Smart multi-shell core composites with responsive dissolution for chemical inflow control.

Effective management of oil and water production is a persistent challenge in hydrocarbon recovery, where premature water breakthrough can severely impact production efficiency. Inflow Control Devices (ICDs) are widely used to regulate fluid entry; however, achieving selective and responsive control over oil and water inflow remains a complex challenge. This study introduces a novel multi-shell core (MSC) composite designed with smart, selectively dissolvable coatings that adapt their wettability in response to fluid type intended for application in chemical autonomous inflow control devices (C-AICDs). The MSC structure incorporates sequential layers of metal oxide nanoparticles (SiO2, TiO2 and Fe2O3) via a scalable ball milling process. These inorganic layers were selected to create fluid-selective dissolution behavior in response to reservoir environments, particularly during transitions from oil to water production phases. Characterizations via XRD, FTIR, DSC, SEM, XPS, nanoindentation, and contact angle confirmed the successful coating structure, composition, mechanical enhancement, and tailored wettability. The coated layer thickness varies with the application and ICD dimensions. We successfully achieved a total thickness of 60 μm using three layers, each averaging 20 μm, which sets a strong foundation for future optimization with higher thicknesses. Dissolution tests under hot seawater and hydrothermal conditions demonstrated delayed oxidation, consistent with staged activation as observed in cyclic voltammetry. The sequential response of the three coating layers (SiO₂ (hydrophilic), TiO₂ (intermediate), and Fe₂O₃ (hydrophobic)) illustrates a clear responsive dissolution mechanism. Each layer dissolves selectively according to the contacting fluid phase, enabling a chemical inflow control process that autonomously regulates flow based on the reservoir environment. These findings contribute to the development of smart, responsive C-AICD materials.