Study On Sedimentary And Reservoir Characteristics Of Chang6Formation In Xinanbian Area

Chang6Formation of Yanchang Group is one of the main development layers inXinanbian area, currently Chang6Formation is not exploitation completely, thus thedevelopment of which is significant to the production increasing of target area. Based onrelevant documents and data of core and well logging, aiming at C’hang6Formation of targetarea, this paper studies on the formation characteristics of sedimentary, petrology, porestructure, physical properties and heterogeneity in order to obtain comprehensive andsystematic knowledge of sedimentary and reservoir characteristics of Chang6Formation.Under the restriction of K4and K2marker layers which develops well in target area, thispaper gives a detailed stratigraphic division and correlation of Chang6Formation based on theprinciple of sedimentary cycle correlation, also establishes stratigraphic correlation profiles.Chang6Formation can be subdivided into Chang6|, Chang62and Chang63. According to thecharacteristics of petrology, structure and paleontology, this paper studies on the sedimentaryfacies and sedimentary system of Chang6Formation in target area. The result shows that: thesedimentary facics of Chang6Formation is meandering river del la front, and the microfacicsinclude underwater distributary channel, interdistributary bay and mouth bar. Based on thereservoir data of petrology，pore structure, properties, heterogeneity, and sensitivity, this paperalso researches on the reservoir characteristics of Chang6Formation, and the result shows:Chang6reservoir of target area is low-permeability, high-heterogeneity and weak-sensitivityreservoir, the result of reservoir evaluation shows that: reservoirs of type I and II have lesseracreages and better physical property, the micro facies of which are mainly underwaterdistributary channel and river mouth bar; type III reservoir has bad physical property, anddominates the region except type I and II areas, the micro facies of which is mainlyinterdistributary bay. Reservoir physical property is dominated by both sedimentary anddiagenesis, and the target formation of researched area has bad physical property. The study onthe sedimentary and reservoir characteristics of Chang6Formation in this paper providesreasonable geological basis for further exploitation.