Spontaneous imbibition of seawater into preferentially oil-wet chalk cores — Experiments and simulations

Yu, Liping; Evje, Steinar; Kleppe, Hans; Kårstad, T.; Fjelde, Ingebret; Skjæveland, S.M.

doi:10.1016/j.petrol.2009.02.008

Cited by 64 publications

(35 citation statements)

References 17 publications

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“…Two sets of relative permeability curves should be defined to represent HS and LS water effect. Also, an interpolant is used to interpolate between the two sets of relative permeability curves [48,53,54], although the correct interpolant is still an open research area. However, in this study, we aimed to examine the hypothesis that multi-component is a dominant mechanism behind low salinity effect.…”

Section: Core-scale Numerical Modelmentioning

confidence: 99%

Effect of multi-component ions exchange on low salinity EOR: Coupled geochemical simulation study

2016

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The mechanism(s) of Low salinity water flooding (LSWF) has been extensively investigated for 15-20 years, as a cost-effective and environmentally friendly technique for improved oil recovery. However, there is still no consensus on the dominant mechanism(s) behind low salinity effect due to the complexity of interactions in the Crude oil/Brine/Rock (COBR) system. While wettability is most agreed mechanism of low salinity EOR effect. Nevertheless, the mechanism(s) behind the wettability change is debated between multi-component ion exchange (MIE) and double layer expansion (DLE) in sandstone reservoirs. This paper aims to investigate the effectiveness of MIE with a coupled geochemical-reservoir model using published experimental data reported by Nasralla and Nasr-El-We created core-scale numerical models with parameters identical to those used in the experiments. We simulated the low salinity effect using a commercial reservoir simulator, CMG-GEM, by coupling three chemical reactions: (1) aqueous reaction, (2) multi-component ion exchange, and (3) mineral dissolution and precipitation. We modelled the adsorption of divalent cations on the surface of the clay minerals during low salinity water injection. Simulation results were compared with the experimental results.Simulation results show that the fractional adsorption of divalent cations (Ca 2+ ) increased almost 25% by injecting a 2,000 ppm NaCl solution, compared to initial 10,000 ppm NaCl. Injecting a 2,000 ppm of CaCl 2 solution, however, significantly increased the adsorbed Ca 2+ from 0.1 to 1, which implies the complete saturation of mineral surface with divalent cations. Moreover, injecting 50,000 ppm of CaCl 2 solution also demonstrated the same effect as the 2,000 ppm CaCl 2 solution but with a faster rate.Upon combining the simulation and experimental results, we concluded that the multi-component ion exchange is not the sole mechanism behind low salinity effect for two reasons. First, almost 10% additional oil recovery was observed from the experiments by injecting the 2,000 ppm CaCl 2 compared with 50,000 ppm CaCl 2 solutions. Even though in both cases the surface is expected to be fully saturated with Ca 2+ according to the geochemical modelling. Second, 6% incremental oil recovery was achieved from the experiments by injecting 2,000 ppm NaCl solution compared with that of 50,000 ppm NaCl. Although 25% incremental adsorption of divalent cations (Ca 2+ ) were presented during the flooding of the 2,000 ppm NaCl solution. Therefore, it is worth noting that the electrical double layer expansion due to the ion exchange needs to be taken into account to pinpoint the mechanism(s) of low-salinity water effect.

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Section: Core-scale Numerical Modelmentioning

confidence: 99%

Effect of multi-component ions exchange on low salinity EOR: Coupled geochemical simulation study

2016

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“…While completely isolated voids would preclude even diffusive mass transport, the fact that the submicron-scale pores are penetrated during the porosimetry measurements suggests that the porosity on different scales is connected, and diffusive mass transport should have been a pervasive mode of solute transfer during diagenesis. While it remains possible that the small pores were not wetted during the mineralization process, wetting behavior increases significantly at elevated fluid pressures and in the presence of dissolved salts (Zhang and Austad, 2006;Yu et al, 2009) and submicron-scale pores in the Stø Formation are likely to have contained fluid.…”

Section: Additional Mechanismsmentioning

confidence: 99%

Interfacial energy effects and the evolution of pore size distributions during quartz precipitation in sandstone

Emmanuel

Ague

Walderhaug

2010

Geochimica et Cosmochimica Acta

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“…However, these studies address drainage and imbibition behavior on a laboratory scale, which describe only one facet of multiphase flow in fractured reservoirs. Experimental evidence [14,34,35,51,52,54,56,58,59,63] supports a more general description of capillary pressure and relative permeability functions, which includes a nonequilibrium effect. Reservoir interpretation that does not recognize the potential for reduced recovery because of non-equilibrium effects may lead to an overestimation of the recovery.…”

Section: Introductionmentioning

confidence: 57%

“…For water-wet media with a finite contact angle, it is possible that the delay time is a few months. This effect is observed in many spontaneous imbibition experiments [14,34,35,51,52,54,56,58,59,63]. During the transition, the wetting-fluid relative permeability is higher than in steady-state conditions.…”

Section: Non-equilibrium Effectsmentioning

confidence: 74%

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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Spontaneous imbibition of seawater into preferentially oil-wet chalk cores — Experiments and simulations

Cited by 64 publications

References 17 publications

Effect of multi-component ions exchange on low salinity EOR: Coupled geochemical simulation study

Effect of multi-component ions exchange on low salinity EOR: Coupled geochemical simulation study

Interfacial energy effects and the evolution of pore size distributions during quartz precipitation in sandstone

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

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