# Investigating the Adsorption Behavior of Zwitterionic Surfactants on Middle Bakken Minerals
## 4 Conclusions  
This study investigated the static adsorption behavior of three zwitterionic surfactants (CG3, CD2, and ME1) on Bakken reservoir core (BRC) samples. Through detailed characterization and laboratory experiments, several critical insights were obtained regarding the adsorption equilibrium behaviors of these surfactants. The following conclusions are drawn based on the study:  
1. XRD analysis confirmed the presence of SiO2 and clay in the BRC, serving as active sites for surfactant adsorption. The identification of is crucial for understanding the mineral composition that helps in explaining the adsorption characteristics observed in the experiments.
2. In formation brine, CG3, CD2, and ME1 exhibited adsorption densities of 3.43 mg/g, 2.12 mg/g, and 1.89 mg/g, respectively. These levels indicate strong surfactant-mineral interactions, critical for EOR applications, though adsorption should be optimized to balance bulk fluid availability.
3. Zwitterionic surfactants CG3, CD2, and ME1 demonstrated relatively high adsorption on Bakken minerals compared to the typical target of less than 1 mg/g. This robust interaction indicates their potential for effective wettability alteration. While high adsorption demonstrates a strong interaction, it is crucial to optimize adsorption densities to ensure that a sufficient amount of surfactant remains in the bulk fluid for efficient reduction in interfacial tension (IFT).
4. Various factors including temperature, initial surfactant concentration, adsorbents, and salinity were found to influence the equilibrium adsorption density, with surfactant concentration and adsorbents exerting more pronounced effects compared to temperature. Understanding the influence of these factors helps in optimizing the adsorption process. By identifying the primary factors affecting adsorption, better control and adjustments can be made to enhance efficiency and effectiveness in practical applications.
5. Electrostatic interaction emerged as the primary driving force for zwitterionic surfactant adsorption. This finding is essential for designing surfactants with optimized charge properties to enhance adsorption on specific mineral compositions.
6. The Langmuir isotherm provided the best fit for the experimental adsorption data, indicating monolayer coverage of zwitterionic surfactants on homogeneous rock surfaces. This finding aids in understanding adsorption mechanisms and predicting surfactant behavior in Bakken reservoir conditions.  
Conceptualization, T.I.O. and A.S.F.; methodology, T.I.O.; validation, T.I.O.; formal analysis, T.I.O.; investigation, T.I.O. and T.F.O.; resources, T.I.O. and L.Y.N.; data curation, T.F.O.; writing--original draft preparation, T.I.O. and D.A.O.; writing--review and editing, A.S.F. and D.A.O.; visualization, L.Y.N.; supervision, A.S.F.; project administration, A.S.F. All authors have read and agreed to the published version of the manuscript.  
The authors recognize the North Dakota Industrial Commission (NDIC), grant number UND273030205 which provided funding for this study. The authors would like to acknowledge [PERSON] for their material donations and technical contributions to the research work.  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** Data is contained within the article.  
**Conflicts of Interest:** Author [PERSON] was employed by the company Circular One Resources. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.