Assessing the viability of different bio-polymers and synthetic-copolymers with modified enzyme-induced carbonate precipitation solutions for sand consolidation applications

Sand production in oil and gas wells is a significant concern, leading to equipment erosion, reduced well productivity, and safety hazards. Researchers have developed an eco-friendly solution to consolidate sand via an Enzyme-induced Carbonate Precipitation (EICP) process. It fortifies loose sand in wells, preventing it from resurfacing. This study addresses this challenge by developing a novel EICP solution effective at high temperatures (120 °C). This advancement goes beyond previous formulations, which often exhibited low strength at elevated temperatures. In this study, we developed six different solutions to consolidate sand at different temperatures with various bio- and synthetic polymers, the resulted sand consolidation has been tested by obtaining the precipitation composition after consolidation, visualizing consolidated sand structures, assessing strength and measuring permeability of the consolidated sand. AN 125, a synthetic copolymer based on Acrylamide and 2-Acrylamido-2-Methylpropane Sulfonic Acid (AM-AMPS), emerged as the most effective additive. It fostered the strongest consolidated sand at both temperatures (2,175 psi at 70 °C and 2,155 psi at 120 °C). It also exhibited superior thermal stability compared to bio-polymers like xanthan gum, which degraded at 120 °C. The EICP solution with AN 125 led to a moderate permeability decrease of around 30% during simulated sand pack flooding, indicating minimal impact on well flow. The developed formulation offers a robust and environmentally friendly approach to sand consolidation in oil and gas wells, enhancing well integrity and production efficiency. Furthermore, this work emphasizes the significance of a proper methodology towards evaluating the suitability of bio-polymers and synthetic copolymers for sand consolidation using EICP formulations.