Positron emission tomography of large rock samples using a multiring PET instrument

Maguire, R. Paul; Missimer, John; Emert, Frank; Townsend, David W.; Dollinger, Hannes; Leenders, Klaus L.

doi:10.1109/23.554819

Cited by 14 publications

(6 citation statements)

References 6 publications

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“…These early measurements were however severely limited in the spatial resolution and only recently positron emission tomography (PET) has (re)emerged to fill this gap, by combining the benefits of multidimensional tomographic imaging with those related to the characteristic radiation of positron-emitting isotopes (Goethals et al 2009). With relevance to the present work, PET has been used to study the porosity of rock samples (Degueldre et al 1996;Maguire et al 1997) and to image transport in sediments (Khalili, Basu & Pietrzyk 1998) and sandstones (Ogilvie, Orribo & Glover 2001). However, with the avowed intention of demonstrating the potential of PET to visualize fluid pathways inside porous samples, most studies so far have been largely qualitative, and the use of this technique for quantitative analyses is just beginning (Gründig et al 2007;Boutchko et al 2012;Fernø et al 2015).…”

Section: Advanced Reservoir Core Analyses With Imaging Techniquesmentioning

confidence: 95%

Quantifying solute spreading and mixing in reservoir rocks using 3-D PET imaging

et al. 2016

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We report results of an experimental investigation into the effects of small-scale (mmcm) heterogeneities on solute spreading and mixing in a Berea Sandstone core. Pulsetracer tests have been carried out in the regime Pe = 6 − 40 and are supplemented by a unique combination of two imaging techniques. X-ray CT is used to quantify subcore scale heterogeneities in terms of permeability contrasts at a spatial resolution of about 10 mm 3 , while [11C]PET is applied to image the spatial and temporal evolution of the full tracer plume non-invasively. To account for both advective spreading and local (Fickian) mixing as driving mechanisms for solute transport, a streamtube model is applied that is based on the 1D Advection Dispersion Equation. We refer to our modelling approach as semi-deterministic, because the spatial arrangement of the streamtubes and the corresponding solute travel times are known from the measured rock's permeability map, which required only small adjustments to match the measured tracer breakthrough curve. The model reproduces the 3D PET measurements accurately by capturing the larger-scale tracer plume deformation as well as sub-core scale mixing, while confirming negligible transverse dispersion over the scale of the experiment. We suggest that the obtained longitudinal dispersivity (0.10 ± 0.02 cm) is rock-rather than sample-specific, because of the ability of the model to decouple sub-core scale permeability heterogeneity effects from those of local dispersion. As such, the approach presented here proves to be very valuable, if not necessary, in the context of reservoir core analyses, because rock samples can rarely be regarded as "uniformly heterogeneous".

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Section: Advanced Reservoir Core Analyses With Imaging Techniquesmentioning

confidence: 95%

Quantifying solute spreading and mixing in reservoir rocks using 3-D PET imaging

et al. 2016

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“…PET imaging is based on the decay of positron-emitting radionuclides and is routinely used as a diagnostic tool in medicine and pre-clinical research. PET was occasionally used to visualize fluids in porous structures, such as crystalline rocks (Degueldre et al 1996), construction materials (Hoff et al 1996) and sediments (Maguire et al 1997;Khalili et al Fig. 2 Pressure gradient during gel injection (left) coincided with the equation dP/dL = 0.02/w f 2 for a fracture width of 0.04 in.…”

Section: Pet-imaging Of Wormhole Development During Chase Water Injectionmentioning

confidence: 93%

The Mechanism for Improved Polymer Gel Blocking During Low-Salinity Waterfloods, Investigated Using Positron Emission Tomography Imaging

Brattekås

Seright

2020

Transp Porous Med

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Polymer gels can be placed in fractures within subsurface reservoirs to improve sweep efficiency during subsequent floods, and its success is largely determined by the gel's ability to completely occupy the fracture volume. Gel volumetric properties may be influenced by mechanical and chemical conditions. In this work, gel volume sensitivity to salinity contrast is investigated. Previous bulk gel studies showed that water-based gel swelled in contact with lower-salinity water and shrunk in contact with higher-salinity water. Recent core-scale experiments demonstrated that gel blocking efficiency after rupture was also impacted by the salinity of the injected water phase. Gel treatments (after gel rupture) become less efficient in controlling fracture flow with time and water throughput during water injection without salinity contrasts. However, by reducing the salinity of the injected water phase with respect to the gel, blocking efficiency may be maintained, or even improved, over time. The coupling between gel deformation during swelling/shrinking and dynamic fluid flow is complex and can initiate changes in mechanical or transport properties, included formation of fluid flow paths through the gel that are not easily distinguished during conventional core floods. In-situ imaging by positron emission tomography (PET) was utilized to gain access to local flow patterns in this work, and combined with pressure measurements to characterize complex flow phenomena in a fractured, gel-filled system. Gel rupture was quantified several consecutive times during low-salinity waterflooding. Increasing rupture pressures indicates continuous gel strengthening during low-salinity water injection. PET imaging revealed that gel swelling occurred during low-salinity waterfloods, to constrict water pathways through the fracture. Gel swelling was sufficient to restrict fracture flow completely, and injected water was diverted into the rock matrix adjacent to the fracture. Injected water continued to pass through gel at elevated pressure gradients, but continuous flow paths did not form. This observation supports the notion of gel as a compressible, porous medium.

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“…Although primarily used as a clinical diagnostic tool, PET has been used to visualize fluids in porous structures including construction materials [Hoff et al, 1996], crystalline rocks [Degueldre et al, 1996], and sediments [Haugan, 2000;Khalili et al, 1998;Maguire et al, 1997]. PET visualization of flow fields in porous sandstones was reported by Ogilvie et al [2001], and more recently in other geomaterials [Dechsiri et al, 2005;Kulenkampff' et al, 2008].…”

Section: Positron Emission Tomography (Pet)mentioning

confidence: 99%

Combined positron emission tomography and computed tomography to visualize and quantify fluid flow in sedimentary rocks

et al. 2015

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Here we show for the first time the combined positron emission tomography (PET) and computed tomography (CT) imaging of flow processes within porous rocks to quantify the development in local fluid saturations. The coupling between local rock structure and displacement fronts is demonstrated in exploratory experiments using this novel approach. We also compare quantification of 3‐D temporal and spatial water saturations in two similar CO2 storage tests in sandstone imaged separately with PET and CT. The applicability of each visualization technique is evaluated for a range of displacement processes, and the favorable implementation of combining PET/CT for laboratory core analysis is discussed. We learn that the signal‐to‐noise ratio (SNR) is over an order of magnitude higher for PET compared with CT for the studied processes.

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Positron emission tomography of large rock samples using a multiring PET instrument

Cited by 14 publications

References 6 publications

Quantifying solute spreading and mixing in reservoir rocks using 3-D PET imaging

Quantifying solute spreading and mixing in reservoir rocks using 3-D PET imaging

The Mechanism for Improved Polymer Gel Blocking During Low-Salinity Waterfloods, Investigated Using Positron Emission Tomography Imaging

Combined positron emission tomography and computed tomography to visualize and quantify fluid flow in sedimentary rocks

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