The Hole Deviation Control Theory Analyses And Application On Positive Displacement Motor

In oil drilling engineering, the workers play much attention on how to increase the rate of penetration during controlling deviation of vertical well The structure of drill-assembly, which uses single bend PDM (positive displacement motor) to control hole deviation, is presented in this paper. Single bend positive displacement motor drill-assembly can work on relatively high rotating velocity under low bit weight, which is not only benefit to heighten the rotating velocity of machine, but also benefit to control hole deviation, and because of structural angle the ability of well straightening is improve. So, It is more effect than traditional pendulum drill-assembly in controlling hole deviation.This paper analyzed the mechanism of well straightening and improving ROP as turnplate and screw drill rotate together, proved technique thought that using positive displacement motor associate with PDC bit to control hole deviation and improving ROP in theory, and established mechanics modal based on the method of finite elements analysis, which present a method to quantitatively analyze screw drill controlling hole deviation.The analysis of single bend PDM against deviation drilldown-hole indicates that during the stable period, the longer the distance between the stabilizers and bit, the bigger the side force will be. Bit weight has little effect on bit's side force. Angle and elbow position have much effect on bit's side force, and that is the theoretic base for designing special PDM against well deviation.Single bend PDM drill-assembly on well straightening shows strong ability in big deviation angle. In order to instruct to use Single bend PDM safely, this paper also analyze its stress-state and the result proved that under the condition of present assembly and work parameter using Single bend PDM is safe.The screw drilldown-hole motor against well deviation technique presented in the paper successfully applied in area tend to deviation, 13051 well in bai 54, T80268 well, T80276 well in 8 area fault zone, K1000 well, K1001 well in kayingdike area dongwan 1 well in dongwan anticline . It can draw a conclusion that this new method of well straightening and improving ROP worth popularized.