龙门山构造变形与油气关系探讨

An approach to the structural deformation and hydrocarbon accumulation in the Longmen Mountains,western Sichuan

龙门山构造变形始于印支期,经历燕山期和喜山期多次递进变形,构造变形时期具有由北向南、由西向东逐渐变晚和构造变形强度西侧强、东侧弱的特点。龙门山冲断带具有南北分段、东西分带和纵向分层的差异变形特征。龙门山逆冲推覆带构造变形强烈,油气保存条件差。山前断褶带主要发育断弯背斜、断展背斜和断挡背斜等,变形适中,油气保存条件好,龙门山山前断褶皱带有利于油气富集,形成构造油气藏。

The structural deformation of the Longmen Mountains, western Sichuan was initiated during the Indosinian, and underwent the polyphase progressive deformation from the Yanshanian to the Himalayan. These deformational processes became progressively younger in age from north to south and from west to east. The Longmenshan thrust fault zone is characterized by N-S stepping, E-W zoning and longitudinal layering. The highly deformation in the overthrust fault zone led to the poor preservation of oil and gas. The fault-fold zones in the frontal parts of the Longmen Mountains are considered to be favourable for the hydrocarbon accumulation and the formation of the structural oil pools because of the moderately deformational conditions.