Preparation and evaluation of cationic bolaform surfactants for water-based drilling fluids

Three cationic bolaform surfactants with different spacer lengths were prepared from the reaction of two moles of triisopropanolamine with one mole of each of the following 1,4-dibromobutane, 1,5-dibromopentane and 1,6-dibromohexane. The chemical structures of the prepared compounds were confirmed via: FTIR spectroscopy, 1H NMR and elemental microanalysis. The surface activity of these bolaform surfactants was studied. The prepared cationic bolaform surfactants were evaluated as viscosifier additives for water-based drilling fluids. The evaluation includes the study of rheological properties of the formulated mud (apparent viscosity, plastic viscosity and yield point, gel strength and thixotropy), effect of temperature on the rheological properties and also, the study of mineralogical properties of the water-based before and after treatment with the prepared surfactants using: X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results of the evaluation were compared to the water-based mud formulated from commercial grade bentonite.