Micro-scale experimental investigations of multiphase flow in oil-wet carbonates. II. Tertiary gas injection and WAG

Qin, Z.; Arshadi, Maziar; Piri, Mohammad

doi:10.1016/j.fuel.2019.116012

Cited by 25 publications

(26 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The principal displacement process during gas injection was direct piston‐like displacement of oil by gas (top row of Figure 8). This contrasts with the observations made in a weakly oil‐wet sample (Qin et al, 2019) and in a previous study using the same Ketton rock under water‐wet conditions (Scanziani, Singh, et al, 2020) where double displacement events—when one phase displaces a second which displaces a third—were common, in particular double drainage where gas displaced oil that displaced water (Øren et al, 1992). The reason for this is the wettability of the system.…”

Section: Resultscontrasting

confidence: 84%

See 1 more Smart Citation

In Situ Characterization of Three‐Phase Flow in Mixed‐Wet Porous Media Using Synchrotron Imaging

Scanziani

Alhosani

Lin

et al. 2020

Water Resources Research

View full text Add to dashboard Cite

We use fast synchrotron X-ray microtomography to understand three-phase flow in mixed-wet porous media to design either enhanced permeability or capillary trapping. The dynamics of these phenomena are of key importance in subsurface hydrology, carbon dioxide storage, oil recovery, food and drug manufacturing, and chemical reactors. We study the dynamics of a water-gas-water injection sequence in a mixed-wet carbonate rock. During the initial waterflooding, water displaced oil from pores of all size, indicating a mixed-wet system with local contact angles both above and below 90 •. When gas was injected, gas displaced oil preferentially with negligible displacement of water. This behavior is explained in terms of the gas pressure needed for invasion. Overall, gas behaved as the most nonwetting phase with oil as the most wetting phase; however, pores of all size were occupied by oil, water, and gas, as a signature of mixed-wet media. Thick oil wetting layers were observed, which increased oil connectivity and facilitated its flow during gas injection. A chase waterflooding resulted in additional oil flow, while gas was trapped by oil and water. Furthermore, we quantified the evolution of the surface areas and both Gaussian and the total curvature, from which capillary pressure could be estimated. These quantities are related to the Minkowski functionals which quantify the degree of connectivity and trapping. The combination of water and gas injection, under mixed-wet immiscible conditions, leads to both favorable oil flow and significant trapping of gas, which is advantageous for storage applications.

show abstract

Section: Resultscontrasting

confidence: 84%

“…Our results suggest that oil recovery is favored in this mixed‐wet system, confirming previous work (Qin et al, 2019). However, the local displacement efficiency is less favorable than observed under near‐miscible conditions (Alhosani et al, 2019).…”

Section: Conclusion With Implications For Storage and Recoverysupporting

confidence: 92%

In Situ Characterization of Three‐Phase Flow in Mixed‐Wet Porous Media Using Synchrotron Imaging

Scanziani

Alhosani

Lin

et al. 2020

Water Resources Research

View full text Add to dashboard Cite

show abstract

“…We find that water is the most non-wetting phase since it occupies the largest pores, followed by gas, with oil most wetting in the smallest pores. This wettability order from most to least wetting -oil, gas, water -has been seen in micro-model experiments 40 but not inside reservoir rocks before, and contradicts previous studies where the oil and gas properties were not representative of subsurface CO 2 storage conditions 28,29 .…”

Section: Distribution Of Co 2 Oil and Water In The Pore Spacecontrasting

confidence: 72%

“…WF2 displaced both oil and CO 2 . Despite a substantial increase in the oil recovery during WF2 (14 ± 2%), as seen in other WAG experiments 28,40 , it results in a lower CO 2 saturation (21 ± 2%), i.e. a lower CO 2 storage capacity after water injection: less CO 2 is stored and indeed some of the injected CO 2 is produced with the oil.…”

Section: Distribution Of Co 2 Oil and Water In The Pore Spacementioning

confidence: 57%

Pore-scale mechanisms of CO2 storage in oilfields

Alhosani

Scanziani

Lin

et al. 2020

Sci Rep

View full text Add to dashboard Cite

Rapid implementation of global scale carbon capture and storage is required to limit temperature rises to 1.5 °C this century. Depleted oilfields provide an immediate option for storage, since injection infrastructure is in place and there is an economic benefit from enhanced oil recovery. To design secure storage, we need to understand how the fluids are configured in the microscopic pore spaces of the reservoir rock. We use high-resolution X-ray imaging to study the flow of oil, water and CO 2 in an oil-wet rock at subsurface conditions of high temperature and pressure. We show that contrary to conventional understanding, CO 2 does not reside in the largest pores, which would facilitate its escape, but instead occupies smaller pores or is present in layers in the corners of the pore space. The CO 2 flow is restricted by a factor of ten, compared to if it occupied the larger pores. This shows that CO 2 injection in oilfields provides secure storage with limited recycling of gas; the injection of large amounts of water to capillary trap the co 2 is unnecessary. With anthropogenic CO 2 emissions into the atmosphere of 37 GtCO 2 in 2018 1 , fuelled by the growth in fossil fuel consumption 2 , any viable solution to avoid dangerous climate change has to involve the rapid and large-scale implementation of CO 2 capture and storage (CCS) 3-9. Although there are abundant CO 2 storage sites in deep saline aquifers 10 , given the short time frame to implement the technology at a global scale, geological storage of CO 2 in the next decade is most practical in depleted oil and gas reservoirs, where the infrastructure including facilities, pipelines, and injection wells, as well as detailed knowledge of the fields already exists, combined with an immediate financial incentive from enhanced oil recovery (EOR) 11-14 , see Fig. 1. In CO 2-EOR projects, the injection of CO 2 into depleted oil and gas reservoirs can result in an additional hydrocarbon recovery, which may offset some of the cost of CO 2 capture and storage 15-17. While depleted oil and gas reservoirs are well known for their commercial quality permitting investment into large-scale EOR-CCS projects, they typically contain abandoned boreholes, which can potentially be conduits for rapid escape of stored CO 2. How should CO 2 injection be designed to maximize storage security? While CO 2 underground migrates over several kilometres, the physical processes that control its movement occur at the micron-scale of the pores within the rock 18. In saline aquifers, subsequent to the injection of CO 2 , water imbibes back into the pore space either at the trailing edge of a rising CO 2 plume or through engineered water injection. Since water wets the rock surfaces in saline aquifers, water flows through wetting layers, leaving CO 2 , the non-wetting phase, stranded in the centres of the larger pores in disconnected blobs, see Fig. 1B; hence a significant amount of CO 2 can become trapped in the subsurface 19,20. This capillary, or residual, trapping is important, as otherwi...

show abstract

“…The presence of double displacement events in 3D was inferred, by Scanziani et al in a water-wet medium [49] at immiscible condition, by Alhosani et al [4] at miscible conditions and by Qin et al [43] in weakly oil-wet media, from static end-state images. To directly observe these events, and investigate the presence of multiple chains of displacement, in this work we used sychtrotron-based X-ray imaging, which captures the dynamics at the pore scale during a displacement [12,9,53,37,45,46].…”

Section: Introductionmentioning

confidence: 95%

Dynamics of enhanced gas trapping applied to CO2 storage in the presence of oil using synchrotron X-ray micro tomography

et al. 2020

View full text Add to dashboard Cite

During CO 2 storage in depleted oil fields, at immiscible conditions, CO 2 can be trapped in the pore space by capillary forces, providing safe storage over geological times-a phenomenon named capillary trapping. Synchrotron X-ray imaging was used to obtain dynamic three-dimensional images of the flow of the three phases involved in this process-brine, oil and gas (nitrogen)-at high pressure and temperature, inside the pore space of Ketton limestone. First, using continuous imaging of the porous medium during gas injection, performed after waterflooding, we observed chains of multiple displacements between the three phases, caused by the connectivity of the pore space. Then, brine was re-injected and double capillary trapping-gas trapping by oil and oil trapping by brine-was the dominant double displacement event. We computed pore occupancy, saturations, interfacial area, mean curvature and Euler characteristic to elucidate these double capillary trapping phenomena, which lead to a high residual gas saturation. Pore occupancy and saturation results show an enhancement of gas trapping in the presence of both oil and brine, which potentially makes CO 2 storage in depleted oil reservoirs attractive, combining safe storage with enhanced oil recovery through immiscible gas injection. Mean curvature measurements were used to assess the capillary pressures between fluid pairs during double displacements and these confirmed the stability of the observed spreading oil layers, which facilitated the double capillary trapping. Interfacial area and Euler characteristic increased, indicating lower oil and gas connectivity, due to the capillary trapping events.

show abstract

Micro-scale experimental investigations of multiphase flow in oil-wet carbonates. II. Tertiary gas injection and WAG

Cited by 25 publications

References 14 publications

In Situ Characterization of Three‐Phase Flow in Mixed‐Wet Porous Media Using Synchrotron Imaging

In Situ Characterization of Three‐Phase Flow in Mixed‐Wet Porous Media Using Synchrotron Imaging

Pore-scale mechanisms of CO2 storage in oilfields

Dynamics of enhanced gas trapping applied to CO2 storage in the presence of oil using synchrotron X-ray micro tomography

Contact Info

Product

Resources

About