Abstract: In one embodiment, a composition of a treatment fluid used to stabilize shale and clay within a hydrocarbon producing formation is provided which includes water, and potassium formate at a concentration to maintain the treatment fluid with a Zeta potential of about ?15 mV or less. In one example, the concentration is within a range from about 1% to about 10% by weight of the treatment fluid and in another example, the concentration is within a range from about 2% to about 6%. The composition may further contain a viscosifying amount of a polygalactomannan compound, such as a guar compound. In one example, the guar compound contains a carboxymethyl hydroxypropyl guar compound or derivatives thereof. The composition may have a Zeta potential of about ?18 mV or less, such as about ?33 mV or less. The composition may further contain calcium carbonate.