Application of Particle Image Velocimetry (PIV) on Newtonian and Two-phase Slurry Flow through the Annulus

The objective of the study is to visualize the impact of fluid flow rate, fluid rheology, drill pipe rotation and eccentricity of drill pipe on cutting transport, transitional velocity profile, the effect of near-wall fluid turbulence and drag stress with and without the solid cuttings bed to mimic best drilling conditions for horizontal wells in ex-situ conditions. The analysis has conducted using combined techniques of Laser-induced Particle Image Velocimetry (PIV), Seeding/fluorescent tracers tracking, and Refractive Index Matching (RIM). Experiments have been performed on a plant-scale multiphase flow loop. The pipe sections of the flow loop and investigation area were made up of acrylic glass to imagine fluid flow patterns better. Biopolymer Flowzan® is used in different concentrations to obtain non-Newtonian characteristics of the liquid. For PIV analysis, seeding particles of a hollow glass material having a uniform diameter of 20 nm and fluorescent particles of size 20-30 μm were used to track and illuminate particles. A class IV LASER was used to illuminate the flow field inside the RIM box. The premixed seeding and fluorescent particles with the flow were tracked to evaluate the velocity field for the respective interested area by the PIV system. A high-speed CCD Phantom® v7.3 camera was utilized to capture flowing particles under the laser field. Both Laser and camera were placed in the normal position to capture PIV images. The refraction Matching Index (RIM) method was applied to calibrate the system by introducing the same fluid inside the RIM box to avoid the error of particle position in the annulus due to glass-liquid-glass refraction. To evaluate the statistics for the desired velocity field of the flow acquired, data was thoroughly investigated with DaVis 8.4 software. Additionally, the turbulent behavior of the slurry flow has also been identified with high preciseness, and the corresponding characteristics of the suspended particles were also observed at the same time. The velocity field outcomes will suggest that at the bottom of the annulus section, the velocity at the near-wall region deviates from the bulk velocity of the fluid because of the solid accumulation tendency. However, a higher flow rate of the slurry may introduce more suspended solid particles, which can eventually result in a uniform velocity field for the whole annulus section. The fluid flow patterns were altered due to drill pipe rotations and solid particles' helical motion. The rotation of the drill pipe resulted in the solid and tracer particles scattered more uniformly in the annular cross-section, which provided a constructive impression on the cutting transport. This technique provides a better prediction of mass and momentum transfer and identification of velocity profiles and pressure drop gradient in multiphase flow on a large scale.