高凝油井电伴热优化计算

针对潍北油田疃3块原油高凝、高含蜡、井筒举升高能耗等导致的井筒举升难题，根据传热学基本原理和两相流理论，建立了井筒电热杆加热数学模型，利用设计的优化计算软件，得到了疃3块3口高凝油井的电加热方式、电加热深度及电加热功率。针对恒功率电伴热系统存在的缺陷，提出了一种新的电伴热优化方法，即电热杆长度、下入位置及加热点分布优化计算，并以疃3块3-X1井为例进行了优化研究。结果表明，恒功率电伴热优化后3口井的加热深度由原来800 m变为448～492 m，人工补充热量由最初的8 kW降至3.69～5.56 kW，降幅达30.5%～53.88%。对电伴热段进行均匀分段，适当增加分段数，可有效降低井筒举升能耗。将油井3-X1的加热段均匀分为10段，每段长度为45 m时，人工补充热量为4.25 kW，与恒功率电伴热系统相比，井筒举升能耗进一步降低23.6 %。

An optimization calculation of electric heat tracing for high-pour-point-oil wells

On the basis of basic principles of the heat transfer and two-phase flow theories, the present paper developed a mathematical model for the wellbore electric heat tracing to solve the high energy consumption problem of shaft lifting due to high pour point and high wax of oils in the Tuan 3 block of the Weibei Oilfield. The electric-heating manner, depth and power of three wells in the Tuan 3 block were obtained by means of the designed optimization calculation software. A new optimization method of the electric heat tracing, i.e. an optimization calculation for the electric pole length, the position of running in and the distribution of heat spots, was proposed in order to remedy the defect inherent in the electric heat tracing system with constant power, and Well 3-X1 was taken as an example to verify this optimization calculation. The results indicated that after the optimization, the electric-heating depth for three wells was reduced significantly, from 800 m to 448～492 m and the artificial heat recharge fell down from the initial 8 kW to 3.69～5.56 kW, declining by 30.5%～53.88%. The energy consumption of shaft lifting could be significantly reduced by dividing the electric heat tracing length uniformly and appropriately increasing the number of segments. For instance, when the electric heat tracing length of Well 3-X1 was divided into 10 segments averagely with 45 m for each, the artificial heat recharge was only 4.25 kW, thus, compared with the electric heat tracing system with constant power, the system with step power could further reduce the energy consumption of shaft lifting by 23.6%.