何绪蕾

摘 要：针对原油在管道集输过程中在管壁结蜡危害的问题，首先分析了管道结蜡沉积机理，在此基础上，综合考虑了蜡分子浓度梯度、管壁处剪切应力、油流温度梯度以及粘度等因素建立结蜡沉积速率模型，根据实际油田地区情况，结合当地季节土壤温度，做了含水率、集油温度、流量等对结蜡速率的影响，研究表明含水率在65%左右，也就是在转相点附近管道结蜡速率最高，主要是原油粘度影响较大;集油温度越高，结蜡速率越低，是由于温度的高低决定了分子的扩散和热运动大小;流量越大，结蜡速率越低，是因为剪切应力破坏了管壁结蜡沉积强度。针对结蜡对管道堵塞腐蚀的影响，选取PIG清管技术进行处理，能够有效的降低管道输送压力，降低管道穿孔风险，在保障年输量的条件下，节约电量高达4.32×105 kW？h，年运行费用减少了123.89×104元。实验结果有助于指导该地区原油集输管道工程设计。

关 键 词：集输管道;机理分析;模型;PIG清管技术

中图分类号：TE 832 文献标识码： A 文章编号： 1671-0460（2015）06-1388-04

Experiment of Paraffin Deposit Rate in Crude Pipeline and Pigging Technology

HE Xv-lei

（Sinopec International Petroleum Exploration and Development Co.， Ltd.， Beijing 100029，China）

Abstract： Aimed at hazards of paraffin deposit rate in crude oil gathering and transferring process， firstly wax deposition mechanism was analyzed.On this basis， considering the wax molecule concentration gradient and wall shear stress， flow， temperature gradient， viscosity and so on， the wax deposition rate model was established. According to actual oil field condition， combined with the local seasonal soil temperature， effect of moisture content， oil temperature and flow rate on the paraffin deposit rate was investigated. The results show that， when the moisture content is about 65%， which is near the phase inversion point， the wax precipitation rate is the highest， which is mainly caused by greater viscosity of crude oil; The higher the oil temperature， the lower the wax precipitation rate， which is due to that the temperature can affect the molecular diffusion and heat movement; The lower the flow rate， the higher the wax precipitation rate， which is due to that the shear stress can damage wall wax deposition. In order to decrease effect of the paraffin deposit rate on pipe blockage and corrosion， the PIG pigging technology can be used， it can effectively reduce the pipeline pressure and the pipeline perforation risk; Under the condition of ensuring annual throughput， 4.32×105 kW·h power can be saved， annual operation cost can be decreased by123.89×104 Yuan. The results help guide for engineering design of crude oil pipeline in the region

Key words： Pipeline; Mechanism analysis; Model; PIG pigging technology

我国开采出来的原油，普遍具有“三高”特点，即高含蜡、高凝点、高黏度，原油在开采和集输过程中，大部分管道原油含蜡质量分数在15%～30%，也有达到40%～50%，含蜡量越高，析蜡温度也越高，析蜡温度高会导致管道容易結蜡，影响原油管道正常输送。原油在管道输送过程中，沿程管道内温度会降低，当温度低于析蜡温度时，原油中的石蜡开始结晶析出，附着在管道内壁上，形成结蜡中心，随着温度的继续降低，管壁内壁附着的晶体逐渐变大、变厚，导致输油管道有效流通内径逐渐变小，输送能力下降，严重时可能造成管道结垢堵塞，各石油储运管道公司每年需要投入大量的资金和人力在管道保温清蜡工作中。……