欠平衡钻井井底压力控制技术

Bottomhole pressure control technology in underbalanced drilling

周英操 刘永贵 鹿志文

ZHOU Ying-cao LIU Yong-gui LU Zhi-wen

大庆石油管理局, 黑龙江大庆 163413 大庆石油管理局钻探集团钻井工程技术研究院, 黑龙江大庆 163413

在欠平衡钻井过程中,井底压力控制技术是其关键技术之一,为准确掌握井底压力的大小,提高井底负压控制精度,开展了3项关键技术研究。首先利用在钻井过程中随钻测量起钻后地面回放的方法,自行研制开发出能够抗180℃高温、具有抗震功能的测量仪器;其次,在原有模型基础上,利用实测数据进行分析,考虑固相和多相流加速度压降的影响,研制开发了流钻欠平衡钻井环空多相流井底压力的计算模型,并推导出机械钻速影响井底压力增量的计算公式;最后,为验证模型精度,开发了钻井监测与分析计算软件,软件计算结果与实测数据对比,误差小于3%。研究表明,3项技术可提高井底压力计算和控制精度,为欠平衡钻井设计计算与精确控制提供了理论依据和实用数据。

The bottomhole pressure control technology is one of the key technologies in underbalanced drilling.Research on three key technologies is carried out in this paper to have a precise knowledge of the bottomhole pressure and improve the precision of controlling the negative pressure of bottomholes.Firstly,a new kind of measurement instruments with antiseismic function and resistant to the high temperature of 180℃ is developed on the basis of using the measurement while drilling(MWD) method.Secondly,a new model for calculating the bottomhole pressure of multiphase flow in annulus in flow-drilling under balance pressure drilling is suggested based on its original model and taking the acceleration drop of solid and multiple phases flow into account.The computational formula on pressure increment in bottomholes affected by drilling speed is deduced as well.Finally,the calculation software is developed for monitoring and analyzing drilling to testify the precision of the new model.The calculation result is less than 3% as compared to the experimental data.The research reveals that these three key technologies can improve the accuracy to calculate and control bottomhole pressure,providing theoretical foundation and practical data for calculating and precisely controlling underbalanced design.

10.3969/j.issn.1000-7393.2007.02.004