Experimental investigation of cuttings lifting efficiency using low and high density polyethylene beads in different hole angles

Abstract

This study investigates the impact of low and high density polyethylene beads on wellbore cleaning using water-based mud at different hole angles of 0°, 60°, and 90°. The polyethylene beads concertation is varied from 1 to 5% by volume. Experimental investigations were accomplished using 11ft long acrylic concentric annulus flow test section with a 1.80in casing inner diameter equipped with a fixed inner pipe of 0.85in as the outer diameter. A total of 66 runs were completed using sand of size ranging from 1.18 – 2.00mm and density of 2.65 g/cc. Mud density and viscosity were maintained at 10 ppg and 7cp respectively, in a flow velocity of 0.80m/s. The densities of low and high density polyethylene beads were 0.92 g/cc and 0.96 g/cc respectively while their size was 3mm in spherical shape. The introduction of polyethylene beads were found to be more efficient in the vertical hole in which the incremental cuttings transport ratio was more than 15% being registered. This was due to sufficient buoyancy force provided by the low density polyethylene beads to counteract the gravity force and reduce the slip velocity of cuttings due to their low densities. In addition, the impulsive force due to collision between beads and sand enabled the cuttings to be lifted more efficiently.