三维高密度电法揭示SAGD地面窜漏通道

Imaging the Ground Leakage Channel of SAGD Based on Three-Dimensional Electrical Resistivity Tomography

超稠油是工业与国防的战略物资。蒸汽辅助重力泄油(steam assisted gravity drainage,SAGD)窜漏是目前最先进的超稠油开发模式急需解决的关键问题,而其中对于SAGD窜漏通道的监测和刻画又是重中之重。本次采用三维高密度电法刻画SAGD窜漏通道,根据准噶尔盆地西北缘北部FCZ1井区测井标定窜漏通道内赋存油水后的电阻率变化,确定研究区窜漏通道的电阻率<3Ω·m,窜漏通道近南北走向,下窄上宽。综合地质与地震资料,认为SAGD窜漏为“腔缝”窜漏模式,即SAGD开发早期未发生窜漏,随着SAGD蒸汽腔形成,向上扩展时逐步与上部地层裂缝带形成沟通,蒸汽沿裂缝垂向向上窜至地面。

Ultra-heavy oil is a strategic material for industry and national defense.Steam-assisted gravity drainage(SAGD)leakage is a critical problem to be solved urgently in the most advanced ultra-heavy oil development mode.The monitoring and characterization of the SAGD leakage channel are the most important.The three-dimensional electrical resistivity tomography is used to characterize the SAGD leakage channel.According to the resistivity change of oil and water in the leakage channel after logging calibration,the resistivity of the leakage channel in the study area is lower than 3Ω·m.The leakage channel is nearly north-south,narrow at the bottom,and wide at the top.Based on the geological and seismic data,it is considered that the SAGD leakage channel is a“cavity-crack”mode.There was no leakage in the early stage of SAGD development.With the formation of the SAGD steam chamber,it gradually communicated with the upper stratum fracture zone during upward expansion,and the steam channeled up to the ground vertically along the fracture.