鄂尔多斯盆地中东部奥陶系马家沟组天然气成藏特征及勘探潜力

摘要

Natural gas is rich in Ordovician Majiagou Formation in the center and east parts of Ordos Basin.Based on the study of sedimentary characteristics and the macroscopic control of tectonic evolution on reservoir development and gas accumulation,it is suggested that the good source-reservoir configuration relationship between the developing Majiagou cyclic reservoirs and the Upper Paleozoic coal measures as source rock is the cause of present multi-bedded gas-bearing reservoirs and wide gas accumulation in the weathering crust at the uppermost part of Ordovician strata.It is convinced that the Lower Paleozoic marine source rocks are of a certain hydrocarbon potential.It is emphasized that longitudinal or lateral migrations of Ordovician gas are important to hydrocarbon accumulation in the Middle and Lower Majiagou Assemblages,in which the potential structural-lithologic combined traps can be predicted to be prospective in recent.%通过对鄂尔多斯盆地中东部奥陶系马家沟组沉积特征及源储配置关系的研究,分析了古隆起的演化对储层发育及天然气聚集的宏观控制作用,提出储层旋回性的发育及其与上古生界煤系烃源岩较好的源储配置关系,是形成多层系含气并在奥陶系顶部风化壳大面积天然气聚集的主要原因,同时认为下古生界海相烃源岩仍然具有一定的生烃能力,强调了奥陶系生成的天然气垂向或侧向运移对马家沟组中下组合成藏的重要性,预测中下组合中的构造-岩性复合圈闭勘探潜力大,是近期盆地下古生界海相碳酸盐岩勘探的重要方向和接替领域.