Application of Polyelectrolyte Complex Nanoparticles to Increase the Lifetime of Poly Vinyl Sulfonate Scale Inhibitor

摘要

Poly(vinyl sulfonate) (PVS) is an effective scale inhibitor in preventing the formation of barium sulfate. However, the low adsorption of PVS onto the rock results in a short squeeze treatment lifetime in reservoir. The application of nano-sized polyelectrolyte complexes (PECs) to increase the treatment lifetime of PVS is examined in this work. Positively charged nanoparticles consisting of poly(ethyleneimine) and PVS were prepared. Sand pack studies were performed to quantify the adsorption and release of PEC-entrapped PVS, and the effect of ionic shock on the release of PEC-entrapped PVS was studied. It was found that an increase in the ionic strength of the displacing fluid released the PVS from the nanoparticle structure. Dynamic tube blocking tests showed that PEC-entrapped PVS increases the squeeze treatment lifetime by 22% compared to unentrapped PVS. The results also suggest that ionic shocks improve the release of PVS, prolonging the treatment by 40% compared to unentrapped PVS.