Understanding Wormholes in Carbonates: Unprecedented Experimental Scale and 3-D Visualization

McDuff, Darren; Shuchart, Chris E.; Jackson, Shalawn K.; Postl, Dieter; Brown, J. Steven

doi:10.2118/134379-ms

Cited by 45 publications

(18 citation statements)

References 5 publications

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“…For example, the study of carbonate rock acidization in advanced EOR leads to a set of governing equations similar to the ones for miscible displacement flow. Also in this case, fingering, meandering flow structures called acidizing wormholes appear, and are governed by a dynamics analogous to the one of viscous fingers [258,259,260,261,262,263,264,265,266].…”

Section: First Contact Miscible Displacement In Eor Processesmentioning

confidence: 99%

Analytical and variational numerical methods for unstable miscible displacement flows in porous media

Scovazzi

Wheeler

Mikelić

et al. 2017

Journal of Computational Physics

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International audienceThe miscible displacement of one fluid by another in a porous medium has received considerable attention in sub-surface, environmental and petroleum engineering applications. When a fluid of higher mobility displaces another of lower mobility, unstable patterns-referred to as viscous fingering-may arise. Their physical and mathematical study has been the object of numerous investigations over the past century. The objective of this paper is to present a review of these contributions with particular emphasis on variational methods. These algorithms are tailored to real field applications thanks to their advanced features: handling of general complex geometries, robustness in the presence of rough tensor coefficients, low sensitivity to mesh orientation in advection dominated scenarios, and provable convergence with fully unstructured grids. This paper is dedicated to the memory of Dr. Jim Douglas Jr., for his seminal contributions to miscible displacement and variational numerical methods

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Section: First Contact Miscible Displacement In Eor Processesmentioning

confidence: 99%

Analytical and variational numerical methods for unstable miscible displacement flows in porous media

Scovazzi

Wheeler

Mikelić

et al. 2017

Journal of Computational Physics

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“…When an interface moves in response to a quantity diffusing towards it, the coupling of its deformation with the flux that moves it generates remarkable dynamics. The Saffman-Taylor experiment is a paragon of this class of systems [1], but many other occurrences manifest themselves in nature through beautifully ramified patterns, such as wormholes in dissolving rocks [2,3], finger-like smoldering in combustion experiments [4], metallic dendrites grown by electrochemical deposition [5,6], the formation of lungs [7,8] or the growth of root systems [9,10,11]. A similar process takes place at a much larger scale when a river drains the groundwater that surrounds it [12,13,14,15].…”

Section: Introductionmentioning

confidence: 99%

Laplacian networks: Growth, local symmetry, and shape optimization

et al. 2017

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Inspired by river networks and other structures formed by Laplacian growth, we use the Loewner equation to investigate the growth of a network of thin fingers in a diffusion field. We first review previous contributions to illustrate how this formalism reduces the network's expansion to three rules, which respectively govern the velocity, the direction, and the nucleation of its growing branches. This framework allows us to establish the mathematical equivalence between three formulations of the direction rule, namely geodesic growth, growth that maintains local symmetry, and growth that maximizes flux into tips for a given amount of growth. Surprisingly, we find that this growth rule may result in a network different from the static configuration that optimizes flux into tips.

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“…Data from McDuff et al (2010) however shows wormholes in all directions for optimum injection rates, but preferably in one direction for low rates. This should be one of the reasons why a simple geometrical extrapolation (i.e., use of interstitial velocity at the wormhole tip) is able to predict the wormhole velocity correctly (i.e., linear wormhole propagation nature in radial geometry).…”

Section: Resultsmentioning

confidence: 93%

HP/HT Carbonate Acidizing—Recent Discoveries and Contradictions in Wormhole Phenomenon

Karale

Beuterbaugh

Pinto

et al. 2016

Day 3 Thu, March 24, 2016

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Matrix acidizing is a technique used for stimulating carbonate formations. Fluids used for this purpose are routinely characterized in the laboratory by means of core flood testing. Though several key insights can be obtained using the laboratory core flood technique, simulating exact downhole environments and extrapolation of the results obtained to field-scale has proven challenging. This paper addresses two specific topics related to acid wormholing-upscaling laboratory results to field scenarios and the interaction of reaction products in high pressure reservoirs.To study the upscaling of acid wormholing experiments in field scenarios, a radial core flood testing apparatus was set up to better mimic actual wellbore acidizing flow conditions. The effects of radial flow path and completion type (i.e. openhole versus cased hole) as well as the applicability of the upscaling wormhole propagation model were studied. Furthermore, CT scans of related core samples were performed to characterize wormhole patterns generated by acid dissolution. In addition, tests were performed at high pressures and flow rates to study the effects of the interaction of reaction products on the wormholing process at typical high bottomhole pressure values.Results from radial core flood techniques showed significant differences in terms of pore volume to breakthrough (PVBT) based on well completion type. Further, a current upscaling algorithm for wormhole propagation modeling was verified by comparison to corresponding experimental data, thus demonstrating the suitability of described linear core flow testing methods for fluid characterization and data modeling. The wormhole propagation model (based on the use of fitting coefficient) is well-justified by the probability of increased fluid loss from the wormhole in the case of deeper radial penetration, which overall reduces the efficiency of wormholing. CT scan results revealed nonuniform radial distribution of wormhole propagation, thus shedding light on challenges associated with achieving 360°stimulation around the wellbore. Experiments at higher pressures showed that, at higher flow rates investigated (or beyond optimum) wormhole propagation has a higher than one third dependence on interstitial velocity, signifying that high pressure reservoirs require greater volumes of acid for proper stimulation. Experimental observations are presented to correlate the results obtained thus far and help resolve controversies between various publications.Presented studies highlight the effects of higher pressure in acid wormholing and signify the need for proper volume accounting in terms of job design. A simple radial core flood technique has been developed in this work, and has an advantage in terms of diversion studies by providing a means of arranging high and low permeability core samples in the same order as formation layers and accounting for fluid entrance position.

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Understanding Wormholes in Carbonates: Unprecedented Experimental Scale and 3-D Visualization

Cited by 45 publications

References 5 publications

Analytical and variational numerical methods for unstable miscible displacement flows in porous media

Analytical and variational numerical methods for unstable miscible displacement flows in porous media

Laplacian networks: Growth, local symmetry, and shape optimization

HP/HT Carbonate Acidizing—Recent Discoveries and Contradictions in Wormhole Phenomenon

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