On the ability of a Darcy-scale model to capture wormhole formation during the dissolution of a porous medium

Golfier, Fabrice; Zarcone, C.; Bazin, Brigitte; Lenormand, R.; Lasseux, Didier; Quintard, Michel

doi:10.1017/s0022112002007735

Cited by 349 publications

(436 citation statements)

References 66 publications

Supporting

Mentioning

413

Contrasting

Unclassified

Order By: Relevance

“…hancing oil production rate when muds and fines deposit at the perforated well pore pipe [4,5,7,9,15,20,26,29,30]. In the technique, acid is injected into matrix to dissolve the rocks and deposits around the well bore and a channel with high porosities is formed.…”

Section: Introduction Matrix Acidization Technique Plays An Importanmentioning

confidence: 99%

“…Because of its importance in enhancing production rate, matrix acidization in carbonate reservoirs has been extensively studied in [4,5,7,9,15,20,26,29,30], but the numerical methods are restricted to finite difference and finite volume methods. In [31], the combination of the finite element method and the finite difference method has been used to simulate the wormhole generation and propagation in carbonate rocks.…”

Section: Introduction Matrix Acidization Technique Plays An Importanmentioning

confidence: 99%

See 1 more Smart Citation

Mixed finite element-based fully conservative methods for simulating wormhole propagation

Kou

Sun

2016

Computer Methods in Applied Mechanics and Engineering

View full text Add to dashboard Cite

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. MIXED FINITE ELEMENT-BASED FULLY CONSERVATIVE METHODS FOR SIMULATING WORMHOLE PROPAGATION *JISHENG KOU † , SHUYU SUN ‡ , AND YUANQING WU § Abstract. Wormhole propagation during reactive dissolution of carbonates plays a very important role in the product enhancement of oil and gas reservoir. Because of high velocity and nonuniform porosity, the Darcy-Forchheimer model is applicable for this problem instead of conventional Darcy framework. We develop a mixed finite element scheme for numerical simulation of this problem, in which mixed finite element methods are used not only for the Darcy-Forchheimer flow equations but also for the solute transport equation by introducing an auxiliary flux variable to guarantee full mass conservation. In theoretical analysis aspects, based on the cut-off operator of solute concentration, we construct an analytical function to control and handle the change of porosity with time; we treat the auxiliary flux variable as a function of velocity and establish its properties; we employ the coupled analysis approach to deal with the fully coupling relation of multivariables. From this, the stability analysis and a priori error estimates for velocity, pressure, concentration and porosity are established in different norms. Numerical results are also given to verify theoretical analysis and effectiveness of the proposed scheme.

show abstract

Section: Introduction Matrix Acidization Technique Plays An Importanmentioning

confidence: 99%

Section: Introduction Matrix Acidization Technique Plays An Importanmentioning

confidence: 99%

Mixed finite element-based fully conservative methods for simulating wormhole propagation

Kou

Sun

2016

Computer Methods in Applied Mechanics and Engineering

View full text Add to dashboard Cite

show abstract

“…In addition, a core size simulation using the network model is computationally very expensive. A two-scale model, averaged model or continuum model [28][29][30] can describe the dissolution patterns based on both the Darcy scale and pore scale. The information achieved by semiempirical equations on the pore scale is passed to the Darcy scale equations to describe 6 the dissolution procedure.…”

Section: Introductionmentioning

confidence: 99%

Parallel simulation of wormhole propagation with the Darcy–Brinkman–Forchheimer framework

Salama

Sun

2015

Computers and Geotechnics

View full text Add to dashboard Cite

The acid treatment of carbonate reservoirs is a widely practiced oil and gas well stimulation technique. The injected acid dissolves the material near the wellbore and creates flow channels that establish a good connectivity between the reservoir and the well. Such flow channels are called wormholes. Different from the traditional simulation technology relying on Darcy framework, the new Darcy-Brinkman-Forchheimer (DBF) framework is introduced to simulate the wormhole forming procedure. The DBF framework considers both large and small porosity conditions and should output better simulation results than the Darcy framework. To process the huge quantity of cells in the simulation grid and shorten the long simulation time of the traditional serial code, a parallel code with FORTRAN 90 and MPI was developed. The experimenting field approach to set coefficients in the model equations was also introduced. Moreover, a procedure to fill in the coefficient matrix in the linear system in the solver was described.After this, 2D dissolution experiments were carried out. In the experiments, different configurations of wormholes and a series of properties simulated by both frameworks were compared. We conclude that the numerical results of the DBF framework are more like wormholes and more stable than the Darcy framework, which is a demonstration of the advantages of the DBF framework. Finally, the scalability of the parallel code was evaluated, and we conclude that superlinear scalability can be achieved.

show abstract

“…Natural heterogeneity of the porous rocks for the case of rapid dissolution of the mineral by the reactant fluid results in localization of the flow path and the formation of highly conductive channels called wormholes [3]. Several studies have revealed a variety of dissolution patterns from face dissolution to uniform dissolution depending on the injection rate and fluid/mineral properties [4][5][6].A number of imaging techniques such as Wood's metal casting, neutron radiography and scanning electron microscopy have been used to study the dissolution patterns. Among them, X-ray micro-computed tomography (micro-CT) is a superior non-destructive imaging method which can create high-resolution images with large field of view [7][8][9][10].…”

mentioning

confidence: 99%

mentioning

confidence: 99%

Chemical dissolution of carbonate rocks: A micro-CT study

Qajar¹,

Arns²

2017

Glob Imaging Insights

View full text Add to dashboard Cite

The evolution of rock microstructure is a result of complex interactions between the rock surface and reactive fluids and depends on the thermodynamic conditions, the rock and fluid composition and the flow regime [1]. At the pore-scale, the dissolution mechanism consists of mass transport of the reactant by diffusion and advection to the solid surface, chemical reaction at the fluid-mineral interface, and the product mass transport away from the surface [2]. Natural heterogeneity of the porous rocks for the case of rapid dissolution of the mineral by the reactant fluid results in localization of the flow path and the formation of highly conductive channels called wormholes [3]. Several studies have revealed a variety of dissolution patterns from face dissolution to uniform dissolution depending on the injection rate and fluid/mineral properties [4][5][6].A number of imaging techniques such as Wood's metal casting, neutron radiography and scanning electron microscopy have been used to study the dissolution patterns. Among them, X-ray micro-computed tomography (micro-CT) is a superior non-destructive imaging method which can create high-resolution images with large field of view [7][8][9][10].In this work, two carbonate core samples were considered for the dissolution experiments. The first sample was an oolitic limestone with multi-modal pore size distribution, while the second one was a wackestone-packstone carbonate with a bimodal pore size. Dissolution experiments were conducted in core plugs of 7 mm diameter using ethylenediaminetetraacetic acid (EDTA) solution at pH 12 as the reactive fluid. The experiments were performed at ambient conditions and were terminated after significant changes occurred in the cores as indicated by the pressure transducers. Details of the experimental procedure were described in [11].The pre-and post-dissolution dry samples were imaged using a high resolution micro-CT scanner at the Australian National University (ANU) [12] with at least 8.5×8.5×8.5 mm field of view and resolutions of less than 5 µm. The post-dissolution image was superposed to the pre-dissolution image using a 3D registration technique developed by Latham, et al. [13]. In the micro-CT image, the grey-scale values of the pixels correspond to the density and composition of the material imaged. Hence, in monomineralic rock, such as the samples studied in this paper, micro-CT images are 3D porosity maps. Figures 1 and 2 show examples of registered slices of the oolitic sample from top and side views, respectively. Visual observations of the images clearly illustrate that the reactive fluid locally increased the pore diameters across most parts of the sample and hence led to a quasi-uniform dissolution pattern. This pattern belongs to local nonequilibrium dissolution category [2] in which there is no sharp interface between the reactive fluid zone and the porous medium.

show abstract

On the ability of a Darcy-scale model to capture wormhole formation during the dissolution of a porous medium

Cited by 349 publications

References 66 publications

Mixed finite element-based fully conservative methods for simulating wormhole propagation

Mixed finite element-based fully conservative methods for simulating wormhole propagation

Parallel simulation of wormhole propagation with the Darcy–Brinkman–Forchheimer framework

Chemical dissolution of carbonate rocks: A micro-CT study

Contact Info

Product

Resources

About