Carbonate acidizing: Modeling, analysis, and characterization of wormhole formation and propagation

Ghommem, Mehdi; Zhao, Weishu; Dyer, Steve; Qiu, Xiangdong; Brady, Dominic

doi:10.1016/j.petrol.2015.04.021

Cited by 117 publications

(53 citation statements)

References 30 publications

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“…For diffusion-limited systems, at high Da II and Pe, the local dissolution of a mineral leads to a focus of the flow to that location. This then leads to further dissolution in those regions, creating interconnected paths of high porosity and permeability (wormholes) (e.g., Carroll et al 2013;Hao et al 2013;Smith et al 2013;Daccord et al 1989Daccord et al , 1993aGolfier et al 2002Golfier et al , 2004Poms et al 2007;Hoefner and Fogler 1988;Fredd and Fogler 1998;Steefel and Maher 2009;Steefel 2008;Steefel and AC 1990;Kang et al 2002;Kalia and Balakotaiah 2007;Ghommem et al 2015;Ott and Oedai 2015). Such wormhole structures may even form for flow through nearly even fractures (Noiriel 2015).…”

Section: Processes Modifying the Pore Spacementioning

confidence: 99%

“…But even in a uniform dissolution regime, the flow focuses during dissolution on preferential flow paths, decreasing the tortuosity (Menke et al 2015). The dissolution patterns and their dependence on the flow rate at which the reactive fluid is injected has been studied intensively over many years (e.g., Daccord et al 1989Daccord et al , 1993aGolfier et al 2002Golfier et al , 2004Poms et al 2007;Hoefner and Fogler 1988;Fredd and Fogler 1998;Steefel and AC 1990;Kang et al 2002;Luhmann et al 2014;Kalia and Balakotaiah 2007;Ghommem et al 2015;Ott and Oedai 2015). Other parameters also influence the dissolution patterns, e.g., the initial permeability and porosity contrast within the porous medium or the distribution of reactive minerals (e.g., Carroll et al 2013;Hao et al 2013;Smith et al 2013;Ellis and Peters 2016).…”

Section: Processes Modifying the Pore Spacementioning

confidence: 99%

“…Other parameters also influence the dissolution patterns, e.g., the initial permeability and porosity contrast within the porous medium or the distribution of reactive minerals (e.g., Carroll et al 2013;Hao et al 2013;Smith et al 2013;Ellis and Peters 2016). The creation of wormholes by the injection of acid at an optimal rate into carbonate oil reservoirs is of particular interest as it allows for a significant increase in permeability with only the minimal amount of reactant necessary (e.g., Daccord et al 1993a;Poms et al 2007;Ghommem et al 2015).…”

Section: Processes Modifying the Pore Spacementioning

confidence: 99%

See 2 more Smart Citations

Porosity–Permeability Relations for Evolving Pore Space: A Review with a Focus on (Bio-)geochemically Altered Porous Media

Hommel¹,

Coltman²,

Class³

2018

Transp Porous Med

244

154

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Reactive transport processes in a porous medium will often both cause changes to the pore structure, via precipitation and dissolution of biomass or minerals, and be affected by these changes, via changes to the material's porosity and permeability. An understanding of the pore structure morphology and the changes to flow parameters during these processes is critical when modeling reactive transport. Commonly applied porosity-permeability relations in simulation models on the REV scale use a power-law relation, often with slight modifications, to describe such features; they are often used for modeling the effects of mineral precipitation and/or dissolution on permeability. To predict the reduction in permeability due to biomass growth, many different and often rather complex relations have been developed and published by a variety of authors. Some authors use exponential or simplified Kozeny-Carman relations. However, many of these relations do not lead to fundamentally different predictions of permeability alteration when compared to a simple power-law relation with a suitable exponent. Exceptions to this general trend are only few of the porosity-permeability relations developed for biomass clogging; these consider a residual permeability even when the pore space is completely filled with biomass. Other exceptions are relations that consider a critical porosity at which the porous medium becomes impermeable; this is often used when modeling the effect of mineral precipitation. This review first defines the scale on which porosity-permeability relations are typically used and aims at explaining why these relations are not unique. It shows the variety of existing approaches and concludes with their essential features.

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Section: Processes Modifying the Pore Spacementioning

confidence: 99%

Section: Processes Modifying the Pore Spacementioning

confidence: 99%

Section: Processes Modifying the Pore Spacementioning

confidence: 99%

See 1 more Smart Citation

Porosity–Permeability Relations for Evolving Pore Space: A Review with a Focus on (Bio-)geochemically Altered Porous Media

Hommel¹,

Coltman²,

Class³

2018

Transp Porous Med

244

154

View full text Add to dashboard Cite

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“…Two features of the reactive-infiltration instability are relevant to the present discussion. The first is the fact that the positivefeedback loop between the flow and dissolution produces patterns across all the spatial scales: from the changes in the microstructure of the rock matrix and preferential opening of macropores [as observed in shales by Wu and Sharma (2015) and Grieser et al (2007)], emergence of core-scale structures such as nonuniform etching of the fracture walls (Ruffet et al 1998), or the formation of wormholelike dissolution channels on the fracture surfaces (Dong et al 1999;Detwiler et al 2003;Szymczak and Ladd 2009) up to the macroscopic forms such as caves or solution pipes in the karst landscape (Ginés et al 2009).…”

Section: Discussionmentioning

confidence: 99%

Wormhole Formation During Acidizing of Calcite-Cemented Fractures in Gas-Bearing Shales

et al. 2019

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A relatively large number of calcite-cemented fractures are present in gas-bearing shale formations. During hydraulic fracturing, some of these fractures will be reactivated and may become important flow paths in the resulting stimulated fracture network. On the other hand, the presence of carbonate lamina on fracture surfaces will have a hindering effect on the transport of shale gas from the matrix toward the wellbore. We investigate numerically the effect of low-pH reactive fluids on such fractures, and show that dissolution of the cement proceeds in a highly nonuniform manner. The morphology of the emerging flow paths ("wormholes") strongly depends on the thickness of the calcite layer. For thick carbonate layers, a hierarchical, fractal pattern appears, with highly branched wormhole-like channels competing for an available flow. For thin layers, the pattern is much more diffuse, with less-pronounced wormholes that merge easily with each other. Finally, for intermediate thicknesses, we observe a strong attraction between shorter and longer wormholes, which leads to the formation of islands of carbonate lamina surrounded by the dissolved regions. We argue that the wormholeformation processes are not only important for the increase of shale-gas recovery, but also can be used for retaining the fracture permeability, even in the absence of proppant.2019 SPE Journal 1 is the main driving process behind the cave formation in karst systems (Dreybrodt 1990;Hanna and Rajaram 1998;Cheung and Rajaram 2002;Szymczak and Ladd 2011). All these studies show that the dissolution of rock fractures is a strongly unstable process, with spontaneous focusing of the flow in high-porosity channels (wormholes). The instability here is, in fact, stronger than the corresponding instability in the dissolving porous media (Szymczak and Ladd 2011), with much weaker stabilization caused by diffusion. It needs to be stressed that both experimental and numerical studies of fracture dissolution have considered homogeneous soluble samples, in which aperture growth is potentially unlimited. In shales, the situation is fundamentally different, because the amount of soluble cement at a given place is finite and, thus, after a certain time, the cement fully dissolves, and the dissolution front moves farther downstream. As it turns out, a limited amount of soluble material significantly influences the dissolution patterns in fractures. Nevertheless, as we show in the present study, the dissolution front is still unstable, with an intense wormhole formation in the system. Besides serving as a means to increase the fracture-matrix transport, such a nonuniform dissolution is potentially important for retaining the fracture permeability even in the absence of proppant Wu and Sharma 2015). Whereas a uniformly etched fracture may close tightly under the load of overburden once the fluid pressure is removed, the nonuniform etching will tend to maintain the permeability. The less-dissolved regions will then act as supports to keep more-dissolved regions op...

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“…That is to say that, horizontal interval depth determines the surficial contact of a wellbore with reservoir. Acidizing divided into to three classifications such as acid washing, acid fracturing and matrix acidizing (Ghommem et al 2015;Msharrafieh et al 2016;Davarpanah et al 2018). The dominant influence of temperature on the reservoir parameters describes as the following phenomena:…”

Section: Introductionmentioning

confidence: 99%

An experimental study of acidizing operation performances on the wellbore productivity index enhancement

Rabbani

Davarpanah

Memariani

2018

J Petrol Explor Prod Technol

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The hydrocarbon fossil fuels are considered as the preferable fuels to provide sufficient energies for industrial purposes. Also, extracting oil from the exploration wells might be a concerning issue in the coming decades, and petroleum engineers push themselves into limits ind novel solutions to enhance the oil recovery factor. Wellbore stimulation procedures exert a profound impact on the current production rate enhancement; respect of the way, reservoir productivity index witnesses a steep rise during the production operation and subsequently would virtually eliminate unnecessary expenditures of other methodologies. Appropriate investigation of acidizing procedures and its significant role in the wellbore production enhancement are utterly dependent on the quality and types of additives, types of acid, acidizing operation and types of formation. The objective of this study is to investigate the effect of injected acid in the carbonated reservoir and subsequently its comparison with the acidizing operations model. Therefore, available well-testing experiments are administered to determine the critical reservoir parameters such as skin factor, reservoir pressure, and permeability. Since then by modeling the wellbore condition in the acidizing operation simulator software, the impact of acidizing on the reservoir is simulated. Consequently, the provided information from software is compared with the real data from well-testing operations. As a result, productivity index is increased dramatically owing to successful acidizing procedures.

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Carbonate acidizing: Modeling, analysis, and characterization of wormhole formation and propagation

Cited by 117 publications

References 30 publications

Porosity–Permeability Relations for Evolving Pore Space: A Review with a Focus on (Bio-)geochemically Altered Porous Media

Porosity–Permeability Relations for Evolving Pore Space: A Review with a Focus on (Bio-)geochemically Altered Porous Media

Wormhole Formation During Acidizing of Calcite-Cemented Fractures in Gas-Bearing Shales

An experimental study of acidizing operation performances on the wellbore productivity index enhancement

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