Static Adsorption and Mathematical Model Applied in EOR Using a Supramolecular Surfactant

Abstract Typical adsorption isotherms show the characteristic Langmuir behavior. However, in the presence of a supramolecular surfactant, its corresponding adsorption isotherms, exhibiting atypical decrement behavior. The static adsorption results on limestone and dolomite show maximum values of 2.40 and 5.98 mgsurfactant/grock, respectively. For explaining this behavior, was developed a new modified mathematical adsorption model, ( d Г d t ) a d s = k a d s c ( Г ∞ − Г ) − k c m c ( c − c c m c ) n Г H ( c − c c m c ) . This model describes the adsorption isotherms in two regions: the first one corresponds to the conventional adsorption increase and the second to decay adsorption phenomena. This decrement behavior is mainly due to the ultra-high salinity and the monomer ⇆ micelle ⇆ vesicle equilibrium in connate water. The new model shows the better fitting with r2 = 0.9743 for limestone and r2 = 0.9668 for dolomite, respect to the Langmuir model r2 = 0.8556. Which represents the accuracy with the experimental values in the adsorption isotherm. Also, it is highlighted the significance of the information provided by the new static adsorption Langmuir mathematical model. That establishes criteria for using a chemical in enhanced oil recovery processes. From the data in the adsorption profile, the optimal concentration for the adsorption process occurs between 1800 - 2000 ppm of supramolecular surfactant. The enhanced oil recovery experiment in ultra-high salinity and hardness is better with an increase in the temperature: 8% at 80 °C, 15% at 90 °C and 20% at 100 °C.