tailieunhanh - Reservoir Formation Damage Episode 2 Part 5

Tham khảo tài liệu 'reservoir formation damage episode 2 part 5', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 332 Reservoir Formation Damage where Na is the total number of aqueous species involved 7V and Nsr denote the total number of aqueous and mineral reactions respectively w and VV represent the rates of the rth aqueous and mineral reactions respectively v ư and denote the stochiometric coefficients of the species a in the aqueous and mineral reactions respectively and qa represents the rate of species a addition per bulk formation volume by means of direct injection of fluids through wells completed in the reservoir. Ion Exchange and Adsorption Reactions Ion exchange and adsorption are surface chemical or surface com-plexation processes leading to the exchange of chemical species between the aqueous solution and mineral surfaces present in geological porous formations Jennings and Kirkner 1984 Lichtner 1985 Kharaka et al. 1988 . Kharaka et al. 1988 explain the difference between ion exchange and adsorption as following The ion exchange model treats the exchange of cations or anions on a constant charge surface and the adsorption model simulates the exchange process on a surface where the surface charge is developed due to the ionization of surface sites at the solutionsurface interface. Therefore adsorption is a more general concept and ion exchange is a special case of adsorption Lichtner 1985 Sahai and Sverjensky 1998 . Among the various surface complexation models Sahai and Sverjensky 1998 facilitate the triple-layer model Yates et al. 1974 for describing the electrical charge near mineral surfaces as described in Figure 13-2 Sahai and Sverjensky 1998 according to Westall 1986 . As indicated in Figure 13-2 this model considers the mineral surface referred to as the ơ-plane for adsorption of hydroxide ions and protons and at a short distance near the mineral surface referred to as the p-plane for adsorption of electrolyte ions and the surface charge is generated by adsorption of the electrolyte ions and protons Sahai and Sverjensky 1998 . Clays present in .