Development and Field Experiment on PDM with Uniform Wall Thickness

The positive displacement motor(PDM) with uniform wall thickness is a new drilling tool developed in recent years,with many technical advantages,such as single high pressure seal,low rotary speed,high torque,short radius of curvature,long service life,thermostable and safe to use,etc,suitable for conventional production well,deep well,inclined well and directional well .On the basis of current development,basic structure and designing principles of PDM at home and abroad,the paper points out the technical characteristics and its main differences compared with conventional PDM.The application and experiments in two blocks in same wells were conducted by two different PDM tools.The on-site data analysis indicates that,by using the PDM with the same wall thickness,the average downhole service time is 193 hours,and single downhole service time is 40% more than conventional PDM,the rate of penetration could be increased by 22%,and the build-up time shortened effectively.