Preparation of sand stabilization and water control agents based on electrostatic, associative, and hydrogen bonding interactions, and elucidation of their action mechanisms

This paper addresses two problems associated with weakly cemented reservoirs: sand production coupled with high water cut. To overcome two issues, two sand stabilization and water control agents PDDM and PDKM, which feature electrostatic, associative, and hydrogen bonding interactions, were fabricated using acrylamide (basic skeleton), methacryloxyethyltrimethyl ammonium chloride (electrostatic adsorption), styrene (association bridge), and two hydrogen bonding monomers as raw materials. The two hydrogen bonding monomers are γ-methacryloxypropyltrimethoxysilane and 2,4-diamino-6-diallylamino-1,3,5-triazine, which function to enhance adsorption and bridging. Their chemical structures were verified. Our main conclusions are: (1) As the hydrogen bonds formed between hydroxyl groups are stronger than those between amino groups, the intermolecular network structure in PDKM is denser than that in PDDM. As a result, the sand stabilization and water control performance achieved using the former is improved by 10%-40% compared to the latter. (2) The results of theoretical (DFT) simulations and atomic force microscopy (AFM) experiments on the two compounds imply that the molecule-molecule (-0.065 Ha) and molecule-quartz sand (-0.085 Ha) interaction energies using PDKM are stronger than those in PDDM. The adhesion force between its adsorption layer and quartz sand is also stronger (122.9 nN). (3) The sand stabilization and water control performance of PDKM is over 40% better than that achieved using the industrial product MEP. Our results show there is sufficient theoretical and experimental evidence to support the use of PDKM in loose weakly cemented reservoirs to reduce costs and increase the extraction efficiency, thus improving the industrial exploitation of these valuable resources.