Additive for drilling fluid used as a shale stabilizing agent in subterranean wellbores

摘要

An additive for drilling fluid used as both a sealing agent to prevent seepage loss and a shale stabilizing agent in subterranean wellbores. The additive includes ground bituminous coal having a selected particle size distribution wherein the bituminous coal is between 60% to 80% of the additive by weight. The additive also includes solvent extracted ground flaxmeal which is between 20% to 40% of the additive by weight.