云南永善-大关地区五峰-龙马溪组页岩气聚集条件及有利区预测

为深入探讨永善-大关地区五峰-龙马溪组页岩气聚集条件、有利区分布和资源潜力，从页岩空间展布、有机地化特征、储层特征、含气性等多方面进行了全面分析。结果表明：五峰-龙马溪组泥页岩发育于海相浅水-深水陆棚沉积环境，具有埋深适中（1000~3000 m）、厚度大（40~120 m）、有机碳含量适中（1.0%~3.0%）、热演化程度高（>2.5%）的特征，页岩储层主要以脆性矿物为主（石英+长石+碳酸盐岩类矿物占35.8%~92.0%），微米-纳米级孔缝发育，具备页岩气生成所需的物质基础和储集空间；五峰-龙马溪组页岩具有较强的吸附能力（平均最大吸附气量2.12 m3/t）和较高的含气量（现场解析气量0.5~3.38 m3/t）；以此为基础，采用多因素叠合法优选了页岩气发育有利区，分布在高桥-新场-天宁寺-木杆向斜所围区域，面积480.58 km2，并采用条件概率体积法初步评价了有利区页岩气资源量为1256.4×108 m3，具有一定的页岩气资源潜力。

Accumulation conditions of shale gas in Wufeng-Longmaxi Formation and prediction of the favorable zone in the Yongshan-Daguan area, Yunnan Province

This work attempted to explore shale gas accumulation conditions, the favorable zone and resources potential in Wufeng-Longmaxi Formation of Upper Ordovician in the Yongshan-Daguan area, Yunnan Province. The spatial distribution, organic geochemical characteristics, reservoir conditions and gas-bearing properties of the shale were comprehensively analyzed. The results show that this shale formed in a shallow-deep water shelf, characterized by a moderate burial depth (1000~3000m), large thickness (40~120m), appropriate total organic carbon content (1.0%~3.0%) and high maturity(>2.0%). The shale reservoir is dominated by brittle minerals (quartz + feldspar + carbonate, 35.8%-92.0%) with many nano-micro pores and cracks which provide favorable material basis and reservoir space for shale gas accumulation. The Wufeng-Longmaxi Formation shale has relatively high adsorption capacity for methane (average maximum adsorbed gas content 2.12%) and large gas content(0.5~3.38m3/t). In light of these features, a favorable zone was determined using the multi-factor superposition method and shale gas resources were evaluated by the conditional probability volume method. It lies in the area of 480.58km2 surrounded by the Gaoqiao-Xinchang-Tianningsi-Mugan syncline, with resources amounting to 1256.4×108m3.