欧利坨区块化学清防蜡技术研究与应用

针对辽河油田欧利坨区块抽油机油井结蜡情况及清蜡方式进行探讨,进行化学清防蜡技术的研究,以解决电加热清蜡成本高、化学清蜡+热洗清蜡地层污染严重等问题,延长热洗周期、降低成本、减少地层伤害,保证油井正常生产。在对欧利坨区块原油性质分析的基础上,从化学防蜡剂参加组成晶核、改善结蜡表面、提高蜡分散性三方面入手,经过室内静态、动态实验筛选出界面张力低、防蜡效果较好的混合型PR-PI/LH-Ⅱ清防蜡剂。经过在欧利坨区块8口油井现场应用试验,热洗平均周期从试验前40 d延长到135 d,生产过程电流稳定,仅这8口试验井每年可节约成本24.72万元,试验证明PR-PI/LH-Ⅱ型清防蜡剂适合欧利坨区块抽油机油井高含蜡原油生产。若将加药车定期加药改为点滴加药泵连续加药或安装井口加药包,防蜡效果会更好。

RESEARCH AND APPLICATION OF CHEMICAL PARAFFIN REMOVAL & CONTROL TECHNIQUES IN BLOCK OULITUO

In view of the paraffin deposition situation in rod pumped wells in block Oulituo in Liaohe oil field,paraffin removal methods are discussed.Chemical paraffin removal and control techniques are studied so as to prolong the hot washing cycle,reduce cost and formation damage and ensure normal production of oil wells.The problems of that paraffin removal with electric heating is too costly and chemical paraffin removal plus hot washing may cause serious formation damage were resolved.Based on the analysis of the crude properties in block Oulitou,chemical paraffin inhibitors are involved in forming crystal nucleus,improving paraffin precipitation surface and improving paraffin dispersivity.After static and dynamic tests in the laboratory,a mixed PR-PI/LH-II paraffin removal and control chemicals with low interfacial tension and good paraffin control effects is selected.After field tests and application in 8 wells in block Oulituo,the average hot washing cycle is extended from 40 days to 135 days and the electric current is stable during production.With only the 8 wells,cost saved can reach to RMB 247 200 Yuan per year.It is proved through the tests that PR-PI/LH-II paraffin removal and control chemical is suitable for the rod pumped wells with high paraffin content in block Oulituo.The paraffin control results will be better if periodic chemical feeding from trucks is converted into continuous feeding from dripping feeder pumps or feeder packages are installed at the wellhead.