Scale dissolvers have successfully been used to restore well productivity in two Statfjord Field wells suffering from scale induced formation damage. Combined with scale inhibitor treatment further production loss has been avoided. The dissolver efficiency towards BaSO4, and SrSO4, is strongly depending on high pH (pH> 9–10) in the treatment slug. Two different scale dissolvers have been tested, and are found to have equally good performance regarding dissolution capasities and effect on production. Well case histories and details about job design and production data before and after the treatments are documented. Combined scale dissolver and scale inhibitor squeeze treatment is implemented as the current scale treatment strategy for the Statfjord Field.
The Upper and Lower Brent reservoirs in the Statfjord Field are developed with a row of sea water injectors, completed below the oil/water contact, to displace oil up structure to the east toward a row of oil producers near the crest of the structure. Key information about the Statfjord Field is listed in table 1.