A Study On Chang6Reservoir Evaluation In Wuqi Oilfield

The Wuqi area of Ordos basin, which possesses abundant resources, has bright prospect in oil and gas exploration. The article takes the four substratums in Wuqi oilfield, Chang611, Chang612,Chang621,Chang622, as the objects of study. By collecting data about outcrop, core, logging, analysis and test, etc., at the same time using sedimentary analysis and geological analysis, in the thesis, sequence division is applied. Types of sedimentary facies are identified, the extension of sand bodies, distribution of sedimentary facies of Chang6oil-bearing beds of Yanchang6Formation in Wuqi are realized by the research above. These characteristics, to find out the favorable target horizon reservoir of exploration and development of oil and gas reservoirs, provide important geological basis.The study shows, delta front facies is main sedimentary facies of the Chang6oil-bearing beds in Wuqi oilfield and the delta front submersed channel sand body as the skeleton of sand, sand cloth appears the direction of general body from the northeast to the southwest.Chang6of the reservoir rock type is main feldspathic fine-grained andstone, interstitial material is kinds of authigenic cement, lower matrix degree. The result indicates the characteristics of the reservoir petrology are lower mineral maturity and high structure maturity. Reservoir diagenetic stage is in the early stage of late diagenesis. Reservoir properties is poor, belonging to very low porosity and very low permeablity reservoir. Microfacies, diagenesis degree, pore structure type,which are the main factors that affect the reservoir properties.Oil-gas distribution is mainly affected by sedimentary facies, reservior properties and heterogeneity. Distributary channel underwater and mouth bar in Delta front are the main parts of the oil and gas migration and accumulation. The enrichment areas of oil and gas are predicted as follows:The advantaged areas in Chang6locate the strip from northeast to southwest in the centre of Wuqi oilfield, which is encircled by Xin8,Wu3,Wu410and Xin38.