鄂尔多斯盆地三叠系延长组砂岩墙（脉）特征及其地质意义

笔者详细分析了鄂尔多斯盆地三叠系延长组野外砂岩墙和岩心砂岩脉的特征,初步阐明了砂岩墙(脉)的形成机制和演化过程:早期沉积的未固结细粒砂岩在后期地震诱发下液化,同时砂体内压力迅速增加,在围岩层的裂隙处闪电般贯入,形成砂岩墙(脉)。结合区域构造背景,认为砂岩墙具有构造指示意义,同时对油藏的形成和破坏具有一定的影响。

Characteristics and geological significance of sandstone dikes in the Triassic Yanchang Formation of the Ordos basin

This paper analyzes in detail the characteristics of sandstone dikes in outcrops and cores in the Late Triassic Yanchang Formation in the Ordos basin and preliminarily elucidates the formation mechanism and evolutionary process of the sandstone dikes. The unconsolidates fine sands deposited in the early stage were liquefied in the late stage in response to earthquakes, and meanwhile with rapidly increasing pressures inside sands, the liquefied sands were injected into the fissures in surrounding rocks very quickly, thus forming sandstone dikes. According the above-mentioned analysis, combined with the tectonic setting, the authors think that sandstone dikes acted as conduits for oil migration and also exerted a certain influence on the formation and destruction of oil accumulations.