我国西部古老海相地层经历了复杂的地质演化过程,深入研究古老地层超压的成因机制和保存条件将有助于分析压力演化、完善油气成藏理论和提高勘探效率。以川中地区为例,利用多种压力数据并结合封隔层分布特征,将磨溪—高石梯地区纵向上划分为5个压力系统,其中包括3个超压系统;各超压系统的成因机制不同,寒武系超压主要是晚期原油裂解生气引起的流体膨胀所致,上三叠统须家河组和二叠系都具有明显的泥岩欠压实特征;下三叠统强超压应该是原油裂解作用附加了石膏脱水作用,膏岩良好的封隔能力是该套强超压保存的关键。良好的封隔层和晚期增压机制是川中古隆起寒武系发育超压的有利条件;后期构造抬升将造成地层压力下降,威远地区因此恢复至常压,磨溪—高石梯地区仍有超压保留。 The ancient marine strata in the west of China experienced complicated geological evolution. Studying the genesis mechanism and preservation conditions of overpressure in ancient strata will help to analyze the evolution of pressure, improve the theory of hydrocarbon accumulation and improve the exploration efficiency. Taking the central part of Sichuan Province as an example, the Moxi - Gaoshiti area is divided into five pressure systems longitudinally, including three overpressure systems and the genesis mechanism of each overpressure system In contrast, the overpressure of the Cambrian is mainly caused by the fluid expansion caused by the cracking of crude oil during the late stage. The Xujiahe Formation and Permian in the Upper Triassic all have obvious mudstone under-compaction characteristics. The strong overpressure of the Lower Triassic should It is the addition of gypsum dehydration to the cracking of crude oil. The good sealing ability of gypsum rock is the key to the overpressure preservation. Good confining layer and late booster mechanism are favorable conditions for Cambrian overpressure development in the Gulong uplift of the central Sichuan; post-structural tectonic uplift will cause the formation pressure to drop, so the Weiyuan area will return to atmospheric pressure, and Moxi-Gaoshiti area still has Overpressure retention.