溶剂辅助SAGD开采油砂快速启动技术

双水平井SAGD技术是油砂开采的主要方式。针对SAGD预热启动时间长的问题，采用蒸汽循环前注入溶剂方式，缩短预热时间，提高蒸汽利用效率。对溶剂与原油混合后降黏效率进行了测试；采用一维填砂模型，开展溶剂注入性能研究；采用三维物理模型，开展不同预热启动方式实验研究，分析SAGD不同启动方式的温度场、压力场随时间的变化规律。并以加拿大油砂为目标进行了SAGD启动方式及工艺参数优化。结果表明，溶剂可以大幅度降低原油黏度，前置注入溶剂可提高蒸汽注入能力，蒸汽-溶剂复合循环启动时间沿程平均降低幅度达15%，蒸汽注入量可减少21.4%。通过油藏数值模拟方法对比得出，加入溶剂井间达到80 ℃需要90 d，时间减少50%。因此，采用蒸汽-溶剂复合循环启动技术，可以有效提高加拿大油砂开采启动效率，并大幅度降低成本。

Quick starting technology of solvent assisted SAGD for oil sand production

Double-horizontal well SAGD technology is a main oil sand production method. To solve the problem that the SAGD preheating starting time is long, the mode of solvent injection before steam cycle is adopted to shorten the preheating time and improve the steam utilization efficiency. The viscosity reducing efficiency after the mixing of solvent and crude oil was tested. Then, the solvent injection performance was studied using the one-dimensional sand pack model. In addition, the different preheating starting modes were experimentally studied using the three-dimensional physical model, to analyze the change laws of temperature field and pressure field over the time in different SAGD starting modes. Finally, SAGD starting mode and technological parameter optimization were carried out on the Canadian oil sand. It is indicated that the solvent can reduce the oil viscosity greatly and solvent pre-injection can improve the steam injection capacity. The steam-solvent combined cycle starting time along the way is reduced by 15% on average and the steam injection volume is reduced by 21.4%. The comparative study by means of the numerical reservoir simulation method shows that after the injection of solvent, it takes 90 d which is 50% shorter to reach the interwell temperature of 80 ℃. In conclusion, the application of the steam-solvent combined cycle starting technology can effectively improve the starting efficiency of Canadian oil sand production and reduce the costs greatly.