Microscopic Effect of Mixed Wetting Capillary Characteristics on Spontaneous Imbibition Oil Recovery in Tight Reservoirs

The understanding of the mechanisms that govern water spontaneous imbibition in mixed wetting capillary channels plays a significant role in operating the oil extraction and energy replenishment for the tight oil reservoirs. In this work, the conservative form phase-field model together with the Nav...

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Main Authors: Yu Pu, Erlong Yang, Di Wang
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Energies
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Online Access:https://www.mdpi.com/1996-1073/18/2/324
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author Yu Pu
Erlong Yang
Di Wang
author_facet Yu Pu
Erlong Yang
Di Wang
author_sort Yu Pu
collection DOAJ
description The understanding of the mechanisms that govern water spontaneous imbibition in mixed wetting capillary channels plays a significant role in operating the oil extraction and energy replenishment for the tight oil reservoirs. In this work, the conservative form phase-field model together with the Navier–Stokes equation is employed to investigate the influence of the mixed wetting distribution and the wetting degree on the imbibition oil recovery effects and microscopic flow characteristics. Results indicate that there exist different oil detachment modes of spontaneous imbibition, and these modes are determined by the coupled effect of mixed wetting fraction and contact angle size. For the mixed wetting capillary with strong oil wetting, when <i>f</i><sub>w</sub> is low, spontaneous imbibition can only partially detach the oil. Low <i>f</i><sub>w</sub> slows down the fluid flow velocity and leads to the small imbibition oil recovery rate. After that, the influence of the surface contact angle size of the mixed wetting capillary is discussed. For the complete detachment mode, the capillary tube presents a form of water phase saturated filling, achieving the optimal imbibition oil recovery effect. For the mixed wetting capillary tube with the combination of weak water wetting and strong oil wetting (i.e., <i>θ</i><sub>w</sub> = 75° and <i>θ</i><sub>o</sub> = 165°), local spontaneous imbibition turbulence can only detach very little oil at the inlet of the water wetting area, ultimately achieving a recovery efficiency of less than 10%. This work illuminates the spontaneous imbibition oil recovery mechanisms and flow potentiality for the different mixed wetting capillary channels.
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spelling doaj-art-3309750a63ad44eeab8d56f5c63666c22025-01-24T13:31:03ZengMDPI AGEnergies1996-10732025-01-0118232410.3390/en18020324Microscopic Effect of Mixed Wetting Capillary Characteristics on Spontaneous Imbibition Oil Recovery in Tight ReservoirsYu Pu0Erlong Yang1Di Wang2Key Laboratory of Ministry of Education for Enhancing Oil and Gas Recovery, Northeast Petroleum University, Daqing 163318, ChinaKey Laboratory of Ministry of Education for Enhancing Oil and Gas Recovery, Northeast Petroleum University, Daqing 163318, ChinaSchool of Architecture and Civil Engineering, Northeast Petroleum University, Daqing 163318, ChinaThe understanding of the mechanisms that govern water spontaneous imbibition in mixed wetting capillary channels plays a significant role in operating the oil extraction and energy replenishment for the tight oil reservoirs. In this work, the conservative form phase-field model together with the Navier–Stokes equation is employed to investigate the influence of the mixed wetting distribution and the wetting degree on the imbibition oil recovery effects and microscopic flow characteristics. Results indicate that there exist different oil detachment modes of spontaneous imbibition, and these modes are determined by the coupled effect of mixed wetting fraction and contact angle size. For the mixed wetting capillary with strong oil wetting, when <i>f</i><sub>w</sub> is low, spontaneous imbibition can only partially detach the oil. Low <i>f</i><sub>w</sub> slows down the fluid flow velocity and leads to the small imbibition oil recovery rate. After that, the influence of the surface contact angle size of the mixed wetting capillary is discussed. For the complete detachment mode, the capillary tube presents a form of water phase saturated filling, achieving the optimal imbibition oil recovery effect. For the mixed wetting capillary tube with the combination of weak water wetting and strong oil wetting (i.e., <i>θ</i><sub>w</sub> = 75° and <i>θ</i><sub>o</sub> = 165°), local spontaneous imbibition turbulence can only detach very little oil at the inlet of the water wetting area, ultimately achieving a recovery efficiency of less than 10%. This work illuminates the spontaneous imbibition oil recovery mechanisms and flow potentiality for the different mixed wetting capillary channels.https://www.mdpi.com/1996-1073/18/2/324tight reservoirsmixed wettabilitypore scaleimbibition mechanismoil detachment
spellingShingle Yu Pu
Erlong Yang
Di Wang
Microscopic Effect of Mixed Wetting Capillary Characteristics on Spontaneous Imbibition Oil Recovery in Tight Reservoirs
Energies
tight reservoirs
mixed wettability
pore scale
imbibition mechanism
oil detachment
title Microscopic Effect of Mixed Wetting Capillary Characteristics on Spontaneous Imbibition Oil Recovery in Tight Reservoirs
title_full Microscopic Effect of Mixed Wetting Capillary Characteristics on Spontaneous Imbibition Oil Recovery in Tight Reservoirs
title_fullStr Microscopic Effect of Mixed Wetting Capillary Characteristics on Spontaneous Imbibition Oil Recovery in Tight Reservoirs
title_full_unstemmed Microscopic Effect of Mixed Wetting Capillary Characteristics on Spontaneous Imbibition Oil Recovery in Tight Reservoirs
title_short Microscopic Effect of Mixed Wetting Capillary Characteristics on Spontaneous Imbibition Oil Recovery in Tight Reservoirs
title_sort microscopic effect of mixed wetting capillary characteristics on spontaneous imbibition oil recovery in tight reservoirs
topic tight reservoirs
mixed wettability
pore scale
imbibition mechanism
oil detachment
url https://www.mdpi.com/1996-1073/18/2/324
work_keys_str_mv AT yupu microscopiceffectofmixedwettingcapillarycharacteristicsonspontaneousimbibitionoilrecoveryintightreservoirs
AT erlongyang microscopiceffectofmixedwettingcapillarycharacteristicsonspontaneousimbibitionoilrecoveryintightreservoirs
AT diwang microscopiceffectofmixedwettingcapillarycharacteristicsonspontaneousimbibitionoilrecoveryintightreservoirs