Adsorption-Desorption of an Amphoteric Surfactant onto Permeable Carbonate Rocks

Abstract

The loss of surfactant from aqueous solutions during the propagation in the reservoirs, especially carbonate reservoirs, is one of the major concerns with chemical oil recovery processes. This is due to the loss of effectiveness of the chemical solution to reduce the oil-water interfacial tension and thus renders the process economically unfeasible. This paper presents, in detail, 10 runs of core flooding tests on dynamic adsorption and desorption of an amphoteric surfactant (OCT-1) onto permeable carbonate rocks, which were conducted in natural carbonate core plugs at reservoir temperature of 100°C and pore pressure of 3100 psi. The surfactant solution was continuously injected into the core plug until the effluent surfactant concentration approached that of the injected surfactant solution, followed by seawater injection until no surfactant was present in the effluent. The effluent surfactant concentrations were analyzed by means of titration technique. Amount of dynimc adsorption and desorption of surfactant solutions was calculated using a new definite integral method. The results showed that the adsorption of the surfactant decreases with increase in the value of the pore geometry parameter, (K/Ф) 0.5 . The adsorption ranges from 0.223 mg/g-rock to 0.597 mg/g-rock for the rocks with permeabilities from 688 md to 110 md. For surfactant concentration of 0.2 wt% OCT-1 in seawater that was used in the study, this level of adsorption implies the surfactant is applicable from adsorption point of view. It was also observed that the adsorption varied with the initial surfactant concentration, as well as relationship between dynamic adsorption and despersion. The value of dispersion, mechanical mixing coefficients and matching adsorption were obtained using dispersion/adsorption equations to match experimental data. This paper presents insights into the adsorption and desorption of the amphoteric type of surfactant on carbonate rocks which could help the application design for a chemical flooding process.

Development and evaluation of foam-based conformance control for a high-salinity and high-temperature carbonate

“…The potential of this SP slug was previously demonstrated for harsh temperature and salinity conditions (Han et al , 2014Zhou et al 2012;Fuseni et al 2013;Wang et al 2015).…”

Alkaline/Surfactant/Polymer (ASP) Flooding

“…As in water, the oxygen provides a dense electron-rich atom that gives the entire molecule a local negative charge site that makes the whole molecule polar and able to participate in hydrogen bonding with water. Amphoteric surfactants [20] may contain both positive and negative charges. These surfactants have not been tested in oil recovery.…”

Comprehensive Investigation of Dynamic Characteristics of Amphoteric Surfactant–Sulfonated Polymer Solution on Carbonate Rocks in Reservoir Conditions

“…The loss of surfactant in the form of adsorption and trapping during surfactant flooding as a tertiary oil recovery process for the reservoirs is the most critical issue that influences its success or failure. 22 , 23 The surfactant retention in both sandstone and carbonate reservoirs depends on many factors that can be divided into two categories. One is determined by the properties of the chemicals themselves such as the type of surfactant, surfactant equivalent weight, ionic strength, PH, etc.…”

“… 24 − 27 The other is related to test conditions such as the type of rock, type of clay and clay content, surfactant concentration, salinity of brine, injection rate, test temperature, etc. 22 , 26 , 28 − 33 Kamal et al 27 and Belhaj et al 34 reviewed static adsorption of different surfactants and described adsorption and retention mechanisms of adsorbing surfactants onto the surface of minerals and how to apply them to the tertiary oil recovery as a displacing agent. For the dynamic adsorption of surfactants, very little work has appeared in the literature.…”