焦石坝页岩气田龙马溪组—五峰组沉积相特征

Sedimentary Facies of the Longmaxi Formation-Wufeng Formations in the Jiaoshiba Shale Gas Field

依据岩心观察、实验分析、录井和测井资料,研究了四川焦石坝页岩气田志留系龙马溪组下部—奥陶系五峰组海相页岩基本特征、沉积环境。龙马溪组下部—五峰组主要为黑色、灰黑色炭质页岩,形成于弱氧化—强还原环境,由含碳低硅,高碳低硅,中碳中硅、低硅,高碳高硅、中硅,富碳高硅7种岩石相构成;沉积微相可划分为深水砂泥质陆棚、深水混积陆棚、深水硅泥质陆棚、深水泥质陆棚4种;页岩沉积经历了一个较为完整的"海进—海退"三级海平面升降旋回,沉积亚相为深水陆棚沉积。研究成果为今后在四川盆地海相页岩地层寻找优质储层、深化认识焦石坝海相页岩储层特征提供了有益的借鉴。

This paper deals with lithologic characteristics and sedimentary environment of marine shale of the Lower Silurian Longmaxi-Ordovician Wufeng Formations in the Jiaoshiba shale gas field, Sichuan basin, based on core observation, experimental analysis, logging and logging data. The marine shale is characterized by low silicon, high carbon and low silicon, medium carbon and medium silicon, medium carbon and low silicon, high carbon and high silicon, high carbon and medium silicon, rich carbon and high silicon and formed in weakly oxidized-strong reducing environment. The sedimentary microfacies may be divided into 4 types such as deepwater sand shale shelf, deepwater mixing product shelf, deepwater silicon argillaceous shelf and deepwater shale shelf.