低渗透油藏CO2驱采油井试井模型  

Well test model research for CO_2 flooding production well in low permeability reservoirs

作　　者：阎燕[1] 李友全[1] 于伟杰[1] 王杰[1] 刘同敬[2,3] 王朝明[4] 

机构地区：[1]中国石化胜利油田分公司勘探开发研究院,山东东营257015 [2]中国石油大学(北京)提高采收率研究院,北京102249 [3]中国石油大学(北京)石油工程教育部重点实验室,北京102249 [4]中国石化石油工程技术研究院,北京100101

出　　处：《断块油气田》2018年第1期80-84,共5页Fault-Block Oil & Gas Field

基　　金：国家科技支撑计划项目“CO2埋存与提高采收率评价研究”(2012BAC26B02);国家科技重大专项课题“低渗-致密油藏高效提高采收率新技术”(2017ZX05009-004);北京市自然科学基金项目“基于数字岩心的数字渗流基础探索研究”(2173061)

摘　　要：低渗透油藏CO_2驱油过程中,采油井的实测压力-压力导数双对数曲线往往后期上翘,采油井的试井压力响应同时受储层渗流能力和流体流动能力改变的影响,但人工压裂形成的物性分区和CO_2溶解导致的黏度分区特征在其中的影响程度尚不明确。文中采用剖面均化方法建立了低渗透油藏CO_2驱采油井试井数学模型,利用Laplace积分变换,求得无因次井底压力解,并通过数值反演获得双对数试井特征曲线。结果显示,低渗透油藏近井渗流介质改造作用是压力双对数曲线出现复合油藏特征的直接原因,而CO_2窜流导致的混合流体流动能力改善并不是导致复合油藏特征的主要原因。在此基础上,采用混合流体黏度修正方法能够快速、准确地量化CO_2驱过程中采油井近井渗流能力的变化。CO_2 flooding has become an attractive enhanced oil recovery method in the world, however due to the fracturing and viscosity improvement, the characteristics of production well pressure responses become very complex. In practices, the pressure responses of CO_2 flooding in low permeability reservoir often show the composite reservoir characteristics. However, the impact of the improvement of mixing fluid flow ability caused by CO_2 dissolution and channeling are not clear. This paper provides a well test model for CO_2 flooding production well in low permeability reservoirs based on profile equalization technology. The dimensionless bottom hole pressure is obtained by using the Laplace integral transform, and then the log-log well test curves are obtained by numerical inversion.The results show that composite pressure response of CO_2 flooding production well are resulted from fracturing or acidification, rather than CO_2 dissolution near the wellbore. On this basis, the proposed method can quantify the near wellbore permeability of production wells quickly and accurately for CO_2 flooding.

关 键 词：CO2驱试井 剖面均化 复合油藏 数学模型 低渗透油藏 压力响应 

分 类 号：TE348[石油与天然气工程—油气田开发工程]