Numerical Simulation on Coiled Tubing Erosion During Hydraulic Fracturing

Abstract

Hydraulic fracturing operation through coiled tubing is a safe, economical, and efficient well stimulation technique. During the operation, the wall of coiled tubing spooled on the reel is abraded and eroded by high-concentration proppants. Because of the high-concentration solid phase, a discrete phase model is not appropriate for erosion prediction during a hydraulic fracture operation. In this paper, the monolayer energy dissipation erosion model is used to predict the erosion of coiled tubing. The simulation results show that the sand particles accumulate at the tubing extrados to form a sliding bed and slide along the tubing wall. Therefore, the erosion of the tubing wall spooled on the reel is mainly due to the friction abrasion caused by the sliding bed of solid particles and is related to the centrifugal force of particles. Erosion rate, which is highest at the coiled tubing extrados, has a cubic relationship to the flow rate of the fracturing fluid, has a linear relationship with the sand volume fraction, and is inversely related to the reel radius. The more viscous the fluid, the more uniform the particles distribute, so the erosion rate is reduced with the increase in fluid viscosity.