Nanofluid System Improves Post Frac Oil and Gas Recovery in Hydrocarbon Rich Gas Reservoirs

Penny, Glenn S.; Zelenev, Andrei S.; Lett, Nathan L.; Paktinat, Javad; O’Neil, Bill

doi:10.2118/154308-ms

Cited by 34 publications

(11 citation statements)

References 16 publications

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“…This indicates a good match between the laboratory measurement and the simulation. In the absence of surfactants, the value of the water/heptane IFT is numerically estimated at 48.8 mN/m, which agrees well with the data reported in literature (Ranatunga et al 2011).…”

Section: Thermodynamic-equilibrium Simulationssupporting

confidence: 89%

Insights Into Mobilization of Shale Oil by Use of Microemulsion

et al. 2016

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Molecular-dynamics simulation is used to investigate the nature of two-phase (oil/water) flow in organic capillaries. The capillary wall is modeled with graphite to represent kerogen pores in liquid-rich resource shale. We consider that the water carries a nonionic surfactant and a solubilized terpene solvent in the form of a microemulsion, and that it was previously introduced to the capillary during hydraulic-fracturing operation. The water has already displaced a portion of the oil in place mechanically and now occupies the central part of the capillary. The residual oil, on the other hand, stays by the capillary walls as a stagnant film.Equilibrium simulations show that, under the influence of organic walls, the solvent inside the microemulsion droplets enables not only the surfactant but also the complete droplet to adsorb to the interfaces. Hence, delivering the surfactant molecules to the oil/water interface is achieved faster and more effectively in the organic capillaries. After the droplet arrives at the interface, the droplet breaks down and the solvent dissolves into the oil film and diffuses. This process is similar to drug delivery at nanoscale.Using nonequilibrium simulations based on the external forcefield approach, we numerically performed steady-state flow measurements to establish that the solvent and the surfactant molecules play separate roles that are both essential in mobilizing the oil film. The surfactant deposited at the oil/water interface reduces the surface tension and acts as a linker that diminishes the slip at the interface. Hence, it effectively enables momentum transfer from the mobile water phase to the stagnant oil film. The solvent penetrating the oil film, on the other hand, modifies flow properties of the oil. In addition, as a result of selective adsorption, the solvent displaces the adsorbed oil molecules and transforms that portion of the oil into the free oil phase. Consequently, the fractional flow of oil is additionally increased in the presence of solvent. The results of this work are important for understanding the effect of microemulsion on flow in organic capillaries and its effect on shale-oil recovery.

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Section: Thermodynamic-equilibrium Simulationssupporting

confidence: 89%

Insights Into Mobilization of Shale Oil by Use of Microemulsion

et al. 2016

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“…The use of microemulsions in improving production from resource shale has been documented in numerous studies [1][2][3][4][5][6]. These studies have demonstrated that microemulsions in the form of complex nanofluids have the potential to restore the effective permeability of the rock, hence, promoting the fluid flow-back from the reservoir during production.…”

Section: Introductionmentioning

confidence: 99%

Insights into Mobilization of Shale Oil using Microemulsion

Bui¹,

Akkutlu²,

Zelenev³

et al. 2015

Unconventional Resources Technology Conference

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Molecular dynamics simulation is employed to investigate the nature of two-phase (oil-water) flow in organic capillaries. The capillary wall is modeled using graphite to represent kerogen pores in liquid-rich resource shale. We consider that the water carries a nonionic surfactant and a solubilized terpene solvent in the form of a microemulsion, and that it has previously been introduced to the capillary during hydraulic fracturing operation. The water has already displaced a portion of the oil in-place mechanically and now occupies the central part of the capillary. The residual oil, on the other hand, stays by the capillary walls as a stagnant film.Equilibrium simulations show that, under the influence of organic walls, the solvent inside the microemulsion droplets enables not only the surfactant but also the complete droplet to adsorb to the interfaces. Hence, delivering the surfactant molecules to the oil-water interface is achieved faster and more effectively in the organic capillaries. Once the droplet arrives at the interface, the droplet breaks down, the solvent dissolves into the oil film and diffuses. This process is similar to drug delivery at nano-scale.Using non-equilibrium simulations based on the external force field approach we numerically performed steady-state flow measurements to establish that the solvent and the surfactant molecules play separate roles that are both essential in mobilizing the oil film. The surfactant deposited at the oil-water interface reduces the surface tension and acts as a linker that diminishes the slip at the interface. Hence, it effectively enables momentum transfer from the mobile water phase to the stagnant oil film. The solvent penetrating the oil film, on the other hand, modifies flow properties of the oil. In addition, due to selective adsorption, the solvent displaces the adsorbed oil molecules and transforms that portion of the oil into the free oil phase. Consequently, the fractional flow of oil is additionally increased in the presence of solvent. The results of this work are important for understanding the effect of the microemulsion on flow in organic capillaries and its effect on shale oil recovery.

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“…How this practice relates to long-term fluid recovery as flowback has not been investigated, although the expectation in such cases is to have little to no produced water. On the other hand, several fluid additives aimed to enhance flowback and hydrocarbon permeability have been designed and tested in the laboratory (Penny et al, 2012;Rostami and Nasr-El-Din, 2014;Zelenev et al, 2010). In these studies, an increase in relative permeability to the hydrocarbon was always accompanied by an increase in fluid flowback, agreeing with expectation from the point of view of relative permeabilities but not necessarily with field observations.…”

Section: Introductionmentioning

confidence: 54%

When Less Flowback Is More: A Mechanism of Permeability Damage and its Implications on the Application of EOR Techniques

Longoria¹,

Liang²,

Nguyen³

et al. 2015

Unconventional Resources Technology Conference

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Only a small fraction of fracturing fluid is recovered as flowback after hydraulic stimulation of low permeability formations. From the point of view of relative permeabilities, the minimization of fracturing fluid losses is desirable to maximize the flow of hydrocarbon. On the other hand, field observations indicate that wells where less fracturing fluid is recovered as flowback performed better in production, leading to an apparent contradiction. We present a physics-based model that can account for both of these observations. Our model is the result of an experimental investigation using a coreflooding sequence that simulates fracturing fluid invasion, fluid flowback and hydrocarbon recovery in a hydrocarbon-rich, hydraulically-fractured reservoir. We elucidate the interplay between capillary suction and viscous displacement of the fracturing fluid and the impact of water blocks on hydrocarbon permeability. This model reveals the inherent relationship between flowback and hydrocarbon production for different initial petrophysical properties and has implications on both well shut-in management and the use of chemical EOR techniques in tight reservoirs.

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Nanofluid System Improves Post Frac Oil and Gas Recovery in Hydrocarbon Rich Gas Reservoirs

Cited by 34 publications

References 16 publications

Insights Into Mobilization of Shale Oil by Use of Microemulsion

Insights Into Mobilization of Shale Oil by Use of Microemulsion

Insights into Mobilization of Shale Oil using Microemulsion

When Less Flowback Is More: A Mechanism of Permeability Damage and its Implications on the Application of EOR Techniques

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