Using Outcrop Data for Geological Well Test Modelling in Fractured Reservoirs

Aljuboori, Faisal Awad; Corbett, Patrick William Michael; Bisdom, Kevin; Bertotti, Giovanni; Geiger, Sebastian

doi:10.3997/2214-4609.201413037

Cited by 10 publications

(12 citation statements)

References 4 publications

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“…The presented workflow enables fast generation of highly detailed realistic fracture networks for use of geomechanical and flow modelling, variations of which have been applied to study different aspects of fracture and fracturematrix flow (e.g. Aljuboori et al, 2015;Arnold et al, 2016;Bisdom et al, 2016c;Egya et al, 2016;Muhammad, 2016;Shah et al, 2016).…”

Section: Discussionmentioning

confidence: 99%

An integrated workflow for stress and flow modelling using outcrop-derived discrete fracture networks

Bisdom

Nick

Bertotti

2017

Computers & Geosciences

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Fluid flow in naturally fractured reservoirs is often controlled by subseismic-scale fracture networks. Although the fracture network can be partly sampled in the direct vicinity of wells, the inter-well scale network is poorly constrained in fractured reservoir models. Outcrop analogues can provide data for population of domains of the reservoir model where no direct measurements are available. However, extracting relevant statistics from large outcrops representative of inter-well scale fracture networks remains challenging. Recent advances in outcrop imaging provide high-resolution datasets that can cover areas of several hundred by several hundred meters, i.e. the domain between adjacent wells, but even then, data from the high-resolution models is often upscaled to reservoir flow grids, resulting in loss of accuracy. We present a workflow that uses photorealistic georeferenced outcrop models to construct geomechanical and fluid flow models containing thousands of discrete fractures covering sufficiently large areas, that does not require upscaling to model permeability. This workflow seamlessly integrates geomechanical Finite Element models with flow models that take into account stress-sensitive fracture permeability and matrix flow to determine the full permeability tensor. The applicability of this workflow is illustrated using an outcropping carbonate pavement in the Potiguar basin in Brazil, from which 1082 fractures are digitised. The permeability tensor for a range of matrix permeabilities shows that conventional upscaling to effective grid properties leads to potential underestimation of the true permeability and the orientation of principal permeabilities. The presented workflow yields the full permeability tensor model of discrete fracture networks with stress-induced apertures, instead of relying on effective properties as most conventional flow models do.

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Section: Discussionmentioning

confidence: 99%

An integrated workflow for stress and flow modelling using outcrop-derived discrete fracture networks

Bisdom

Nick

Bertotti

2017

Computers & Geosciences

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“…Fine-scale modelling has been used widely to investigate various problems of recovery mechanisms and flow behaviour in both conventional and fractured reservoirs (e.g., [1, [32][33][34]). These models help to obtain an accurate result by avoiding the common simulation issues and artefacts such as upscaling problems and numerical convergence errors that frequently occurred at the reservoir scale modelling and simulation [3,35,36].…”

Section: Setup Of Numerical Modelsmentioning

confidence: 99%

Using Low Salinity Waterflooding to Improve Oil Recovery in Naturally Fractured Reservoirs

et al. 2020

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Low salinity waterflooding is an effective technique to accelerate and boost oil recovery. The impact of this technique has been investigated widely in laboratories for various scales and rock typing, most of which have demonstrated a potential improvement in oil recovery. This improvement has been attributed to several chemical and physical interactions that led to a change in the wettability to become more water-wet, as well as a reduction in the residual oil saturation. Meanwhile, it is rare to find a discussion in the literature about the efficiency of low salinity flooding in naturally fractured reservoirs. Therefore, in this work, we investigate the potential advantages of this method in fractured reservoirs using numerical simulations. A new approach to estimate the weighting factor using a tracer model has been proposed to determine the brine salinity and, hence, its properties in the mixing region. We have also used the relative permeability curves as a proxy for any physical and chemical mechanisms which are not represented explicitly in the model. The simulation outcomes highlighted the advantage of low salinity waterflooding in fractured reservoirs. An increment in oil recovery by 10.7% to 13% of Stock Tank Oil Initially In Place (STOIIP) was obtained using the dual- and single-porosity model, respectively. Therefore, the low salinity waterflooding technique represents a promising low-cost, effective method in fractured reservoirs.

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“…The National Research Council (1996) suggested the idea of using geologically realistic outcrop fracture patterns to guide subsurface fracture modelling. In recent work, the use of deterministic discrete fracture networks (DFNs) based on trace digitization from the photogrammetry of outcrop analogues was investigated by Bisdom et al (2017) and Aljuboori et al (2015) for reservoir fluid flow simulation and well testing. Outcrop-derived DFNs encapsulate 2-D fracture network properties at a scale that cannot be characterized using either standard surface approaches (scanlines and satellite imagery) or subsurface techniques (seismic imaging/borehole imagery/core sampling).…”

Section: Introductionmentioning

confidence: 99%

“…They found considerable variation in fracture topology, orientation, intensity, and length distributions in the interpretations. Andrews et al (2019) made a detailed quantification of subjective bias in scan-line-based fracture data collection, the associated effects on derived fracture statistics, and suggested protocols for managing the variations. Peacock et al (2019) delved into the multiple reasons for bias and the resulting implications for modelling.…”

Section: Introductionmentioning

confidence: 99%

An automated fracture trace detection technique using the complex shearlet transform

et al. 2019

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Abstract. Representing fractures explicitly using a discrete fracture network (DFN) approach is often necessary to model the complex physics that govern thermo-hydro-mechanical–chemical processes (THMC) in porous media. DFNs find applications in modelling geothermal heat recovery, hydrocarbon exploitation, and groundwater flow. It is advantageous to construct DFNs from the photogrammetry of fractured outcrop analogues as the DFNs would capture realistic, fracture network properties. Recent advances in drone photogrammetry have greatly simplified the process of acquiring outcrop images, and there is a remarkable increase in the volume of image data that can be routinely generated. However, manually digitizing fracture traces is time-consuming and inevitably subject to interpreter bias. Additionally, variations in interpretation style can result in different fracture network geometries, which, may then influence modelling results depending on the use case of the fracture study. In this paper, an automated fracture trace detection technique is introduced. The method consists of ridge detection using the complex shearlet transform coupled with post-processing algorithms that threshold, skeletonize, and vectorize fracture traces. The technique is applied to the task of automatic trace extraction at varying scales of rock discontinuities, ranging from 100 to 102 m. We present automatic trace extraction results from three different fractured outcrop settings. The results indicate that the automated approach enables the extraction of fracture patterns at a volume beyond what is manually feasible. Comparative analysis of automatically extracted results with manual interpretations demonstrates that the method can eliminate the subjectivity that is typically associated with manual interpretation. The proposed method augments the process of characterizing rock fractures from outcrops.

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Using Outcrop Data for Geological Well Test Modelling in Fractured Reservoirs

Cited by 10 publications

References 4 publications

An integrated workflow for stress and flow modelling using outcrop-derived discrete fracture networks

An integrated workflow for stress and flow modelling using outcrop-derived discrete fracture networks

Using Low Salinity Waterflooding to Improve Oil Recovery in Naturally Fractured Reservoirs

An automated fracture trace detection technique using the complex shearlet transform

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