四川盆地五峰组-龙马溪组页岩气高产地质原因及启示——以涪陵页岩气田JY6-2HF为例

涪陵页岩气田开发的巨大成功（JY6-2HF井累产超过3×10⁸ m³）为五峰组-龙马溪组页岩气勘探开发提供了新的启示，这一成功的关键在于①焦石坝地区位于鄂西-渝东五峰组-龙马溪组深水沉积区，WF2—LM4笔石带页岩厚度较大，具有较好的页岩气富集的物质基础；②JY6-2HF井主要穿行在WF2—LM4笔石带页岩层位中，该套优质页岩与中东-北非的“Lower Hot Shale”具有全球可对比性。涪陵、威远和长宁等页岩气田开发井的主要水平段也都在这段笔石带之中，该笔石带页岩具有有机碳含量高（TOC>3%）、有机质孔最发育（有机质孔隙度>4%）和含气量高（6.87~9.02 m³/t）等特点。综合分析认为，在类似的地质和工程条件下，页岩气井水平轨迹在WF2—LM4笔石带页岩中穿行比例决定了页岩气单井产量和最终可采储量（EUR）。研究成果将为四川盆地及其周缘五峰组-龙马溪组页岩气和世界其他地区志留系页岩气勘探开发提供参考。

Geological factors contributing to high shale gas yield in the Wufeng-Longmaxi Fms of Sichuan Basin: A case study of Well JY6-2HF in Fuling shale gas field

The great success of shale gas development in Fuling (the cumulative production of Well JY6-2HF has exceeded 300 million cubic meters) provides new enlightenment for the exploration and development of Wufeng-Longmaxi Formations' shale gas reservoir.The keys for the success are:(1) the Wufeng-Longmaxi Formations in Jiaoshiba area were deposited in deep water.The WF2-LM4 graptolitic zone shale is relatively thick,laying a better material basis for shale gas enrichment.(2) The lateral of Well JY6-2HF is mainly emplaced in WF2-LM4 graptolitic zone,which contains high-quality shale comparable to the "Lower Hot Shale" in Middle East-North Africa.Most of the laterals of shale gas wells in Weiyuan and Changning shale gas fields are also emplaced in this graptolitic zone,which is characterized by high total organic carbon content (TOC >3%) and high gas content (6.87-9.02 m³/t),and highly-developed organic pores (organic porosity >4%).Comprehensive analysis shows that under similar geological and engineering conditions,the wells with longer laterals emplaced in WF2-LM4 graptolitic zone generally have higher test production and estimated ultimate recovery (EUR).The research results are of referential value to the exploration and development of Wufeng-Longmaxi Formations' shale gas in Sichuan Basin and its periphery,and of the Silurian shale gas in other parts of the world.