Patent ID: 11492534

Abstract:
A method of drilling a subterranean geological formation is described. The method includes driving a drill bit to form a wellbore into the subterranean geological formation thereby producing a formation fluid including hydrogen sulfide (H2S). The method includes injecting a drilling fluid into the subterranean geological formation through the wellbore. The drilling fluid composition includes 0.25 to 2 wt. % of a primary H2S scavenger, which is potassium permanganate, and an invert emulsion, which includes a continuous phase including a vegetable oil which is at least one selected from the group consisting of corn oil, soybean oil, rapeseed oil, canola oil, sunflower oil, safflower oil, peanut oil, and cottonseed oil and a dispersive phase including water. The potassium permanganate present in the drilling fluid composition reacts with the H2S present in the formation fluid to produce a dispersion of manganese-containing particles which are at least one selected from the group consisting of manganese sulfide and manganese sulfate.