Flow behaviour of supercritical CO2 and brine in Berea sandstone during drainage and imbibition revealed by medical X-ray CT images

Zhang, Yi; Nishizawa, Osamu; Kiyama, Tamotsu; Chiyonobu, Shun; Xue, Ziqiu

doi:10.1093/gji/ggu089

Cited by 62 publications

(27 citation statements)

References 22 publications

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“…Zhang et al . () found that even in a rock that is seemingly core‐scale homogeneous (e.g., the Berea sandstone, in this study), there are small‐scale bedding layers with different porosities. A slight heterogeneity in porosity can significantly affect the fluid distribution during fluid displacement.…”

Section: Introductionmentioning

confidence: 55%

“…North and Best (2014) reported resistivity anisotropy (between 15% and 25%) in clean visually uniform sandstones that were fully saturated with brine. Zhang et al (2014) found that even in a rock that is seemingly core-scale homogeneous (e.g., the Berea sandstone, in this study), there are small-scale bedding layers with different porosities. A slight heterogeneity in porosity can significantly affect the fluid distribution during fluid displacement.…”

mentioning

confidence: 52%

“…high‐porosity layers also have large pore size for this Berea sandstone (see Zhang et al . for details). Consequently, part of the brine phase was preserved in the low‐porosity layers during the injection.…”

Section: Resultsmentioning

confidence: 99%

“…Due to the high resolution of the CT scanner and the low X‐ray attenuation of the pressure vessel, the fluid saturation in the rock could be calculated to high accuracy Zhang et al . (). We confirmed that the operation of CT did not interfere with the electrical signals of the complex resistivity measurements.…”

Section: Methodsmentioning

confidence: 97%

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Effects of fluid displacement pattern on complex electrical impedance in Berea sandstone over frequency range 10⁴–10⁶ Hz

Zhang

Park

Nishizawa

et al. 2016

Geophysical Prospecting

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To better understand the effect of fluid distribution on the electric response of rocks saturated with oil and brine, we conducted experimental studies on the complex electrical impedance in a Berea sandstone, together with in situ acquisitions of oil distribution images employing a high‐resolution medical X‐ray computed tomography. We performed two tests of brine displacement by oil under high (10 MPa) and low (5 MPa) pressures, which were accompanied by fingering and stable displacement patterns, respectively. The measured complex impedance data were fitted to the Cole model to obtain the resistance, capacitance, peak frequency of the imaginary impedance, and the exponent α of the rock–fluid system. With increasing oil saturation, the resistance showed an increasing trend, whereas the other three parameters decreased. The fingering displacement exhibited lower resistance and capacitance than the stable displacement. The analysis of the resistance changes using a simple parallel connection model indicates that there are more components of residual brine in parallel connections in the fingering pattern than in the stable displacement pattern at the same saturation. We also interpreted the normalised changes in the capacitance (or apparent dielectric constant) with respect to the oil saturation via an analysis of the shape factor of fluid distribution based on the Maxwell–Wagner–Brugermann–Hanai model. The changes in the shape factor suggest that the pinch‐off of the brine in parallel connection by the oil is a dominant mechanism reducing the capacitance. In the stable displacement, most of the connections in the brine phase are immediately pinched off by oil displacement front at a local oil saturation of 65%. Conversely, in the fingering displacement, there is a transition from the bulk or layered brine to the pinched‐off at a local oil saturation below 60%. The analyses indicate that the difference in the fluid distribution under different fluid conditions is responsible for the non‐Archie behaviour.

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Section: Introductionmentioning

confidence: 55%

mentioning

confidence: 52%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 97%

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Effects of fluid displacement pattern on complex electrical impedance in Berea sandstone over frequency range 10⁴–10⁶ Hz

Zhang

Park

Nishizawa

et al. 2016

Geophysical Prospecting

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“…The difference in distribution is mainly led by the capillary force field, which, in turn is related to the pore-size distribution (Zhang et al, 2014). The effect of the capillary force field is enhanced by the invasion-percolation mechanism.…”

Section: Resultsmentioning

confidence: 99%

Saturation-path dependency of P-wave velocity and attenuation in sandstone saturated with CO₂ and brine revealed by simultaneous measurements of waveforms and X-ray computed tomography images

et al. 2015

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We performed a laboratory experiment to measure compressional (P)-wave velocity and its attenuation in low-permeability striped sandstone at ultrasonic frequency during drainage (CO 2 injection) and imbibition (brine injection). X-ray computed tomography (CT) images of the rock sample were simultaneously recorded during the injections. On the basis of the CT images, we calculated the CO 2 saturation inside a prolatespheroid-shaped volume (the first Fresnel zone) that enclosed the wave-propagation path. The relationship of P-wave velocity and that of attenuation to the CO 2 fraction were then obtained. Both relationships showed nonuniqueness with remarkable hysteresis in a drainage-imbibition cycle. To explain the nonunique relationship of P-wave velocity to the CO 2 fraction, we investigated the continuous random patchy saturation model by using exponent-type autocorrelation. The nonunique relationship of velocity to the CO 2 fraction was explained by the model with a correlation length from an order of tens of millimeters in drainage to an order of hundreds of microns in imbibition. We also examined the potential influence of the fractal dimension of CO 2 distribution by using the fractal patchy saturation model and a von-Kármán-type autocorrelation function. The fractal dimension of pore-space modulus as related to CO 2 distribution was estimated on the basis of the CT images. The fractal dimension during imbibition found a larger value than that during drainage. The change in fractal dimension had a limited effect on velocity and attenuation changes. These nonunique relationships might have a significant impact on the use of seismic methods for estimation of CO 2 volume in an inhomogeneous storage reservoir.

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The study of heterogeneous two‐phase flow around small‐scale heterogeneity in porous sandstone by measured elastic wave velocities and lattice Boltzmann method simulation

et al. 2014

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Two-phase fluid flow is strongly controlled by small-scale (subcore-scale) heterogeneity of porous sandstone. We monitor the heterogeneous/anisotropic two-phase flow (CO 2 and water) in porous sandstone and conduct multichannel V P and V P anisotropy measurements under super critical CO 2 conditions during CO 2 injection (drainage) and water reinjection (imbibition) processes. In drainage, V P shows large reduction (~10%) in all sections of the core sample and changes from the bottom inlet side to upper outlet side. It is considered that V P reduction reflects the CO 2 movement in the specimen. The V P anisotropy of the upper two planes indicates clear increase. The results of this experiment indicate the heterogeneous CO 2 flow around laminae in porous sandstone and characteristic behavior of these laminae as a barrier for CO 2 . On the other hand, flow of water is not affected by this barrier. This characteristic CO 2 water flow around laminae is observed in the numerical simulation results. This simulation study also indicates that the capillary number is not directly affected on two-phase fluid flow around small-scale heterogeneity in porous sandstone. These results suggest that the small-scale heterogeneity behaves as a CO 2 gate and strongly controls CO 2 behavior in porous sandstone.It is well known that fluid flow in porous sandstone is strongly affected by small-scale heterogeneity of sedimentary structures (millimeter to centimeter scale). In the case of multiphase fluid flow (e.g., N 2 , CO 2 , and brine), the nonwetting phase fluid (N 2 and CO 2 ) can show complex behavior. Recent studies have successfully KITAMURA ET AL. Key Points: • The gate effect of small-scale heterogeneity on CO 2 flow in porous sandstone • Monitoring of anisotropic CO 2 flow around lamina by V P and V P anisotropy • Water and CO 2 flow simulation by LBM in heterogeneous sandstone

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Flow behaviour of supercritical CO2 and brine in Berea sandstone during drainage and imbibition revealed by medical X-ray CT images

Cited by 62 publications

References 22 publications

Effects of fluid displacement pattern on complex electrical impedance in Berea sandstone over frequency range 10⁴–10⁶ Hz

Effects of fluid displacement pattern on complex electrical impedance in Berea sandstone over frequency range 10⁴–10⁶ Hz

Saturation-path dependency of P-wave velocity and attenuation in sandstone saturated with CO₂ and brine revealed by simultaneous measurements of waveforms and X-ray computed tomography images

The study of heterogeneous two‐phase flow around small‐scale heterogeneity in porous sandstone by measured elastic wave velocities and lattice Boltzmann method simulation

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Flow behaviour of supercritical CO2 and brine in Berea sandstone during drainage and imbibition revealed by medical X-ray CT images

Cited by 62 publications

References 22 publications

Effects of fluid displacement pattern on complex electrical impedance in Berea sandstone over frequency range 104–106 Hz

Effects of fluid displacement pattern on complex electrical impedance in Berea sandstone over frequency range 104–106 Hz

Saturation-path dependency of P-wave velocity and attenuation in sandstone saturated with CO2 and brine revealed by simultaneous measurements of waveforms and X-ray computed tomography images

The study of heterogeneous two‐phase flow around small‐scale heterogeneity in porous sandstone by measured elastic wave velocities and lattice Boltzmann method simulation

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Effects of fluid displacement pattern on complex electrical impedance in Berea sandstone over frequency range 10⁴–10⁶ Hz

Effects of fluid displacement pattern on complex electrical impedance in Berea sandstone over frequency range 10⁴–10⁶ Hz

Saturation-path dependency of P-wave velocity and attenuation in sandstone saturated with CO₂ and brine revealed by simultaneous measurements of waveforms and X-ray computed tomography images