The Effect of pH and Salinity on the Rheological Properties of Drilling Mud Formulation from Natural Polymers

Drilling muds are designed to perform certain functions of drilling operation. Some of the functions are to cool and lubricate the drilling bit, transmit hydraulic power to drill bit, provide filter cake and remove drilling cuttings and maintaining wellbore stability. Various additives with specific properties are added in the mud to help prevent the challenges encountered during drilling process. The work studies the effect of pH and salt on the rheological properties of drilling mud formulation from two natural polymers (Terminaliamantaly(TM) exudate and Guar gum) with the use of Model 35 viscometer. Drilling mud formulation with these polymers was investigated at pH of (7.05, 8.15, 10.07, and 11.13) and salt concentrations of (2, 4, 6, 8 and 10g/ml). Results obtained from drilling mud with TM exudate were compared with drilling mud with guar gum. It was found thatthe rheological properties of drilling mud with Terminaliamantaly exudates increased for higher pH as compared to drilling mud with Guar gum. The increase in salinity reduced the effectiveness of the rheological properties of the mud such that as the salinity in drilling mud increased, the rheological properties of drilling mud with Terminaliamantaly and Guar gum decreased. The performance is attributed to flocculation, dispersion and hydration behavior of particles in the mud.