Physicochemical Interactions During Surfactant Flooding of Fractured Carbonate Reservoirs

Seethepalli, Anita; Adibhatla, Bhargaw; Mohanty, Kishore K.

doi:10.2118/89423-pa

Cited by 233 publications

(147 citation statements)

References 27 publications

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“…These adsorption values are similar to those found for SDS on calcite and dolomite surfaces by Tabatabal et al 25 The pHs of all the surfactant solutions used for the adsorption experiment were found to be between 6 and 7 before contacting the calcite powder. However, after adsorption the pH values of the supernatant were found to be around 8.…”

Section: Resultssupporting

confidence: 88%

“…25 Fig . 19 shows the adsorption isotherm for the anionic surfactants 4-22, 5-166 and SS-6566 in the absence and presence of Na 2 CO 3 .…”

Section: Resultsmentioning

confidence: 99%

“…The higher cost of cationic surfactants compared to anionic surfactants (which are usually priced at ~1 US$ per kg) and relatively higher concentration required (~1 wt%) has encouraged others to evaluate anionic surfactants for fractured carbonates [25][26] in the presence of a low concentration potential determining ions. Chen et al 27 into matrix blocks has been studied for the last 50 years.…”

Section: Introductionmentioning

confidence: 99%

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Dilute Surfactant Methods for Carbonate Formations

Mohanty¹

2006

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There are many fractured carbonate reservoirs in US (and the world) with light oil.Waterflooding is effective in fractured reservoirs, if the formation is water-wet. Many fractured carbonate reservoirs, however, are mixed-wet and recoveries with conventional methods are low (less than 10%). The process of using dilute anionic surfactants in alkaline solutions has been investigated in this work for oil recovery from fractured oil-wet carbonate reservoirs both experimentally and numerically. This process is a surfactant-aided gravity drainage where surfactant diffuses into the matrix, lowers IFT and contact angle, which decrease capillary pressure and increase oil relative permeability enabling gravity to drain the oil up.Anionic surfactants have been identified which at dilute concentration of 0.05 wt% and optimal salinity can lower the interfacial tension and change the wettability of the calcite surface to intermediate/water-wet condition as well or better than the cationic surfactant DTAB with a West Texas crude oil. The force of adhesion in AFM of oil-wet regions changes after anionic surfactant treatment to values similar to those of water-wet regions. The AFM topography images showed that the oil-wetting material was removed from the surface by the anionic surfactant treatment. Adsorption studies indicate that the extent of adsorption for anionic surfactants on calcite minerals decreases with increase in pH and with decrease in salinity.Surfactant adsorption can be minimized in the presence of Na 2 CO 3 .Laboratory-scale surfactant brine imbibition experiments give high oil recovery (20-42% OOIP in 50 days; up to 60% in 200 days) for initially oil-wet cores through wettability alteration and IFT reduction. Small (<10%) initial gas saturation does not affect significantly the rate of oil recovery in the imbibition process, but larger gas saturation decreases the oil recovery rate. As 3 the core permeability decreases, the rate of oil recovery reduces, and this reduction can be scaled by the gravitational dimensionless time.Mechanistic simulation of core-scale surfactant brine imbibition matches the experimentally observed imbibition data. In-situ distributions observed through simulation indicate that surfactant diffusion (which depends on temperature and molecular weight) is the rate limiting step. Most of the oil is recovered through gravitational forces. Oil left behind at the end of this process is at its residual oil saturation. The capillary and Bond numbers are not large enough to affect the residual oil saturation.At the field-scale, 50% of the recoverable oil is produced in about 3 years if the fracture spacing is 1 m and 25% if 10 m, in the example simulated. Decreasing fracture spacing and height, increasing permeability, and increasing the extent of wettability alteration increase the rate of oil recovery from surfactant-aided gravity drainage. This dilute surfactant aided gravitydrainage process is relatively cheap. The chemical cost for a barrel of oil produced is expected to be less th...

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Section: Resultssupporting

confidence: 88%

“…25 Fig . 19 shows the adsorption isotherm for the anionic surfactants 4-22, 5-166 and SS-6566 in the absence and presence of Na 2 CO 3 .…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dilute Surfactant Methods for Carbonate Formations

Mohanty¹

2006

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“…Recently, natural imbibition under conditions of ultra-low oil-water IFT (i.e., lower than 10 -2 mN/m) with anionic surfactants have been reported by Hirasaki and Zhang (2004), Seethepalli et al (2004), Abidhatla andMohanty (2006), andZhang (2007). Obviously, the contribution of capillary forces to the natural imbibition is not significant under the ultra-low oil-water IFT.…”

Section: Production Features and Recovery Mechanismsmentioning

confidence: 99%

Chemical Flooding in Naturally Fractured Reservoirs: Fundamental Aspects and Field-Scale Practices

Jamaloei

2011

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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Résumé -Inondation chimique dans les réservoirs naturellement fracturés : aspects fondamentaux et pratiques de plein champ -Des méthodes appropriées devraient être utilisées pour augmenter la récupération d'huile des réservoirs naturellement fracturés (RNFs). Un des candidats pour augmenter cette récupération d'huile de ces réservoirs est l'injection d'eau contenant des agents chimiques. Cet article met en lumière les résultats techniques et les défis de cette technique. La classification, les caractéristiques de production, les mécanismes de rétablissement du RNFs et les résultats significatifs de l'injection d'eau contenant des agents chimiques dans ces réservoirs sont passés en revue et analysés. Ce papier vise à être un outil de référence utile aux ingénieurs intéressés par l'injection d'eau contenant des agents chimiques dans les RNFs. Abstract -Chemical Flooding in Naturally Fractured

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“…Reservoir wettability and its effect on oil recovery have been the subject of numerous studies [4,18,30,49,56]. However, these studies address drainage and imbibition behavior on a laboratory scale, which describe only one facet of multiphase flow in fractured reservoirs.…”

Section: Introductionmentioning

confidence: 99%

Upscaling of fractured oil reservoirs using homogenization including non-equilibrium capillary pressure and relative permeability

Salimi

Bruining

2011

Comput Geosci

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Recovery from incompletely water-wet fractured reservoirs can be extremely low. A reason for the low recovery is related to wetting issues, whereas the reason for slow recovery can be the non-equilibrium behavior of capillary pressure. One of the non-equilibrium theories is developed by Barenblatt et al. and it modifies both capillary pressure and relative permeabilities. The other theory is developed by Hassanizadeh et al. and it only deals with non-equilibrium effects for capillary pressure. To incorporate non-equilibrium in larger-scale problems, we apply homogenization to derive an upscaled model for fractured reservoirs in which the nonequilibrium effects are included. We formulate a fully implicit three-dimensional upscaled numerical model. Furthermore, we develop a computationally efficient numerical approach to solve the upscaled model. We use simulations to determine the range of delay times and capillary-damping coefficients for which discernable effects occur in terms of oil recovery. It is shown that at low Peclet numbers, i.e., when the residence time of the fluids in the fracture is long with respect to the imbibition time, incorporation of delay times of the order of few months have no significant effect on the oil recovery. However, when the Peclet number is large, the delay times reduce the rate of oil recovery. We discuss for which values of the delay time (Barenblatt) and capillary-damping coefficient (Hassanizadeh), significant delays in oil production occur.

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Physicochemical Interactions During Surfactant Flooding of Fractured Carbonate Reservoirs

Cited by 233 publications

References 27 publications

Dilute Surfactant Methods for Carbonate Formations

Dilute Surfactant Methods for Carbonate Formations

Chemical Flooding in Naturally Fractured Reservoirs: Fundamental Aspects and Field-Scale Practices

Upscaling of fractured oil reservoirs using homogenization including non-equilibrium capillary pressure and relative permeability

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