• Effect of nanofluid on CO2-wettability reversal of sandstone formation; implications for CO2 geo-storage

      Sahito, Muhammad Faraz; Jha, Nilesh Kumar; Arain, Zain-Ul-Abedin; Memon, Shoaib; Keshavarz, Alireza; Iglauer, Stefan; Saeedi, Ali; Sarmadivaleh, Mohammad (2020-02-01)
      HypothesisNanofluid treatment is a promising technique which can be used for wettability reversal of CO2-brine-mineral systems towards a further favourable less CO2-wet state in the existence of organic acids. However, literature requires more information and study with respect to organic acids and nanoparticles’ effect at reservoir (high pressure and high temperature) conditions. ExperimentsTherefore, we have measured in this study that what influence small amounts of organic acids exposed to quartz for aging time of (7 days and 1 year) have on their wettability and how this impact can be reduced by using different concentrations of nanoparticles at reservoir conditions. Precisely, we have tested lignoceric acid (C24), stearic acid (C18), lauric acid (C12) and hexanoic acid (C6) at 10−2 Molarity, as well as, we have also used different concentrations (0.75 wt%, 0.25 wt%, 0.1 wt%, 0.05 wt%) of silica nanoparticles at realistic storage conditions. FindingsThe quartz surface turned significantly hydrophobic when exposed to organic acids for longer aging time of 1 year, and significantly hydrophilic after nanofluid treatment at optimum concentration of 0.1 wt%. It was observed that most nanoparticles were mechanistically irreversibly adsorbed on the surface of quartz sample. This wettability shift thus may increase CO2 storage capacities and containment security.
    • Effect of nanofluid on CO<inf>2</inf>-wettability reversal of sandstone formation; implications for CO<inf>2</inf> geo-storage

      Ali, Muhammad; Sahito, Muhammad Faraz; Jha, Nilesh Kumar; Arain, Zain Ul Abedin; Memon, Shoaib; Keshavarz, Alireza; Iglauer, Stefan; Saeedi, Ali; Sarmadivaleh, Mohammad (2020-02-01)
    • A hybrid multi-criteria decision making method for site selection of subsurface dams in semi-arid region of Iran

      Amal, Dortaj Author, Two (2020-04-30)
      Water shortage is one of the most critical problems all around the world, especially in arid and semi-arid regions. Using groundwater can be an efficient solution in such lands. Although significant care and appropriate water resource management strategies are required to be implemented. Nowadays, subsurface dams (SSD) are widely used worldwide since they are proved to have advantages over surface dams in some cases. Selection of the suitable site for SSD construction is critical. This selection is made based on advantages and disadvantages of each location. Multi-criteria decision-making methods (MCDM) is an efficient method for optimum site selection. In this study, 10 regions were chosen as alternatives for construction of subsurface dams in Isfahan province of Iran. These alternatives were then ranked using ELECTRE I, II and modified ELECTRE III based on geological, hydrological, climatological and socio-economical criteria. Results from different ELECTRE methods are combined by applying the grade average, and Borda and Copeland ranking strategies. Application of an advanced MCDM method reduced uncertainties in subsurface dams (SSD) site selection. Alternative 5 (Hoseinabad) was introduced as the best location for subsurface dam construction. This methodology can be used as a basis for more detailed field investigations.