Ven-K™ is a highly efficient, multipurpose mud conditioner for water base muds. Ven-K™ is a pre-reacted salt of potassium hydroxide and lignite. Ven-K™ is primarily used as a fluid loss additive and shale control additive in potassium base shale control systems. Ven-K™ is also used in water base muds to (1) reduce viscosity and gels in order to maintain desirable flow properties; (2) improve aging characteristics in high temperature fluids by controlling fluidity; (3) reduce high pressure, high temperature filtrates and provide tough, thin filter cakes; (4) thin and emulsify oil-in-water or liquid lubricant containing fluids; (5) reduce effects of contaminants; and (6) control the equivalent circulating density by maintaining suitable flow properties. Ven-K™ is convenient and economical to use. It is compatible with most chemicals used in water base drilling fluids. Ven-K™ can be used to thin almost all types and densities of water base drilling fluids. It is particularly designed for use in potassium base shale control systems.