Functional scale inhibitor nanoparticle capsule delivery vehicles for oilfield mineral scale control

Abstract

Phosphonates are an important class of scale inhibitors for oilfield mineral scale deposition control. Scale inhibition for wellbore formation and downhole tubing is managed by injecting (squeezing) phosphonates deep into the reservoir. In order to enhance the transportability of phosphonates inside formation, phosphonate-containing nanomaterials are prepared as a delivery vehicle for this purpose. In this study, phosphonate–polymer nanoparticle capsules have been synthesized by using SiO₂ nanoparticles as the building blocks and polymer aggregates as the template. The physicochemical properties of the prepared inhibitor capsule particles were examined and the impact of synthesis temperature was evaluated. The role of the prepared inhibitor capsule particles as scale inhibitor delivery vehicles was assessed via a series of laboratory column transport experiments. It shows that the inhibitor capsule particles are transportable in crushed sandstone medium and a number of physicochemical conditions can impact the particle transport process, including preflush solution chemistry, temperature, back pressure and medium grain size. Additionally, sandstone core transport study indicates that the inhibitor capsule particles can travel through a consolidated sandstone core. The ability of the prepared inhibitor capsule particles to transport in both crushed and consolidated formation can expand the application of such material for both onshore and offshore scale control operations.