龙门山中段前缘金马侏罗系油气成藏条件分析

Jurassic Reservoir-forming Conditions of Jinma Structure in the Front of Mid-segment of Longmenshan Mountain

金马构造位于龙门山中段鸭子河构造的下倾方向,蓬莱镇组、遂宁组和沙溪庙组泥岩盖层发育,并且西侧有桂花向斜与关口断层相隔,中下侏罗统保存条件良好。储层为河道砂体,岩性主要为细—中粒岩屑砂岩,砂岩成分和结构成熟度较低,储层非均质性较强,储集类型为裂缝—孔隙型,有利储层是成藏的基础。通过气源对比,认为侏罗系天然气主要来自须五段,烃源断层是成藏的重要条件。

Jinma Structure is located at the downdip of Yazihe Structure of middle segment of Longmenshan Mountain. In this structure, Penglaizhen, Suining and Shaximiao formations, mudstone caprock, are developed. There are Guihua Syncline and Guankou Fault in the west. The middle and lower Jurassic formations are characterized by better conservation. And the reservoir, also fluvial sandstone, mainly consists of fine- to middle-grained lithic sandstone with low sandstone composition and small textural maturity;it is characterized by stronger heterogeneity and reservoir type is of fractured-porous. It is considered after gas source correlation that Jurassic gas mainly comes from Xujiahe 5 Member and hydrocarbon source fault is an important to form reservoir.