Reservoir Characteristics And Favorable Areas Prediction Of Chang 6 Oil Reservoirs In Yanchi Region,Jiyuan Oilfield

The development degree of Chang 6 oil reservoirs in Yanchi area,Jiyuan oilfield is relatively low and lacks comprehensive and systematic research.In order to improve geological understanding,under the guidance of sedimentology,petroleum geology and logging interpretation,the reservoir characteristics and main controlling factors for reservoir formation of Chang 6 oil reservoirs in Yanchi area are discussed in depth by means of many analytical and testing methods,such as common thin section,casting film,scanning electron microscopy and mercury injection,and the favorable target area is finally delineated.Reservoir petrological research shows that the rock types of Chang 6 oil reservoirs in Yanchi area,Jiyuan oilfield are mainly feldspathic sandstone and lithic feldspathic sandstone.Chang 6 oil reservoirs is in the middle diagenetic stage A.The influence of diagenesis on reservoir quality has two sides,while most diagenesis reduce reservoir quality.The average porosity and permeability of the reservoir are 10.05%and 0.45 m D,which belong to the low porosity and ultra-low permeability reservoir.but reservoir quality has been improved by relatively developed fractures in some blocks.On the basis of previous geological research,Chang 6 oil reservoirs in Yanchi area,Jiyuan oilfield is comprehensively evaluated according to the indexes of sandstone thickness,porosity,permeability,fracture density,etc.The evaluation result shows that Chang 62~2and Chang 62~1 substratums have better reservoirs.Structure plays a role in oil and gas accumulation.The monoclinal background lays the foundation for lithologic reservoirs.Local nose-shaped uplifts become favorable zones for oil and gas accumulation.Finally,according to sedimentary,structural and reservoir characteristics,68 favorable areas for prediction and 26 favorable areas for production are delineated to provide reserves guarantee for capacity construction.