Abstract
The practice of scale squeeze treatments to oil/gas production wells to prevent inorganic scale formation has been applied for over 30 years and during that period of time different mechanisms to retain the inhibitor chemical have been evaluated. The simple mechanism of inhibitor retention adsorption/desorption has been complemented over the years by enhanced adsorption via mutual solvent and full precipitation of the active inhibitor as calcium salt onto the mineral surface of the reservoir.
This study has been conducted to understand if the retention of phosphonate and phosphate ester inhibitors can be improved by adsorption of a charged polymer onto the rock prior to application of the scale inhibitor or if application of the same polymer enhancer after adsorption of the scale inhibitor will extend squeeze life. These tests have been carried out using pack floods at 85°C with synthetic North Sea produced water and the details of the extension in treatment life observed are correlated to the inhibitor type tested and the sequence of application of the polymer enhancer. This study shows how the different functional groups within the scale inhibitors interact with the mineral surface and polymer enhancer to extend treatment lifetimes and so potentially reducing the frequency of squeeze treatments and therefore total cost of operations.
