TY - JOUR
T1 - Impact of Sub-core-scale Heterogeneity on Meter-Scale Flow and Brine Displacement in Drainage by CO2
AU - Moreno, Z.
AU - Rabinovich, A.
N1 - Publisher Copyright:
©2020. American Geophysical Union. All Rights Reserved.
PY - 2021/1
Y1 - 2021/1
N2 - Studies of CO2-brine two-phase flow are predominantly carried out on core samples or reservoir-scale domains. In this work we investigate intermediate-scale flow considering a cubic rock with 1 m3 volume incorporating sub-core (mm)-scale heterogeneity. First, a coreflooding experiment is analyzed to estimate subcore permeability spatial distribution and the results are used as input into the meter-scale model without any upscaling required. High-resolution numerical simulations are conducted to model CO2 injection into a brine saturated rock. We find significant differences between the meter-scale rock simulation and core experiment saturation distributions resulting from highly influential boundary effects on the core scale and pronounced gravity impact on the meter scale. A detailed analysis of flow and brine trapping in rock simulations is presented considering different flow models and permeability structures. It is shown that gravity and capillary heterogeneity have substantial impact on the saturation in the deeper regions, which exhibit sufficiently low capillary pressure, and these regions also show increased trapping of brine. Two trapping mechanisms are discussed: Type I which is a result of entry pressure considerations and Type II, which occurs due to lack of CO2 connectivity. The two types of trapping are found to be correlated to the permeability structure. A formula is presented relating between trapping and permeability statistical parameters, that is, variance of log-permeability and correlation length scale, as well as to the Bond number characterizing the ratio between gravity and capillary effects.
AB - Studies of CO2-brine two-phase flow are predominantly carried out on core samples or reservoir-scale domains. In this work we investigate intermediate-scale flow considering a cubic rock with 1 m3 volume incorporating sub-core (mm)-scale heterogeneity. First, a coreflooding experiment is analyzed to estimate subcore permeability spatial distribution and the results are used as input into the meter-scale model without any upscaling required. High-resolution numerical simulations are conducted to model CO2 injection into a brine saturated rock. We find significant differences between the meter-scale rock simulation and core experiment saturation distributions resulting from highly influential boundary effects on the core scale and pronounced gravity impact on the meter scale. A detailed analysis of flow and brine trapping in rock simulations is presented considering different flow models and permeability structures. It is shown that gravity and capillary heterogeneity have substantial impact on the saturation in the deeper regions, which exhibit sufficiently low capillary pressure, and these regions also show increased trapping of brine. Two trapping mechanisms are discussed: Type I which is a result of entry pressure considerations and Type II, which occurs due to lack of CO2 connectivity. The two types of trapping are found to be correlated to the permeability structure. A formula is presented relating between trapping and permeability statistical parameters, that is, variance of log-permeability and correlation length scale, as well as to the Bond number characterizing the ratio between gravity and capillary effects.
KW - CO storage
KW - CO-brine flow
KW - capillary trapping
KW - meter scale
KW - permeability statistics
KW - subcore heterogeneity
UR - http://www.scopus.com/inward/record.url?scp=85098528844&partnerID=8YFLogxK
U2 - 10.1029/2020WR028332
DO - 10.1029/2020WR028332
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AN - SCOPUS:85098528844
SN - 0043-1397
VL - 57
JO - Water Resources Research
JF - Water Resources Research
IS - 1
M1 - e2020WR028332
ER -