控压钻井技术在白28井的应用

控压钻井系统主要由钻井参数监测系统(包括井下PWD)、决策分析系统、电控系统、地面自动节流控制及回压补偿系统组成,通过在井口施加连续回压来实现井底压力的恒定控制,能有效解决窄密度窗口地层和高温高压地层所出现的钻井复杂问题。白28井的应用结果表明,使用控压钻井技术,在控压钻进工况下可将井口压力波动控制在0.2 MPa以内,控压停泵和起下钻工况下可将井口压力波动控制在0.5～0.8 MPa,井底压力波动控制在1.0～1.5 MPa,可保证井底压力当量密度在控制范围内;能够快速发现溢流和井漏等复杂情况并进行有效控制,确保了施工过程的安全,实现了钻井安全和勘探开发的目标。

Application of Pressure Control Drilling Technology in Well 28 of Bai

The pressure control drilling system mainly consists of drilling parameter monitoring system(including downhole PWD),decision-making analysis system,electric control system,ground automatic throttle control and back pressure compensation system.The constant control of bottomhole pressure is achieved by producing continuous back pressure.It can effectively solve the complex drilling problem in narrow density window formations and high temperature and high pressure formations.The application in Well 28 of Bai shows that use of pressure control drilling technology can control wellhead pressure fluctuation within 0.2 MPa under pressure control drilling conditions.The wellhead pressure fluctuation is controlled between 0.5 and 0.8 MPa under the condition of pump stopping or tripping.Control of bottomhole pressure fluctuation between 1.0 and 1.5 MPa can ensure the bottomhole pressure equivalent density is kept within the scope of control.The technology can rapidly discover complex conditions such as overflow and leakage and conduct an effective control of them.As a result the safety of construction process is ensured and the goal of drilling safety is achieved.