志丹油田侏罗纪沉积前古地貌特征与延10油藏分布

Controls of Palaeogeomorphology on Yan′an Formation Reservoir before Jurassic Deposition and Reservoir Characteristics in Zhidan Oil Field

延安组延10油层组是鄂尔多斯盆地中生界重要的含油层段之一,通过对志丹油田侏罗系延安组沉积前岩相古地理分析,总结了影响志丹油田延安组延10油藏分布的古地理环境。侏罗纪中、下统富县—延10期的沉积是对前侏罗纪古地貌的填平补齐,在古陆、残丘与沟谷交错分布、起伏不平的地貌背景下,往往在古高地的斜坡带沉积形成楔状砂岩体,经后期的差异压实作用,极容易形成岩性—构造圈闭,有利于油气成藏。而且侏罗系延10油藏具有储层物性好,边底水活跃,有利于开发的特点。

Yan′an formation Yan 10 member is one of the most important oil layers of Mesozoic Erathem in Ordos basin. By means of analyzing lithofacies-palaeogeography before Jurassic Yan′an formation deposition, the paleogeographic environment of control Yan′an formation Yan 10 reservoir distribution was summarized in Zhidan oil field. The deposition from Fuxian to Yan 10 period of middle and lower of Jurassic fills and levels up the palaeogeomorphology of early Jurassic. Under the physiognomy of the intermeshing distribution and hypsography of ancient land, kopje and channel, the sphenoid sand body was formed on the ramp region of paleohigh, and lithologic-structural trap was very easily formed with the late differential compaction, then reservoir was readily formed. Moreover, Jurassic Yan 10 reservoir has the characteristics of good reservoir and active edge-basal ground water, and it is favorable for development.