A Study on Temperature Effect of Water Displacement Efficiency in High Pour Point Oil Reservoir

高凝油由于其含蜡量高、凝固点高，温度对其流变特性影响较大。高凝油油藏在常规注水开发过程中容易出现析蜡问题，导致水驱油效率低，直接影响高凝油油藏的开发效果。针对南苏丹P高凝油油藏具有很强析蜡趋势的特点，通过室内实验，在不同注水温度下进行了一维长岩芯含气油实验、一维长岩芯脱气油实验和一维短岩芯脱气油实验来研究温度对水驱油效率的影响；同时，建立了三维四相拟组分模型，在模拟研究中对析蜡反应进行了设计，并考虑高凝油油藏模拟的全部关键因素，预测结果更为准确。结果表明：在析蜡点前，温度对水驱油效率影响较大。高于析蜡点，随温度的增加，原油黏度对温度敏感性降低，驱油效率增加的幅度逐渐减小，因此建议注水温度高于析蜡点。Temperature has a great effect on the rheological property of high pour point oil because of its high wax content and high pour point. During the development of high pour point oil reservoir,wax precipitation easily occurs in the conventional water flooding process,leading to low efficiency of water flooding,which has direct impacts on the development performances. A series of laboratory experiments are conducted under circumstances where temperatures of injected water are different to study the influence of temperature on the water displacement efficiency in the P high pour point oil reservoir,South Sudan. The experiments include:one-dimensional long core live oil experiment,one-dimensional long core degassed oil experiment and one-dimensional short core degassed oil experiment. In addition,a 3D four-phase pseudo-component model is established. Wax precipitation is designed in the simulation model,and all the key factors are considered in the high pour point oil reservoir simulation,making the predicting results more accurate. Laboratory investigation and numerical simulation results show that the temperature has great impacts on the water displacement efficiency before the wax appearance temperature (WAT). When the temperature is higher than WAT,oil viscosity is less sensitive to temperature with the temperature increasing,and the rate of increased oil displacement efficiency decreases. So it is suggested that water temperature should be higher than WAT.国家科技重大专项(2011ZX05032002；2011ZX05058)。中文核心期刊要目总览(PKU)中国科技核心期刊(ISTIC)中国科学引文数据库(CSCD)1113-1183