四川盆地及周边上奥陶统五峰组观音桥段岩相特征及对页岩气选区意义  

Guanyinqiao Member lithofacies of the Upper Ordovician Wufeng Formation around the Sichuan Basin and the significance to shale gas plays, SW China

作　　者：王玉满[1] 董大忠[1] 黄金亮[1] 李新景[1] 王淑芳[1] 

机构地区：[1]中国石油勘探开发研究院

出　　处：《石油勘探与开发》2016年第1期42-50,共9页Petroleum Exploration and Development

基　　金：国家重点基础研究发展计划(973)项目(2013CB228001);国家页岩气重大专项(2011ZX05018-001)

摘　　要：以钻井和露头资料为基础,依据岩石矿物、地球化学和测井数据,对四川盆地及周边上奥陶统五峰组观音桥段地层分布和岩相特征开展研究。观音桥段地层分布总体受海平面变化控制,与上下围岩接触关系区域变化大,在盆地内呈整合接触,在盆地外存在整合接触区和缺失区;在盆地内一般为深水硅质页岩相和钙质硅质页岩相,岩性与上下围岩基本相似,在盆地外主体为浅水泥灰岩相或缺失区,且在盆地外泥灰岩相整合接触区,岩性与围岩差异大。研究证实:观音桥段岩相是判断五峰组—龙马溪组页岩气储集层质量优劣的重要标志,对页岩气选区具有重要地质意义;川南—川东—川东北坳陷区为优质储集层发育区和页岩气勘探开发的有利区,观音桥段缺失区为"甜点"层缺失和页岩气勘探风险区,观音桥段泥灰岩相区的储集层质量和勘探前景则界于前两者之间。The stratigraphic distribution and lithofacies features of the Guanyinqiao Member of the Upper Ordovician Wufeng Formation around the Sichuan Basin were studied based on the data of drilling, outcrops, rock minerals, geochemistry and logging. The stratigraphic distribution of the Guanyinqiao Member is generally dominated by sea-level variation. This formation is in conformable contact with the overlying and underlying formations inside and locally outside the basin and is locally lost outside the basin. The Guanyinqiao Member is usually composed of deep-water siliceous shale and calcareous and siliceous shale facies, similar to those overlying and underlying lithologies inside the basin; and composed of shallow marl facies or lost, greatly different from the surrounding lithologies in the conformable area outside the basin. The study confirmed that the lithofacies of the Guanyinqiao Member is of great significance to the identification of the reservoir properties of the Wufeng and Longmaxi formations shale gas and to the selection of shale gas. The exploration and development of shale gas is promising in the depressions in the south, east and northeast of the Sichuan Basin, where good reservoirs are developed. The zone where the Guanyinqiao Member is lost has no ＂sweet spot＂ formation and is risky in exploring shale gas. The reservoir quality and exploration prospect of the Guanyinqiao Member marl zones are between the two zones mentioned above.

关 键 词：四川盆地 页岩储集层 上奥陶统五峰组 地层分布 岩相特征 沉积环境 页岩气勘探选区 

分 类 号：TE122.1[石油与天然气工程—油气勘探]