Visualizing conformance control mechanisms in high-temperature reservoirs: a microfluidic analysis of Pickering emulsified gel systems

Abstract

In the context of mature oil fields, the management of water production stands out as a formidable challenge. Our prior research endeavors (Saikia et al. J Pet Sci Eng 2020, ACS Omega 2021) have introduced an innovative Pickering emulsified gel system tailored for the precise adjustment of relative permeability in high-temperature reservoirs. To make this system work better, it is required to fully understand how it controls water flow. Traditionally, conformance control studies rely on data from core flooding tests, CT scans, and nuclear magnetic resonance (NMR) techniques, among other methods. However, these traditional approaches often struggle to provide real-time visual data, which limits their accuracy in predicting how conformance mechanisms actually work. In our research study, using two distinct glass micromodels (Micromodel I-water-wet and Micromodel II-oil-wet), we conducted Pickering emulsified gel treatments at 105 °C. Microfluidic analysis revealed that the emulsion enters the pore space as slugs, coalescing during injection. The subsequent gelation of the aqueous phase restricts water flow, while oil preferentially flows through specific channels created by the separated oleic phase. These findings challenge the previously proposed Thin Film mechanism, suggesting instead a Relative Permeability Modified Channel Flow. This research provides a deeper understanding of the Pickering emulsified gel system’s conformance control mechanism, highlighting its potential for managing water production in high-temperature reservoirs.