Fine Evaluation Of Dense Oil Reservoir In Yanchang Ordos Basin

The Ordos Basin has abundant oil and gas reserve,and the existing exploration data shows that this area has special geological condition,which has very favorable condition for the formation of dense oil and enrichment.Though the development of dense oil reservoirs is still in the early stage nowadays,it is very important to study the development,and more and more attention be paid.The target layers of the study of dense oil reservoirs are mainly Chang 6,Chang 7,Chang 8,which have low porosity and low permeability.Comprehensive lithology,lithology assemblage,logging curve and other factors to extend the sedimentary microfacies in the western exploration area.Sedimentary facies studies have shown that the main developmental sedimentary facies are delta front subfacies,shore shallow lake subfacies,semi-deep lake subfacies and deep lake subfacies.The sand body in the area has an effective thickness,including underwater distributary channel sand body,front edge sand,beach dam,turbidite sand body and other reservoirs.Studying by many means,concluding core analysis,cast sheet,scanning electron microscopy and mercury intrusion experiments,macroscopic petrological characteristics and micro-physical properties of the reservoir can be knowned.Combined with modern computer quantitative calculation and numerical simulation,including Surfer,Grapher,DoubleFox and other professional and technical softwares,we can draw contour maps and digital simulation plane maps,and the establishment of lithology,physical properties(porosity,permeability),pore type and pore structure and other parameters can be get,and reservoirs classification and evaluation can be built.Then this can be kown,overall Chang 6 reservoir is the best,Chang 8 the second,and Chang 7 is the worst.