METHOD OF DRILLING-IN PRODUCING HYDROCARBON FORMATION Russian patent published in 2000 - IPC

FIELD: oil-and-gas producing industry. SUBSTANCE: method may be used in drilling wells on deposits of hydrogen sulfide-containing gas and sulfur-bearing oil in washing to surface of formation fluids entering the well, for instance, in balanced or differential-pressure drilling. The method includes cutting of rocks, lifting of cuttings from hole bottom by means of drilling mud treated prior to its supply to well with reagent for binding hydrogen sulfide; reconditioning of drilling mud service properties by screening and regulation of drilling mud parameters. Reagent for binding of hydrogen sulfide is used in the form of metal chelate complex. Prior to reconditioning of drilling mud, reagent for binding of hydrogen sulfide contained in drilling mud is regenerated. Sulfur compounds are separated from drilling mud and utilized. Due to use of reagent for binding hydrogen sulfide in the form of metal chelate complex, its regeneration directly in closed circulation of drilling mud prior to reconditioning of the latter the method provides for ecologically safe drilling in hydrogen sulfide-containing producing formation and low cost of reagent for binding of hydrogen sulfide. EFFECT: higher efficiency. 2 dwg, 2 tbl