TY - JOUR
T1 - Wetting mechanism and alteration of nano-sized shale pores
T2 - Insights from contrast variation small angle neutron scattering
AU - Zhang, Tao
AU - Hu, Qinhong
AU - Xiao, Yufeng
AU - Nagy, Gergely
AU - Yang, Shengyu
AU - Yuan, Bao
AU - Jiang, Hanqiu
AU - Ke, Yubin
AU - Wang, Qiming
N1 - Publisher Copyright:
© 2024 Elsevier B.V.
PY - 2024/11/1
Y1 - 2024/11/1
N2 - Wettability of tight shale is crucial for fluid flow and mass transport process in energy geosciences. However, understanding the interfacial chemistry and wetting mechanisms at sub-nano-pore scales remains a formidable challenge. In this study, the Contrast Variation technique of Small Angle Neutron Scattering (CV-SANS) is employed to investigate shale's interfacial chemistry using reagents that possess a range of different polarities, including water, n-decane, toluene, and dimethyl methanamide. Through five different experimental strategies, we have demonstrated a successful modification of shale wettability, ranging from enhancement, weakening, to reversal. Delving into the mechanisms, we illustrated the crucial role of pre-existing liquid films in these changes, where the uniquely co-existing polar and non-polar functional groups in dimethyl methanamide acted as a conduit for interfacial chemistry adjustments. Furthermore, a solvent immersion led to matrix dilation as well as liberation of residual oil-occupied pores, resulting in altered pore size distributions, with hydrogen bonding playing a significant role in the polar groups. Interestingly, despite shale exhibiting a stronger affinity for oil over water, hydrophilic solvents induced more substantial dilation than lipophilic ones. Collectively, this work elucidates the dynamic change of interfacial chemistry via the configuration of polarity using chemical reagents, and the CV-SANS technique underscores its invaluable utilities in decoding the interfacial wettability traits in nanopore space of shale.
AB - Wettability of tight shale is crucial for fluid flow and mass transport process in energy geosciences. However, understanding the interfacial chemistry and wetting mechanisms at sub-nano-pore scales remains a formidable challenge. In this study, the Contrast Variation technique of Small Angle Neutron Scattering (CV-SANS) is employed to investigate shale's interfacial chemistry using reagents that possess a range of different polarities, including water, n-decane, toluene, and dimethyl methanamide. Through five different experimental strategies, we have demonstrated a successful modification of shale wettability, ranging from enhancement, weakening, to reversal. Delving into the mechanisms, we illustrated the crucial role of pre-existing liquid films in these changes, where the uniquely co-existing polar and non-polar functional groups in dimethyl methanamide acted as a conduit for interfacial chemistry adjustments. Furthermore, a solvent immersion led to matrix dilation as well as liberation of residual oil-occupied pores, resulting in altered pore size distributions, with hydrogen bonding playing a significant role in the polar groups. Interestingly, despite shale exhibiting a stronger affinity for oil over water, hydrophilic solvents induced more substantial dilation than lipophilic ones. Collectively, this work elucidates the dynamic change of interfacial chemistry via the configuration of polarity using chemical reagents, and the CV-SANS technique underscores its invaluable utilities in decoding the interfacial wettability traits in nanopore space of shale.
KW - Contrast variation
KW - Interfacial chemistry
KW - SANS
KW - Shale
KW - Swelling
KW - Wettability
UR - http://www.scopus.com/inward/record.url?scp=85203642600&partnerID=8YFLogxK
U2 - 10.1016/j.molliq.2024.125962
DO - 10.1016/j.molliq.2024.125962
M3 - Article
AN - SCOPUS:85203642600
SN - 0167-7322
VL - 413
JO - Journal of Molecular Liquids
JF - Journal of Molecular Liquids
M1 - 125962
ER -