The rheological behaviour of drilling mud formulated with sodium hydroxide extracts of Bitter-leaf (BL), Pawpaw (PL), Almond (AL) and Moringa (ML) leaves applied as surfactant (emulsifiers) was studied. The rheological properties (plastic viscosity (PV), yield point (YP), and gel strength) of the mud
were measured using standard procedures. The mud specific gravity for BLEM and PLEM was observed to give same value (1.08) as that of the C1 mud. pH of the formulated mud were all alkaline and in the order BLEM (8.6) > PLEM (8.3) > ALEM (8.3) > C1(8.3) > MLEM (8.2) > C2 (8.2). The highest PV (19cP)
was recorded by PLEM at 30ºC, while the least value (6cP) was by C2 at 60ºC temperatures. Highest YP (70 1b/100ft2) was recorded by C2 while the lowest YP value (22 1b/100ft2) by C1 both at 30ºC. Gel strength at 10 seconds showed reduction in value as the temperature increased for MLEM, ALEM,
C2 and C1 formulated mud and recorded maximum of 45 1b/100 ft2 at 30ºC for C2 while the lowest gel strength was reported by C1 at 60ºC. The results obtained from the study showed that the various alkaline plant extracts used as emulsifying agent have no negative effect on the rheological properties
of the formulated mud, rather it enhances the rheological properties even after aging of the mud at 65oC. These results therefore, show the need to use the various plant extracts as alternative additive (emulsifying agent) in the formulation of water based drilling mud.
Keywords: NaOH-plant extracts, rheological properties, surfactant, drilling mud, emulsifying agentSubscription