基于成像测井的泥页岩裂缝研究:以焦石坝区块为例

富有机质泥页岩裂缝类型及其发育分布特征是影响页岩气聚集与散失的重要因素。基于岩心观测和高分辨微电阻率成像测井（FMI），对焦石坝区块2口关键井（JYA井和JYB井）裂缝发育特征进行了精细标定与定量解释，并在此基础上联合含气性资料简要探讨了裂缝对页岩含气性的影响。研究结果表明，JYA井和JYB井主力层段及下伏地层裂缝差异较小，均以层理缝为主，但上覆盖层具有明显差异。JYA井上覆盖层天然裂缝发育程度较低，以高阻缝为主，高导缝和断层次之，三者的倾角变化范围分别为20.31°~75.83°（平均44.65°）、16.65°~61.17°（平均39.43°）和36.41°。裂缝线密度最高为0.6条/m，其中断层仅为0.025条/m，页岩系统封闭能力较好，压裂投产为高产井。JYB井上覆盖层天然裂缝发育程度较高，且以断层为主，高阻缝和高导缝次之，三者的倾角分别介于13.71°~72.23°（平均37°）、6.9°~78.49°（平均37.9°）和13.53°~61°（平均32°）之间。裂缝线密度高达0.98条/m，其中断层线密度约为0.654条/m，页岩系统封闭能力较差，压裂投产为低产井。裂缝发育类型及其程度决定了不同区块页岩气保存条件与页岩气富集程度。 

Research on mud shale fractures based on image logging: A case study of Jiaoshiba area

The fracture type, development and distribution characteristics of organic-rich mud shale are important factors that affect the accumulation and dissipation of shale gas.Based on core observation and high resolution micro-resistivity image logging (FMI), the fracture development characteristics of two key wells (JYA well and JYB well) in Jiaoshiba area were described and quantitatively interpreted.Besides, the influence of fracture on shale gas-bearing property is discussed in combination with gas-bearing data.The results show that there is little difference between JYA well and JYB well in main formation and underlying formation, and the bedding fracture is the main one, but the seal condition has obvious difference.The natural fracture of the direct seal of the JYA well is relatively low, mainly high-resistance fracture, followed by high-conductivity fracture and fault.The dip angle is 20.31°-75.83° (average 44.65°), 16.65°-61.17° (average 39.43°) and 36.41°, respectively.The line density of fracture in JYA well is 0.6 bar/ m, of which fault is 0.025 bar/m.The sealing condition of JYA well is well, and the production fracturing is high-yield.However, the natural fracture of the seal condition of the JYB well is relatively high, and mainly fault, followed by high-resistance fracture and high-conductivity fracture.The dip angle is 13.71°-72.23° (average 37°), 6.9°-78.49° (average 37.9°) and 13.53°-61° (average 32°), respectively. The linear density of fracture in JYB well can reach 0.98 bar/ m, of which fault is 0.654 bar/ m.The sealing condition of JYB well is low, and the production fracturing is low-yield.Fracture type and its degree determine the condition of shale gas preservation and the degree of shale gas enrichment in different blocks.