Thanks for visiting. This is my personal webpage. Here you will find information about myself, research interests, publications, etc. Comments and questions are more than welcome!
The intended purpose of this webpage is to get in touch with people of similar interests willing to collaborate, or need help.
I do research on ENERGY AND MINERAL RESOURCES RECOVERY & GROUNDWATER REMEDIATION, and like the smell of ink on paper in new books.

Research topics

1. Understanding the impact of hydraulic fracturing additives on the mobility and transport of heavy metals

The fate of organic fracturing fluid additives contained in unconventional oil and gas (UOG) wastewater and its effect on the mobility and transport of heavy metals at deep geological formation conditions is unknown. This research is to provide new information and computational tools to predict the fate of organic fracturing additives and its effect on the mobility and transport of heavy metals in shale gas reservoirs and Class II Underground Injection Control (UIC) wells. New information along with developed computational tools will be used to confirm the physical feasibility of shallow aquifers pollution due to the upward migration of UOG wastewater through natural faults and fractures, as well as to design optimum injection schemes and monitoring protocols to prevent the pollution of shallow aquifers.

IMG_1842               IMG_0145-3-katie
Pouyan Ebrahimi,                    Katie Spencer,
Ph.D. Student                            Undergraduate Student (former)

2. Coupling of GCS and MEHR through the stimulation of microbial methanogenesis in depleted oil reservoirs

The goal of this research is to prove that geological CO2 storage (GCS) and microbial enhanced hydrocarbon recovery (MEHR) can be coupled through the stimulation of microbial methanogenesis in depleted oil reservoirs. To test this hypothesis, parallel experimental and numerical modeling and simulation studies on the response of indigenous microbial communities to the combined injection of CO2 and a nutrient solution are conducted using rock, formation water and crude oil samples collected from the Cushing oil field of Oklahoma. Preliminary experimental results have shown that protein-rich matter and moderate acidic conditions stimulates the microbial methanogenesis from CO2 and biodegradable crude oil (alkanes).

josh              toby3
Joshua York,                              Toby Williams,
M.S. Student                              Undergraduate student (former)

3. Simulation of geological CO2 storage in depleted oil reservoirs under biotic conditions

Recent studies on the impact of CO injection on the microbial community of saline aquifers using molecular biology techniques have shown that methanogenic microbes and sulfate-reducing bacteria (SRB) are capable of adapting to the extreme conditions of GCS. A metabolic shift occurs avoiding the complete inhibition of the microbial community. Similar responses have been observed in oil reservoirs flooded with CO2, where the concentration of H2-forming microbes either increased or remained unchanged, which imply that in depleted oil reservoirs and deep saline aquifers used for long-term storage of CO2, the fate and trapping of CO2 may be affected by the activity of indigenous microbial communities. The goal this research is to assess the fate of CO2 in depleted oil reservoirs where the availability of nutrients and/or the combined injection of CO2 and a nutrient solution can result in the microbial conversion of CO2 and crude oil to CH4. Numerical modeling and simulation studies using a new TOUGHREACT module capable of simulating the multiphase reactive transport of multicomponent fluids (CO2-CH4-H2S-N2-H2 gas mixtures and brine) under biotic conditions are being conducted. The accuracy of the new TOUGHREACT module will be tested against batch experiment results of the microbial conversion of CO2 and crude oil to CH4 stimulated by the combined supply of CO2 and a nutrient solution.

Babak Shabani
Ph.D. Student

4. Pore-scale simulations of flow properties of reservoir rocks

Besides a consistent kinetic model for the dissolution/precipitation and aqueous phase reactions of solutes, and a suitable equation of state (EOS) to represent the solubility of gases in the aqueous phase, the use of multiphase reactive transport simulation programs needs of accurate information on the flow properties of the reservoir rock. FIB-SEM techniques in combination with the capabilities of CFD simulation programs (COMSOL Multiphysics) are used to reconstruct the microstructure of reservoir rocks and conduct pore-scale simulations of flow properties of reservoir rocks at the nano-scale level.

5. Microbial enhanced hydrocarbon oil recovery (MEHR) 

Microbial growth and their biogeochemical reaction products can lead to significant changes in porosity and permeability of reservoir rocks. Reduction in porosity and permeability may be caused by the growth of microbes and the deposition of extra-polymeric substances (EPS) in the void space of rocks, whereas an increase in porosity and permeability may occur due to the dissolution of rocks accelerated by produced organic acids during microbial growth. The objective of this research is to develop reactive transport models to mechanistically understand the complex interplay between microbial growth, EPS production, and the interactions between the microbial byproducts and rocks. This research is expected to help in identifying the controlling factors that govern the selective plugging of oil/gas reservoirs to enhance hydrocarbon recovery.

6. Biodegradation of spilled oil in sea water

After or during the oil spill it is of common practice to introduce chemical dispersants near the spill region. Under these conditions, spilled oil can not only dissolve in sea water, but also form oil droplets. Although large oil droplets can arise to the sea surface due to the buoyancy effect, previous studies suggest that small oil droplets would not rise to the surface but remain in underwater. Thus, spilled oil can exist in both dissolved form and as oil droplets in deep water. In order to be able to predict the biodegradation rate of the fraction of oil in the form of droplets, a new model for the biodegradation kinetics of dispersed oil droplets has been developed. The next step is to couple flow and transport processes with biodegradation to explicitly simulate the evolution of oil composition with time to more accurately represent what occurs after oil spills.

7. Heavy oil upgrading with supercritical water

If heavy crude oil resources are to be exploited, efficient, environmentally benign and inexpensive upgrade technologies are desirable. To fulfill these conditions, upgrading without coke formation is required, and supercritical water processing is an attractive option to achieve this aim. Specific features of potential supercritical water processes have been reported: the yield of asphaltenes and resins can be reduced; the fraction of aromatics is reduced, while the yield of saturated compounds is increased; in addition the removal of sulfur, nitrogen and metal fractions is possible. These results suggest that supercritical water serves both as a reaction medium, and a reactive species, and thus the supercritical reaction atmosphere may provide effective upgrading conditions for heavy oil without the need for a catalyst.

8. Heap and underground leaching of minerals

The main objective of this research is the elucidation of the catalytic effect of thermophiles in leaching sulfide minerals, various new findings are contributing to a better understanding of interactions among chemical, physicochemical and microbiological factors. In order to bridge laboratory results and field applications, novel kinetic models and advanced mathematical models to assess the auto-thermal performance of heap and underground leaching systems are being developed. The methodologies employed in this research will be used to assess the impact of microbial activity on the leaching of heavy metals from shale gas rocks at deep geological formation conditions.

Google Scholar Citations

E-mail: vilcaez@hotmail.com

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