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Treatment and Characterization of Hydraulic Fracturing Fluids

Kekacs, Daniel

Abstract Details

2014, Master of Science, Ohio State University, Civil Engineering.
This work is a contribution to the growing body of literature that characterizes the materials and wastes associated with hydraulic fracturing. First, a synthetic hydraulic fracturing fluid recipe was developed from disclosed industry formulas and produced using commercial additives in use by hydraulic fracturing operators. Laboratory experiments employed a standard method to evaluate aerobic biodegradation potential of the fluid mixture by monitoring the removal of dissolved organic carbon (DOC) from solution by microorganisms in untreated lake water and by microorganisms in an inoculum of municipal wastewater sludge, and were conducted within a range of substrate concentrations and ambient salinities. Specific yields and specific growth rates were calculated from cell growth enumerated with flow cytometry coupled to substrate utilization. Microbial community dynamics were assessed using 454-sequencing of the 16S rRNA gene. Microorganisms reduced bulk DOC by 51% to >90%, indicating that natural aerobic remediation may be a viable option for reduction of organic compounds in hydraulic fracturing fluid. However, salinity concentrations in excess of 20 g/L inhibited organic compound degradation. After a week of exposure to the synthetic fluid, the initially-diverse microbial communities were dominated (>79%) by Pseudomonas sp., which are associated with organisms that can degrade a diverse range of hydrocarbons. Approximately 20% of added carbon was converted to biomass with implications for cell growth, infrastructure fouling, and well productivity. A substantial fraction of carbon was incompletely oxidized to acetone during biodegradation of the synthetic fluid, but the parent compound(s) of produced acetone remain unknown. These data constrain an upper limit for biodegradation potential in aerobic conditions of a hydraulic fracturing fluid released to the surface, and guide our understanding of the microbial that may characterize an impacted environment. Second, factors influencing the mobility of hydraulic fracturing fluids in the subsurface were evaluated. Subsurface processes alter the physical and chemical properties of fluid injected for hydraulic fracturing, with implications for its transport and fate in fractured or porous media. Models used to evaluate potential hydraulic fracturing fluid migration lack formation-specific data to constrain temporal and thermal variation of the physical parameters that govern fluid movement. Density increases of 9.8% and viscosity increases of 26.5% were observed in produced water samples from three horizontally-drilled wells in the Marcellus shale, Pennsylvania, USA over a period of 11 months after hydraulic fracturing. Fluid density and viscosity rapidly increased during the first two weeks after fluid injection due to greater concentrations of dissolved inorganic ions and plateaued within two months. When experimentally subjected to formation-relevant temperatures, mean density and viscosity decreased by up to 2.7% and 44.4%, respectively, between 20 and 60 °C. These measurements yield new data to better constrain constitutive relations in models evaluating potential hydraulic fracturing fluid migration between a wellbore terminus and the shallow subsurface, and highlight the importance of models that can incorporate variable fluid viscosity.
Paula Mouser (Advisor)
John Lenhart (Committee Member)
Kelly Wrighton (Committee Member)
122 p.

Recommended Citations

Citations

  • Kekacs, D. (2014). Treatment and Characterization of Hydraulic Fracturing Fluids [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1406297620

    APA Style (7th edition)

  • Kekacs, Daniel. Treatment and Characterization of Hydraulic Fracturing Fluids. 2014. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1406297620.

    MLA Style (8th edition)

  • Kekacs, Daniel. "Treatment and Characterization of Hydraulic Fracturing Fluids." Master's thesis, Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1406297620

    Chicago Manual of Style (17th edition)