电加热油藏采油物理模拟研究

PHYSICAL MODELING OF OIL PRODUCTION IN ELECTRICAL HEATED RESERVOIR

根据方程分析法 ,结合工程判断 ,导出了一套电加热油藏采油物理模拟相似准则。建立了低压三维电加热油藏采油物理模型系统 ,提出了进行电加热油藏采油物理模拟的实验方法。在此基础上 ,对单井电加热油藏采油进行了物理模拟实验研究。研究结果表明 ,单井电加热油藏能够在油藏中建立起稳定的温度分布 ,有效地提高油藏温度。油藏温度是井筒径向距离的函数 ,温度沿径向距离近似地按指数规律衰减。对于有一定冷采产量的稠油油藏 ,选用周期性加热采油生产方式 ,其经济效益较好 ;对于冷采产量很低或没有冷采产量的稠油油藏 ,宜选用周期性焖井预热采油生产方式 ,并根据油藏特点和产出液情况优化焖井预热时间和生产周期。在相同的加热时间内 ,加热电功率大 ,油藏温度高 ,但并不是越大越好 ,当功率达到一定程度以后再提高加热功率 ,油藏温度增加并不明显。在电加热油藏的采油生产过程中 ,电加热功率不稳定 ,随生产时间变化。油层电导率低时 ,输入电能利用率高 ,加热效果好。

On the basis of equation analysis and engineering practice, some similarity criterions for physical simulation of oil recovery of reservoir by means of electrical heating are deduced. An 3 dimensional experimental system for the electrically heated oil reservoir is built. Some physical modeling experiments on oil recovery of single well in the electrical heated reservoir are made. The results of the experiments show that a stable distribution of temperature for oil recovery can be established in electrical heated oil reservoir, which can enhance the temperature of oil reservoir around the well bore, and increase the rate of oil production. The temperature of reservoir decreases approximately in exponential with the distance to the center of well bore. The producing methods for the electrical heated reservoir depend on the output of normal recovery. For the heavy oil reservoir with normal output, periodically heating reservoir are suggested in the process of production. For the reservoir without normal output, periodically preheating reservoir are recommended. The higher the heating electrical power is, the higher the temperature of reservoir is. Whereas the electrical power has little effects on the temperature of reservoir while the power reaches a particular value. The electric power varies with the heating time in the period of heating. When the reservoir has low conductivity, the input power can be utilized efficiently.