Near-wellbore laboratory simulation system to evaluate chemical sand consolidation with Epoxy/g-C3N4-NS nanofluid: an experimental and simulation study

Abstract In loose sandstone reservoirs, sand enters the wellbore along with the production fluid. Sand production causes numerous problems, such as the erosion of downhole, wellhead, and surface equipment, ultimately leading to a decline in production. In this paper, the authors present a new epoxy-based nanofluid for controlling sand production. To demonstrate its effectiveness, a near-wellbore laboratory simulator system (NeWSS) was developed, which takes into account all downhole conditions, such as the radial distribution of flow, temperature, and reservoir pressure. The epoxy/g-C 3 N 4 -NS nanofluid has two special properties. First, carbon nitride nanosheets were used as an active strengthening agent to increase the compressive strength of the epoxy resin after curing. Second, a bubbling agent was used to create micro- and macro-pores, facilitating the movement of the production fluid and ultimately increasing permeability. Laboratory results showed that the optimum concentrations of the bubbling agent and g-C 3 N 4 -NS are 3 wt% and 0.5 wt%, respectively. The preflush solution (3% KCl, 3% surface modifier, and 5% organic solvent) used to remove formation fluids (oil and brine) before nanofluid sand consolidation resulted in good adhesion of the nanofluid to the sand matrix and significantly increased the compressive strength of the porous area. Results from the near-wellbore laboratory simulation system under reservoir conditions (90 °C and 2800 psig) show that the regained permeability is above 90% when the epoxy/g-C 3 N 4 -NS nanofluid is used along with preflush and overflush solutions. Moreover, the presence of the optimum concentration of g-C 3 N 4 -NS in the epoxy-based nanofluid increased the failure stress of the hollow cylinder sample by 0.7 MPa.