INCREASING THE INJECTIVITY INDEX AND PRODUCTIVITY INDEX OF WELLS

摘要

The injectivity index of injection wells and the productivity index of producing wells in fluid communication with a hydrocarbon-bearing formation is improved by injecting about 1-500 gallons of a micellar dispersion per vertical foot of hydrocarbon-bearing formation, thereafter injecting about 1-500 gallons of a mobility buffer per vertical foot of hydrocarbon-bearing formation, and injecting sufficient displacing fluid to displace the micellar dispersion to a radius of at least about 7.5 feet from the well bore, and thereafter injecting about 1-500 gallons of a solution capable of counteracting the decrease in permeability caused by the mobility reducing agent in the mobility buffer. For example, the micellar dispersion can be followed by a mobility buffer containing water and a partially hydrolyzed, high molecular weight polyacrylamide and this followed by 0.1-50 volumes of water per volume of mobility buffer and this, in turn, followed by about 1-500 gallons of a sodium hypochlorite solution per vertical foot of hydrocarbon-bearing formation. The displacing fluid and the mobility buffer can be substantially hydrocarbon in an "oil-wet" reservoir.