Surfactant/Foam Process for Aquifer Remediation

Hirasaki, George J.; Miller, Clarence A.; Szafranski, Robert C.; Lawson, J.B.; Akiya, Naoko

doi:10.2118/37257-ms

Cited by 83 publications

(42 citation statements)

References 19 publications

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“…In communicating and noncommunicating systems with foam, a significant fraction of the injected gas was diverted to the low permeability medium and overall displacement from both low and high permeability zones improved significantly. Other studies regarding heterogeneous porous media also found that foam had the capability to reapportion a fraction of injected fluids from high to low permeability strata [12][13][14][15][16] .…”

Section: Spe 75181mentioning

confidence: 89%

Estimation of Foam Mobility in Heterogeneous Porous Media

Kovscek

Bertin

2002

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractIt has been shown experimentally, both here and elsewhere, that foaming gas is a promising technique for achieving mobility control and diverting injected fluid to low permeability strata within heterogeneous porous media. However, the factors most important for diversion have not been stated and explored definitively. Gas mobility in the presence of foam depends critically on foam bubble size; bubble size may vary with permeability, porosity, surfactant type and concentration, and the velocity of liquid and gas. This paper adopts a local-equilibrium, scaling perspective to describe quantitatively foamed gas mobility within heterogeneous porous media. Conventional and percolation network scaling ideas are employed. The equations developed indicate, for instance, that porosity plays an important role in setting gas mobility because it reflects the relative abundance of foam germination and termination sites per unit volume of porous media. Liquid velocity is also important because gas mobility is inversely proportional to this factor. Predictions are checked via comparison to new experimental results. The experimental system is composed of a 0.395 porosity, 5.35 µm 2 synthetic sandstone and a 0.244 porosity, 0.686 µm 2 natural sandstone. The cores are arranged in parallel and communicate through common injection and production conditions. Nitrogen is the gas phase and a classical alphaolefin sulfonate (AOS 1416) in brine is the foamer. Three types of experiments were conducted. First, gas alone was injected into the system after presaturation with the foamer solution. Second, gas and foamer solution were coinjected at an overall gas fraction of 90% into cores presaturated with surfactant. Each core accepted a portion of the injected gas and liquid according to the mobility within the core. Lastly, gas and foamer solution were coinjected into the individual, isolated porous media in order to establish baseline behavior. The results show that in-situ generation of foam is an effective method for improving the sweep efficiency of lower permeability strata. The results also confirm predictions that foamed gas can be more mobile in lower permeability porous media.

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Section: Spe 75181mentioning

confidence: 89%

Estimation of Foam Mobility in Heterogeneous Porous Media

Kovscek

Bertin

2002

All Days

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“…However, it is difficult to find uniform Berea sandstone at permeabilities in this range, and foam generation is known to be easier in heterogeneous media, especially when flow is across layer boundaries. 6,7,9,[11][12][13]16,29 It is possible that these data were affected by core heterogeneity.…”

Section: Experiments At Fixed Quality (Type 1 and 2)mentioning

confidence: 99%

Foam Generation in Porous Media

et al. 2002

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractIn steady gas-liquid flow in homogeneous porous media with surfactant present, there is often observed a critical injection velocity or pressure gradient ∇p min at which "weak" or "coarse" foam is abruptly converted into "strong foam," with a reduction of one to two orders of magnitude in total mobility: i.e., "foam generation." Earlier research on foam generation is extended here with extensive data for a variety of porous media, permeabilities, gases (N 2 and CO 2 ), surfactants, and temperatures. For bead-and sandpacks, ∇p min scales like (1/k), where k is permeability, over 2½ orders of magnitude in k; for consolidated media, the relation is more complex. For dense-CO 2 foam, ∇p min exists but can be less than 1 psi/ft. If pressure drop, rather than flow rates, is fixed, one observes an unstable regime between stable "strong" and "coarse" foam regimes; in the unstable regime ∇p is nonuniform in space or variable in time. Results are interpreted in terms of the theory of foam mobilization at a critical pressure gradient.

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“…Typically, ∇p in published studies is large in both the high-quality and low-quality regimes, which could make it difficult to obtain strong foam with sufficient injectivity for environmental applications. 6,7 …”

Section: Foam Flow Regimesmentioning

confidence: 99%

“…6,7 Foam is an unstable dispersion of gas in water, partially stabilized by dissolved surfactant in the water. 8,9 Foam reduces mobility, which tends to even-out flow in the presence of permeability contrasts and gravity.…”

Section: Introductionmentioning

confidence: 99%

Extending Foam Technology from Improved Oil Recovery to Environmental Remediation

Mamun

Rong

Kam

et al. 2002

SPE Annual Technical Conference and Exhibition

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractIn the petroleum industry, foams are used for improved oil recovery, reducing gas breakthrough to productions wells, and diverting acid in well-stimulation treatments. A substantial body of research on foam for these applications is extended here to the high-permeabilities and low pressures of environmental remediation, through both laboratory experiments and computer simulations based on the laboratory results.New data confirm that the two steady-state flow regimes identified by Alvarez et al. for petroleum applications exist under conditions relevant to groundwater remediation. The low-quality regime is strongly shear-thinning, in agreement with Alvarez et al. The high-quality regime is more sensitive to surfactant concentration than the low-quality regime, while the low-quality regime is more sensitive to permeability. Therefore, diversion between layers differing in permeability would be more effective in the high-permeability regime, while the low-quality regime has advantages for injectivity and liquid diversion.A foam simulator can be fitted to these steady-state foam data. Simulations indicate that foam can propagate without gravity segregation over long distances at an overall average pressure gradient of well under 1 psi/ft. Moreover, a simple correlation for gravity segregation developed for petroleum applications works well for aquifers overlain by a vadose zone, as long as the assumptions of that correlation (Newtonian rheology, incompressible flow) are satisfied.Local steady state would not be achieved in the field if pressure gradient were insufficient for foam generation, however. New results indicate that at moderate ∇p foam may exist in an unstable regime between strong and coarse foam.

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Surfactant/Foam Process for Aquifer Remediation

Cited by 83 publications

References 19 publications

Estimation of Foam Mobility in Heterogeneous Porous Media

Estimation of Foam Mobility in Heterogeneous Porous Media

Foam Generation in Porous Media

Extending Foam Technology from Improved Oil Recovery to Environmental Remediation

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