二氧化碳驱油岩石物理分析及地震正演模拟

Rock physical analysis and seismic forward modeling for CO_2 flooding

二氧化碳驱油不仅可以封存二氧化碳以控制全球气候变暖,而且可以提高采油率,具有十分重要的研究意义.但目前仅能简单监测二氧化碳驱油的效果和二氧化碳采出情况,驱油过程的精细监测成为薄弱环节,制约着二氧化碳驱油的进一步发展.地震法作为一种相对成熟的地球物理勘查方法,具有实现二氧化碳气驱过程描述的技术可行性.本文参考国内外研究成果,从基础研究入手,应用胜利油田二氧化碳驱先导试验区的实际数据,通过流体替换及正演模拟方法,分别对理论模型、单井资料进行二氧化碳驱油过程岩石物理参数变化分析,并进一步研究了叠前叠后地震响应特征变化规律,取得了二氧化碳驱油地震响应特征的阶段性认识,对二氧化碳驱油的地震监测相关研究工作具有一定的借鉴意义.

CO_2 flooding not only can seal carbon dioxide to control global warming,but also can improve the recovery. So it has very important research significance. However except for monitoring carbon dioxide production,the process of oil displacement becomes a weak link,which restrict the further development of CO_2 flooding.The seismic method as a relatively mature geophysical exploration method,has technical feasibility to describe the oil displacement process.This paper draws on the research achievements made in China and the rest of the world. Starting from basic research and using the actual data furnished from a pilot area at Shengli Oilfield, it analyzes,by means of fluid replacement and forward modeling,the physical parameter variation of rocks in the process of CO_2 flooding with respect to theoretical model as well as individual well data.Moreover,this paper also studies the pre-and post-stack seismic response characteristic variation pattern and comes up with milestone appreciation of seismic response characteristics in CO_2 flooding. The work of this paper may have a value of reference for research in seismic monitoring of CO_2 flooding.