Vilcaez's Research


Computational Modeling, Earth Resources, Environment
Assistant Professor

Office:       103B Noble Research Center
Phone:       405-744-6361
Fax:           405-744-7841

Ph.D.          2009  Tohoku University, Japan
M.Eng.        2006   Gunma University, Japan
B.Eng.        1998   Univ. of St. Francis Xavier, Bolivia

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 naturally faults and fractures, as well as to design optimum injection schemes and monitoring protocols to prevent the pollution of shallow aquifers.



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).


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.


Microbial enhanced hydrocarbon oil recovery through selective plugging of high permeability zones
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.



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.


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.


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.


University of Tokyo, Japan
1. Advances in simulation (F2014), Co-teaching
2. Global environment (F2011 and F2013)
3. Environmental petroleum and mineral engineering (S2011, S2012), Co-teaching

Oklahoma State University
1. Groundwater modeling (S2015)
2. Contaminant transport (F2015)
3. Geochemistry (F2015, F2016)

1. American Geophysical Union (AGU)
2. Society of Petroleum Engineers (SPE)
3. American Chemical Society (ACS)
4. Geological Society of America (GSA)
5. Geochemical Society (GS)

External (completed, *denotes Principal Investigator)

1. *J. Vilcáez. “Reactive transport modeling and simulation of microbial CH4 generation in depleted oil
reservoirs”. Arai Science and Technology Foundation Research Grant (1,000,000 JY ($10,000)). April,
2013-March, 2014.
2. *J. Vilcáez. Japan Oil, Gas and Metals National Corporation (JOGMEC), Collaborative Research with
the University of Tokyo. Development of an organic matter-injection method for biogenic
restoration of subsurface methane gas deposits (2,000,000 JY ($20,000)). April, 2012-March, 2013.

External (pending, *denotes Principal Investigator)
1. *J. Vilcáez, M. Elshahed, J. Puckette. “Understanding the impact of organic hydraulic fracturing
additives on the mobility and transport of heavy metals in shale gas reservoirs ”. National Science
Foundation (NSF), Environmental Engineering program (total $304,999, share $222,913). Submitted
October 20, 2016.
2. *J. Vilcáez, M. Elshahed. “Biogenic recycling of CO2 to CH4 in depleted oil reservoirs”. National
Science Foundation (NSF), Geobiology and Low-temperature Geochemistry program (total $318,539,
share $236,663). Submitted September 19, 2016.

External (not funded, *denotes Principal Investigator)
1. *J. Vilcáez, D. Akob (USGS), A. Mumford (USGS), T. Halihan. “Risk of groundwater pollution by heavy
metals and organic compounds from unconventional oil and gas (UOG) wastewater”. National
Institute of Water Resources, Water resources Research National Competitive Grants Program
(share $184,880). February 25, 2016.
2. 2. * P. Jaiswal, J. Vilcáez, M. Prasad, V. Kumar. “Flow-induced physio-chemical changes in porous
media and their time-lapse seismic response: a multidisciplinary characterization approach”. U.S.
Department of Energy, Development of Technologies for Sensing, Analyzing, and Utilizing Novel
Subsurface Signals in Support of the Subsurface Technology and Engineering (SubTER) Crosscut
Initiative (share $40,000). May 5, 2016.
3. *J. Vilcáez. “Biogenic Recycling of CO2 to CH4 in Depleted Carbonate Oil Reservoirs”. National
Science Foundation (NSF), Geobiology and Low-temperature Geochemistry program (total
$295,316). September 9, 2015.

Internal (completed)
1. FY 2017 A&S Summer Research and +1 Supplement Program, Oklahoma State University-College of
Arts & Sciences. Risk assessment of groundwater pollution by hydraulic fracturing fluid migration
($7778 + $1000).
2. FY 2016 A&S Summer Research and +1 Supplement Program, Oklahoma State University -College of
Arts & Sciences. Restoration of CH4 deposits driven by the injection of CO2 and stimulating nutrients
($7778 + $1000).
3. FY 2015 Spring Travel Program. Oklahoma State University -College of Arts & Sciences. Biogenic
recycling of geologically stored CO2 to CH4 ($1000).

Internal (not funded, * denotes Principal Investigator)
1. *J. Vilcáez, B. Fathepure, P. Jaiswal. “Biogenic CH 4 recovery from organic feedstock in depleted oil
reservoirs”. Oklahoma State University, Sun Grant Program South Central Region (total $176,155).
June 1, 2015.



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