欠平衡钻井井底压力预测与控制技术

BOTTOMHOLE PRESSURE PREDICTION AND CONTROL TECHNOLOGY IN UNDERBALANCED DRILLING

平立秋 汪志明 魏建光

Ping Liqiu Wang Zhiming Wei jianguang

中国石油大学石油天然气工程学院, 北京 102249

Oil and Gas Institute of Petroleum University, Beijing 102249

在欠平衡钻井过程中,为避免井底压力波动过大,引起过平衡状态,对产层造成伤害,保持全过程欠平衡钻井十分必要。分析了影响井底压力波动的因素,介绍了国内外在井底压力控制技术方面的最新研究成果,总结了欠平衡钻井井底压力预测技术研究现状。通过分析该研究领域内存在的不足及应用上的局限性,提出了解决井底压力波动的最新压力预测及控制技术的研究方向,即建立井筒和地层耦合的动态欠平衡钻井模型,实时监测和控制井底压力,在起下钻及接单根过程中,用地层流体的适当流入来代替中断的地面注入过程,避免井底压力波动过大而引起过平衡的钻井状态,保持全过程欠平衡钻井,最大限度地保护产层。另外,为了保证欠平衡钻井井底压力预测的有效性,提出了井底压力预测应采用稳态模型和动态模型结合的新方法。

This paper presented the necessity of maintaining 100% underbalanced conditions during underbalanced drilling operation.The factors affected bottomhole pressure fluctuation were analyzed.The new development of bottomhole pressure control and prediction technology in underbalanced drilling was introduced.The deficiency in the study and limitation in use was presented.The innovation method of solving bottomhole pressure fluctuation was given:the dynamic model by coupling wellbore and formation flow characteristic was established to predict wellbore pressure current time.During tripping and drilling connections,the reservoir influx substituted for the interrupted surface injection to control bottomhole pressure fluctuation.These conditions should allow preservation of underbalanced conditions and consequently avoid formation damage.To predict bottomhole pressure effectively,the combination of dynamic and steady state models should be studied.

10.3969/j.issn.1000-7393.2005.06.006