四川盆地嘉陵江组天然气藏的形成与演化研究

三叠统嘉陵江组碳酸盐岩是四川盆地内重要的产层之一。对嘉陵江组天然气组成和碳同位素特征的分析表明：嘉陵江组的天然气干燥系数大，热演化程度高，油型气和煤型气混源特征明显，但川中地区除外，主要为高熟油型气。经盆地区域构造活动和成藏要素分析，恢复了嘉陵江组天然气成藏过程，建立了川中、川东和川南地区典型构造带嘉陵江组天然气的成藏模式，发现嘉陵江组气藏均经历了古油藏—古气藏—现今气藏的漫长演化过程，与印支运动、燕山运动和喜马拉雅运动密切相关。四川盆地嘉陵江组天然气成藏遵循：高压驱动，流体跨层流动，断层裂缝疏导，膏盖油裂解气成藏的规律。

STUDY ON THE FORMATION AND EVOLUTION OF GAS ACCUMULATION IN LOW-ER TRIASSIC JIALINGJIANG FORMATION OF SICHUAN BASIN

Based on the analysis of the composition and carbon isotopic characteristics of natural gas, it is confirmed that the natural gas of Jianglingjiang Formation has a large drying coefficient and high thermal evolution, showing an apparent feature that gas always comes from both oil-type and coaliferous source rocks, with an exception existed in Middle Sichuan region, where the accumulational gas is mainly composed by high-mature oil-type gas. The regional tectonic activities and accumulation elements of the whole basin are analyzed in this paper, the accumulation process of Jialingjiang Formation is rebuilt, and the accumulation model of natural gas of typical structural belts in the Middle, Eastern and Southern Sichuan Basin are established separately. It is found that all the Jialingjiang gas pool have experienced a long evolutionary history of ancient oil accumulation, ancient gas accumulation and current gas accumulation, and this process has a close relationship with the Indosinian movement, Yanshan movement and Himalayan movement. The law that Jialingjiang natural gas accumulation follows is as follows：fluid-drive with highpressure, cross-layer migration of fluid, condution by fault and fracture, oil cracking to gas accumulation sealed by gypsum layers.