Hydrogen Bonds-Enhanced Organoclay-Free Oil Based Drilling Fluid System

Conventional oil based drilling fluids or muds (OBMs) using organophilic clay as viscosifier and rheological control agent cannot carry drill cuttings and suspend weighting materials effectively in oil well drilling process. It also causes excessive viscosity of drilling fluids, which lowers the rate of penetration. For the sake of solving these problems, in this study, hydrogen bonds-enhanced organoclay-free oil based drilling fluid was proposed. Firstly key additives (emulsifier, filter reducer) for OBMs with highly electronegative groups that might form hydrogen bonds were synthesized. In addition, a hydrogen bonding linker was synthesized and used to connect other additives to form a hydrogen bonding network in OBMs. The properties of drilling fluids were characterized by rheological measurements, static filtration experiments and plugging experiments. Experimental results show that, compared with the conventional OBM, the hydrogen bonds-enhanced organoclay-free OBMs substantially increased yield point (YP) and gel strengths, reduced filtration loss and exhibited a better plugging ability on high-permeability sand cores. Besides, a higher stability was also observed.