Oil Enrichment Regularity Of Chang2Oil-bearing In Yujiaping Area Of Zichang Oil Field

Ordos basin is in the north of Shaanbei Slope, which is rich in Mesozoic Petroleum. Based on research and observation of the outcrops and the cores, date of this area such as costing thin sections, SEM (scanning electron microscopy), physical property, size analysis, porosity image, well logging and oil testing was comprehensively used in this paper. With methods and theories of stratigraphy, Sedimentology reservoir geology, logging geology and petroleum gelogy, the stratum of Chang2Formation was divided and sublayers were compared; Analysis of the sedimentary facies and sand body distribution characteristics.According to the traditional division method, this paper divided Chang2Fonnation into Chang2-, Chang22, Chang23using main and auxiliary symbol layer of this region, cyclical control and depth reference methods to make strata correlation.Through the sedimentary characteristics of studying regin, this paper belives that the Chang2is river sedimentary facies, Chang22and Chang23develop braided river deposit, Chang2’mainly develops meandering river deposit. River channel sand dam is main sand body, which development is controlled by sedimentary facies and the channel sand zonal distributes from eastnorth to weatsouth.Data analysis such as costing thin sections, mercury and phycury and physical property shows that the reservoir character of Chang2Formation in the target area is with low compositional maturity and high structure maturity. Porosity types are intergranular pore and emposieu, the structure of porosity is mesoporous and thin throat, the reservoirs mainly in low permeability (II type). Reservoir character is apparently controlled by sedimentary facies, diagenesis followed.On above, the oil enrichment regularity of Chang2Formation (oil-bearing) in the north of Shaanbei Slope was summarized.