Summary
Polymeric scale inhibitors are widely used in the oil and gas field because of their enhanced thermal stability and better environmental compatibility. However, the squeeze efficiency of such threshold inhibitors, not only polymeric scale inhibitors but also phosphonates, is typically poor in conventional squeeze treatment. In this research, nanoparticle (NP)-crosslinked polymeric scale inhibitors were developed for scale control. Nearly monodispersed boehmite [γ-AlO(OH)] NPs with average size of 2.8 nm were synthesized and used to crosslink sulfonated polycarboxylic acid (SPCA). Crosslinked AlO(OH)-SPCA nanoinhibitors were produced and developed to increase the retention of SPCA in formations by converting liquid-phase polymeric scale inhibitors into a viscous gel. Study of sorption of SPCA onto AlO(OH) NPs under different pHs with and without assistance of Ca2+ was discussed. In addition, study of sorption of various types of scale inhibitors [SPCA; phosphino-polycarboxylic acid (PPCA); and diethylenetriaminepentatakis(methylene phosphonic acid) (DTPMP)] onto AlO(OH) NPs was performed. Squeeze simulation of neat 3% SPCA, AlO(OH) (3%)-SPCA (3%) NPs, and AlO(OH) (3%)-SPCA (3%)-Ca NPs was investigated. The results showed that the addition of Ca2+ ions improves the squeeze performance of SPCA, and the normalized squeeze life (NSL) of such material (8,952 bbl/kg) was improved by a factor greater than 60 compared with that of SPCA alone (152 bbl/kg).
