Comparison between carboxymethyl cellulose (CMC) and palm oil fuel ash (POFA) as alternatives in fluid loss agent

Abstract

In drilling operation, fluid loss can be defined when high hydro static pressure compared to formation pressure that caused the mud filtrate lost to the permeable formation. Fluid loss agent are used to control the process and avoid potential reservoir damage. Drilling fluid formulation has become important in the effort of obtaining right formulated drilling fluid. The purpose of this study is to investigate the potential of Palm Oil Fuel Ash (POFA) additive in water-based drilling fluid as fluid loss agent. Performance of WBM with POFA additive will be compared to basic mud and WBM with Carboxymethyl Cellulose (CMC) additive as commercial fluid loss agent. There are 10 samples prepared in this project including 1 basic WBM sample, 3 different concentration of POFA mud sample, 3 different concentration of CMC mud sample and 3 different concentration of combined mud sample with 50% CMC 50% POFA additive. The 3 concentrations were tested are 0.5 g, 1.0 g and 1.5 g. The rheological properties;plastic viscosity, yield point and gel strength of all water-based mud samples in this project were analyzed at 75°F and 250 °F temperature. The filtration were tested for both Low Pressure Low Temperature (LPLT) at 75°F with 100 psi pressure and High Pressure High Temperature (HPHT) at 250°F with 500 psi to study the fluid loss property on both conditions. Rheology properties in for 75°F temperature showed that POFA has good plastic viscosity within the range but not good in yield point and gel strength reading compared to CMC. For high temperature, POFA showed degradation in the rheological properties. Based on both fluid loss test in LPLT and HPHT, POFA showed recommended result for LPLT condition but it reduces in performance with higher fluid loss at HPHT condition.