控压钻井线性节流阀及其控制

针对现有节流阀难以满足实时精细调控的难题,设计出了在25%~85%的开度范围内压降随开度线性变化的节流阀,进行了整体结构设计,并通过性能试验验证了设计理论。针对井口回压控制不够精确、响应速度慢的问题,提出了一种井口回压三层反馈控制方法,实现了底层开度曲线直接控制,中间层压力快速粗调,外层压力精细调节。开发了井口回压控制模块,通过实验验证了控制方法的响应时间和精度,井口回压控制精度达到±0.1 MPa,最大响应时间为28s。

Linear choke valve and its control technology for managed pressure drilling

It is difficult for choke valve to achieve precise real-time regulation, so a new choke valve was designed for pressure drop varying linearly with choke opening in the opening range of 25% -85%. Accordingly, the overall structural design was completed, and the design theory was validated by performance test in this study. The problems such as imprecise back-pressure control at well head and slow response speed were studied to propose a three-layer feedback control method for wellhead back pressure, so as to achieve the direct control of bottom opening curve, the fast rough adjustment of middle-layer pressure and the fine regulation of outer pressure. The wellhead back pressure control module was developed, and the response time and precision of control method were validated through experiments. Thus, the control precision of wellhead pressure reached ±0.1 MPa and the maximum response time was 28 s.