贝尔湖坳陷构造迁移与油气分布

本文分析了贝尔湖坳陷的形成发育，指出在构造应力不均衡作用及其方式转换作用下，坳陷边缘锯齿状断裂活动具早期北段强、晚期南段强的迁移性。坳陷受西缘断裂控制呈单断式，其发育规模北小南大，发育时间北早南晚，沉降中心，沉积中心也具有南向迁移性，即坳陷北部早期沉积物较厚，有湖相沉积，但回返早，坳陷南部后期沉降幅度大，湖相沉积发育。因而，自北向南，油源岩成熟门限足较接近，但含油气层位增加，厚度增大，表明坳陷中部

TECTONIC MIGRATION AND DISTRIBUTION OF OIL AND GAS IN BUIR LAKE DEPRESSION

This paper analyzes the formation and development of Buir lake depression and points out that tectonic stresses are unbalanced and stress system is transformed. Thus the saw-toothed fault activity at the depression border is characterized by a migration with northern part strong at early stage and southern part strong at late stage. The depression is controlled by the fault at western border and is in the form of single-fault, and its scale of development is smaller in north than in south, its time of development earlier in north than in south, subsidence center and depcenter of depression also migrates southward. The north of the depression obtained the thick sediments with deep lacustrine factes at early stage and uplift earlier,while the south had a deep subsidence at late stage with development of lacustrine factes.Thus from the north to the south, mere hydrocarbon-bearing section appears and thickness increases although the maturing threshold of source rock is relatively the same, which shows the middle and the south of the transformation of tectonic stress field that makes the tectonic belt at the cross of faults being in favour of hydrocarbon accumulation.