Investigation on multiphase flow of multi-size cuttings particles and non-Newtonian drilling fluids in oil and gas horizontal well drilling using kinetic theory of granular flow

• Published in: Energy (Oxford) 2023-11, Vol.282, p.128878, Article 128878
• Main Authors: Pang, Boxue, Ren, Xianghui, Liu, Zaobao, Wang, Xin, Liu, Xu
• Format: Article
• Language: English
• Subjects: Cuttings transport; Horizontal well drilling; Kinetic theory of granular flow; Oil and gas; Particle size composition
• ISSN: 0360-5442
• DOI: 10.1016/j.energy.2023.128878

Effective cuttings transport has long been a challenge in oil and gas horizontal drilling, and inadequate wellbore cleaning can result in severe drilling accidents including stuck pipe. The transportation of multi-size cuttings by non-Newtonian drilling fluids in the horizontal wellbore with a rotating drill pipe was systematically investigated using the kinetic theory of granular flow. Collisions between particles and their two-way coupling with drilling fluid turbulence were modeled. Flow regime of multi-size cuttings has been predicted, and effects of particle size composition characteristics were studied. The spatial inhomogeneity of the non-Newtonian fluid viscosity and the sedimentation of particles result in a complex stratified flow regime for multi-size cuttings transport. Cuttings concentration and drilling fluid axial velocity distributions both show swaying phenomena with drill pipe rotation. Moreover, the secondary flow regions appear with negative tangential velocities. The cuttings transport ratio (CTR = 0.846) is the best in the case of cuttings with different particle sizes injected in a uniform concentration. While in the case where the concentration of injected multi-size cuttings is negatively correlated with particle size, the cuttings velocity fluctuations caused by collisions and frictions are the most severe, and the borehole cleaning is the worst (CTR = 0.803). •Multi-size cuttings transport in oil and gas drilling is numerically studied.•Particles collisions and their two-way coupling with turbulence are modeled.•Complex spiral stratified flow regime for multi-size cuttings is predicted.•Effects of particle size composition characteristics on hole cleaning is studied.