The performance of waste frying palm oil biodiesel as ester-based drilling fluid

Abstract

Ester based mud (EBM) derived from vegetable oil has been known as one of the alternative for conventional oil-based mud due to its environmental friendly properties. However, the cost for ester, or biodiesel, derived from virgin oil are relatively high compared to conventional oil-based mud. The used of waste frying palm oil (WFPO) could be the best option to tackle the cost related problem. The waste frying palm oil derived ester should be tested to meet the required properties as the drilling fluids such as rheological properties, environmentally friendly, and its compatibility to the rubber and seal elements. Hence, this study was done in order to investigate the use of biodiesel generated from waste frying palm oil to fullfill the above requirements. WFPOB shows good mud properties except for HTHP filtrate loss where it exceeds beyond control value. But, for the blending of 70:30 Sarapar to WFPOB mud shows some reduction in HTHP filtrate loss. For rubber compatibility test, NBR components had been exposed to three different temperature, 27oC , 80oC and 125oC for one and two weeks. WFPOB mud give greater changes in rubber compound. The presence of WFPOB in blending mud shows some reduction in rubber changes rate. However, the NBR components lost more than 80% of its initial strength after exposure at 125oC due to incompatibility of NBR components at such high temperature. As for toxicity study, the Cyprinus Caprio (carp fish) has been used as test organism. The LC50 of WFPOB and the blending mud obtained in this study is 56,000 ppm and 32,000 ppm which lies under Practically Non-Toxic category in toxicity classification. The result shows that the WFPOB mud can be used as base oil in drilling mud formulation with certain limitation. At the same time, the possibility of WFPOB blending with other mineral oil such as Sarapar can be made to improve the technical requirements and meet the environmental requirements.