Numerical simulation of fluid flow and experiment on downhole friction reduction tool

In this article, a new friction reduction tool is designed for drilling of horizontal wells, and its performance is investigated using computational fluid dynamics simulation technique, laboratory experiment, and field testing. According to flow field analysis, the spiral diversion channel has obvious disturbance effect on fluid, which can help cutting transport and reduce cutting bed accumulation. Tensile test is carried out and tensile resistance of the friction reduction tool is 90 ton. Shearing test is also conducted to examine the shear resistance capacity of the pins that support rollers. Under the lateral load of 20 MPa, large deformation of the pins is observed, but they are not broken. The function of friction and torque reduction is verified using experimental apparatus for drill string dynamics of horizontal well. Field testing is also completed in a real well. The accumulated operational time of the friction reduction tool is more than 130 h and its fatigue life reaches up to 3 x 10(5) cycles. The simulations and experiments indicate the designed tool can effectively reduce friction and torque in horizontal wells. The work presented in this article can provide a technological basis and scientific reference for the development and application of friction reduction tool in horizontal wells.