Comparison of Water-Based Drilling Muds with Hydroxyapatite Nanoparticles and Copper II Oxide Nanoparticles for Lifting Cuttings Through Rotating Drill Pipes at Different Hole Inclinations

Drilling deviated wellbores has raised concerns about proper cutting transport. Cuttings settling downhole can create stationary cutting beds, causing drilling mishaps like stuck pipes. High fluid velocity is typically required to efficiently erode a stationary bed, but this is constrained by hydraulic and wellbore geometry. When this occurs, pipe rotation can erode the bed mechanically and enable efficient cutting transport even with lower fluid velocities. Therefore, this study formulated water-based mud (WBM) with hydroxyapatite nanoparticles (n-HAp) to examine the effect of pipe rotation on cutting transport in deviated wells. It was compared with copper II oxide nanoparticles (CuO NP) in terms of rheology, filtration, and cutting transfer efficiency (CTE). The CTE of n-HAp amounts (0.4–2.0 g) in moving cuttings with diameters of 0.80 to 3.60 mm through deviated wellbores of 40 to 65° at a 3.5 m/s fluid velocity with 60 and 120 rpm pipe rotation speeds was determined. Compared with CuO NP, n-HAp findings demonstrated enhanced rheology and CTE. However, for fluid loss control, n-HAp was slightly less effective compared to CuO NP. For all deviated angles, n-HAp increased the CTE by 9.5–50%, while CuO NP increased it by 3.4–38.7% at 120 rpm. Compared with 60 rpm, a higher CTE occurred at 120 rpm. Moreover, CTE occurs in the following manner: 40° > 65° > 45° > 60° > 50° > 55°. It suggests that stationary bed formation is more likely to occur at inclinations of 50–55°. These findings are crucial for drilling deviated wells.