Reservoir characteristics and controlling factors of Jurassic Yan 10 Member sandy braided river of M34 Block,Ordos Basin
In order to clarify the characteristics and controlling factors of sandy braided fluvial reservoir of Yan 10 Member in M34 Block,Ordos Basin.The data of core,thin section,scanning electron mi-croscopy and reservoir physical properties were used to discuss the macro and micro reservoir character-istics,diagenesis evolution and controlling factors,as well as predict the favorable reservoir distribu-tion.The results show that the reservoir rock types of Yan 10 Member are abundant,mainly include feldspathic quartz sandstone and lithic quartz sandstone,and the sandstones have good textural maturity and component maturity,the reservoir space is mainly composed of intergranular pores,dissolution pores intercrystal pores and microscope.The pore structure can be divided into three types:mid-pore and mid-throat,small pore and fine throat,fine pore and micro-fine throat.The reservoir physical prop-erties are poor,characterized by low porosity and low permeability as a whole,as well as a relative good correlation between porosity and permeability.The diagenesis mainly includes compaction,cementa-tion,dissolution and metasomatism,the Yan 10 Member is currently in the stage A2 of mesodiagenesis,the porosity decreased to 11.20％-16.30％after multi-stage diagenesis evolution.The high quality reser-voir is controlled by lithologic,sedimentation,diagenesis and tectonism,lithologic is the fundamental conditions for the formation of the high-quality reservoir.The fine sandstones rich in quartz and feldspar have the best physical properties.The sedimentation is the material basis of high-quality reservoir,the physical properties of the main channel and mid-channel bar sandbodies are the best.The compaction and cementation have destructive effects on reservoir physical property,and the compaction is the main factor in making the properties of reservoirs poor.The dissolution can help the forming of secondary pores,improve the physical property of reservoir.Structure fractures are important supplement to form favorable reservoir spaces,which can further improve the physical properties of the reservoir.The fa-vorable reservoir can be divided into three types:Ⅰ,Ⅱ and Ⅲ,the type Ⅰ could be act as the favorable reservoir zones for the future exploration,such as M30-6X,M34-2,M30-4 areas.The results are signif-icant for the next exploration deployment of the research area.
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