下寺湾油区延长组长7油层湖底扇沉积特征

下寺湾油田三叠系延长组长7油层在深湖相泥岩中发育巨厚的含油浊积砂体,拓宽了油气勘探领域。长7油层组主要发育浊积扇沉积中扇亚相、外扇亚相,中扇亚相可以识别出辫状水道、水道间漫溢、无水道席状砂等微相,其中辫状水道是主要的储集砂体;长7浊积扇为三角洲前缘分流河道沉积物继续滑落至深湖区形成的湖底扇沉积,受控于湖盆底形及其前缘分流河道,呈宽缓带状东北-西南向展布。对鄂尔多斯盆地东南部长7油层浊积沉积体系特征,垂向演化规律和有利储积砂体的分布规律研究,对指导和加快长7油层油气勘探具有重要意义。

Yanchang Formation Chang 7 Reservoir Sublacustrine Fan Characteristics in Xiasiwan Oilfield

Xiasiwan oilfield Triassic Yanchang formation Chang 7 reservoir is fully developed thick oil turbidite sandstones in deep lake mudstone,which extends and broadens the oil and gas exploration area.Chang 7 oil formation mainly develops middle fan subfacies and outer fan subfacies of turbidite fan.Middle fan subfacies can recognize microfacies,such as braided channel,watercourses overflowing and no waterway sheet sand.The braided channel is the main reservoir sand body.Chang 7 turbidite fans is the lake fan deposits which is the delta front distributary channel sedimentary continuing fallen into the deep lake area.It is controlled by the lake pelvic floor shape and its front distributary channels.It broadly and widely strip lies in the direction of northeast to southwest.To the Ordos basin southeast area Chang 7 reservoir turbidite sedimentary system characteristics,researches of the vertical evolution pattern and favorable reservoir sand distribution pattern have significant meaning of guiding and accelerating the Chang 7 reservoir oil and gas exploration.