InterPore2025

Spatio-Temporal X-ray Imaging of Pickering Nanodroplets in Instability and Interaction in Porous Media

21 May 2025, 11:35

15m

Oral Presentation (MS10) Advances in imaging porous media: techniques, software and case studies MS10

Speaker

Dr Boxin Ding (Peking University Shenzhen Graduate School)

Description

Nanomaterials have been extensively applied for subsurface science and engineering. Generally, challenges arise due to the aggregation and deposition in the subsurface environments. The retention of the nanomaterials before the target zone reduces the amendment effectiveness and the hydraulic conductivity of the formation being treated. In this study, Pickering nanodroplet is demonstrated as an effective alternative vehicle to deliver nanomaterials in porous media with minimal retention. Two types of Pickering nanodroplets are synthesized via high-energy sonication method: one by bare iron oxide nanoparticle and the other by polymer-coated iron oxide nanoparticle. Displacement experiments were designed to evaluate the transport and retention behavior of the Pickering nanodroplets in porous media through in-situ measurements and effluent analysis. We show that the coating of the nanoparticle and ionic strength of carrier fluid for the Pickering nanodroplets determine the mode of their transport: minimal retention (I), maximum retention along the core (II), and strong retention near the inlet of the core (III). Polymer-coated nanoparticles-stabilized nanodroplets under an ionic strength of less than 0.5 M exhibit minimal retention (<0.5 wt.%) but show maximum retention (>80 wt.%) along the core under an ionic strength of 1.0 M. Significant retention (>40 wt.%) at the inlet of the core occurs for the bare nanoparticle stabilized-nanodroplets and the polymer-coated nanoparticle-stabilized nanodroplets under an ionic strength of 2.0 M. We observe the polymer detaching from the nanoparticle only in transport mode III. In transport mode II, we also report a clear-cut accumulation of the Pickering nanodroplets at the frontal end of the injection slug. These findings advance our understanding to design optimal Pickering nanodroplets for subsurface applications, with the potential to significantly enhance the effectiveness of environmental amendments in contaminated environments or other applications in oil and gas industry comprising fracture characterization or improved oil recovery.