Transport of cuttings is crucial in a horizontal drilling operation. Effective removal of cuttings is necessary for efficient drilling. An experimental investigation has been carried out to analyze the flow behaviour of solid cuttings in different drilling environments with visualization techniques.
This study investigates the cuttings transport mechanism in a horizontal annulus section. A 6.16 m long and 4.5″ × 2.5″ annulus section was used to model the real-time drilling behaviour with different flow rates, drill pipe rotations and eccentric positions. Water as a Newtonian fluid was used as drilling mud and 2–3 mm solid glass beds were used to simulate the drill cuttings. The in-situ volume fraction of cuttings in the annulus was estimated by Electrical Resistivity Tomography (ERT) analyzer. Visualization technique used to estimate the moving bed velocity in the horizontal annulus section. A highspeed camera was used to capture the transport phenomena of the moving solid particle at 2000 frames per second. The highspeed camera can effectively track each particle in the system. Analysis of high-speed camera revealed different cuttings transport phenomena like rolling of cuttings, stationary cuttings bed and cuttings suspended into the drilling mud.
Experimental investigation revealed that drill pipe rotation helps in cuttings bed movement and resist the formation of large cuttings dune in the annulus formation. Also, this study revealed that eccentric annulus shows less annular solid volume compared to a concentric annulus; however, an eccentric annulus is harder to clean compared to a concentric annulus section.