Increasing the compressive strength of a high clay content sandstone reservoir by chemical sand consolidation with minimal permeability reduction.

The integrity of geological formations is critically affected when external forces surpass the rock’s inherent resistance, particularly during oil and gas extraction. Insufficient formation strength to counteract declining flow pressure can result in the migration of sand particles towards the wellbore. The selection of sand control techniques is influenced by a multitude of factors, including well and reservoir conditions, operational methodologies, resource availability, and economic viability. A prevalent chemical strategy for mitigating sand migration in oil reservoirs involves the in-situ consolidation of sand using resin. This technique effectively bonds sand particles within the reservoir through an auxiliary substance, thereby minimizing sand production. In this study, we explore the efficacy of various resins—furan, epoxy, melamine formaldehyde, urea formaldehyde, and vinyl ester—on the chemical consolidation of sandstone reservoirs with high clay content for the first time. The presence of clay poses significant challenges to achieving effective polymer bonding due to its interference with both sand particle cohesion and consolidation fluid penetration. Furthermore, clay expansion can hinder enhancements in compressive strength. Our tests under static and dynamic conditions demonstrated that furan and epoxy resins yielded promising results: furan resin achieved a residual permeability of 79% with a compressive strength of 1668 psi; epoxy resin exhibited a residual permeability of 62% with a compressive strength of 1579 psi. To comprehensively evaluate resin performance, additional assessments were conducted, including wettability tests, FESEM analysis, viscosity measurements, and CT imaging. These findings provide valuable insights into optimizing chemical consolidation strategies in clay-rich sandstone reservoirs.