实验模拟指示曲线法确定气井合理生产压差

Application of Lab-Simulation of Indicative Curves in Determination of Reasonable Production Pressure Difference in Gas Wells

通过对气井的二项式方程以及采气指示曲线的分析可知:为充分利用地层能量,采气指示曲线上翘点所对应的气井流压即为气井的合理流压,该点所对应气井的生产压差即为气井的合理生产压差,在此理论基础上,采用实验模拟研究的方法,根据油气藏实验模拟相似定律,充分模拟地层条件下井筒壁附近储集层采气指示曲线,确定合理流动压差,进一步转化为气井的合理生产压差。通过对长庆油田8口井的实验研究,得出该地区一类储集层气井的合理生产压差应该控制在2.5MPa以内,二类储集层气井的合理生产压差应该控制在3.5MPa以内,三类储集层气井的合理生产压差应控制在4.5MPa以内。

The analyses of binomial equation for gas wells and gas production indicative curves are conducted,and show that to fully utilize in-situ energy,the flowing pressure of gas well corresponding to tilting or upwarping point indicative curve from gas wells should be the reasonable flowing pressure of gas wells,while the production pressure difference at this point can be used as the reasonable production pressure difference.Based on this theory,adopting lab simulation approach and scaled physical mod-eling of petroleum reservoir,this paper presents full simulation of gas producing indicative curves from nearby sidewall under the reservoir conditions,determining reasonable flowing pressure difference,and conversing it to reasonable production pressure differ-ence of gas well.From the lab analyses of8wells in Changqing oilfield,it is concluded that the reasonable production pressure differences of gas wells should be controlled within2.5MPa for Class I reservoir,3.5MPa for Class II reservoir and4.5MPa for Class III reservoir.