准噶尔盆地西北缘风城地区二叠系风城组沉积相研究

The Sedimentary Faceis Research of Fengcheng Formation of Permian in Fengcheng Area, the Northwestern Margin of Junggar Basin

近几年勘探表明,准噶尔盆地西北缘风城地区二叠系风城组具巨大勘探潜力,该组储层以云质类岩石为主。为查明该区风城组沉积环境、沉积微相的展布特征,通过岩心观察、薄片鉴定、测井和录井资料分析,对该区沉积相特征进行研究。结果表明,准噶尔盆地西北缘风城地区二叠系风城组主要发育云质岩类岩石,含少量砂岩类、泥岩类。通过沉积相研究,结合研究区的构造背景、气候特征和沉积环境,认为研究区物源主要有两个:西部F26井以西物源、北部FC011井以北物源。风城组沉积期,研究区主要发育半深湖亚相沉积,在靠近物源区发育扇三角洲前缘水下分流河道沉积物及席状砂沉积物。沉积体系研究表明,该区风城组云质岩类岩石主要形成于半封闭咸水湖湾沉积环境,沉积环境对储层物性有较明显的控制作用,并据此建立了研究区冲积扇-扇三角洲-湖泊相的沉积模式。

Recent years exploration shows that Fengcheng formation of Permian in the northwestern margin of Junggar basin has great potential for exploration. The main reservoir in this area is dolomitic reservoir. In order to find out the sed- imentary environment and sedimentary microfacies distribution characteristics, providing reference for oil and gas explo- ration, In this paper, by means of the core observation, identification of thin sections, the comprehensive analysis of data of well logging and logging, we studied the sedimentary facies. The results show that the research area mainly develops dolomitic rock, only a small amount of sandstone and mudstone are developed. Based on the sedimentary facies research, combining the tectonic background, climate characteristics and sedimentary environment of research region, two major provenances are proposed ： the west of western well F26 provenance and north of northern well FCOII provenance. Ill Fengcheng formation sedimentary periods, the study area mainly develops semi-deep lake facies, the fan delta front sub- distributary channel sediments and sheet sand constitute the main depositional systems near the source area, Feng I h, Feng II seelion, tile area .f water increases anti the range of elastic deposits （leereases, the Feng Ill is similar t. Feng 11, without big change, according to the depositional systems, it shows that dolomitic rocks in the Fengcheng area are/brmed in semi-block salt bay sedimentary environment, reservoir physical properties are clearly controlled by sedi- mentary environment, which is the basic for us to build up the alluvial fan-fan detla-lacustrine Facies sedimentary system.