Flooding surfactant

Chemical techniques change the physical properties of either the displacing fluid, or of the oil, and comprise of polymer flooding and surfactant flooding. 

In the 1990s, the thmst of surfactant flooding work has been to develop surfactants which provide low interfacial tensions in saline media, particularly seawater require less cosurfactant are effective at low concentrations and exhibit lower adsorption on rock. Nonionic surfactants such as alcohol ethoxylates, alkylphenol ethoxylates (215) and propoxylates (216), and alcohol propoxylates (216) have been evaluated for this appHcation. More recently, anionic surfactants have been used (216—230). 

Chemical EOR methods are based on the injection of chemicals to develop fluid or interfacial properties that favor oil production. The three most common of these methods are polymer flooding, alkaline flooding, and surfactant flooding. 

Of the chemical EOR technologies, surfactant flooding is the most complex, the farthest from commercial feasibility, and the most challenging in terms of research needs, yet it has the greatest ultimate potential. It involves injecting surfactants. 

To develop improved alkali-surfactant flooding methods, several different injection strategies were tested for recovering heavy oils. Oil recovery was compared for four different injection strategies [641] ... 

Alkali/polymer flooding Alkali/surfactant/polymer flooding Alkaline-assisted thermal oil recovery Alkaline steamflooding Polymer-assisted surfactant flooding Water-alternating gas technology... 

Polyaromatic hydrocarbons absorb strongly to humus and other soil components, rendering these contaminants difficult to remove by thermal, physical, or chemical means, and unavailable for biodegradation. To desorb polyaromatic hydrocarbons from soil, surfactant flooding processes and soil-washing processes or treatments to enhance the biodegradation of polyaromatic hydrocarbons have been considered. 

H. Dakhlia. A simulation study of polymer flooding and surfactant flooding using horizontal wells. PhD thesis, Texas Univ, Austin, 1995. 

Blends of surfactants optimized for seawater or reservoir brine salinity include linear alkylxylene sulfonate/alcohol ether sulfate mixtures (454,455). Alkyl- and alkylarylalkoxymethylene phosphonates (456), and amphoteric surfactants (457,458) have also been evaluated for use in surfactant flooding. 

Enhanced surfactant flooding, 23 532 Enhancement factor, gas absorption with reaction, 1 47-48 Enhancement programs, aquatic organisms, 3 183, 198 Enhancement reagents, 12 102 Enhancer, 10 688 Enichem oxo-alcohols, 17 725 Enkaid, molecular formula and structure, 5 92t... 

When this pressure drops, it can be built-up again by water flooding. Unfortunately, after these primary and secondary processes, there still remains up to 70% of the oil adsorbed on the porous clays. Consequently, in recent years, there have been tremendous efforts made to develop tertiary oil recovery processes, namely carbon dioxide injection, steam flooding, surfactant flooding and the use of microemulsions. In this latter technique, illustrated in Fig. 1, the aim is to dissolve the oil into the microemulsion, then to displace this slug with a polymer solution, used for mobility control, and finally to recover the oil by water injection ( 1). 

The mobihzation of NAPL, particularly dense DNAPL, in response to surfactant flooding can be used to enhance remediation based on pump-and-treat extraction techniques because it increases the soluble contaminant levels. 

The cost of implementing an in situ surfactant flood will vary significantly from site to site. Because costs of full-scale implementation do not exist, currently available cost estimates are based on hypothetical examples and extrapolation from field pilot tests. For typical waste sites having contamination limited to the upper 15 m (49 ft) below ground surface, estimated costs range from 1.4 million per hectare to 18 million per hectare, or approximately 90 to 990/m ( 65 to 750/yd ) of treated contaminated soil (D16070D, p. ES-4). 

The quantification of the formulation of SOW systems was studied in detail during the 1970 s when a considerable research drive was dedicated to enhanced oil recovery by surfactant flooding methods [2], The basic concepts came from Winsor s work on the phase behavior of SOW systems and its R ratio of interactions between the surfactant molecules adsorbed at interface and oil and water [3], which has been presented thoroughly in a review book [4]. 

The structure and thermodynamics of formation of mixed micelles is of great theoretical interest. Micelles are also present and often integrally involved in practical processes. For example, in a small pore volume surfactant flooding process (sometimes called micellar flooding), the solution injected into an oil field generally contains 5-12 weight X surfactant (i) and the surfactant is predominately in micellar form in the reservoir water. In detergency, solubilization can be... 

The use of chemicals to coax more oil out of the ground has been investigated for many years. Chemically enhanced methods are of three major types (1) polymer flooding (2) surfactant flooding and (3) alkaline flooding. 

The use of cosolvents to achieve neutral-buoyancy surfactant floods has also been investigated (Shook et al, 1997, 1998 Kostarelos et al, 1998). 

Figure 3.29 Illustrations of changes occurring in physical properties and other phenomena in the region of the optimal salinity for enhanced oil recovery using surfactant flooding. From Sharma [235]. Copyright 1991, Plenum Press.

Figure 9.2 Illustration of an in situ surfactant flood for the displacement and production of DNAPL contaminants from a contaminated subsurface zone. From Battelle [538], Copyright 2002, Naval Facilities Engineering Command.

Several successful field demonstrations of in situ surfactant flooding for NAPL soil remediation have been conducted [523,526,528,530,538,539] and design and implementation manuals are available [538-540],... 

Austad, T. Milter, J. Surfactant Flooding in Enhanced Oil Recovery in Surfactants, Fundamentals and Applications in the Petroleum Industry, Schramm, L.L. (Ed.), Cambridge University Press Cambridge, 2000, pp. 203-249. 

Fountain, J.C., Field Tests of Surfactant Flooding in Transport and Remediation of Subsurface Contaminants, American Chemical Sotiety Washington, 1992, pp. 182-191. 

Reppert, T.R. Bragg, J.R. Wilkinson, J.R. Snow, T.M. Maer Jr., N.K. Gale, W.W. Second Ripley Surfactant Flood Pilot Test in Proc., 7th Symposium on Enhanced Oil Recovery, Society of Petroleum Engineers Richardson, Texas, 1990, paper SPE/DOE 20219. 

Mass transfer in surfactant systems is important in many areas. One such field that is particularly important is the surfactant flooding of oil fields (1-4), which is an attractive candidate for tertiary oil recovery. Consequently diffusional processes of aggregates such as micelles and microemulsions (5-9) have been studied extensively. 

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