CO<sub>2</sub> Wettability of Sandstones: Addressing Conflicting Capillary Behaviors

Garing, Charlotte; Benson, Sally M.

doi:10.1029/2018gl081359

Cited by 31 publications

(24 citation statements)

References 29 publications

(52 reference statements)

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“…The core flooding setup is similar to the one used in previous experiments (Krevor et al, ; Ni et al, ; Perrin & Benson, ) and details can be found in the supporting information (Text S1, Figure S1). The core was not fired before the experiment, due to the low clay content (Shipton et al, ) and because previous studies have shown that firing in CO 2 /water/sandstone (with low clay content) system does not change experimental results and wetting properties (Garing & Benson, ). The core was first dried in the oven for several days and then wrapped using the same layering protocol as for the single phase experiment (section ).…”

Section: Methodsmentioning

confidence: 99%

Subcore Scale Fluid Flow Behavior in a Sandstone With Cataclastic Deformation Bands

Romano

Zahasky

Garing

et al. 2020

Water Resources Research

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Accurate determination of petrophysical and multiphase flow properties in sandstones is necessary for reservoir characterization, for instance for carbon dioxide and hydrogen storage in geological formations or for enhanced oil recovery. Several studies have examined the effect of heterogeneities, such as fractures, bedding planes, and laminae, on core-scale fluid flow. However, the influence of deformation bands that commonly occur in high porosity sandstones is poorly understood. In this study, we consider a core sample of Navajo sandstone characterized by diagonally oriented deformation bands and two laminae perpendicular to the core axis, as determined from micro X-ray computed tomography (micro-CT). Positron emission tomography is used to derive the single phase hydrodynamic properties of the core. A CO 2 drainage experiment is conducted in the water-saturated core and imaged with a medical X-ray CT scanner. Medical CT enables CO 2 saturation quantification with increasing CO 2 injection rate. Experimental results and the accompanying numerical simulations indicate that both the laminae and the deformation bands act as capillary barriers, with the laminae forming weaker capillary barriers than the deformation bands. The deformation bands have lower permeability and porosity due to grain crushing, and a very high capillary entry pressure that inhibits CO 2 migration across the bands. At the reservoir scale, deformation bands form conjugate sets and are often present in thick anastomosing clusters that define lozenge-shaped compartments. These findings have important consequences for subsurface fluid flow. For example, the presence of deformation bands may reduce the storage capacity and injectivity in carbon storage reservoirs.

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Section: Methodsmentioning

confidence: 99%

Subcore Scale Fluid Flow Behavior in a Sandstone With Cataclastic Deformation Bands

Romano

Zahasky

Garing

et al. 2020

Water Resources Research

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“…Interestingly, time‐dependent changes in brine wettability after extended exposure (periods of months) to CO 2 have been observed for limestone sands, and along with increasing in CO 2 pressure, correlated to increased volumes of capillary trapped CO 2 (Wang & Tokunaga, ). However, this phenomenon remains poorly understood, and other authors have found results for similar systems to the contrary (Garing & Benson, ). Time‐dependent wetting alteration may well be an important factor when attempting to translate core‐scale results to the reservoir.…”

Section: Resultsmentioning

confidence: 91%

“…Advancements in X‐ray imaging and microtomographic techniques have enabled in situ contact angle measurements thus providing direct insight into wetting behavior (e.g., Wildenschild & Sheppard, ); however, these are limited in their volume of investigation (typically mm 3 ). At the larger core scale (several centimeters), inferences regarding wettability are largely taken from capillary pressure curves (e.g., Garing & Benson, ) or relative permeability behavior (e.g., Al‐Menhali et al, ) with saturation measured by X‐ray or volumetric methods (Saeedi et al, ). One alternative approach for studying fluid wettability in rock cores is via nuclear magnetic resonance (NMR) relaxometry measurements which are inherently sensitive to brine‐surface interactions (e.g., wetting) and can also provide quantitative saturation information.…”

Section: Introductionmentioning

confidence: 99%

Capillary Trapping of CO₂ in Sandstone Using Low Field NMR Relaxometry

Connolly

Vogt

Mahmoud

et al. 2019

Water Resources Research

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Injecting carbon dioxide into geological formations for long-term storage is considered integral to reducing greenhouse gas emissions. Residual trapping of CO 2 is a primary storage mechanism, whereby CO 2 ganglia are trapped in the pore space by capillary forces. Experimental knowledge of residual trapping processes in rocks is critical to the development of safe storage strategies. Here we present a quantitative low field 1 H nuclear magnetic resonance (NMR) core flooding study of CO 2 residual trapping in three different sandstones. It was found that transverse relaxation (T 2 ) measurements were sensitive to the dissolution of paramagnetic ions from rock matrix minerals after exposure to carbonic acid; this response was observed on time scales relevant to core flooding experiments (i.e., minutes to hours). Subsequently, a brine aging protocol was designed and implemented to minimize this chemical effect, and hence, by applying the well-known T 2 -pore size relationship, changes in T 2 time distributions during core flooding could be related to displacement of brine from pores of different sizes. Comparison of T 2 distributions for partially CO 2 /brine-saturated cores to previously published data for N 2 /H 2 O systems shows an increased displacement of brine from small pores by CO 2 . Furthermore, results from cyclical brine/CO 2 injections showed an increase in the total volume of residually trapped CO 2 and an increase in trapping efficiency; compared to the results observed for N 2 /H 2 O, however, the improvement in trapping efficiency with cyclic injection was less pronounced. Potential causes for the observed differences are discussed in the context of effective N 2 and CO 2 wetting. Key Points:• NMR T 2 relaxation enhancement from paramagnetic ion dissolution from rock cores exposed to carbonic acid was measured • Cyclical brine/CO 2 injection increases trapped CO 2 volumes and trapping efficiency • Differences in the drainage of different pore size for CO 2 /brine and N 2 /water flooding suggest differences in wettability

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“…Past experimental studies have shown that N 2 is an excellent analogue for CO 2 . Although contact angle and surface tension values are different in N 2 /water and CO 2 /water systems, it has been shown that in both conditions the rocks are strongly water-wet and the difference in wetting states can be corrected for, in multiphase flow analysis (Al-Menhali et al, 2015;Garing and Benson, 2019;Niu et al, 2015;Pini and Benson, 2013;Plug and Bruining, 2007).…”

Section: Multiphase Core Flooding Experiments With Medical Ct Scannermentioning

confidence: 99%

EXTREME CAPILLARY HETEROGENEITIES AND IN SITU FLUID COMPARTMENTALIZATION DUE TO CLUSTERS OF DEFORMATION BANDS IN SANDSTONES

Romano¹,

Garing²,

Minto³

et al. 2020

Geological Society of America Abstracts With Programs

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Previous work has shown that individual deformation bands act like capillary barriers and influence fluid saturation. More common in nature, however, are clusters of deformation bands that form complex three dimensional geometries. The aim of this study is to analyze the extent and mechanisms of fluid compartmentalization due to clustered bands. Drainage multiphase fluid flow experiments were performed on a Navajo sandstone core sample characterized by diversely oriented clusters of deformation bands, that sub-divide the host rock into several compartments. Medical X-ray CT images were acquired while nitrogen was injected at progressively higher flow rates into a water-saturated core during transient and steady-state conditions. Spatial and temporal analyses of the non-wetting phase plume migration suggest that deformation bands act like capillary barriers and contribute to the development of an extremely tortuous saturation front. Differential pressure behavior across the core is linked to the breakthrough of N 2 into the individual compartments, resulting in highly variable N 2 saturation throughout the experiment. Migration into downstream compartments occurs via the exceedance of capillary entry pressure in portions of the bands. Simulation models of simplified systems demonstrate that capillary end effects and discontinuities in the deformation bands impact fluid saturation. The experiments and models presented here show that clusters of deformation bands have the potential to strongly compartmentalize a sandstone reservoir. Hence, prior analysis of the geometry of deformation band structures in a reservoir could significantly reduce the risk of overestimating reservoir capacity, and improve predictions of fluid mobility.

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CO₂ Wettability of Sandstones: Addressing Conflicting Capillary Behaviors

Cited by 31 publications

References 29 publications

Subcore Scale Fluid Flow Behavior in a Sandstone With Cataclastic Deformation Bands

Subcore Scale Fluid Flow Behavior in a Sandstone With Cataclastic Deformation Bands

Capillary Trapping of CO₂ in Sandstone Using Low Field NMR Relaxometry

EXTREME CAPILLARY HETEROGENEITIES AND IN SITU FLUID COMPARTMENTALIZATION DUE TO CLUSTERS OF DEFORMATION BANDS IN SANDSTONES

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CO2 Wettability of Sandstones: Addressing Conflicting Capillary Behaviors

Cited by 31 publications

References 29 publications

Subcore Scale Fluid Flow Behavior in a Sandstone With Cataclastic Deformation Bands

Subcore Scale Fluid Flow Behavior in a Sandstone With Cataclastic Deformation Bands

Capillary Trapping of CO2 in Sandstone Using Low Field NMR Relaxometry

EXTREME CAPILLARY HETEROGENEITIES AND IN SITU FLUID COMPARTMENTALIZATION DUE TO CLUSTERS OF DEFORMATION BANDS IN SANDSTONES

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CO₂ Wettability of Sandstones: Addressing Conflicting Capillary Behaviors

Capillary Trapping of CO₂ in Sandstone Using Low Field NMR Relaxometry