Adsorption of Sulfonates on Reservoir Rocks
Authors: Somasundaran P. , Hanna H.S. 
Published: December 2007

Abstract
Abstraction of Mahogany sulfonate AA (Trade Mark) and recrystallized dodecylbenzenesulfonate by Na-kaolinite, sandstone, and limestone was studied as a function of relevant variables such as pH, ionic strength, and type of inorganic electrolyte added. In most cases, such factors affect not only the abstraction capacity of the solid particles, but also the shape of the abstraction isotherm. Particularly, the inorganic species in the system were found to influence the abstraction and the desorption of dodecylbenzenesulfonate by kaolinite, based upon their size and solvation properties. Thus, appearance of a maximum in this system was related to the predominance of smaller exchangeable "predominance of smaller exchangeable "structure-making" ions. Introductions of larger "Structure-breaking" ions tends to eliminate such maxima. The role of ions (such as silicate, phosphate, chloride, calcium, sodium, ammonium) are examined and possible mechanisms are discussed. Implications of possible mechanisms are discussed. Implications of these observations in developing the capability to control abstraction should be noted.

Introduction
A major problem that affects the efficiency of tertiary oil production by micellar flooding is the loss of surfactants from interaction with minerals and their dissolved components. Trushenski et al. have observed the existence of a retention maximum near the critical micellar concentration range followed by a minimum for the system Berea sandstone/Mahogany petroleum sulfonate-isopropyl alcohol micellar fluid petroleum sulfonate-isopropyl alcohol micellar fluid at 110 degrees F (43 degrees C). Similar studies on reservoir rock minerals by Bae et al. Gale and Sandvik, Hill et al. Hurd, and Somasundaran et al. have been discussed earlier Bae et al. observed the presence of a maximum for abstraction in the systems they investigated. Other recent studies on abstraction on reservoir minerals include those of Malmberg and Smith, Trogus et al., and Lawson and Dilgren. The phenomenon of abstraction maximum and minimum is of much theoretical and practical interest. However, mechanisms of surfactant abstraction in such reservoir/surfactant systems are not yet established fully and as such their abstraction behavior generally cannot be predicted. Also, no fully substantiated reasons east to account for the presence of the maximum or minimum. Our objective presence of the maximum or minimum. Our objective is to study the abstraction behavior of relevant surfactants on reservoir rock minerals under various experimental conditions to understand the mechanisms involved in this interfacial process and to identify conditions under which surfactant retention can be minimized. Results obtained here for the abstraction of recrystallized dodecylben-zenesulfonate by treated kaolinite in various inorganic electrolytes are given with a summary of results obtained previously for the abstraction of certain sulfonates by Berea sandstone, agricultural limestone, and Bedford limestone.

Background
Our previous work clearly has shown that the nature of the abstraction isotherm obtained depends to a large extent on the type of sulfonate used, the morphological and mineralogical characteristics of the rock, and the type of electrolytes present in solution.
SPEJ
P. 221