四川盆地涪陵页岩气田单井可压性地质因素研究

页岩储层的脆性矿物含量、脆性指数、水平应力差异系数等是影响页岩可压性的主要因素，而四川盆地涪陵页岩气田五峰组-龙马溪组一段①~⑤小层页岩储层的脆性矿物含量（>50%）、脆性指数（>50%）、水平差应力差异系数（<0.2）等基本相似，因此，利用上述参数无法有效评价该区块单井的可压性。根据涪陵页岩气田大量已钻单井资料，从埋深、构造形态、裂缝发育特征等地质因素出发，评估了各地质因素对单井可压性的影响。结果表明:（1）埋深是影响单井可压性最重要的地质因素，埋深越大，储层压裂难度越大；（2）构造形态会对压裂产生较为明显的影响，负向构造形态压裂难度大于正向构造；（3）天然裂缝发育的非均质性也会导致压裂难度增大，缝网延伸困难，影响储层改造效果，降低单井产能。 

Geological factors of well fracability in Fuling shale gas field,Sichuan Basin

Brittle mineral content, brittle index and horizontal stress difference coefficient of shale reservoirs are the main factors influencing shale fracability. The ①-⑤ layers from the Wufeng Formation to the first member of Longmaxi Formation in the Fuling shale gas field have similar brittle mineral content (>50%), brittle index (>50%), and horizontal stress difference coefficient (<0.2). Therefore, the above parameters can not be used effectively to evaluate the fracability of a single well in this block. Based on a large amount of single well data, the authors assessed the influence of various geological factors on the fracability of a single well by geological factors such as burial depth, structural form and fracture development characteristics. The results showed that:(1) Burial depth is the most important geological factor affecting single well fracability, and the greater the burial depth, the greater the difficulty of reservoir fracturing; (2) Structural morphology has a more obvious effect on fracturing, and fracturing is more difficult in negative structures than in positive ones; (3) The heterogeneity of natural fractures will also lead to the increased difficulty of fracturing, the difficulty of extending seam networks, affecting the effect of reservoir reconstruction and reducing the productivity of a single well.