基于油砂温敏特征的蒸汽辅助重力泄油蒸汽腔监测

Monitoring of steam chamber in steam-assisted gravity drainage based on temperature sensitivity of oil sand

利用加拿大Kinosis油砂典型岩心开展了温敏岩石物理特征实验测量、模型计算和频散现象分析,应用于研究区油砂蒸汽辅助重力泄油(SAGD)开发蒸汽腔发育形态的时移地震监测研究。研究表明,对于弱胶结、低阻抗的油砂,利用聚醚醚酮树脂代替常规钛合金设计超声波基座进行超声波测试,可以提高信号能量、信噪比,得到清晰的初至波形。随着温度的变化,研究区稠油可出现玻璃态、准固态和液态这3种相态,玻璃态温度点和液态温度点分别为-34.4℃和49.0℃,准固态的稠油具有明显频散现象。高含油饱和度油砂的弹性特征主要由稠油性质决定,低含油饱和度油砂的弹性特征主要受骨架颗粒刚度控制。油砂的弹性参数具有明显的温敏特征,将温度从10℃提高到175℃,其纵、横波速度都会明显降低。基于实验数据建立油砂纵波阻抗与温度之间的定量关系图版,并通过时移地震反演实现了研究区目的层段蒸汽腔温度变化预测。

Thermosensitivity experiments and simulation calculation were conducted on typical oil sand core samples from Kinosis,Canada to predict the steam chamber development with time-lapse seismic data during the steam assisted gravity drainage(SAGD).Using ultrasonic base made of polyether ether ketone resin instead of titanium alloy can improve the signal energy and signal-to-noise ratio and get clear first arrival;with the rise of temperature,heavy oil changes from glass state(at–34.4℃),to quasi-solid state,and to liquid state(at 49.0℃)gradually;the quasi-solid heavy oil has significant frequency dispersion.For the sand sample with high oil saturation,its elastic property depends mainly on the nature of the heavy oil,while for the sand sample with low oil saturation,the elastic property depends on stiffness of the rock matrix.The elastic property of the oil sand is sensitive to temperature noticeably,when the temperature increases from 10℃to 175℃,the oil sand samples decrease in compressional and shear wave velocities significantly.Based on the experimental data,the quantitative relationship between the compressional wave impedance of the oil sand and temperature was worked out,and the temperature variation of the steam chamber in the study section was predicted by time-lapse seismic inversion.