基于多次接触特性曲线的二氧化碳驱最小混相压力预测方法  

A new method to forecast the CO2-oil minimum miscibility pressure based on multicontact curve

作　　者：李菊[1] 李实[2] 

机构地区：[1]中国石油大学(北京)地球物理与信息工程学院,北京102249 [2]中国石油勘探开发研究院,北京100083

出　　处：《油气地质与采收率》2014年第1期51-54,114,共4页Petroleum Geology and Recovery Efficiency

基　　金：国家重点基础研究发展规划"973"项目"油藏机理及相关地质体CO2埋存机理与潜力评价"(2011CB707302);国家自然科学基金项目"超低渗油藏注气提高采收率理论与技术研究"(U1262101)

摘　　要：二氧化碳驱是提高采收率的有效方法之一,二氧化碳混相驱可以更大程度地提高原油采收率。最小混相压力是评定二氧化碳驱能否实现混相的关键参数。通过二氧化碳与原油多次接触过程,得到多次接触特性曲线,并对二氧化碳驱混相过程的多次接触特性曲线特征进行分析;综合温度和原油组成等因素的影响,建立了多次接触特性曲线最小值预测的关联公式,进而提出预测最小混相压力的新方法,即通过二氧化碳驱多次接触特性曲线最小值的确定过程来获得最小混相压力。采用该方法对二氧化碳驱的最小混相压力进行预测,其结果与细管实验法预测结果的相对误差小于8%。基于多次接触特性曲线的最小混相压力预测方法,无须确定关键系线,避免了系线分析法和混合单元格法中计算关键系线的算法收敛的不稳定性,并且克服了经验法未考虑多次接触过程的缺点,因此更为实用、准确。Miscible and/or near miscible gas injection processes are those among the most widely used enhanced oil recovery tech-niques. And, a CO2-oil miscible flooding is more effective to enhance the local displacement efficiency. The successful design and im-plementation of a miscible CO2injection project is dependent upon the accurate determination of MMP(minimum miscibility pres-sure), the pressure above which the displacement process becomes multicontact miscible. This paper considers the multicontact pro-cess during the miscible flooding, and presents a method to get the characteristics curve of multicontact, and analyzes the character ofcharacteristics curve for CO2flooding, and combines some main factor(reservoir temperature, oil composition) that may infect MMP,then, we suggest a correlation to make a prediction for the minimum value of characteristics curve of multicontact. Based on the workabove, we suggest a new method to predict MMP for CO2flooding. Our method needn't locate the key tie lines, and avoid the unfavor-able factors existing in the MOC and the mixing-cell method which leads to the failure of MMP prediction, so as to overcome the short-coming of traditional correlation which didn't consider the process of multicontact. For all of these reasons, our method becomes morepractical and more accurate. The prediction error for our method is within 8%.

关 键 词：最小混相压力 二氧化碳 多次接触特性曲线 关联公式 预测方法 

分 类 号：TE341[石油与天然气工程—油气田开发工程]