Propagation in porous media

In oil recovery processes, the formation of an oil bank is very important for an efficient oil displacement process in porous media. This was established from studies on the injection of an artificial oil bank followed by the surfactant formulation which can produce ultralow interfacial tension with the injected oil. We observed that the oil recovery increased considerably and the residual oil saturation decreased with the injection of an oil bank as compared to the same studies carried out in the absence of an injected oil bank (54). Figure 17 schematically represents the oil bank formation and its propagation in porous media, which is analogous to the snowball effect. If an early oil bank is formed then it moves through the porous medium accumulating additional oil ganglia resulting in an excellent oil recovery, whereas a late oil bank formation will result in a poor oil recovery. 

Echigo, R., Y. Yoshizawa, K. Hanamura, and T. Tomimura. 1986. Analyticzd and experimental studies on radiative propagation in porous media with internal heat generation. International Heat Transfer Conference 8 827. 

This chapter reports adsorption data for a number of surfactants suitable for mobility control foams in gas-flooding enhanced oil recovery. Surfactants suitable for foam-flooding in reservoirs containing high salinity and hardness brines are identified. The results of adsorption measurements performed with these surfactants are presented surfactant adsorption mechanisms are reviewed and the dependence of surfactant adsorption on temperature, brine salinity and hardness, surfactant type, rock type, wettability and the presence of an oil phase is discussed. The importance of surfactant adsorption to foam propagation in porous media is pointed out, and methods of minimizing surfactant adsorption are discussed. 

Retention The surfactant must be able to propagate in porous media with minimal retention losses. 

Biot, M.A., 1962. Mechanics of deformation and acoustic propagation in porous media. Journal of Applied Physics 33 pp. 1482-1498. 

Forest L, Gibiat V, Woignier T (1998) Biot s theory of acoustic propagation in porous media applied to aerogels and alcogels. J Non-Cryst Solids 225 287-292... 

De Leo R (2008) Long-term operational experience with the HERMES aerogel RICH detector. Nuclear Instruments Methods Phys Res A Accelerators, Spectrometers, Detectors, and Associated Equipment 595 19-22 Forest L, Gibiat V, Woignier T (1998) Biot s theory of acoustic propagation in porous media applied to aerogels and alcogels. J Non-Cryst SoUds 225 287-292... 

The second method uses acoustic waves. It gives information about the deposit porosity and can be used with a nontransparent module. With this method, it is also possible to follow the deposit kinetics. This method has to be calibrated because of the lack of knowledge about the theory of acoustic waves propagation in porous media. Thus, the common use of both methods on the same module will enable complementary information about the deposit to be obtained. 

Mixed Micellization and Desorption Effects on Propagation of Surfactants in Porous Media... 

Kennedy, L.A., Fridman, A.A., Saveliev, A.V. 1995. Superadiabatic combustion in porous media wave propagation, instabilities, new type of chemical reactor. Fluid Mechanics Res 22 1-25. 

The flame velocity in porous media is determined by the effective longitudinal thermal conductivity, which strongly depends on the velocity of the gas. Quenching of the flame as the cold wall is approached and the resulting incompleteness of combustion of the fuel material have been the subject of investigation in many recent studies, both theoretical and experimental. In particular, the question of flame propagation in a mixture of methanol and air has been considered theoretically,10 and the incomplete combustion of hydrocarbon mixtures was studied experimentally.11... 

Friedmann, F. Jensen, J.A. Some Factors Influencing the Formation and Propagation of Foams in Porous Media in Proc. 56th. SPE Calif. Regional Meeting, Society of Petroleum Engineers Richardson, TX, 1986, paper SPE 15087. 

Babkin, V.S., A. A. Korzhavin, and V.A. Bunev. 1991. Propagation of premixed gaseous explosion flames in porous media. Combustion Flame 87 182-90. 

Retention in Porous Media. Anionic surfactants can be lost in porous media in a number of ways adsorption at the solid—liquid interface, adsorption at the gas—liquid interface, precipitation or phase-separation due to incompatibility of the surfactant and the reservoir brine (especially divalent ions), partitioning or solubilization of the surfactant into the oil phase, and emulsification of the aqueous phase (containing surfactant) into the oil. The adsorption of surfactant on reservoir rock has a major effect on foam propagation and is described in detail in Chapter 7 by Mannhardt and Novosad. Fortunately, adsorption in porous media tends to be, in general, less important at elevated temperatures 10, 11). The presence of ionic materials, however, lowers the solubility of the surfactant in the aqueous phase and tends to increase adsorption. The ability of cosurfactants to reduce the adsorption on reservoir materials by lowering the critical micelle concentration (CMC), and thus the monomer concentration, has been demonstrated (72,13). 

The existence of important coupled diffusion-dynamic processes in porous media is well-documented empirically. The Russian literature contains many descriptions of earthquake-induced altered (generally enhanced) production from reservoirs of modest porosity (i.e. elastic conditions with no potential for compaction). Anecdotal evidence for increased well levels, release of fine-grained material into wells, and enhanced stream flow after earthquakes (Manga et al. 2003) has been reported. Triggering of sympathetic secondary earthquakes at a distance is well-known, and it is also known that the time of propagation for the triggering energy is far slower than the velocity of compressional, shear, or other common waves that are sufficiently conservative to travel hundreds of kilometres. 

For fluids in porous media, this propagator contains information on the diffusion coefficient of the fluid, and information on the pore geometry, as will now be discussed. 

Biot, M.A. 1962b. Generilized theory of elastic propagation in porous dissipative media. Journal of the Acoustical Society of America, 34 1254-1264. 

The kinematics of moving fronts and interfaces has been studied in different physical contexts for over two hundred years. Most notable are the studies of free surfaces in ocean hydrodynamics and vortex sheets in free space (e.g., see Lamb, 1945), and more recently, flame propagation dynamics in combustion analyses. The following derivation, which applies to fluid fronts in porous media, is given in Chin (1993a). Let us consider a moving front or interface located anywhere within a three-dimensional Darcy flow (e.g., any surface marked by red dye), and let (()(x,y,z) denote the porosity. Furthermore, denote by u, v, and w the Eulerian speed components, and describe our interface by the surface locus of points... 

---