控制压力钻井技术全尺寸模拟井试验及分析

指出了控制压力钻井技术室内试验存在的不足,给出了控制压力钻井技术全尺寸模拟井试验的原理、方法和设备,验证了控制压力钻井技术的工艺流程和控压设备的可操作性以及自动控制系统控制能力。试验结果表明,该试验流程配套简单,可以较好地模拟钻井的整个过程,通过对采集控制系统的不断调试,掌握了其调节特性,为现场试验起到了很好的指导作用;同时指出,处理气体溢流时,必须配置针对极端非线性、时变和多变量耦合等过程特性的智能控制器。如果控压钻井自动节流管汇配套的是常规液压驱动的节流阀,在钻井泵启、停过程中,流量的变化速度远远高于节流阀的反应速度,而且井筒内流体存在巨大的惯性,套压控制过程中,ECD变化达到0.3,因此应采用电动钻机,这样可以逐步缓慢降低钻井泵的排量,从而实现恒井底压力控制。

Full-size Simulation Well Experiment and Analysis of Pressure Control Drilling Technology

The weakness in the laboratory test of pressure control drilling technology was pointed out.The principle,method and equipment of the technology were given.The technological process of the technology,the operability of the pressure control equipment and the control capacity of the automatic control system were verified.The experimental findings show that the matching of the experimental procedure is simple and the whole drilling process can well be simulated.The regulation property of the collection and control system is grasped through its constant debugging,which can serve as a good guide to its field test.At the same time it is pointed out that the intelligent controller must be allocated to deal with gas overflow concerning the process characteristics of extreme linearity,time varying and multivariable coupling.If the pressure control drilling automatic throttle manifold is matched with the throttling valve of conventional hydraulic drive,the variation velocity of flowrate is far above the reaction velocity of throttle in the process of startup and shutdown of drilling pump.Moreover,there exists great inertia with the fluid in well bore.In the process of casing pressure control the ECD change reaches 0.3.Therefore,the electric drive drilling rig should be adopted so as to decrease the displacement of drilling pump gradually and achieve constant borehole pressure control.