Polymer flooding is one of the promising enhanced oil recovery techniques being applied to improve oil recovery from various oil fields since the early 60s, with polymer adsorption being the one of major drawbacks. Polymer enhanced oil recovery technique has been widely used in sandstone reservoirs and has limited applicability to carbonate reservoirs mainly due to prevailing harsh conditions in these reservoirs. This paper provides a comparative study of polymer flooding focusing on polymer adsorption in both sandstone and carbonate reservoirs including the polymer adsorption types, adsorption mechanisms, and factors affecting polymer adsorptions in both reservoirs.
This paper aims to describe an investigative study behind the effect of fluid leak-off in a dual porosity system and hydraulic fracture propagation geometry on improving the hydrocarbon recovery. This is achieved through the application of the Perkin-Kern-Nordgren-Carter Equation II (PKN-C) and Pseudo Three-Dimensional-Carter Equation II (P3D-C) models in analyzing the fracture propagation geometry using an in-house numerical code. This investigation provides an insight to the complexities associated within hydraulic fracturing treatment design. Thus, this may ultimately assist future fracturing operations in the region.
For decades there has been an interest in water alternate gas (WAG) injection. WAG injection improves oil recovery on both microscopic and macroscopic levels by combining the benefits of conventional waterflooding and gas injection. This research is aimed at the optimization of WAG injection. The investigated field case study is named Volve, which is a decommissioned field in the North Sea. Sensitivity analysis of WAG injection on this base case was studied. The following parameters were considered; WAG ratio, time to start WAG, total gas slug size, cycle slug size, and tubing diameter. A full two-level factorial design was utilized for the sensitivity study. Sensitivity study results showed that the total slug size is the most important parameter followed by time to start WAG, and then cycle slug size. WAG ratio appeared on some of the interaction terms while tubing diameter effect was found to be negligible.
In this study, three new models that accommodate the sorption and desorption effects have been developed and studied for an unconventional tight reservoir by utilizing Knudsen's and Langmuir's models. The new models have been analyzed using synthetic data and compared to previously published models that cater to the same phenomena. The suggested new model presented is solved using MATLAB numerical method for linear flow. Comparing results using different fluid flow models has been analyzed and proved that the new modified model has better estimation utilizing various case studies. It has been observed that the diffusion system becomes more prominent in regulating flow velocity with low permeability of the formation rock and low viscosity of the flowing fluid. Additionally, the sorption mechanism contribution to the flow increases with low permeability of the medium and low viscosity of the flowing fluid leading to release gas trapped in pores and rock surfaces.
Electrochemical hydrogenation and oxidation of furfural (model bio-oil compounds) is an efficient and environmentally friendly process, particularly with the use of renewable electricity and water-derived hydrogen. Novel nitrogen-doped manganese-cobalt on carbon nanoparticles catalyst (prepared with the hydrothermal process) has been used effectively as an electrocatalyst for furfural conversion to furfural alcohol and furonic acid with high conversion and selectivity. The process can be carried out at ambient conditions and acidic medium. The yield, selectivity, and faradic efficiency for furfural conversion in a single electrochemical cell were found to be highly dependent on catalyst loading, potential, reaction conditions (e.g. pH), and residence time. The optimized electrochemical furfural conversion can reach around 70 percent within three hours of operation.
Desert pristine sands were collected, sieved, characterized and tested for the separation of surfactant-stabilized oil in water (O/W) emulsions in a cross-flow sand bed filter unit under the simulated natural gravity (ΔP = 0.1 bar). The wettability and morphology of sands was characterized. It was revealed that natural sand is a promising material for this application with superhydrophilicity and underwater superoleophobicity. It achieved separation efficiency and flux comparable or higher than commercial microfiltration membranes under natural gravity conditions, while the separation efficiency and flux are relatively stable with respect to the operation parameters
The Graphene Oxide (GO)/ Metal Organic Frameworks (MOFs) hybrid material has attracted the attention of researchers because of the synergistic effect of the two in the CO2 capture process, which can significantly enhance the CO2 capture performance of the hybrid material with respect to the individual adsorption of each of them. However, it is difficult to directly explore the role played by each of them in the hybrid material through experiments, as there may be some competing effects. Therefore, this research adopts computational simulation method to explore this problem by constructing a simplified GO/MOF-5 hybrid material model and exploring its properties. GO can play an important role in the CO2 capture process by the hybrid materials, significantly improving the adsorption selectivity and adsorption capacity of MOFs. Under the condition of 313K and 0.15bar, the CO2 capture performance of 30wt%GO/MOF-5 is 4 times that of pure MOF-5.
This work belongs to a long-term project implementing molecular dynamics (MD) and quantum mechanics (QM) as economic and time-saving tools to design ad-hoc corrosion inhibitor molecules, reaching the most of their adsorptive capabilities for internal metal protection. Our recent publication provides molecular insights on the effect of the aqueous media on three CIs adsorption, abbreviated TEPA, iTEPA and HC-iTEPA on iron surface. The QM parameters in water solvation anticipated higher electron transfer ability of iTEPA in aqueous conditions compared to TEPA and iTEPA, thus, leading to stronger adsorption on iron surface, corroborated by the MD simulations. Molecular dynamic simulations showed that nearly 53%, 39%, 59% reduction in adsorption energies was detected for single inhibitor molecule of TEPA, iTEPA, and HC-iTEPA shifting from water to CO2-saline media, respectively. Nevertheless, the multi-inhibitors study revealed strong adsorption of TEPA and iTEPA on the iron.
Lithium air batteries have attracted high attention especially in sustainable development fields, since they are promising storage devices with high energy density of 1000 Wh kg-1. It has been under development to address serious problems such as finite oil resources, high fuel prices and to meet the demand of vehicles electrification. Lithium-air batteries structure plays an important role in providing pathways for discharge products, oxygen and lithium ions. However major problems such as clogging, cathode passivation and low stability need to be avoided. Thus, metal-organic frameworks are a class of outstanding candidates as cathodes for Lithium-air batteries since they have high surface areas, tailorable pore sizes and catalytic centers. To get rid of these predicaments MOF-derived carbons were fabricated and tested in LAB using aprotic electrolyte. Three different classes of MOFs were investigated ZIF-8, MOF-177 and Ni-MOF74.
Molecular self-assembly occurs in nature in various forms with a wide range of applications in biology, chemistry and material science. For example, DNA condensation, the physiologically significant phenomenon of DNA assembly in all life forms, has been heavily studied. Experiments report ion effect in DNA condensation, while the fundamental physical principles governing this unique assembly process are still not fully understood. To provide a fundamental understanding, we employ computer simulations to study the DNA condensation process. We examined the role of sequence in divalent ion conditions and analyzed the intermolecular forces. We observed a strong correlation between the counterion dynamics and DNA-DNA interactions. The attraction among DNA molecules is facilitated by ions that bridge between strands and the bridging ion structure highly correlate with DNA sequence. Based on our analysis, we design DNA sequences that assemble readily in the presence of divalent salt.
