Study of hydraulic fracturing flowback in Oklahoma

Abstract

This thesis investigates the physicochemical characteristics and environmental implications of fracturing fluid flowback in Oklahoma, highlighting the complex interactions between hydraulic fracturing fluids and geological formations. The study focuses on the flowback fluids collected from an operational oil extraction facility, comparing samples from the pumping equipment and a waste pound site.

The research adopts a multifaceted analytical approach, utilizing advanced light microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) to explore the micro and nanostructures present in the flowback fluids. This detailed analysis reveals significant variability in sample composition, evident from the distinct coloration and crystalline structures observed in pump-derived versus pound-derived samples. SEM and TEM analyses illustrate diverse morphologies such as perfect hexagons, nanoflowers, and larger polygonal structures, while XRD data confirm the presence of common salt and various other minerals and metal oxides influenced by fluid-rock interactions.

Part of the study involves evaluating the potential environmental impacts of the fluid components, particularly the high salinity levels and the presence of contaminants such as heavy metals and hydrocarbons. The findings highlight concerns about groundwater contamination risks and the broader environmental implications of disposing of such high-salinity water.

Furthermore, experimental combustion tests and lead acetate trials were conducted to assess the combustibility of the flowback fluids and the presence of hydrogen sulfide, adding layers of complexity to understanding the chemical characteristics of the flowback fluids. These tests underline the potential environmental hazards and the need for rigorous management strategies.

This study enhances our understanding of the physicochemical properties of fracturing flowback fluids and underscores the critical environmental challenges posed by hydraulic fracturing operations.