COMPOSITION OF DRILLING FLUID AND METHOD USEFUL IN DRILLING BOREHOLES IN WATER SENSITIVE FORMATIONS

摘要

The disclosure in various embodiments is related to compositions and methods for preparing drilling fluid used for drilling boreholes in water-sensitive formations inoilandgasdrillingoperations. The drilling fluid is water based synergistic polymer-colloid complex that withstands working temperatures of at least 150 °C and pH greater than or equal to 12. The drilling fluid comprises polyacrylamide, humate, clay hydration inhibitor, water loss regulator, viscosity regulators, density regulator, alkali metal salts and suspending agents. The drilling fluid removed drill cuttings from the wellbore, cooled and lubricated the drill bit, aided in support of the drill pipe and drill bit, and provided a hydrostatic head to maintain the integrity of the wellbore walls and prevented well blowouts.