Study of nanomaterials and glass beads on rheological properties and lubricity of water based mud

Abstract

Torque and drag arises from the frictional forces which occur between the wellbore and the rotating drill string. Among the method to reduce torque and drag is by using lubricant. Water based mud (WBM) produced coefficient of friction (CoF) higher than oil based mud (OBM) and synthetic based mud (SBM). However, due to the environmental concerns, the use of OBM and SBM are restricted that caused the industry seeking for ways to improve lubricity of WBM. In this study, Multi Walled Carbon Nanotubes (MWCNTs), nanosilica and glass beads with different sizes 90- 150 µm and 250-425 µm were used as lubricants. This study focused on the effect of different concentration of MWCNTs, nanosilica and glass beads on the mud rheological properties and lubricity of WBM. The CoF for mud without nanomaterials and glass beads is 0.238. The optimum concentration of glass beads about 4 ppb into the mud gives lower CoF value with torque reduction up to 30%. A finer glass bead gives the best performance in improving the lubricity of drilling fluid compare to coarse glass beads. The finding shows that the addition of 0.01 ppb of nanomaterials contributed to the optimum torque reduction up to 45%. In general, the addition of nanomaterials and glass beads at optimum concentration shows the reduction on CoF. Hence, the addition of these lubricants in the WBM also gives some improvement in the mud rheological properties.