Examination of the change in returning molecular weight obtained during inhibitor squeeze treatments using polyacrycate based inhibitors

摘要

Scale inhibitors based on small polyelectrolytes are often employed in oilfield scale prevention treatments. These materials are injected into the near-well formation of producers in a scale inhibitor "squeeze" treatment. When the well is brought back on production, the objective is for the return concentration level of the inhibitor in the produced brine to be at or above a certain threshold level, C_t. THis threshold level is the minimum inhibitor concentration required to prevent the formation of mineral carbonate or sulphate scales in that well. The squeeze lifetime depends strongly on the nature of the interaction between the inhibitor and the formation either through an adsorption or "precipitation" mechanism. Both adsorptionand precipitation processes depend on the molecular weight of the scale inhibitor, as well as on a range of other factors. However, polymeric inhibitor species always display some degree of polydispersity (spread of molecular weight),