摘要
CO2驱是一种能大幅度提高原油采收率的三次采油技术,国内该项技术的研究和应用起步较晚,多以先导试验为主。苏北盆地溱潼凹陷经过10余年的探索,已经在5个低渗油田开展了CO2驱先导试验和推广应用,针对这5个油藏利用一维细管模拟和油藏数值模拟方法开展了注气时机、段塞尺寸和注气部位的研究,并应用典型实例进行了分析,认为先期注入提高混相压力,可更有效地缩短两相区过渡带,增加油相中溶解的CO2含量,降低油相粘度和油气界面张力,进而提高混相程度,更有利于驱油;采用大尺寸段塞可加大CO2波及区域,较好地保持地层能量,从而提高油井见效率,增强驱替效果;高部位注气可有效地抑制重力超覆,减少CO2气体过早地产出和突破的机会。就苏北盆地低渗油藏而言,采用先期注入、大尺寸段塞和高部位注气不失为一种成熟有效的提高采收率方法。
As a kind of tertiary oil recovery technology, CO2 flooding can substantially improve the oil recovery ratio which in China started late on its researching and applying, and now is more likely to be sporadic pilot tests. After more than ten years of exploration in Qintong sag, Subei basin, CO2 flooding pilot tests has been conducted and applied in 5 low permeability oil fields. This paper studied the 5 low permeability oil fields with one-dimensional tubule simulation and reservoir numerical simulation, and on this basis, carried out researches of gas injection timing, the slug size, and the gas injection parts. This text stated that improving the miscible pressure in the early injection can more effectively shorten the two phase transition zone, increase the CO： disso- lution rate, reduce the viscosity of oil phase and interracial tension of oil and gas, thus, can increase the degree of miscible. In terms of the low permeability reservoir in Subei basin, early injection as well as large size slug can be considered as a mature and effective method to improve oil recovery.
出处
《现代地质》
CAS
CSCD
北大核心
2015年第4期950-957,共8页
Geoscience
关键词
CO2驱
先期注入
段塞尺寸
注气部位
低渗油藏
Co2 flooding
early injection
slug size
gas injection part
low permeability reservoir
