The effect of wettability on capillary trapping in carbonates

Alyafei, Nayef; Blunt, Martin J.

doi:10.1016/j.advwatres.2016.02.001

Cited by 69 publications

(37 citation statements)

References 32 publications

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“…In addition, surface roughness of a rock may lead to a small‐scale mixed‐wet pattern. During primary drainage only the peaks of the rock surface contact the crude oil and are altered to oil‐wet, while the deep holes on the surface related to the microporosity of the rock remain water‐wet (Alyafei & Blunt, ; Kovscek et al, ; Schmatz et al, ). The resolution of the recorded μCT images is not sufficient to observe such a pattern, but the contact angle distribution obtained in this system indicates its presence.…”

Section: Resultsmentioning

confidence: 99%

The Effect of Mixed Wettability on Pore‐Scale Flow Regimes Based on a Flooding Experiment in Ketton Limestone

Rücker

Bartels

Singh

et al. 2019

Geophysical Research Letters

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Darcy‐scale multiphase flow in geological formations is significantly influenced by the wettability of the fluid‐solid system. So far it has not been understood how wettability impacts the pore‐scale flow regimes within rocks, which were in most cases regarded as an alteration from the base case of strongly water‐wet conditions by adjustment of contact angles. In this study, we directly image the pore‐scale flow regime in a carbonate altered to a mixed‐wet condition by aging with crude oil to represent the natural configuration in an oil reservoir with fast synchrotron‐based X‐ray computed tomography. We find that the pore‐scale flow regime is dominated by ganglion dynamics in which the pore space is intermittently filled with oil and brine. The frequency and size of these fluctuations are greater than in water‐wet rock such that their impact on the overall flow and relative permeability cannot be neglected in modeling approaches.

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Section: Resultsmentioning

confidence: 99%

The Effect of Mixed Wettability on Pore‐Scale Flow Regimes Based on a Flooding Experiment in Ketton Limestone

Rücker

Bartels

Singh

et al. 2019

Geophysical Research Letters

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“…Although our chosen technique was user dependent and was likely to result in a certain degree of uncertainty, we manually adjusted the thresholds to produce results that we considered visually correct. To further reduce this uncertainty we benchmarked our results where possible with those found in previous studies (Boone et al, 2014;Derluyn et al, 2014;Mehmani and Prodanović, 2014;Alyafei and Blunt, 2016;Bultreys et al, 2016b). The micrographs in Figure 1 show the segmented gray scale images from the six samples analyzed in this study.…”

Section: Image Processingmentioning

confidence: 95%

The Influence of Microporous Cements on the Pore Network Geometry of Natural Sedimentary Rocks

2019

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We investigate the pore network geometry and permeability of six natural sandstones and carbonate rocks. Using 3D microtomographic images, we segment each rock sample into three phases: Solid matrix of grains, macropores containing void spaces, and a third microporous phase containing nanometer-sized pores beyond the resolution of the image. In the majority of our samples, the microporosity exists inside cements deposited as a secondary phase along the surface of grains. Within the macropores, the pore radius, coordination number, throat radius, and throat length display a power law relation with porosity. We also find that the permeability of the aggregate depends on the porosity following the relation k = k 0 φ 3.32 , where log k 0 = 5.52 (mD). The fraction of connected porosity shows a strongly non-linear reduction with an increase in the volume fraction of microporous cement.

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“…Where Pc -capillary pressure; Pn -non-wetting pressure; Pw -wetting pressure Typically, oil recoveries from such fractured reservoirs are usually very poor with average recovery factor of about 10-35% [25], [36], [44], however, if such oil-wet surface can be rendered water-wet, spontaneous imbibition of water into the matrix pores (where most of the oil resides) massively increases recovery factors to 50-70% [48][49][50][51]. However, water wet media exhibit increased snap-off events which lead to increased residual oil saturations after water breakthrough and subsequent poor oil recovery [86]. The relevance of wetting and its effect on rock-fluid properties cannot be over emphasize, aside from its importance in subsurface reservoir evaluation, it is of great relevance for characterization and selection of materials.…”

Section: Introductionmentioning

confidence: 99%

Wettability alteration of oil-wet limestone using surfactant-nanoparticle formulation

Nwidee

Lebedev

Barifcani

et al. 2017

Journal of Colloid and Interface Science

115

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Wettability remains a prime factor that controls fluid displacement at pore-scale with substantial impact on multi-phase flow in the subsurface. As the rock surface becomes hydrophobic, any oleic phase present is tightly stored in the rock matrix and produced (hydrocarbon recovery) or cleaned up (soil-decontamination) by standard waterflooding methods. Although surface active agents such as surfactants have been used for several decades for changing the wetting states of such rocks, an aspect that has been barely premeditated is the simultaneous blends of surfactants and nanoparticles. This study thus, systematically reports the behaviour of surfactants augmented nanoparticles on wettability alteration. Contact angle, spontaneous imbibition, and mechanistic approaches were adopted to assess the technical feasibility of the newly formulated wetting agents, tested over wide-ranging conditions to ascertain efficient wetting propensities. The contact angle measurement is in good agreement with the morphological and topographical studies and spontaneous imbibition. The wetting trends for the formulated systems indicate advancing and receding water contact angle decreased with increase in nanoparticle concentration and temperature, and the spontaneous water imbibition test also showed faster water-imbibing tendencies for nanoparticle-surfactant exposed cores. Thus, the new formulated nanoparticle-surfactant systems were considered suitable for enhancing oil recovery and soil-decontamination, particularly in fractured hydrophobic reservoirs.

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The effect of wettability on capillary trapping in carbonates

Cited by 69 publications

References 32 publications

The Effect of Mixed Wettability on Pore‐Scale Flow Regimes Based on a Flooding Experiment in Ketton Limestone

The Effect of Mixed Wettability on Pore‐Scale Flow Regimes Based on a Flooding Experiment in Ketton Limestone

The Influence of Microporous Cements on the Pore Network Geometry of Natural Sedimentary Rocks

Wettability alteration of oil-wet limestone using surfactant-nanoparticle formulation

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