柴达木盆地北缘西段第三系构造基本样式及石油地质意义

上新世晚期以前 ,柴达木盆地北缘地区西段一直处于较稳定的沉降阶段 ,以河湖相沉积为主 ,没有发生较大的构造运动。地震反射原理和地质分析表明 ,冷湖—鄂博梁构造带为上新世中期 (N22 )之后一次性形成 ,在此前第三系不存在明显的构造变形。柴达木盆地北缘地区油气藏均为上新世晚期开始形成的原生油气藏 ,区内侏罗系油藏研究及油气资源评价应结合上覆地层的构造演化进行。初步分析认为 ,柴达木盆地新生界构造单一 ,北缘西段构造样式在盆地内具有代表性。

BASIC STRUCTURAL STYLE OF TERTIARY IN THE WESTERN PART OF THE NORTHERN AREA IN THE QAIDAM BASIN AND ITS PETROLEUM SIGNIFICANCE

The western part of the northern area in the Qaidam Basin underwent an evolution of steady sinking during Tertiary (before the later stage of Pliocene),which was filled with sediments of river and lake facies.Analyses through the principle of seismic reflection and geological information show that the structural belts of Lenghu Eboliang,for the structural layer of Tertiary,was built due to a tectonic movement taken place in the middle of Pliocene.Before that there was no tectonization but subsidence.The oil reservoirs found in the northern area of the Qaidam Basin are original and was formed after the middle of Pliocene.So the studies of oil reservoirs and resources assessment in Jurassic should be done by the combination with the evolution of the overlying structural layers.