库车坳陷典型构造天然气运移过程物理模拟

Physical simulation on gas migration process of typical structure in Kuqa Depression

详细分析了库车坳陷典型构造地质模型 ,基于天然气沿断裂“泵吸”运移机制及相似性原理 ,建立了相应的微缩实验模型。物理模拟结果表明 :直接连接烃源岩和圈闭的盐下断裂是天然气运移效率相对较高的充注断裂 ,天然气在圈闭中聚集成藏取决于断裂组合输导模式。由盐下断裂和不连接圈闭的穿盐断裂构成的天然气输导模式及由盐下断裂构成的天然气输导模式应是库车坳陷输导天然气最有效的模式。天然气向圈闭中运移的效率高 ,有利于形成天然气的大规模聚集 ,可形成大气田。而由盐下断裂和圈闭顶部突破断裂构成的天然气输导模式及仅由穿盐断裂构成的天然气输导模式向圈闭输导天然气的效率相对较低 ,不利于天然气的大规模聚集 。

The geographic models for the typical structures in Kuqa Depression were analyzed.On the basis of the mechanism of gas migration through fault and the similarity principles,an experimental model was established.The physical simulation results show that the fault below salt directly connected by hydrocarbon resource rocks and traps is the packing fault,in which gas migration velocity can get the top.The gas accumulation and formation of gas reservoir rely on the transmission models formed by fault combination.There are two efficient models for gas migration in Kuche Depression.One is the combined model formed by fault below salt and cutting salt,and another is the model formed by fault below salt only.The transmission model formed by fault below salt and breakage faults on the top of traps and the models formed by fault cutting salt only were not helpful for generating large-scale gas pools,and only some small gas fields were formed or there were gas shows.