Study On Sedimentary Facies,Reservoir Characteristics And Main Controlling Factors Of Qixia Formation,Western Sichuan Basin

In this paper,many research results on the basis of the northern area Qixia group in west sichuan province as the research object,the comprehensive application of multiple related discipline knowledge,collecting and analyzing a large amount of data,in many different geology professional basic course for theoretical guidance,make full use of all kinds of outdoor exploration and indoor analysis testing data,Qixia group in western sichuan north main control factors of sedimentary facies,reservoir characteristics and development has carried on the system research,obtained the following results and understanding:1.The lithology of Qixia formation mainly consists of thick layer massive grayish-gray limestone,interbedded dolomite and dolomite limestone,containing siliceous tuberculosis and strips.There are foraminifera,brachiopods,flies,red-green algae,corals and other biological fossils.2.According to the characteristics of rock,paleontological composition,section structure identification of sedimentary facies marks,such as the western sichuan area north of the middle Permian Qixia group is divided into tidal flat,restricted platform,open platform,platform edge,such as the types of sedimentary facies,and analyzes its sub facies and microfacies research.3.The reservoir rocks of Qixia formation are mainly karst limestone,dolomite limestone,medium-coarse crystalline dolomite,etc.With the atmospheric fresh water-buried-table was born under the denudation and tectonic fracture,developed by mixing water-hydrothermal-burial dolomitization of formation of the grain(saddle,coarse grain and fine grain)dolomite,this kind of dolomite in the study area as the main reservoir rock types.The dolomite strata are mainly developed in the second section of Qixia formation in the longitudinal direction,and can be well tracked and compared in the northern area of western Sichuan.4.The development of Qixia formation reservoir is affected by many controlling factors,including sedimentary facies,diagenesis and structural fracture.Based on the existing oil and gas shows,physical parameters,diagenesis,favorable rock types,such as analysis,in the northwestern sichuan basin area Qixia group is the most favorable exploration zones,to have good physical property of thick dolomite im crumbs beach development zone,the general development chip raw beach zone are mainly in other areas,dolomitization is weak,mainly for the dissolution and tectonic fracture reconstruction of crumbs limestone reservoir.