustrine deltaicand lacustrine deposits.Among them, the underwater distributary channel sand bodiesare not developed in chang4+52sedimentary period,only partially extends to the lakein the short distance.In addition to developing a shallow lake sand bar and distal bar.The distribution range of sand body confluence and continuity was more in chang4+51sedimentary period than it was in chang4+52sedimentary period,as well as theprogradation of rivers, all of the above makes it more beneficial for the reservoirsands.Deeply studies on the reservoir characteristics and diagenesis combined with thethin-section analysis, scanning electron microscope materials, mercury penetrationand physical property analysis materials,and the result of the studies indicates:The rock types of Chang4+5in this region are mostly feldspar lithic sandstoneand lithic feldspar sandstone,next are arkose and litharenite. Cuttings types are metamorphic lithic based. The pore types include residual intergranular pore,intergranular dissolved pore.The reservoir also features in low displacement pressure,low median capillary pressure, and medium pore throa. Reservoirs are of goodphysical properties with mesopore and low permeability.Compaction, cementation, metasomatism and denudation are the dominantdiagenesis in the study area. Combining the date the study area is roughly divided intochlorite films,carbonate cementation, illite cementation-feldspar dissolved hole,illite-siliceous cementation and kaolinite cementation-feldspar dissolved hole fivelapidofacies types.continue to the sedimentary environment and diagenesis, analyse the maincontrolling factors that favorable to the reservoir development, then concludes that thediagenesist is the key and the sedimentary environment is the basis. The quantity ofcements showed a negative correlation with the reservoir physical properties as awhole. The impacts of Diagenesis on reservoir properties are both destructive andconstructive, compaction and cementation are the main reasons for destroying primarypores, and dissolution is of great importance in reforming the reservoir physicalproperty.
Keywords/Search Tags:Ordos basin, LongDong area, Chang4+5, reservoir feature, main factor
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