Facile one-pot synthesis of metal-phosphonate colloidal scale inhibitor: Synthesis and laboratory evaluation

Abstract

Mineral scale deposition is a serious flow assurance concern threatening the safety and integrity of oilfield operations. Subsurface and wellbore scale control is commonly managed by scale squeeze treatment. Compared to the conventional chemical inhibitor pill applied in a scale squeeze treatment, colloidal scale inhibitor materials are capable of enhancing inhibitor transportability in formation medium and extending squeeze lifetime. A number of functional scale inhibitor colloidal materials have been synthesized in the previous studies including the crystalline low solubility materials. However, these reported synthesis routes are complicated to follow, involving extensive experimental setup. In this study, a one-pot synthesis route has been presented to prepare metal-phosphonate colloidal inhibitor (MPCI) material in a facile and economical manner. This method is based upon a citrate-assisted approach where a low solubility MPCI material with 40 nm particle size can be produced. Laboratory transport experiment suggests that calcium-based MPCI can be transportable through sand medium at representative oilfield conditions with 100% breakthrough realized within 2.5 pore volumes in sand-packed column. Laboratory squeeze simulation tests indicate that this material is able to return inhibitor with a stable return concentration for an extended squeeze lifetime. The calculated normalized squeeze lifetime of calcium-based MPCI is as high as 1100 m3 kg−1 in sand medium. Magnesium and Zirconium based MPCI can increase the stabilized inhibitor return concentration up to 3 mg L−1. This study expands our understanding of the colloidal inhibitor materials and promotes the potential field application of such materials for oilfield scale squeeze treatment.