Measurement of Surfactant Loss in Porous Media
Authors: Smith Larry , Malmberg E.W. , Kelley Hoy W. 
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.
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Abstract
For comparison purposes, adsorption losses of surfactant systems may be determined by injecting the formulation into berea sandstone cores at the temperature and with the brine of the proposed application. The surfactant injection is followed by flushing with brine and, eventually, isopropyl alcohol. The surfactant eluted in the isopropyl alcohol is taken to be that adsorbed.
Experiments have shown the procedure to yield reproducible data and good material balances.

Introduction
Surfactants in contact with reservoir mineral exhibit several types of behavior. Adsorption of the surfactant by the mineral is of interest since the concentration of the surfactant in the liquid phase is decreased and the efficiency and life of the process is diminished.
A few recent papers on surfactant systems for tertiary oil recovery have discussed loss of the surfactants by adsorption. The methods of determining adsorption losses in these papers include:flowing surfactant over a bed of crushed rock, flushing with brine, drying, and extraction of the adsorbed surfactant with methanol-benzene;analysis of effluent fractions from berea cores by gravimetric methods and determination of surfactant loss by material balance;recirculation of surfactant through a berea core to equilibrium and determination of the adsorption loss by material balance; andflowing surfactant through a berea core, flushing with brine followed by 50 percent isopropyl alcohol and analysis for percent isopropyl alcohol and analysis for radioactive surfactant in the effluent.
While similar in many respects to these methods, the procedure described affords reliable data with facility in the screening of surfactant systems for comparative adsorption losses.
PROCEDURE PROCEDUREA core previously equilibrated with the brine and at the temperature of interest is injected with the surfactant system under study until equilibrium is reached. Effluent samples are collected with time and analyzed by appropriate methods for the surfactants in the system. The surfactant flood is followed by a flush of brine until the effluent contains no measurable surfactant.