定向滑动钻进控制新方法研究

在用螺杆钻具进行定向钻井时，由于井眼摩阻大，常导致工具面调整困难和滑动钻进托压。针对该问题，研究了有效结合了顶驱可编程控制器和传感器的滑动钻进控制新方法。首先，分析研究了钻具滑动前后摩擦力的变化规律和控制扭矩旋转钻具减小井眼摩阻的方法。然后，通过5个传感器的实时数据采集，依据现场技术人员的经验和操作方法，将其转换为计算机可以执行的控制程序，建立了以可编程控制器为核心的人机控制界面，用可编程控制器计算了调整工具面所需的旋转角度，并将工具面准确调整到设计的角度；根据大钩悬重和压差Δp判断是否出现托压，出现托压时用可编程控制器计算不改变工具面的旋转扭矩，以计算的扭矩为限值左右旋转钻具减小井眼摩阻，直到压差Δp0，解决滑动托压。相关应用表明，新方法能大幅减小井眼摩阻，提高机械钻速，是目前螺杆钻具滑动钻进中最有效的控制方法。 

New Control Approach Directional Slide Drilling

During directional drilling using screw drill,difficult adjustment of tool face as well as back pressure in slide drilling are often encountered due to the high drag force of the wellbore.To address these problems,a slide drilling control system based on the top drive’s programmable logic controller(PLC) integrated with sensors was researched and developed by utilizing accurate positioning and rotation from top drive,The variation of the friction of drill string before and after sliding as well as the method of reducing wellbore drag by controlling drill string rotary torque were researched and analyzed.Through the real-time data acquisition of 5 sensors,the experiences and reasoning methods of directional driller are transformed to a set of control program,thus a human-computer interaction interface with PLC as the core is built.The PLC calculates the rotary angle required at the tool face and then accurately adjusts the tool face angle to the designed angle.The hook weight and differential pressure are used to determine if back pressure.After the rotary torque value without making any changes of the tool face angle is calculated by PLC,the top drive rotates the drill string clockwise or counterclockwise according to calculated torque value to reduce the wellbore drag until the differential pressure is greater than zero,thus sliding back pressure could be solved.Application result shows that the new method can significantly reduce wellbore drag force and improve the ROP,and is currently the most effective method in solving screw drill slide drilling.