四川盆地须家河组沉积格局及概念模式

The Sedimentary Pattern and Conceptual Mode of Xujiahe Formation in Sichuan Basin

摘要: 四川盆地晚三叠世须家河期为湖泊–三角洲沉积。由于周缘山系的抬升与剥蚀，导致盆地周缘沉积保存不全或缺失，从而对四川盆地晚三叠世须家河期的沉积格局认识存在很大的分歧。在前人研究的基础上，通过对现代“满盆砂”湖盆——鄱阳湖沉积的分析，并类比同类型盆地，为四川盆地晚三叠世须家河期建立“近海宽浅型敞流湖盆”的新概念模式，对进一步确定主体区沉积相、微相的类型及储层关系，预测主体区有利储层相带的展布具有重要意义，为普光气田须家河组的后期勘探开发提供地质依据。

Abstract: The reservoirs in the Late Triassic Xujiahe Formation in Sichuan Basin belonged to lake-delta se-diments. Due to the uplift and denudation of the surrounding mountains, the deposition around the basin remained incomplete or missing; therefore it caused great differences on the under-standing of sedimentary pattern of the Late Triassic Xujiahe Formation in Sichuan Basin. Based on the previous studies, by comprehensive analysis on the “full sand” basin (e.g. Poyang Lake) and analog of the same type of basins, a new conceptual model of “offshore wide and shallow open lake basin” was establish for the Late Triassic Xujiahe Period in Sichuan Basin. It is of great significance for further determination of the types of sedimentary microfacies and its relationship with reservoirs, and for predicting the distribution of favorable reservoir facies belts in the main areas. It provides a geological basis for further exploration and development of the Xujiahe Formation in the Puguang Gas Field.