The Ordovician Wufeng Formation-Silurian Longmaxi Formation organic-rich shales distributed widely and stably in Southern Sichuan Basin were investigated based on drilling data.Geological evaluation of wells show that the shale reservoirs have good properties in the Yibin,Weiyuan,Zigong,Changning,Luzhou,Dazu areas,with key parameters such as TOC,porosity,gas content similar to the core shale gas production zones.Moreover,these areas are stable in structure,good in preservation conditions and highly certain in resources.The shale reservoirs have a burial depth of 4 500 m or shallow,a total area of over 2× 104 km2 and estimated resource of over 10× 1012 m3,so they are the most resource-rich and practical areas for shale gas exploitation in China.Through construction of the Changning-Weiyuan national demonstration region,the production and EUR of shale gas wells increased significantly,the cost of shale gas wells decreased remarkable,resulting in economic benefit better than expected.Moreover,the localized exploration and development technologies and methods are effective and repeatable,so it is the right time for accelerating shale gas exploitation.Based on the production decline pattern of horizontal wells at present and wells to be drilled in the near future,at the end of the 13th Five Year Plan,the production of shale gas in southern Sichuan Basin is expected to reach 10 billion cubic meters per year.The resources are sufficient for a stable production period at 30 billion cubic meters per year,which will make the South Sichuan basin become the largest production base of shale gas in China.%基于钻井资料,对川南地区奥陶系五峰组—志留系龙马溪组大面积连续稳定分布的富有机质页岩进行了研究.通过单井地质评价,认为宜宾、泸州、大足等地区的页岩储集层品质好,TOC、孔隙度、含气量等关键参数与威远、自贡、长宁等建产区有相似性;研究区构造整体稳定,保存条件好,资源落实程度高;埋深4 500 m以浅可工作面积超过2× 104 km2,地质资源量超过10×1012 m3,是中国页岩气资源最丰富、开发最现实的区块.经过长宁—威远国家级示范区建设,单井产量和单井最终可采储量大幅提高,单井成本大幅降低,经济效益好于预期,形成的本土化勘探开发主体技术和方法有效、可复制,快速上产的条件成熟.根据目前水平井的生产递减规律和未来投入的工作量,预计“十三五”末川南地区页岩气年产量将达到100×108 m3以上,具备建成300×108 m3年产规模并长期稳产的潜力,有望使川南地区成为中国最大的页岩气生产基地.
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