Use of Coconut Fibre as a Suitable pH and Rheology Enhancer

Abstract

This paper studied the use of coconut fibre as a substitute for caustic soda in drilling fluids for the improvement of pH in a water-based mud. The coconut coir was dried in the sun for 7 hours and ground into very fine particles, after which it was placed in an electronic oven at a temperature of 105°C for 1 hour to remove any remaining moisture. Sieving using a 200 mm sieve was then done. Eleven mud samples were formulated, varying the concentrations of coconut fibre in each sample and various tests, including mud density, viscosity and pH, were carried out on them. The pH of all mud samples falls in the range 9.2 to 9.5 as compared to the control sample (A) of pH 9.0, which is a good range for waterbased muds to minimize corrosion of the in-hole metal components. It means that the addition of coconut fibres improved the pH of the muds, which shows their viability as suitable replacements for sodium hydroxide. A plot of the true Bigham yield point (TBYP) versus mass concentration of coconut fibre was done to optimize the quantity of the coconut fibre to be added to the mud to produce a minimum yield point of 20 Lb/100ft2 required to initiate flow and improve the pH, which was estimated to be 3.5 gram. The results showed that coconut fibre is a good substitute for caustic soda (NaOH). They also act as good fluid loss and help improve the performance of polymers in the mud.