Core Flood Evaluation of Solvent Compositional And Wettability Effects On Hydrocarbon Solvent Foam Performance

Mannhardt, K.

doi:10.2118/99-13-21

Cited by 11 publications

(21 citation statements)

References 33 publications

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“…Consider, for example, the experiments of Figure 2 . Pressure drops during injection of 1% Cla-16AOS/Snorre gas are essentially the same in Experiments [8] and [12] . The corgi is therefore considered fully aged at Experiment [8 1 , i .e.…”

Section: Ageing Effects On Foam Performancementioning

confidence: 52%

Foam Propagation in Snorre Reservoir Core - Effects of Oil Saturation and Ageing

Mannhardt¹,

Svorstøl²

1997

IOR 1997 - 9th European Symposium on Improved Oil Recovery

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A s eries of foam floods was conduct ed in Snorre re s e rvoir core at 90°C and 300 bar, at different o il saturations . The rate of foam propagation and the time requir ed to reach the maximum attainable apparent foam viscosi ty depended strongly on oil saturation. Apparent foam viscosity decreased steeply at a "critical " oil saturation of 13 to 15%. Extremely high apparent foam viscosities , up to 1000 cP, veere generated at miscible gas flood residual oil saturat i on (13%) . Above the critical oil saturation, strong foam with apparent vi scosities of about 200 cP vee re sti11 formeel, compared to apparent gas viscosities in the absence of surfactant of 0 .5 to 0 . 7 cP . The effect of gas composition (Snorre field gas , methane , nitrogen) on foam pe rform ance was minor . Significant re sidual gas mobility reduction was observed during gas injection into the foam-filled corgi . . INTRODUCTIO NFoams have b e en considered for mobili ty or profile control in gas injection IOR processes, for blockéng and d ive rting using either conventional or gell ed foams , and for controlling GOR at production Wells . In a mobili ty control application, goud foam stability to oil and love surfactant adsorption are essenbal , but mode rate mobili ty re duction is sufficient. If foam is to be placed into swept (love oil saturation) zones to dive rt gas flow into unswept zone s , a faam witti intermediate or love stabil ity to oil may be adequate , but high resistance to flow under an applied pressure gradient is required . A foam treatment to reduce GOR at production W ells require s a foam witti high flow resistance an d goud stabili ty to oi l ; moderate or high adsorption le vels may b e acceptable for a near-wellbore treatment . Whatever the application , the foam has to propagate away from the wellbore in order to be effective .Studies of foam propagation r e po rt varied results, but agree in concluding that foazn propagation d epends c ri tical ly on injection strategy (1-4) . Irani and Solomon (1) found that faam does not propagate du ring altemating injection of small surfactant slugs and C02 or during surfactant/C02 co-inj ection in an oil-free slim tube . The relativel y smalt volume of injected surfactant soluti on did not propagate past the inlet section of the corgi, resulting in a high pressure gradient near the corgi inlet only . The au thors conclude that gas and liquid do not move through the slim tube simultaneously du ring co-injection, bit that faam forens where gas and suifactant contact each e ther. B y contrast, a dual stug injection method consisting of a large stug of dilute surfactant solution followed by C0 2 resulted in effective foam propagation in the absence and presence of residual oil . Hudgins and Chung (3) found th at faam gen eration and propagation depends on WAG ratio and injection sequence in an oi1-free slim tube . At a residual oil saturation of 23%, faam was formeel only when the surfactant stug was large enough to fill the slim tub e, and foam was g enerated only in the t...

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Section: Ageing Effects On Foam Performancementioning

confidence: 52%

Foam Propagation in Snorre Reservoir Core - Effects of Oil Saturation and Ageing

Mannhardt¹,

Svorstøl²

1997

IOR 1997 - 9th European Symposium on Improved Oil Recovery

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“…The experimental set-up ( Figure 1) basically represents a standard core-flow experiment which has been described in detail by Mannhardt et al (23) The pore volume of the cores was measured by the gas expansion method and the absolute permeability to air was also measured. The cores were saturated with brine by evacuating, flushing with CO 2 , evacuating again, imbibing brine and pumping 10 or more pore volumes of brine at a back pressure of 0.2 MPa.…”

Section: Simulation Of Laboratory Foam Floodsmentioning

confidence: 99%

Numerical Simulation of Foam Flooding For Sweep Improvement Abstract

Shrivastava

Coombe²,

Singhal

et al. 1999

Journal of Canadian Petroleum Technology

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Foams are used for mobility control in Enhanced Oil Recovery operations involving injection of gases or steam. The ability of foams to lower the mobility of the injected fluid, under certain conditions, helps in reducing gravity override and channeling leading to improved sweep efficiency and oil recovery. A series of foam-flood experiments were carried out for implementing the process in a carbonate reservoir currently under miscible flood. The present paper focusses on simulation of a few of these experiments using a steady-state foam model with an objective of establishing parameters critical to field implementation. The mobility reduction factor and the threshold water saturation at which the foam breaks down were studied using numerical models that simulated laboratory experiments. A field scale model validated by actual foam-tests was employed to evaluate the effect of the duration of Surfactant Alternating Gas (SAG) injection cycle, reservoir heterogeneity, and economic aspects of the process. It was established that favourable conditions for creation and propagation of foam for combating gravity override may exist in certain heterogeneous reservoirs, where paths of least resistance for flow of surfactant solution (from injectors to producers), occur via upper pay intervals containing mobile gas. Introduction Mobilization and displacement of oil by injected gases (hydrocarbon, CO2, N2, air, or steam) dominate the Enhanced Oil Recovery (EOR) processes throughout the world(1). However, due to higher mobility and lower density with respect to the displaced oil, these gases tend to bypass and override the oil-rich zones, resulting in poor sweep and recovery efficiency. Foams under certain reservoir settings can help improve the sweep efficiency by lowering the mobility of injected gas(2). The key to success of the foam application, therefore, lies in identifying the conditions under which it could be utilized to economically improve the sweep and oil recovery in a gas injection process. The nature of foam in porous media has been a contentious issue. There are two differing views(3–5) concerning fluid movement in the presence of foam flow of foam as a body or flow of water and gas as separate phases. The parameters used to define the characteristics of the foam are, therefore, related to the property of the "foam" or to the property of water and gas phases. Foam quality or fractional flow to gas, compressibility, and apparent viscosity characterize the foam. Injection pressure, pressure-drop between injector and producer, injectivity index, mobility reduction factor, foam flow resistance, apparent foam viscosity, and reduced relative permeability to gas are the measures of foam effectiveness in reducing the mobility of injected gas, leading to improved sweep. These are common indicators of strength and stability of the foam in porous media. We consider that the foam moves as a body in the porous media. Attempts have been made by various workers(6–8) to identify the mechanisms involved in generation, propagation, and decay of foam in the porous media. The effect of presence of oil phase on propagation of foams in porous media has been extensively researched(9–11).

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“…This is typically determined in the laboratory by measuring the pressure gradient during simultaneous injection of gas and surfactant solution (~PJoam) and during brine and gas injection (~Pnofoam) under identical conditions. The MRF is a good indicator of presence of foam and its effectiveness, but trends at different experimental conditions may be overwhelmed by experimental errors (Mannhardt, 1995).…”

Section: Mobility Reduction Factormentioning

confidence: 99%

“…The FFR provides a means of normalizing pressure gradients by taking into account absolute permeability, wetting liquid viscosity and gas flow velocity. A calculated foam flow resistance does not provide an immediate indicator for presence of foam, unless it is compared with the same parameter for baseline experiment for brine/solvent flow under similar conditions (Mannhardt, 1995). As can be seen, the FFR is inversely proportional to krg• When applied to the steady state experiments, the above indicators do not explicitly take into account the differences in fluid saturations in the absence and presence of foam (i.e.…”

Section: Foam Flow Resistancementioning

confidence: 99%