TY - JOUR
T1 - CO2-switchable nanohybrids for enhancing CO2 flooding in tight reservoirs
T2 - From stable colloids to a relevant viscoelastic fluid
AU - Liu, Rui
AU - Pu, Wanfen
AU - Sheng, James J.
AU - Du, Daijun
N1 - Funding Information:
We acknowledge Chinese Postdoctoral Science Foundation ( 2017M612994 ), and Scientific and technological Supporting Program ( 2016FZ0114 ) by Science & Technology Department of Sichuan Province for financial support of this work. The authors appreciate Siyuan Huang and Dr. Warzywoda Juliusz of Whitacre College of Engineering, Texas Tech University for their assistance on TEM images of nanoparticles.
Publisher Copyright:
© 2017 Elsevier Ltd
PY - 2017/11/5
Y1 - 2017/11/5
N2 - Conventional CO2 EOR techniques based on microscale chemicals have limited efficiency in tight reservoirs because the micro-nanopores of these reservoirs impede their injectivity and propagation in porous media. This work elucidated a novel well-defined silica nanohybrids named DMA-NPs with the distinct CO2 switchability for enhancing CO2 flooding in tight reservoirs. DMA-NPs densely encapsulated with a CO2-functional moiety of dimethylamine was synthesized by sequential surface modification and amidation reaction. The proof-to-concept for the CO2-switchable nanohybrids was studied by TEM, TGA, SEM, 1H NMR, FT-IR, DLS, rheological measurements and core flooding tests. The results indicated that DMA-NPs underwent reversibly physical transition, from stable colloidal particles with hydrodynamic diameter of 62 nm to a relevant viscoelastic fluid, by repeatedly bubbling CO2 or introducing air to remove CO2. Moreover, DMA-NPs dispersion whose viscosity was close to water, could preferentially flow through dominant porous media. When the dispersion met with the displacement front of CO2, these stable colloidal particles self-assembled into a relevant viscoelastic fluid which reduced CO2 mobility and diverted CO2 into a lower permeable zone, and thus more than 30% of original oil in place bypassed by the initial CO2 displacement was recovered.
AB - Conventional CO2 EOR techniques based on microscale chemicals have limited efficiency in tight reservoirs because the micro-nanopores of these reservoirs impede their injectivity and propagation in porous media. This work elucidated a novel well-defined silica nanohybrids named DMA-NPs with the distinct CO2 switchability for enhancing CO2 flooding in tight reservoirs. DMA-NPs densely encapsulated with a CO2-functional moiety of dimethylamine was synthesized by sequential surface modification and amidation reaction. The proof-to-concept for the CO2-switchable nanohybrids was studied by TEM, TGA, SEM, 1H NMR, FT-IR, DLS, rheological measurements and core flooding tests. The results indicated that DMA-NPs underwent reversibly physical transition, from stable colloidal particles with hydrodynamic diameter of 62 nm to a relevant viscoelastic fluid, by repeatedly bubbling CO2 or introducing air to remove CO2. Moreover, DMA-NPs dispersion whose viscosity was close to water, could preferentially flow through dominant porous media. When the dispersion met with the displacement front of CO2, these stable colloidal particles self-assembled into a relevant viscoelastic fluid which reduced CO2 mobility and diverted CO2 into a lower permeable zone, and thus more than 30% of original oil in place bypassed by the initial CO2 displacement was recovered.
KW - CO switchable properties
KW - Enhanced oil recovery
KW - Relevant viscoelastic fluid
KW - Silica nanohybrids
KW - Tight reservoirs
UR - http://www.scopus.com/inward/record.url?scp=85028344839&partnerID=8YFLogxK
U2 - 10.1016/j.matdes.2017.08.023
DO - 10.1016/j.matdes.2017.08.023
M3 - Article
AN - SCOPUS:85028344839
VL - 133
SP - 487
EP - 497
JO - Materials and Design
JF - Materials and Design
SN - 0264-1275
ER -