Modification and Performance Evaluation of the Viscosity of Water-Based Mud at Different Hole Angles for Cuttings Transport Using Sodium Dodecyl Sulfate Modified Polyethylene Glycol-Nanosilica Composite

The Viscosity of drilling muds is very critical while drilling for crude oil and the intrinsic behaviour between the viscosity and hole angles for cuttings transport is still under examined. This informs the need to formulate water-based mud (WBM) with polyethylene glycol-silica composite modified by sodium dodecyl sulfate (PEG-SiO 2 NC-SDS) to assess the impact of varying viscosities on the cuttings transport efficiency (CTE) of the WBM, which were compared with that of commercial nanosilica (SiO 2 NP). The drilling muds were tested at different hole angles (0, 30, 45, 60, 75, and 90 o ), pipe eccentricities (e = 0 and 1.0), and the CTE was examined in a field-oriented laboratory cuttings transport flow loop. The flow loop comprises a 16-ft-long annulus with a 1.2-ft. diameter non-rotating drill pipe inside a 2.4-ft. diameter outer pipe. Sandstone particles between 0.50 and 4.00 mm were injected while circulating the mud via the test chamber. The results unveiled improved plastic viscosity of the WBM at 78 o F by 60% and 20% with the optimum 1.5 g PEG-SiO 2 NC-SDS and 1.0 g SiO 2 NP concentrations, respectively. The API fluid loss of the WBM decreased from 10.2 ml to 5.4 ml and 9.6 ml with 1.5 g PEG-SiO 2 NC-SDS and 1.0 g SiO 2 NP, respectively. The optimum viscosities and higher flowrates were more efficient for larger cuttings sizes at larger hole angles of 75 o and 90 o . Smaller cuttings were the easiest to lift at all hole angles, while the largest cuttings were the most difficult to lift. Hole angles of 45 o and 60 o are very difficult to clean, but the 60 o -hole angle is the most difficult. However, these two-hole angles need special attention during the mud formulation. Overall, the CTE of the various mud samples varies considerably with viscosity, flowrate, hole angle, and eccentricity, and the PEG-SiO 2 NC-SDS showed superior mud properties and cuttings lifting performance over SiO 2 NP, which could be befitting for drilling operations.