COMPOSITIONS FOR DRILLING FLUIDS USEFUL TO PRODUCE FLAT TEMPERATURE RHEOLOGY

摘要

A drilling fluid additive characterized by a drilling fluid viscosity regulating property which imparts a stable rheological profile to an oil based drilling fluid characterized by a substantially constant equivalent circulating density over a temperature range of about 120°F to about 40°F or a substantially constant high shear rate viscosity reading measured at 600 rpm. The present invention further provides an oil based drilling fluid including a continuous base oil phase; a weighting agent; a filtrate reducer; an emulsifier; and an effective amount of a rheological additive. The oil based drilling fluid exhibits a substantially constant equivalent circulating density and a substantially constant high shear rate viscosity reading over a temperature range of about 120°F to about 40°F.