川东北地区普光气田长兴—飞仙关气藏成藏模式与成藏过程

POOL FORMING PATTERN AND PROCESS OF THE UPPER PERMIAN-LOWER TRIASSIC,THE PUGUANG GAS FIELD, NORTHEAST SICHUAN BASIN,CHINA

四川盆地川东北地区随着普光1井、2井在二叠系长兴组和三叠系飞仙关组储层中喷出高产工业天然气流,发现了四川盆地有史以来储量最大的天然气田———普光气田。研究表明,普光气田主要以二叠系长兴组台地边缘形成的礁滩和白云岩组合以及三叠系飞仙关组浅海开阔台地相沉积的粒屑滩、鲕粒滩为储层,后期埋藏溶蚀孔为主要储集空间。天然气主要来自中下寒武统、下二叠统、上二叠统烃源岩。印支、燕山及喜马拉雅运动都对普光古圈闭及油气藏的形成有重大影响。普光气藏属于构造—岩性复合孔隙型气藏,其成藏模式与成藏过程经历了原生油藏阶段、气藏阶段和改造定型阶段。普光气田的成藏模式与成藏过程对广大川东北地区勘探类似天然气藏具有借鉴与指导意义。

As the two wells （Puguang 1 and Puguang 2） have produced a large amount of commercial natural gas from the Upper Permian Changxing Formation and Lower Triassic Feixianguan Formation in the northeast of Sichuan Basin, the Puguang natural gas field has become the biggest in the basin. The Upper Permian Changxing Formation reservoir rock is dolomite and coral shoal of platform margin facies. The Lower Triassic Feixianguan Formation reservoir rock is calcirudite shoal and ollite shoal of open shallow marine platform facies. The reservoir space is mainly dissolved pores buried late. Natural gas comes from the Lower-Middle Cambrian, Lower Permian, Upper Permian source rock. It is very important that, the Puguang paleotrap and gas pool are affected by the Yanshan and Himalayas tectonic movements. The Puguang gas pool is a structural-lithologic pore gas pool which has experienced primary oil pool stage, gas pool stage and reformation and definition stage. It is significative for exploration in the northeast Sichuan Basin.