Reducing Torque and Drag in Extended-Reach Wells Using Thermoplastic Polymers for Protective Sliding Rings

Extended-reach drilling represents an advanced way of drilling and accessing reservoirs that were previously economically not feasible to drain, impossible to reach or in an environmentally sensitive area. One of the main issues that appears while drilling such wells is caused by the high values of friction factor which cause high values of torque and drag. One of the suggested solutions is to use a protective sliding ring made from materials such as POM, Teflon and PA6 in combination with lubricants added to a polymer mud system. First, measurements were conducted on a lubricity tester to choose the best material and, after finishing, a mechanical wear test was conducted on a specially designed device to measure mechanical wear. Results showed that Teflon showed lower values of friction factor in comparison to steel and the mechanical wear was minimal. The lowest value of friction force was recorded for blocks made from Teflon in tested mud systems. It is also noticeable that, in polymer mud with weighting additives and lubricant, the value of the friction force is higher than in polymer mud with lubricant only.