二氧化碳对原油中胶质沥青质作用的可视化研究

发布时间：2018-01-21 05:22

本文关键词： 胶质沥青质二氧化碳高压显微固相沉淀实验可视化提高采收率　出处：《特种油气藏》2017年02期 　论文类型：期刊论文

【摘要】：为明确CO_2驱油过程中胶质沥青质沉淀原因,从原油中分离出胶质和沥青质分别与正庚烷和甲苯配置成胶质模拟液和沥青质模拟液,并用2种模拟液分别与CO_2组成不同摩尔分数的二元体系,通过高压显微固相沉淀实验,观察2个体系中固相颗粒的变化规律,探究CO_2对胶质沥青质的作用机理。实验表明:胶质模拟液-CO_2体系中CO_2的摩尔分数达到12.50%时,胶质颗粒发生沉淀,随CO_2含量增加沉淀半径增大;当CO_2摩尔分数增至35.00%时,胶质沉淀开始沉积,发生聚集;当CO_2的摩尔分数大于50.00%时,降低体系压力至泡点压力以下,CO_2先从正庚烷液相中析出,后从液状胶质聚集体中析出。沥青质模拟液-CO_2体系在泡点压力处颗粒半径最大;随CO_2含量增加,沥青质颗粒沉淀半径增大;当CO_2摩尔分数增至60.00%时,沥青质颗粒发生聚集形成沉积。该项研究对于分析CO_2驱过程中胶质沥青质对沉淀的贡献情况、沉淀生成的主要原因以及如何减小沉淀对生产造成的伤害具有重要指导作用,对于增强原油的运移能力进而提高储层原油采收率具有理论指导意义。
[Abstract]:In order to clarify the cause of glial asphaltene precipitation during CO_2 flooding, colloid and asphaltene were separated from crude oil with n-heptane and toluene to form colloidal and asphaltene simulant, respectively. Two kinds of simulated solution and CO_2 were used to form binary system with different mole fraction, and the changes of solid particles in the two systems were observed by high-pressure micro-solid precipitation experiment. The experimental results show that the colloidal particles precipitate when the mole fraction of CO_2 reaches 12.50%. The precipitation radius increases with the increase of CO_2 content. When the molar fraction of CO_2 increased to 35.00, the colloid precipitation began to deposit and aggregation occurred. When the molar fraction of CO_2 is greater than 50.00g, the lower the pressure of the system to the bubble point pressure, the COS-2 precipitates from the n-heptane liquid phase. Then precipitated from the liquid colloid aggregates. The asphaltene simulative liquid-COSP _ 2 system has the largest particle radius at the bubble point pressure. With the increase of CO_2 content, the precipitation radius of asphaltene particles increases. When the mole fraction of CO_2 is increased to 60.00g, the asphaltene particles aggregate and form deposition. This study contributes to the analysis of the contribution of glial asphaltene to precipitation in the process of CO_2 flooding. The main reasons of precipitation formation and how to reduce the damage caused by precipitation have important guiding significance for enhancing the migration capacity of crude oil and improving oil recovery of reservoir oil.
【作者单位】：中国科学院渗流流体力学研究所;中国石油勘探开发研究院;提高石油采收率国家重点实验室;国家能源二氧化碳驱油与埋存技术研发(实验)中心;中国石油长庆油田分公司;
【基金】：国家重点基础研究发展计划“973”项目“孔隙介质中相态实验与理论研究”(2011CB707304) 国家油气重大专项“CO_2驱油与埋存油藏工程技术及应用”(2016ZX05016-001) 中国石油天然气股份有限公司专项“长庆油田低渗透油藏CO_2驱油与埋存关键技术研究应用”(2014E3606)
【分类号】：TE357.7
【正文快照】： 5.中国石油长庆油田分公司,陕西靖边718500)0引言CO2驱油过程中会伴随胶质沥青质产生沉淀,在地层、井筒附近和生产管线沉积,影响驱油效率和生产过程[1-6]。已有研究发现原油中胶质对沥青质起胶溶分散作用[7-10],以维持石油的胶质稳定性,而CO2驱油过程打破了原油中各组分的平衡

【相似文献】