油气藏评价与开发 ›› 2019, Vol. 9 ›› Issue (6): 51-55.

• 石油工程 • 上一篇    下一篇

CO2萃取作用对最小混相压力的影响实验研究

齐桂雪   

  1. 中国石化中原油田勘探开发研究院,河南濮阳 457000
  • 收稿日期:2019-07-18 出版日期:2019-12-26 发布日期:2019-12-30
  • 作者简介:齐桂雪(1984 —),女,博士,工程师,从事提高油气采收率研究。通讯地址:河南省濮阳市华龙区中原东路360号,邮政编码:457001。E-mail: yushan225@163.com
  • 基金资助:
    中国石化集团公司研究课题“东濮高压低渗油藏改善气驱效果关键技术”(P17003-4);,“气藏型储气库方案优化设计研究”(P18096-2)

Effect of CO2 extraction on minimum miscibility pressure

QI Guixue   

  1. Research Institute of Exploration and Development, Sinopec Zhongyuan Oilfield Company, Puyang, Henan 457000, China
  • Received:2019-07-18 Online:2019-12-26 Published:2019-12-30

摘要:

为了厘清CO2驱过程中萃取作用对最小混相压力的影响,明确气体前缘及气体波及后最小混相压力的变化情况,通过高温萃取实验、色谱分析手段,分别研究了不同萃取压力条件下CO2萃取率,以及萃取过程中萃取油与残余油组分分布特征,同时采用界面张力消失法定量分析萃取油、残余油最小混相压力的变化。实验结果表明:在实验温度95 ℃、实验压力10 ~ 45 MPa条件下,超临界CO2可以萃取原油各个碳数的组分,萃取油中C5-20摩尔质量达到80 %以上;超临界CO2对原油的萃取率、萃取油最小混相压力及残余油最小混相压力,均与萃取压力正相关;受萃取作用及压力影响,在CO2驱替运移过程中最小混相压力是个动态变化值,最小混相压力满足关系:MMP残余油>MMP原油>MMP萃取油;萃取油、残余油最小混相压力与组分分布有关,地层油中影响混相的关键组分为C5-10组分和C26+组分。研究结果对进行CO2混相驱设计及混相带预测提供较好借鉴。

关键词: CO2萃取率, 油相组分分布特征, 最小混相压力, 地层油关键组分, CO2

Abstract:

In order to clarify the effect of extraction on miscible pressure during CO2 flooding and make clear the characteristics of minimum miscible pressure of gas front or after gas sweep, the CO2 extraction rate under different pressure and the distribution characteristics of oil components in the extraction process are studied by the extraction experiments under high temperature and chromatographic analysis. The changes of minimum miscible pressure of extracted oil and residual oil are quantitatively analyzed by the interfacial tension vanishing method. Under the experimental condition of 95 ℃ and 10 ~ 45 MPa, the supercritical CO2 can extract the components of each carbon number of the crude oil, and more than 80 % of the extracted oil is C5-20. The extraction rate of supercritical CO2 and the minimum miscibility pressure of extracted oil and residual oil are positively correlated with the extraction pressure. Under the influence of extraction and pressure, the minimum miscible pressure in the CO2 displacement and migration process is a dynamic value, which reduces in the following order: residual oil, crude oil and extracted oil. The minimum miscibility pressure of extracted oil and residual oil is related to component distribution. The critical components affecting miscibility in formation oil are C5-10 and C26+ components. The study result provides good reference for CO2 miscible displacement design and miscible phase prediction.

Key words: CO2 extraction rate, distribution characteristics of oil components, minimum miscible pressure, formation oil critical component, CO2 flooding

中图分类号: 

  • TE357