Preliminary investigations on glycol-enhanced water-based drilling fluids

This paper investigates the inhibitive effects of some water-based muds prepared with polymers, glycol and inorganic electrolytes formulated to reduce the instability of shaly formations encountered in the drilling of hydrocarbon wells. Experimentals have been carried out by means of hot rolling test and capillary suction time techniques. Results show that the addition of small amounts of glycol to inhibitive systems, such as KCl + PHPA water based drilling fluids, allow the acquisition of inhibition values typical of oil-based muds, a class of fluids which is subject to stricter and stricter environmental regulations. Glycol enhanced water-based drilling fluids are environmentally acceptable and potentially non-toxic.