Abstract
In drilling operations, polymers such as carboxymethyl cellulose and polyanionic cellulose (PAC) are frequently employed as additives to decrease filtrate loss in water-based drilling fluids. In some countries these additives are imported requiring the use of the Nation’s scare foreign exchange and increase in the Capital expenditure of the drilling operation. Consequently, cheap, and easily accessible local materials that can perform a similar role are being considered. In lieu of this reality, a composite mix of sawdust and coconut fiber, was assessed as a potential additive for fluid loss control in water-based drilling mud, and the outcomes were compared with carboxymethyl cellulose (CMC), sawdust only additive, and coconut fiber only additive. Furthermore, in order to ascertain the best combination ratio for the sawdust and coconut fiber for optimum fluid loss control, the study experimented on three combinations of 50% and 50%; 75% and 25% and 25% and 75% in a 5g concentration of 350ml water-based mud. The result shows the composite combination of 75% sawdust and 25% coconut fiber produce the best data for fluid loss control among the composite samples. A comparison of the result with a 2.5g of CMC showed that while CMC sample had a better fluid loss of 12.3ml, the best composite sample had a fluid loss of 14.5ml; a slight difference of 2.2ml. In addition, the effect of the composite mix of sawdust and coconut fiber on the pH, density, and mud cake thickness of the water-based mud was evaluated in the laboratory and the result were presented and it showed that the composite samples had an incremental effect on the pH, and density of the water-based mud.

Key words: Coconut fibre, fluid loss, water based mud, CMC, PAC, sawdust