大牛地气田东北地区山西组-下石盒子组沉积特征及发育模式

综合运用岩心观察、薄片鉴定、测井相分析等多种手段,对鄂尔多斯盆地大牛地气田东北地区山西组-下石盒子组沉积相进行了系统研究.结果表明,大牛地气田东北地区山西组-下石盒子组发育了辫状河三角洲体系,三角洲平原亚相发育,主要沉积微相有辫状分流河道、天然堤、洪泛平原、平原沼泽和分流间滩等.在相分析的基础上,进一步研究了区内沉积微相的平面展布特征及其演化规律,认为区内山1期为近海湖泊辫状河三角洲,到山2期以后演化为内陆湖泊三角洲.建立了大牛地气田东北地区山西期-石盒子期的沉积发育模式.

Depositional characteristic and depositional model of Shanxi Formation to Xiashihezi Formation in the Daniudi gas field, Ordos Basin, China

On the basis of the geological sedimentary background,the paper studies the depositional system of Shanxi Formation to Xiashihezi Formation in the northeast of the Daniudi area in Ordos Basin by different methods.The research shows that the system is a delta depositional system of braided streams.The research area is mainly located in a delta plain environment including distributary-braided channels,natural levees,flood basins,flatland morasses and distributary beaches.The evolvement pattern in vertical indicates that Shan 1 stage was a paralic braided delta and was evolved into a inland lake delta after the period of Shan 2 stage and finally the depositional model of Shanxi stage to Xiashihezi stage was established in the northeast the Daniudi gas field.