ABSTRACT
To prevent or reduce problems of clay adhesion to bits during drilling operations, surfactants, commonly called drilling detergents, have been used in conjunction with water based mud. The adsorption of a surfactant onto a metal surface may include the dispersion forces, dipolar interaction and electrostatic effects. Nonionic surfactant C exhibits the highest value of adsorbed clay. Surfactant D, which shows an intermediate wetting condition, is worse than the system comprising no surfactant, i.e. higher adhesion of clay than the mud without surfactant. The electrostatic interactions result from the presence of electrical charges on the surfactant molecules and the solid adsorbent. Adsorption of surfactant onto the drilling bit surface was studied using X-ray photoelectron spectroscopy. A laboratory procedure was developed that quantifies the relative percent of clay adhesion onto drilling bits as a function of the amount and molecular character of the surfactant used.
