低温无机铝凝胶调剖体系的研制和性能研究

Development and Performance Study of Low Temperature Inorganic Aluminum Gel Profile Control System

目前部分水解聚丙烯酰胺凝胶体系广泛应用于油田调剖堵水中。常规的交联剂体系成胶温度较高,调堵效果易受到矿化度、地层吸附及剪切的影响,难以应用于低温高矿化度油藏。以AlCl_(3)为反应物、六亚甲基四胺C_(6)H_(12)N_(4)为pH值调节剂、二水合柠檬酸钠Na_(3)C_(6)H_(5)O_(7)·2H_(2)O为控制剂,制备了一种适用于低温油藏、耐盐性强、热稳定性较好且成交时间可控的铝凝胶堵剂体系。研究了反应物和pH值调节剂浓度、温度、矿化度及控制剂对铝凝胶成胶时间、成胶强度的影响,并用物理模拟实验评价了铝凝胶的注入性能、封堵性能和耐冲刷性能。研究结果表明:该铝凝胶堵剂体系在40℃下成胶时间为2.5~29 h,且连续可控;体系可耐高钙高盐;60℃条件下体系可在较长时间内保持较高强度。物理模拟实验结果表明:低温铝凝胶体系具有较好的注入性能、封堵性能和耐冲刷性能,其封堵率在95%以上,可以满足低温油藏调堵的需要。

At present,the partially hydrolyzed polyacrylamide gel system is widely used in profile control and water shutoff in oil field.The conventional crosslinker system is difficult to be used in low temperature high-salinity oil reservoirs due to its high gelation temperature and plugging effect easily affected by salinity,formation adsorption and shear.An aluminum gel blocking agent system was prepared by using anhydrous aluminum chloride as reactant,hexamethylenetetramine as pH regulator and sodium citrate dihydrate as control agent,which is suitable for low-temperature oil reservoirs and has high salinity resistance,thermal stability and controllable transaction time.The effects of reactant and pH regulator concentration,temperature,salinity and control agent on gelation time and gelation strength of the aluminum gel were studied.The injection performance,plugging performance and erosion resistance of the aluminum gel were evaluated by physical simulation experiments.The results show that the gelatin time of the aluminum gel plugging system is 2.5~29.0 h at 40℃and can be continuously controlled.The system can resist high calcium and high salt and can maintain high strength for a long time at 60℃.The physical simulation results show that the low temperature aluminum gel system has good injection performance,plugging performance and erosion resistance,and its plugging rate is over 95%,which can meet the needs of low-temperature reservoir profile control and water shutoff.