川西坳陷北部断褶带中二叠统异常流体压力分布特征及成因分析

含油气盆地中温压场的研究是探明油气成藏机理的核心问题，特别是古压力的恢复对研究油气的运移、聚集甚至储层的成岩、烃类的生成都起着至关重要的作用。文中以现今地层压力为约束，应用盆地模拟法恢复了川西北断褶带中二叠统的压力演化过程，并利用构造挤压应力模型定量分析超压主控因素。恢复结果显示，川西北中二叠统则发育两期超压，特别是侏罗纪—早白垩世末，受构造挤压应力作用超压快速累积，且不同构造单元受挤压应力的影响差别较大。近造山带发育弱超压，晚白垩世之后恢复至常压；远离造山带的褶皱带和前渊带则发育超压—强超压，且受侧向挤压应力的影响，构造抬升后仍然保持超压—强超压的状态。 

Distribution characteristics and genetic analysis of the abnormal fluid pressure in the middle Permian in the northern fault-fold zone of the western Sichuan Depression

The temperature and pressure field is the key point for studying on the mechanism of hydrocarbon accumulation in the petroliferous basin, and the reconstruction of paleo-pressure particularly plays an important role in the study of hydrocarbon migration and accumulation, and even diagenesis in reservoirs and hydrocarbon generation for source rocks. In this paper, with pressure distribution as constraint, the paleo-pressures in the middle Permian of the northwestern Sichuan Basin were reconstructed by adopting basin modeling. In the northwest fault-fold belt of the Sichuan Basin two stages of overpressure developed, in the middle Permian, especially from the late Jurassic to the end of early Cretaceous.The overpressure accumulated rapidly in reservoirs under the effect of compressive stress which varied greatly in different structural units. The weak overpressure developed near the orogenic belt, which recovered to normal pressure after the late Cretaceous; but the strong overpressure developed in the fold and foredeep zone far from the orogenic belt even after the structure uplift, which was mainly controlled by the external compressive stress from northwest.