准噶尔盆地车排子地区下侏罗统八道湾组沉积演化及有利区预测

Sedimentary facies analysis of the Lower Jurassic Badaowan Formation in Chepaizi Area,Junggar Basin

根据单井和连井相分析,以岩心分析、测井、钻井及地震资料为基础,研究准噶尔盆地车排子地区下侏罗统八道湾组沉积相类型及沉积演化过程;采用井—相控结合方法,分析沉积微相演化和平面展布特征。结果表明:八道湾组主要发育辫状河三角洲沉积体系,其中辫状河和辫状河三角洲是优势沉积相,辫状河三角洲平原比辫状河三角洲前缘物性好。结合沉积厚度、砂地比、连井剖面特征及沉积相平面展布特征,将研究区八道湾组自下而上划分为5个沉积发育时期(MSC1-1、MSC1-2、MSC2、MSC3-1及MSC3-2),不同沉积时期可容空间(A)和沉积物供应(S)相对变化不同,使古水深由浅到深再到浅,由辫状河相向湖泊和沼泽演化,整体呈现湖退—湖进—湖退沉积演化模式。Ⅰ类有利勘探区比Ⅱ类有利勘探区更易形成优质储层,红车断裂带附近斜坡区是有利勘探开发区,八道湾组煤系地层是有利勘探开发层位。该结果对研究准噶尔盆地车排子地区沉积演化过程具有指导意义。

In accordance with single well and company well analysis,on the basis of core analysis,well logging,drilling and seismic data,the types of sedimentary facies and sedimentary evolution of the Lower Jurassic Badaowan Formation in Chepaizi Area of Junggar Basin are investigated.The results show that the Badaowan Formation mainly develops braided river delta depositional systems,and the braided river and braided river delta are dominant sedimentary facies,then braided river delta plain is better than the braided river delta front.From the evidence that characteristics of sedimentary thickness,sand-land ratio,well-connected section and sedimentary facies distribution,the Badaowan Formation in the study area can be divided into five sedimentary periods(MSC1 1,MSC1 2,MSC2,MSC3 1 and MSC3 2)from bottom to top.The relative changes of accommodation space(A)and sediment supply(S)in different sedimentary periods make the paleo-water depth from bottom to top,from shallow to deep and then to shallow,from braided river facies to lake and swamp evolution,the overall present lake regression-lake transgression-lake regression sedimentary evolution model.With methods of well control and phase control,the evolution and plane distribution characteristics of sedimentary microfacies are explorated,so that the high-quality reservoir is easier to be formed in classⅠthan in classⅡfavorable exploration area.It is considered that the slope area near the Hongche Fault Zone is favorable for exploration zones,and the coal measures strata of Badaowan Formation are beneficial to exploration and production.