Full Tensor Upscaling of Geologically Complex Reservoir Descriptions

Wen, Xian‐Huan; Durlofsky, Louis J.; Lee, S.H.; Edwards, Michael G.

doi:10.2118/62928-ms

Cited by 18 publications

(7 citation statements)

References 23 publications

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“…To further reduce the effects of the assumptions implied by different choices of boundary conditions, we also consider the effects of including a layer of "skin" around the averaging volume. This approach extends the domain on which Eq (10) is solved for each averaging volume, beyond the boundaries of that averaging volume [35,36] (see also Fig 1). As the calculation of effective conductivity through Eq (8) still only considers the averaging volume, this has the effect of moving the boundaries away from the region used for calculation and thus hopefully minimising boundary condition effects.…”

Section: Closure Problem Boundary Conditionsmentioning

confidence: 99%

Homogenisation for the monodomain model in the presence of microscopic fibrotic structures

Lawson¹,

Santos²,

Turner³

et al. 2020

Preprint

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Computational models in cardiac electrophysiology are notorious for long runtimes, restricting the numbers of nodes and mesh elements in the numerical discretisations used for their solution. This makes it particularly challenging to incorporate structural heterogeneities on small spatial scales, preventing a full understanding of the critical arrhythmogenic effects of conditions such as cardiac fibrosis. In this work, we explore the technique of homogenisation by volume averaging for the inclusion of non-conductive micro-structures into larger-scale cardiac meshes with minor computational overhead. Importantly, our approach is not restricted to periodic patterns, enabling homogenised models to represent, for example, the intricate patterns of collagen deposition present in different types of fibrosis. We first highlight the importance of appropriate boundary condition choice for the closure problems that define the parameters of homogenised models. Then, we demonstrate the technique's ability to correctly upscale the effects of fibrotic patterns with a spatial resolution of 10 µm into much larger numerical mesh sizes of 100-250 µm. The homogenised models using these coarser meshes correctly predict critical pro-arrhythmic effects of fibrosis, including slowed conduction, source/sink mismatch, and stabilisation of re-entrant activation patterns. As such, this approach to homogenisation represents a significant step towards whole organ simulations that unravel the effects of microscopic cardiac tissue heterogeneities.

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Section: Closure Problem Boundary Conditionsmentioning

confidence: 99%

Homogenisation for the monodomain model in the presence of microscopic fibrotic structures

Lawson¹,

Santos²,

Turner³

et al. 2020

Preprint

View full text Add to dashboard Cite

show abstract

“…In such systems, the importance of properly modeling the effects of grid orientation and the magnitudes of inaccuracies has been demonstrated [5] by contrasting diagonal and full tensor simulations. In general, the permeabilities in the horizontal part are formed by rotating the principle values of oriented permeability into the new horizontal coordinate system.…”

Section: Grid Orientation Correctionmentioning

confidence: 99%

A New Approach to Thin Oil Zone Modeling in High-Dipping Multilayered Reservoirs

Tolstukhin

Olivier

2010

All Days

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This paper focuses on maximizing oil recovery from thin oil rim in a high-dipping, multilayered reservoir in the North Sea. Oil output from thin oil zones between a gas cap and an aquifer is limited to uneconomical rates caused by water coning and gas cresting. Horizontal wells are widely used in thin oil rim development due to the limited pressure drawdown applied to the formation. The horizontal wells should be optimally positioned within the oil zone to avoid premature gas and water breakthrough. Critical issues for thin oil zone reservoir modeling are correct grid representation of internal heterogeneities, fluid saturation distribution, fluid contacts, horizontal well trajectories and flow displacement properties. In a stratigraphic grid, the lack of resolution affects the fluid contacts movement within the high-dipping reservoir layers. Similarly for a horizontal grid, thin reservoir intervals are truncated due to a 'stair-casing' effect, which leads to loss of communication within the layers. A hybrid grid was constructed to combine the benefits of the horizontal grid in the oil zone together with the stratigraphic grid in the water and gas zones. Such a grid framework provides the best modeling approach for representing the transition zone and fluid contact movements. In the study, the prediction of oil, gas and water production in the transition zone was difficult because the crude oil altered formation wettability after hydrocarbon migration and reservoir structure tilting. Multiphase flow was modeled by integrating the key dynamic reservoir controls, translated into end-point correlations above the free water level based on multivariate SCAL data analyses. Comparative analyses of alternative modeling techniques exhibited clear differences in the response for coning development and optimal well placements.

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“…This modifies the fluidbreakthrough times and therefore compromises the overall flow characteristics of the model. Wen et al 16 recently proposed the border-region method, which may alleviate the severity of this problem. They propose including neighboring cells in the estima- tion of the effective permeabilities, which may preserve the directional anisotropy of the models.…”

Section: Scaleup Analysis Of An African Oil Fieldmentioning

confidence: 99%

Insights Into Upscaling Using 3D Streamlines

Chawathé

Taggart

2004

SPE Reservoir Evaluation &Amp; Engineering

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Large, multimillion-cell geological models are frequently constructed in an effort to "capture" the vertical heterogeneity measured by well logs and the areal heterogeneity inferred by the depositional environments. These criteria often result in fine-scale models at a resolution of 0.1 to 0.3 m vertically and 30 to 100 m areally, resulting in reservoir models on the order of 10 7 grid cells. Recourse is made to upscaling to obtain coarsened but computationally efficient flow-simulation models. The coarsened models commonly result in no more than 1 to 5% of the original grid size, underscoring the need for judicious upscaling. Of greater importance is demonstrating, for the chosen grid dimensions, that the upscaled representation is both reasonable and optimal in the sense that a significantly better template would be difficult to obtain.We consider two nonuniformly coarsened models to demonstrate the issues involved and show that the use of 3D streamline methods offers insightful alternatives to decoupled analysis for both the scaleup template design and the pre-and post-diagnostics. We confine ourselves to property-upscaling methods that use local grid information as opposed to estimating upscaled properties based on some global measure. For this class of problems, we demonstrate that the diagnostic phases are necessarily separate from the upgridding and upscaling processes. Upgridding, Upscaling, and Homogenization TheoryUpscaling internally comprises two processes-upgridding, whereby the fine grid is optimally coarsened in such a way as to preserve the fractional-flow characteristics of the fine grid, and actual upscaling, whereby the effective properties for the coarsened grid are computed with established mathematical theories. In general, upgridding is achieved through the identification and preservation of features that have significant correlation lengths and

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Full Tensor Upscaling of Geologically Complex Reservoir Descriptions

Cited by 18 publications

References 23 publications

Homogenisation for the monodomain model in the presence of microscopic fibrotic structures

Homogenisation for the monodomain model in the presence of microscopic fibrotic structures

A New Approach to Thin Oil Zone Modeling in High-Dipping Multilayered Reservoirs

Insights Into Upscaling Using 3D Streamlines

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