Mobility control by polymer solutions

Jennings, R.R., Rogers, J.H., West, T.J., 1971. Factors influencing mobility control by polymer solutions. JPT (March), 391-401 Trans. AIME, 251. 

Jennings, R. R., J. H. Rogers, et al. (1971). "Factors Influencing Mobility Control By Polymer Solutions." SPE Journal of Petroleum Technology(03). 

Mobility Control by Polymer Solutions, " J. Pet. Tech., (March, 1971), 391-401. 

At the present time the improvement of areal and vertical (volumetric) sweep efficiency takes a great deal of room in secondary and tertiary oil recovery. One of the widely used and perspective methods is mobility control by diluted aqueous solutions of different polyacrylamides (1,2). In the middle of the sixties some authors (3,4) proposed that the viscosity enhancement and the non-Newtonian flow behavior of the solutions were responsible for the reduction of phase mobility. Mungan (5,6), Gogarty (7), Dauben and Menzie (8) have pointed out, however, that the sorption phenomenon plays a decisive role in the flow characteristics of the polymer solutions and carrier phases. In the papers devoted to... 

Waterflood mobility ratios can be controlled by dilute solutions of certain polymers which provide a displacing fluid with considerably reduced mobility. Reservoir parameters and flood performance are emphasized in this paper to provide data relating to polymer flood applicability. 

Pseudozan is an exopolysacchaiide produced by a Pseudomonas species. It has high viscosities at low concentrations in formation brines, forms stable solutions over a wide pH range, and is relatively stable at temperatures up to 65° C. The polymer is not shear degradable and has pseudoplastic behavior. The polymer has been proposed for enhanced oil-recovery processes for mobility control [1075]. 

Martel, K. E., Martel, R., Lefebure, R., and Gelinas, P. J., 1998, Laboratory Study of Polymer Solutions Used by Mobility Control During in Situ NAPL Recovery Ground Water Monitoring Remediation, Vol. 18, No. 3, pp. 103-113. 

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). 

Polymers increase the viscosity of the soil washing fiuids. Increased viscosity provides mobility control, which reduces the fingering of the displacing fiuid past the displaced fluid. It also helps ensure that the contaminated area is efficiently contacted by the soil washing solution. 

Early researchers sought to choose appropriate surfactants for mobility control from the hundreds or thousands that might be used, but very little of the technology base that they needed had yet been created. Since then, work on micellar/polymer flooding has established several phase properties that must be met by almost any EOR surfactant, regardless of the application. This list of properties includes a Krafft temperature that is below the reservoir temperature, even if the connate brine contains a high concentration of divalent ions (i.e., hardness tolerance), and a lower consolute solution temperature (cloud point) that is above the reservoir temperature. 

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