| 摘要 |
METHOD OF RESTORING PERMEABILITY AROUND WELLBORES (D#78,894-F) The invention is a method of restoring the permeability of an underground hydrocarbon formation adjacent to a wellbore which comprises injecting a first aqueous solution of hydrochloric or hydrofluoric acid into a formation interval where permeability has decreased due to polymer plugging and producing that acid out of the well after a soaking period. A second solution of about 200 ppm to about 2% by weight of chlorine dioxide is injected into the same interval and followed by a third solution of hydrochloric or hydrofluoric acid. The second and third solutions are allowed to soak in the formation for about 4 to about 48 hours before placing the well back on injection or production. |
