延长组(群)的沿革

STUDY OF THE YANCHANG FORMATION

延长组是鄂尔多斯盆地内中—晚三叠世形成的一套河—湖相岩石地层,是鄂尔多斯盆地内主要含油气地层之一。对延长组的研究已有近百年,但很多学者在科研和生产中的应用,至今仍存在意见分歧,有的称其为延长组,有的称其为延长群。追溯延长组的诞生历史,研究其历史沿革之经过,并根据现如今业内权威部门及其相关著作的观点,该套地层应称之为延长群,延长群可划分为四个岩性组,分别为:瓦窑堡组、永坪组、胡家村组和铜川组,在此基础上可将延长群做二级和三级划分,建议在区域地质研究和油田开发生产中均采用延长群这一划分方法。

The Yangchang Formation in was formed fiver-lacustrine facies in the middle to late Tri- assic period in Ordos Basin. is also one of the major oil and gas reservoirs in Ordos Basin. It has a hundred years of study history. However, many scholars still have different opinions about Yangchang Formation. Some of them called it as the Yangchang Formation, and the others called it as the Yanchang Group. This is not conducive to divide the flow unit accurately during the oilfield development in the basin and not conducive to accurately determining the water injection with desti- nation in the oil well stimulation in the implementation, and it also is not conducive to the develop- ment and exploitation of oil and gas from the basin. Tracing the history of the Yanchang Formation, and according to the industry authority departments and some relevomt book＇ s point Of view, it should be referred to the Yangchang~ Group, and the group can be divided into four lithology forma- tions, including Wayaobao Formation, Yongping Formation, Hujiacun Formation and Tongchuan Formation.