Patent ID: 7268100

Claim:
A method for drilling a wellbore hole to a target formation through one or a plurality of reactive shale and/or clay zones comprising the steps of: providing a water-based drilling fluid comprising: an effective amount of a choline salt or a plurality of choline salts given by the general formula: HOCH 2 CH 2 N + (CH 3 ) 3 .R 1 COO − wherein R 1 is an alkyl group, alkenyl group, alkynyl group, an aryl group, an alkaryl group, an aralkyl group, alkenylaryl group, aralkenyl group, alkynylaryl group, aralkynyl group hetero atom analogs, where the hetero atom is selected from the group consisting of boron, nitrogen, oxygen, fluorine, phosphorus, sulfur, chlorine, bromine, iodine, and mixture or combinations thereof, or mixtures or combinations thereof, a foamer, and water; circulating the drilling fluid through the wellbore hole during drilling, and injecting a gas into wellbore hole to reduce a hydrostatic pressure of the drilling fluid, where the hydrostatic pressure of the drilling fluid is less than a hydrostatic pressure of the formation through which the wellbore hole is being drilled and where the effective amount of the choline salt or the plurality of choline salts is sufficient to reduce a swelling tendency of reactive shales and/or clays during operations.