Numerical analysis of flow erosion on drill pipe in gas drilling

The majority of this paper investigates the factors affecting the erosion rate of drill pipe using the computational fluid dynamics (CFDs) methodology. A three-dimensional drill pipe-casing annulus including drill pipe connector is selected as computational domain in this investigation. CFD models are proposed to obtain the flow field distribution in annulus and predict the erosion rate of drill pipe, which include both a gas-cuttings two-phase hydrodynamic model and an erosion model. The impacts of gas velocity and drill pipe eccentricity on erosion rate have been reasonably captured. Based on the analysis of calculated flow characteristics, a structure optimized scheme by reducing the slope of drill pipe connector is put forward to decrease the erosion rate and increase the life of drill pipe.