渝东石炭系岩相古地理及有利储集相带研究

Lithofacies palaeogeography and favorable reservoir facies belts of Carboniferous in East Chongqing

川东石炭系是四川盆地的主要产气层,渝东地区石炭系研究程度较低,勘探工作进展缓慢。通过对地层、层序和沉积相的研究,总结出渝东地区石炭系地层的展布特征、层序特征、沉积相类型与分布特征,以及重点层位沉积相的控制因素。研究认为:渝东地区石炭系整体沉积较薄,地层具有东薄西厚、南薄北厚的特征,沉积自下而上是一个海侵过程,沉积地貌由早期的东低西高、北低南高,逐渐过渡到晚期的西低东高、南低北高,有利沉积相带为颗粒滩,主要受由鄂西海而来的潮汐沟道控制。

Carboniferous formation is the important gas productive reservoir in East Sichuan. The research and exploration of Carboniferous is lowly developped in East Chongqing area. Based on the analysis of formation, sequence and sedimentary facies of Carboniferous in the area, this paper summarizes the stratigraphic distribution features, sequence features, types and distribution features of sedimentary facies and the control factors of sedimentary facies in the important zones. The study restrlts show that Carboniferous formation is thin on the whole in the area, with the thin in east and the thick in west and with the thin in south and the thick in north. The sedimentation is an ingression process from bottom to top. The sedimentary physiognomy is from the low in east and high in west, low in north and high in south in early period to the low in west and high in east, low in south and high in north in late period. The favorable sedimentary facies belts are the particle beach, which is mainly controlled by the tide and channels from ocean trough of West Hubei.