摘要
基于对低渗气藏渗流机理的研究,在Rawlines和Schellhardt指数式产能方程的基础上,分析了启动压力梯度的影响,推导出了适合低渗气井的产能预测公式及地层压力计算公式。产能测试数据分析表明,启动压力梯度Gps增大,气井绝对无阻流量qaof增大,同时,地层压力p与波及半径r在半对数曲线p-lgr上其形态也越呈现出"S"形。对于地层压力梯度而言,启动压力梯度Gps越小,井眼附近的地层压力梯度变化越快;启动压力梯度Gps越大,井眼附近地层压力梯度变化相对平缓,在井壁附近很小的区域以外,地层压力梯度几乎等于启动压力梯度。
Based on the study of percolation mechanism of low permeability gas reservoirs and Rawlines and Schelldardt exponential productivity equation,the influence of starting pressure gradient was studied,a new productivity prediction formula and a new formation pressure calculation formula were derived.The analysis results of productivity data analysis indicated that as the starting pressure gradient G ps increased,the absolute open flowq aof of the gas well increased.At the same time,the formation pressure pand swept radius r were in ' S ' shape in the p-lgrcurve.As for the pressure gradient,the lower the starting pressure gradient G ps is,the faster it changes near the wellbore,the higher the G ps is,it changes relatively smooth near the wellbore,in the smaller area near the wellbore,the formation pressure gradient is almost equal to the starting pressure gradient.
出处
《石油天然气学报》
CAS
CSCD
2013年第4期118-121,168,共4页
Journal of Oil and Gas Technology
关键词
低渗气藏
启动压力梯度
产能预测
指数式产能方程
渗流机理
low permeability gas reservoir
starting pressure gradient
productivity prediction
exponential productivity equation
percolation mechanism
