Patent ID: 6143698
Filing Date: 2000-11-07
Classification: C09K

Abstract:
A method for preparing a borehole in the earth to produce hydrocarbons therefrom, comprising:drilling the borehole while circulating a mud therein which comprises a polysaccharide and optionally comprises finely divided solids dispersed therein to form a filtercake on surfaces of the borehole essentially free of oxidants and bromine and bromate generating agents; andintroducing a filtercake removal fluid in the wellbore, in contact with a subterranean formation containing the hydrocarbons to be produced, for a duration effective to substantially remove the filtercake in the vicinity of the subterranean formation, wherein the filtercake removal fluid comprises a clear brine comprising a halide salt having a density of at least 1.08 g/cm.sup.3 (9 lb/gal) and a bromine or bromate generating agent dissolved in the brine.