Synthesis of starch functionalized sulfonic acid co-imidazolium/silica composite for improving oil recovery through chemical flooding technologies

Polymer flooding in HPHT reservoirs using modified biopolymers and their composites acquire incremental attention nowadays. Some literature reported about limitations of native starch through enhanced oil recovery applications regarding bacterial degradation, thermal and ionic stability under severe reservoir environment. In the present study, functionalization of the starch biopolymer with thiol derivative then oxidation of thiol to sulfonic acid by environmentally friendly oxidants has been prepared and confirmed, after that starch derivative copolymerized with vinyl-containing monomers by free radical/redox emulsion polymerization in presence of silica seeds. Spectroscopic characterization and structure determination carried out by different spectroscopic techniques comprising FTIR, 1H NMR, while particles size measured through DLS and TEM, and thermal analysis determined by TGA analysis. Evaluation of the prepared composite as a novel enhanced oil recovery (EOR) candidate as well as the precursors conducted at simulated reservoir condition, where the oil recovery factor and water cut percentage calculated relevant to injected pore volume. The flooding data indicate that the prepared starch functionalized sulfonic acid co-imidazolium/silica composite is favorable for enhanced oil recovery applications as it can withstand high temperature and salinity conditions and the recovery factor reaches 39% of residual oil saturation.