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Berlin Brandenburg

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  • 1
    Language: English
    In: Advances in Water Resources, Jan, 2013, Vol.51, p.217(30)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.advwatres.2012.07.018 Byline: Dorthe Wildenschild (a), Adrian P. Sheppard (b) Keywords: X-ray tomography; Porous media characterization; Multi-phase flow; Image analysis and quantification Abstract: a* We provide a review of recent developments and advances in pore-scale X-ray tomographic imaging of subsurface porous media. a* The particular focus is on immiscible multi-phase fluid flow and quantitative analyses. a* Advances in both imaging techniques and image processing are discussed and future trends are addressed. Author Affiliation: (a) School of Chemical, Biological, and Environmental Engineering, Oregon State University, Corvallis, OR 97331, USA (b) Department of Applied Mathematics, Research School of Physics and Engineering, Australian National University, Canberra, ACT 0200, Australia
    Keywords: Image Processing Equipment -- Methods ; Image Processing -- Methods
    ISSN: 0309-1708
    Source: Cengage Learning, Inc.
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  • 2
    In: Geophysical Research Letters, 28 September 2016, Vol.43(18), pp.9677-9685
    Description: We utilize synchrotron X‐ray tomographic imaging to investigate the pore‐scale characteristics and residual trapping of supercritical CO (scCO) over the course of multiple drainage‐imbibition (D‐I) cycles in Bentheimer sandstone cores. Capillary pressure measurements are paired with X‐ray image‐derived saturation and connectivity metrics which describe the extent of drainage and subsequent residual (end of imbibition) scCO trapping. For the first D‐I cycle, residual scCO trapping is suppressed due to high imbibition capillary number (Ca ≈ 10); however, residual scCO trapping dramatically increases for subsequent D‐I cycles carried out at the same Ca value. This behavior is not predicted by conventional multiphase trapping theory. The magnitude of scCO trapping increase is hysteretic and depends on the relative extent of the sequential drainage processes. The hysteretic pore‐scale behavior of the scCO‐brine‐sandstone system observed in this study suggests that cyclic multiphase flow could potentially be used to increase scCO trapping for sequestration applications. We observe cyclic pore‐scale behavior of supercritical CO2 (scCO2) via synchrotron X‐ray microtomography Residual scCO2 saturation increases over multiple drainage‐imbibition (D‐I) cycles reaching a value of 50% after three cycles The ultimate driver for this behavior may be a combination of cycling and associated surface chemistry reactions
    Keywords: Co 2 Sequestration ; Residual Trapping ; Capillary Trapping ; Cyclic Injections ; X‐Ray Microtomography ; Multiphase Flow
    ISSN: 0094-8276
    E-ISSN: 1944-8007
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  • 3
    Language: English
    In: Journal of Petroleum Science and Engineering, Sept, 2012, Vol.94-95, p.155(10)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.petrol.2012.06.031 Byline: Ryan T. Armstrong, Dorthe Wildenschild Keywords: microbial enhanced oil recovery; biosurfactant; bioclogging; micromodel; water flooding; multiphase flow; interfacial curvature Abbreviations: AOR, additional oil recovered; BSD, blob size distribution; IFT, interfacial tension; MEOR, microbial enhanced oil recovery; NAPL, non-aqueous phase liquid; NSPB, non-surfactant producing bacteria; OOIP, original oil in place; RCD, radius of curvature distribution; SPB, surfactant producing bacteria; USBM, U.S. bureau of mines method Abstract: Microbial Enhanced Oil Recovery (MEOR) is a process where microorganisms are used for tertiary oil recovery. Numerous mechanisms have been proposed in the literature through which microorganisms facilitate the mobilization of residual oil. Herein, we focus on the MEOR mechanisms of interfacial tension reduction (via biosurfactant) and bioclogging in water-wet micromodels, using Shewanella oneidensis (MR-1) that causes bioclogging and Bacillus mojavensis (JF-2) that produces biosurfactant and causes bioclogging. Micromodels were flooded with an assortment of flooding solutions ranging from metabolically active bacteria to nutrient limited bacteria to dead inactive biomass to assess the effectiveness of the proposed MEOR mechanisms of bioclogging and biosurfactant production. Results indicate tertiary flooding of the micromodel system with biomass and biosurfactant was optimal for oil recovery due to the combined effects of bioclogging of the pore-space and interfacial tension reduction. However, biosurfactant was able to recover oil in some cases dependent on wettability. Biomass without biosurfactant that clogged the pore-space also successfully produced additional oil recovery. When analyzing residual oil blob morphology, MEOR resulted in oil blob size and radius of curvature distributions similar to those obtained by an abiotic capillary desaturation test, where flooding rate was increased post secondary recovery. Furthermore, for the capillary number calculated during MEOR flooding with bioclogging and biosurfactant, lower residual oil saturation was measured than for the corresponding capillary number under abiotic conditions. These results suggest that bioclogging and biosurfactant MEOR is a potentially effective approach for pore morphology modification and thus flow alteration in porous media that can have a significant effect on oil recovery beyond that predicted by capillary number. Author Affiliation: School of Chemical, Biological and Environmental Engineering, Oregon State University, 103 Gleeson Hall, Corvallis, OR 97331-2702, USA Article History: Received 19 October 2011; Accepted 15 June 2012
    Keywords: Petroleum Mining -- Investigations ; Petroleum Mining -- Analysis ; Surface Active Agents -- Analysis ; Surface Active Agents -- Investigations ; Bacteria -- Investigations ; Bacteria -- Analysis
    ISSN: 0920-4105
    Source: Cengage Learning, Inc.
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  • 4
    Language: English
    In: Transport in Porous Media, 2012, Vol.92(3), pp.819-835
    Description: Microbial enhanced oil recovery (MEOR) is a technology that could potentially increase the tertiary recovery of oil from mature oil formations. However, the efficacy of this technology in fractional-wet systems is unknown, and the mechanisms involved in oil mobilization therefore need further investigation. Our MEOR strategy consists of the injection of ex situ produced metabolic byproducts produced by Bacillus mojavensis JF-2 (which lower interfacial tension (IFT) via biosurfactant production) into fractional-wet cores containing residual oil. Two different MEOR flooding solutions were tested; one solution contained both microbes and metabolic byproducts while the other contained only the metabolic byproducts. The columns were imaged with X-ray computed microtomography (CMT) after water flooding, and after MEOR, which allowed for the evaluation of the pore-scale processes taking place during MEOR. Results indicate that the larger residual oil blobs and residual oil held under relatively low capillary pressures were the main fractions recovered during MEOR. Residual oil saturation, interfacial curvatures, and oil blob sizes were measured from the CMT images and used to develop a conceptual model for MEOR in fractional-wet systems. Overall, results indicate that MEOR was effective at recovering oil from fractional-wet systems with reported additional oil recovered (AOR) values between 44 and 80%; the highest AOR values were observed in the most oil-wet system.
    Keywords: Microbial enhanced oil recovery ; X-ray microtomography ; Multiphase flow ; Interfacial curvature
    ISSN: 0169-3913
    E-ISSN: 1573-1634
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  • 5
    Language: English
    In: Advances in Water Resources, Sept, 2012, Vol.46, p.55(8)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.advwatres.2012.05.009 Byline: Ryan T. Armstrong (a), Mark L. Porter (b), Dorthe Wildenschild (a) Keywords: Capillary pressure; Interfacial curvature; Young-Laplace; Drainage; Imbibition; Computed microtomography Abstract: a* Computed tomography datasets were analyzed for interfacial curvature. a* Curvature and transducer-based measurements compare well. a* Disconnected and connected phase interfaces have significantly different curvatures. a* Connected phase interfacial curvature relaxes as the system equilibrates. Author Affiliation: (a) School of Chemical, Biological, and Environmental Engineering, Oregon State University, 103 Gleeson Hall Corvallis, OR 97331-2702, United States (b) Los Alamos National Laboratory, Earth and Environmental Sciences Division, Los Alamos, NM 87545, United States Article History: Received 12 December 2011; Revised 18 May 2012; Accepted 18 May 2012
    ISSN: 0309-1708
    Source: Cengage Learning, Inc.
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  • 6
    Language: English
    In: Journal of Petroleum Science and Engineering, September 2012, Vol.94-95, pp.155-164
    Description: Microbial Enhanced Oil Recovery (MEOR) is a process where microorganisms are used for tertiary oil recovery. Numerous mechanisms have been proposed in the literature through which microorganisms facilitate the mobilization of residual oil. Herein, we focus on the MEOR mechanisms of interfacial tension reduction (via biosurfactant) and bioclogging in water-wet micromodels, using (MR-1) that causes bioclogging and (JF-2) that produces biosurfactant and causes bioclogging. Micromodels were flooded with an assortment of flooding solutions ranging from metabolically active bacteria to nutrient limited bacteria to dead inactive biomass to assess the effectiveness of the proposed MEOR mechanisms of bioclogging and biosurfactant production. Results indicate tertiary flooding of the micromodel system with biomass and biosurfactant was optimal for oil recovery due to the combined effects of bioclogging of the pore-space and interfacial tension reduction. However, biosurfactant was able to recover oil in some cases dependent on wettability. Biomass without biosurfactant that clogged the pore-space also successfully produced additional oil recovery. When analyzing residual oil blob morphology, MEOR resulted in oil blob size and radius of curvature distributions similar to those obtained by an abiotic capillary desaturation test, where flooding rate was increased post secondary recovery. Furthermore, for the capillary number calculated during MEOR flooding with bioclogging and biosurfactant, lower residual oil saturation was measured than for the corresponding capillary number under abiotic conditions. These results suggest that bioclogging and biosurfactant MEOR is a potentially effective approach for pore morphology modification and thus flow alteration in porous media that can have a significant effect on oil recovery beyond that predicted by capillary number. ► MEOR mechanisms of biosurfactant production and bioclogging are investigated. ► Abiotic recovery by increasing capillary number was also investigated. ► Blob size and interfacial curvature distributions are measured. ► Oil recovery was optimal with simultaneous bioclogging and biosurfactant production. ► Biotic and abiotic oil mobilization proceeded in a similar manner.
    Keywords: Microbial Enhanced Oil Recovery ; Biosurfactant ; Bioclogging ; Micromodel ; Water Flooding ; Multiphase Flow ; Interfacial Curvature ; Engineering ; Geology
    ISSN: 0920-4105
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  • 7
    Language: English
    In: Advances in Water Resources, January 2013, Vol.51, pp.217-246
    Description: ► We provide a review of recent developments and advances in pore-scale X-ray tomographic imaging of subsurface porous media. ► The particular focus is on immiscible multi-phase fluid flow and quantitative analyses. ► Advances in both imaging techniques and image processing are discussed and future trends are addressed. We report here on recent developments and advances in pore-scale X-ray tomographic imaging of subsurface porous media. Our particular focus is on immiscible multi-phase fluid flow, i.e., the displacement of one immiscible fluid by another inside a porous material, which is of central importance to many natural and engineered processes. Multiphase flow and displacement can pose a rather difficult problem, both because the underlying physics is complex, and also because standard laboratory investigation reveals little about the mechanisms that control micro-scale processes. X-ray microtomographic imaging is a non-destructive technique for quantifying these processes in three dimensions within individual pores, and as we report here, with rapidly increasing spatial and temporal resolution.
    Keywords: X-Ray Tomography ; Porous Media Characterization ; Multi-Phase Flow ; Image Analysis and Quantification ; Engineering
    ISSN: 0309-1708
    E-ISSN: 1872-9657
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  • 8
    Language: English
    In: Computational Geosciences, 2010, Vol.14(1), pp.15-30
    Description: Image analysis of three-dimensional microtomographic image data has become an integral component of pore scale investigations of multiphase flow through porous media. This study focuses on the validation of image analysis algorithms for identifying phases and estimating porosity, saturation, solid surface area, and interfacial area between fluid phases from gray-scale X-ray microtomographic image data. The data used in this study consisted of (1) a two-phase high precision bead pack from which porosity and solid surface area estimates were obtained and (2) three-phase cylindrical capillary tubes of three different radii, each containing an air–water interface, from which interfacial area was estimated. The image analysis algorithm employed here combines an anisotropic diffusion filter to remove noise from the original gray-scale image data, a k-means cluster analysis to obtain segmented data, and the construction of isosurfaces to estimate solid surface area and interfacial area. Our method was compared with laboratory measurements, as well as estimates obtained from a number of other image analysis algorithms presented in the literature. Porosity estimates for the two-phase bead pack were within 1.5% error of laboratory measurements and agreed well with estimates obtained using an indicator kriging segmentation algorithm. Additionally, our method estimated the solid surface area of the high precision beads within 10% of the laboratory measurements, whereas solid surface area estimates obtained from voxel counting and two-point correlation functions overestimated the surface area by 20–40%. Interfacial area estimates for the air–water menisci contained within the capillary tubes were obtained using our image analysis algorithm, and using other image analysis algorithms, including voxel counting, two-point correlation functions, and the porous media marching cubes. Our image analysis algorithm, and other algorithms based on marching cubes, resulted in errors ranging from 1% to 20% of the analytical interfacial area estimates, whereas voxel counting and two-point correlation functions overestimated the analytical interfacial area by 20–40%. In addition, the sensitivity of the image analysis algorithms on the resolution of the microtomographic image data was investigated, and the results indicated that there was little or no improvement in the comparison with laboratory estimates for the resolutions and conditions tested.
    Keywords: Multiphase flow ; Porous media ; Computed microtomography ; Image analysis ; Marching cubes
    ISSN: 1420-0597
    E-ISSN: 1573-1499
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  • 9
    Language: English
    In: Vadose Zone Journal, 2012, Vol.11(1), p.0
    Description: Advancements in noninvasive imaging methods such as X-ray computed tomography (CT) have led to a recent surge of applications in porous media research with objectives ranging from theoretical aspects of pore-scale fluid and interfacial dynamics to practical applications such as enhanced oil recovery and advanced contaminant remediation. While substantial efforts and resources have been devoted to advance CT technology, microscale analysis, and fluid dynamics simulations, the development of efficient and stable three-dimensional multiphase image segmentation methods applicable to large data sets is lacking. To eliminate the need for wet-dry or dual-energy scans, image alignment, and subtraction analysis, commonly applied in X-ray micro-CT, a segmentation method based on a Bayesian Markov random field (MRF) framework amenable to true three-dimensional multiphase processing was developed and evaluated. Furthermore, several heuristic and deterministic combinatorial optimization schemes required to solve the labeling problem of the MRF image model were implemented and tested for computational efficiency and their impact on segmentation results. Test results for three grayscale data sets consisting of dry glass beads, partially saturated glass beads, and partially saturated crushed tuff obtained with synchrotron X-ray micro-CT demonstrate great potential of the MRF image model for three-dimensional multiphase segmentation. While our results are promising and the developed algorithm is stable and computationally more efficient than other commonly applied porous media segmentation models, further potential improvements exist for fully automated operation. Journal Article.
    Keywords: Engineeringalgorithms ; Computerized Tomography ; Efficiency ; Fluids ; Glass ; Image Processing ; Optimization ; Three-Dimensional Calculations;
    ISSN: Vadose Zone Journal
    E-ISSN: 1539-1663
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  • 10
    Language: English
    In: Advances in Water Resources, September 2012, Vol.46, pp.55-62
    Description: ► Computed tomography datasets were analyzed for interfacial curvature. ► Curvature and transducer-based measurements compare well. ► Disconnected and connected phase interfaces have significantly different curvatures. ► Connected phase interfacial curvature relaxes as the system equilibrates. Synchrotron-based tomographic datasets of oil–water drainage and imbibition cycles have been analyzed to quantify phase saturations and interfacial curvature as well as connected and disconnected fluid configurations. This allows for close observation of the drainage and imbibition processes, assessment of equilibrium states, and studying the effects of fluid phase disconnection and reconnection on the resulting capillary pressures and interfacial curvatures. Based on this analysis estimates of capillary pressure calculated from interfacial curvature can be compared to capillary pressure measured externally with a transducer. Results show good agreement between curvature-based and transducer-based measurements when connected phase interfaces are considered. Curvature measurements show a strong dependence on whether an interface is formed by connected or disconnected fluid and the time allowed for equilibration. The favorable agreement between curvature-based and transducer-based capillary pressure measurements shows promise for the use of image-based estimates of capillary pressure for interfaces that cannot be probed with external transducers as well as opportunities for a detailed assessment of interfacial curvature during drainage and imbibition.
    Keywords: Capillary Pressure ; Interfacial Curvature ; Young–Laplace ; Drainage ; Imbibition ; Computed Microtomography ; Engineering
    ISSN: 0309-1708
    E-ISSN: 1872-9657
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