Reservoir Characteristic Study Of The Chang-3 Oil Group Of Yanchang Formation In Chenghua Area,Ordos Basin

In this thesis Erdos basin area Chenghua Chang 3 reservoir as the research object,the sedimentology and petroleum geology field of advanced theories and methods as a guide,the full use of drilling core observation,thin section identification,SEM analysis,the sedimentary facies,diagenesis and reservoir reservoir characteristics are deeply analyzedWe believe that through research and analysis of Chang 3 source of sediments from northeast and southwest of the ancient river,River Delta northeast was developed,mainly developed delta front deposition.Generally considered front sand bodies of the favorable facies is mainly underwater distributary channel and mouth bar,to control the thickness of sandbody controlled by sedimentary facies with that,the delta front distributary channel sandstone is the main reservoir sand body,obvious overlapping distribution.The thin section observation showed that reservoir in lithic arkose and lithic sandstone rock group is the main points to fine sandstone,well sorted,the main pore types are intergranular pore,feldspar dissolved pore and debris dissolved pore are common.The diagenesis of the study area were fine,the existence of the long-term and stable compaction(pressolution),cementation,dissolution and metasomatism in local area.In the process of pore evolution,compaction and cementation of carbonate rocks of the lower porosity,lower reservoir despite the dissolution ability.Can make the sandstone porosity increased,enhanced porosity and permeability of sandstone,but because the development of carbonate dissolution is limited,so to enhance the reservoir capacity.The study area is divided into diagenetic stage shows the area as a whole in the middle diagenetic stage A-B.The porosity and permeability data show that the main reservoir of study area is low porosity and low permeability reservoir.The porosity between between10%~12%,between the permeability between 0.1 * 10-3 um2 ~0.5 * 10-3 um2,porous medium.Mercury injection curves show that the length of the mercury 3characteristics for high slope approximation for platform type.For the low porosity and low permeability reservoir,relatively good prospects.A comprehensive study of the area of reservoir evaluation showed that the 33 main development of class II reservoir,chang 32,31 main development of class II and III reservoir,chang 33 reservoir quality is higher than the overall length of 32,31 for the further exploration and development of oil and gas supply the favorable target.