油井酸化后原油有机氯的生成机理及其控制  

FORMATION MECHANISM AND CONTROL OF ORGANOCHLORINE IN CRUDE OIL AFTER OIL WELL ACIDIFICATION

作　　者：刘红星[1] Liu Hongxing(Petroleum Engineering Institute of Zhongyuan Oilfield Branch, Sinopec, Puyang 457001, He’nan, China)

机构地区：[1]中国石化中原油田分公司石油工程技术研究院,河南濮阳457001

出　　处：《精细石油化工》2020年第6期55-60,共6页Speciality Petrochemicals

基　　金：中原油田重点科技创新项目(2019302);中原油田科技工程项目(2017KF06)。

摘　　要：针对近年来中原油田部分油井酸化后原油有机氯超标的问题,室内模拟研究酸化过程中不同反应体系和反应条件对文二联脱水原油有机氯含量的影响,采用X射线光电子能谱技术和有机元素分析方法对反应前后的油样进行测试。实验结果表明,盐酸是影响有机氯含量的主要因素,盐酸纯度越低、浓度越大,反应温度越高、时间越长,原油有机氯增加值越大。对比不同原油馏分反应前后有机氯含量和有机元素含量变化,反应生成的有机氯主要集中于204~320℃馏分油中,分析生成机理主要有两个方面,一是原油中的烷烃与工业盐酸中的游离氯发生氯化反应,二是原油中段馏分中的S、O等杂原子物质和盐酸发生亲核取代反应,其中后者占主导地位。提出了对储层温度和原油中硫含量较高的油井进行酸化措施时的有机氯防控对策,一是需严格控制盐酸使用浓度和反应时间,二是尽量降低反应温度和提高酸液返排率。在文72-277等17口井现场试验表明,采取了有机氯防控对策的酸化施工控制有机氯效果显著。Aiming at the problem of excessive organochlorine content in crude oil of some oil Wells after acidification in Zhongyuan oilfield in recent years,the effects of different reaction systems and reaction conditions on the organochlorine content of dehydrated crude oil in Wen-II Gathering Station were studied by indoor simulation.The oil samples before and after reaction were tested by X ray photoelectron spectroscopy and organic element analysis method.The results show that hydrochloric acid is the main factor affecting the content of organochlorine.The added value of crude oil organochlorine becomes greater as the hydrochloric acid purity decreases,and as the hydrochloric acid concentration,the reaction temperature and reaction time increase.Comparing the organochlorine content and organic element content change before and after the reaction of different crude oil fractions,the organochlorine produced by the reaction is mainly concentrated in 204320℃distillate oil,and the formation mechanism is mainly two aspects.One is the chlorination reaction between alkanes in crude oil and free chlorine in industrial hydrochloric acid,the other is the nucleophilic substitution reaction between heteroatom material such as S,O and hydrochloric acid in the middle fraction of crude oil,in which the latter is dominant.This paper proposes prevention and control countermeasures of organochlorine when acidizing wells with high reservoir temperature and high sulfur content in crude oil,the first of which is to strictly control the concentration of hydrochloric acid and reaction time,the second is to minimize the reaction temperature and increase the acid flowback rate.The field tests of 17 wells in Wen 72-277 show that through acidizing treatment adopting organochlorine prevention and control countermeasures,the control effect of organochlorine is remarkable.

关 键 词：酸化 原油有机氯 生成机理 防控对策 

分 类 号：TE357.2[石油与天然气工程—油气田开发工程] TE39