Study of cuttings lifting with different annular velocities using partially hydrolyzed polyacrylamide and enriched polypropylene-nanosilica composite in deviated and horizontal wells

Cuttings lifting to the surface is a special function of drilling muds and it can lead to undue torque and drag, differential pipe sticking and wellbore collapse if this function is not effectively applied. In this study, cuttings lifting to the surface separating facility by water-based mud (WBM) containing enriched polypropylene-nanosilica composite (PP-SiO2 NC) modified by (3-aminopropyl) triethoxysilane (APTES) and those formulated with partially hydrolyzed polyacrylamide (PHPA) were examined. The effect of different annular velocities (66.1, 92.4, 118.8, 138.6, 234.1 ft/min), cuttings diameter (0.5-0.99, 1.0-1.99, 2.0-2.79, 2.8-4.0 mm) and hole inclinations (45 degrees, 60 degrees, 75 degrees and 90 degrees) in a cuttings rig simulator (2.4-in. x 1.2-in., 16-ft. long annulus) with and without pipe rotation were investigated. The results showed that more cuttings were lifted out of the hole with higher concentrations of APTES modified PP-SiO2 NC in WBM than with the PHPA muds, which is due to increased colloidal forces that increase the interaction between the cuttings and the APTES modified PP-SiO2 NC particles. The lifting of cuttings significantly depends on flow rate. The lifting will increase with an increase in the annular velocity and with the whirling motion of the drill pipe with or without enriched PP-SiO2 NC or PHPA. This is because higher flow rate produces larger axial forces to drive the cuttings and reduces the cuttings slip velocity. The recovery of cuttings is most difficult at the hole angle of 45 degrees, due to the decreased in the axial annular velocity with increasing hole deviation. The laboratory results indicate improved lifting ability of the WBM with the presence of the APTES modified PP-SiO2 NC, demonstrating the necessity for its application in a cuttings transport process.