新构造运动活跃的柴达木盆地含油气系统特征

柴达木盆地在中国大地构造格局中 ,处于阿尔金山、祁连山与昆仑山断褶带组成的三角区域。在地球自转与大洋扩张的地球动力作用下 ,处于南北夹挤的应力环境中 ,使盆地北缘与阿尔金山断褶带及祁连山断褶带南缘舒勒山断裂的边界 ,处于挤压走滑的地球动力环境中。由于喜马拉雅运动第三幕以来的新构造运动 ,造成了中国地貌的现今态势 ,柴达木盆地区域的地貌系 2 0Ma的产物。柴达木盆地所在的青海地区年均发生Ms大于等于 4 6级地震 1 82次 ,1937年发生于托索湖 (冬给措纳湖 )西的Ms7 5级地震造成长达 30 0km的地表形变带至今仍清晰可见 ,说明新构造运动在柴达木盆地活跃而强烈 ,是油气勘探决策时的首要因素。新构造运动对油气藏的作用 ,从已发现的油气田中总结发现有对早期形成的油气田的破坏作用、次生油气藏的形成作用、裂缝型油气藏的形成作用、第四系气田的形成作用等。因此 ,研究次生油气藏、裂缝型油气藏与第四系气藏的特征 ,以及适应的勘探理论与原则 ,是柴北缘油气勘探决策的关键。柴北缘有利靶区应为活动断裂带、不整合面隆起区、良好区域盖层的配伍地区 ;柴北缘的有利目的层的择优排序应为第三系、第四系、侏罗系。由于新构造运动活跃而强烈 ,油气总会有外泄或扩散 ,因此地表油气显示与化探异常是

CHARACTERISTIC OF THE HYDROCARBON SYSTEM IN CHAIDAM BASIN WITH AN ACTIVE NEW STRUCTURAL MOVEMENT

Chaidam Basin locates in the triangle region that consists of Aerjin mountain, Qilian mountain and Kunlun mountain fault fold belt in the earth structure of China. Under the earth force of the earth rotation and ocean extension in the stress environment with extrusion from south and north, the basin boundary and the margin of Aerjin and Qilian mountains fault fold belt locate is an earth force environment of extrusion and strike slip. The effect of new structural movement on oil and gas reservoirs includes breakdown effect in early formed oil and gas fields, formation effect on secondary oil and gas reservoirs, formation effect on fractural oil and gas reservoirs and formation effect on Quaternary gas fields. Because of the active and strong new structural movement, oil and gas always leak out and diffuse, surface oil and gas shows and geochemical exploration abnormality is the tracer of oil and gas fields. There is not probability of reservoirs discovery in the area with no geochemical exploration abnormality. Geochemical exploration abnormality is an important evidence for exploration planning decision.