The squeezing of scale inhibitors into the near well bore region of oil producing wells is a recognised solution to downhole scale prevention. In many cases, this downhole application leads to an initial decrease in the well productivity, which can recover to the pre squeeze level with time. However, in some reservoirs this recovery does not happen, and the well suffers a permanent loss in productivity after the squeeze.
Following such a loss in well productivity caused by an initial squeeze treatment, this paper details the development of a successful squeeze treatment for a water sensitive reservoir in the North Sea using an aqueous based sulphonated co-polymer scale inhibitor.
The paper summarises the additional core plug testing undertaken to evaluate the damage mechanism, the modifications made to the treatment design to minimise the damaging effects and culminates with the successful results from the application of the modified squeeze treatment. These results show that well stimulation and extended squeeze lifetime were achieved compared to the initial squeeze and to other previous applications of this inhibitor in similar water sensitive reservoirs.