四川盆地二叠系茅口组油气藏勘探发现与启示

二叠系茅口组是四川盆地勘探时间最早、目前勘探活动最活跃的层系之一.茅口组气藏按其储层类型可以分为裂缝型、岩溶缝洞型、热液白云岩型、滩相白云岩型和泥灰岩型5类,以岩性气藏为主,在不同区带、不同组段气藏类型表现出差异多样化特征.在梳理前期茅口组勘探成果和分析不同类型气藏特点基础上,明确了台缘滩、台内滩和深缓坡等有利沉积相带...

Reservoir exploration of the Permian Maokou Formation in the Sichuan Basin and enlightenment obtained

The Permian Maokou Formation among the first batch of exploration targets is one of the most actively explored formations in the Sichuan Basin. Gas reservoirs in the formation can be classified into five types in terms of reservoir characteristics， that is， reservoirs of fracture type， karst fractured-vuggy type， hydrothermal dolomite type， shoal dolomite type and marl type， and are dominated by lithologic reservoirs. These types of gas reservoirs show diverse characters in different stratigraphic intervals and different plays. The previous exploration results of Maokou Formation and characteristics of different gas reservoirs， demonstrate that favorable sedimentary facies zones such as marginal-platform shoals， intra-platform shoals and deep gentle slopes serve as basic conditions for reservoir development， and pseudocontemporaneous dolomitization， late hydrothermal dolomitization， epigenetic karstification， and tectonic transformations such as folds and faults are the keys to forming high-quality reservoirs therein. It is pointed out that karst fractured-vuggy reservoirs， dolomite reservoirs of shoal facies and marl reservoirs in the first member of Maokou Formation （Mao 1 Member） as controlled by facies （geomorphology）， characterized by continuous distribution and high quality， are the main exploration targets in the future. The northeastern and southern-southeastern parts of Sichuan Basin are the most favorable play fairways for the exploration of Maokou Formation. The superposition of various reservoir types and exploration fields is of value to setting up a holistic pattern for exploration.