Master of Science (MS), Wright State University, 2021, Earth and Environmental Sciences

Amplitude anomalies in pre-stack seismic data have widely been used in the oil and gas industry as a risk analysis tool when exploring for hydrocarbons. AVO analysis is most often applied to poorly consolidated Tertiary rocks due to the compressibility of these strata when natural gas and porosity are present. In contrast, well-lithified carbonate rocks are less prone to producing a pre-stack amplitude response due to the rigidity of their frame. Pre-stack seismic data of a 2-D seismic profile were conditioned and interpreted to identify amplitude variation with offset (AVO) attributes corresponding to the presence of hydrocarbons within the North Vernon Limestone (NVL) interval in the Illinois Basin. The seismic data were acquired over the Glen Ayr oil field in Vigo County, Indiana, and in the Old Hill oil field in Clay County, Indiana prior to wells being drilled. Production in both fields is from porous dolomites draped by tight limestone or dolomites over a Silurian reef complex We show that with appropriate pre-stack data conditioning subtle AVO responses in Illinois Basin carbonates may indicate the presence of hydrocarbons. Seismic line CM-46-12 (Clay) and CM-27-14 (Vigo) were both analyzed using AVO attributes to identify anomalous zones that may relate to the presence of hydrocarbons. Seismic Line CM-27-14 was further interpreted using pre-stack inversion to provide additional information pertaining to the reservoir rock properties. The results on both seismic lines show strong, negative AVO gradients along the NVL interval, whereas nonproductive intervals exhibit either positive or no amplitude gradient. Pre-stack inversion of lime CM-27-14 shows high impedance zones which are consistent with the presence of tight dolomite atop the reef structure. Low-impedance, low VP/VS ratio zones correlate to the hydrocarbon bearing porosity zones of the NVL interval.

Committee: Ernest C. Hauser Ph.D. (Committee Chair); Paul McColgan Ph.D. (Committee Co-Chair); Doyle R. Watts Ph.D. (Committee Member) Subjects: Geology; Geophysics

Master of Science (MS), Wright State University, 2017, Earth and Environmental Sciences

Constraining the composition, structure, and origin of basement provinces, deep assemblages of Precambrian rocks, is largely dependent on deep boreholes and geophysical techniques. This is especially true for the eastern U.S. midcontinent. Here, I employ regional 2-D seismic reflection, Bouguer gravity, and aeromagnetic data to interpret the upper crust below west-central Indiana. Seismic reflection data were donated to Wright State University in 2015. Geopotential data are available through the USGS and affiliates. These geophysical data, together, are analyzed in a regional geologic context. Three distinct seismic stratigraphic sequences are observed on 2-D sections. The first, uppermost sequence, typified by continuous, high-amplitude, stratified reflections is constrained by boreholes and previous seismic investigations as the Paleozoic sedimentary sequence that masks the midcontinent basement. The Cambrian Mt. Simon Sandstone constitutes the base of this unit, which is underlain by the second, poorly reflective, westward-thinning sequence. Weak internal reflections create an apparent angular unconformity with the base of the Mt. Simon and appear concordant with reflections of the basal seismic package. This unit, termed the Wilbur sequence, compares well with the seismic character of the Middle Run Formation of western Ohio and Kentucky. A third, well-reflective sequence is observed at the base of the record. Stratal geometries, such as onlap and stratigraphic terminations, are locally observable on regional east-west profiles. A positive Bouguer anomaly appears associated with the apparent structural closure of this sequence, herein termed the Quincy, below northeast Owen County. Geophysical signatures of the Quincy suggest a depositional origin, composed of low-magnetic igneous rocks (rhyolites) sourced from midcontinent volcanic centers and clastic sediments from collapsed calderas. These data facilitate two alternative hypotheses. The pattern seen in (open full item for complete abstract)

Committee: Ernest Hauser Ph.D. (Advisor); Doyle Watts Ph.D. (Committee Member); David Dominic Ph.D. (Committee Member) Subjects: Geology; Geophysics

Master of Science, The Ohio State University, 2017, Earth Sciences

Turbidite channels are important conduits of clastic sediments into the deep ocean, with coarser-grained deposits creating potential reservoirs for hydrocarbons. In this study, three-dimensional seismic data and borehole logs from three industry wells were used to interpret channel systems, lithology, and overall depositional trends in the Orca and Choctaw mini-basins, located on the outer continental slope in the Gulf of Mexico in ~1645-2470 m (5400-8400 ft) of water. These mini-basins have previously been shown to have strong indications of gas hydrate in core samples and geophysical data, and the primary goal of this study was to identify coarse-grained sediments within channel systems that could serve as potential hydrocarbon reservoirs. To accomplish this, thirty-five channels were mapped in the ~2900 m (9500 ft) of sediment between the seafloor and top of salt. Channels were grouped into two broad morphological types to predict where coarse-grained sediments within each system were likely to occur. Basin depositional trends were also assessed to show how progressive salt withdrawal impacts channel occurrence by shifting topographic lows, in turn influencing where coarse-grained sediments are ultimately deposited. This research provides a detailed assessment of the turbidite channel systems in the Orca and Choctaw basins, and serves as model for future studies using seismic and well log analysis to interpret turbidite channel systems in deepwater basins.

Committee: Derek Sawyer (Advisor); Ann Cook (Committee Member); Mike Wilkins (Committee Member) Subjects: Earth; Geological; Geology; Geomorphology; Geophysical; Geophysics

Master of Science (MS), Wright State University, 2014, Earth and Environmental Sciences

Using well logs and AVO gradient analysis, I identify and characterize a package of reflectors associated with the Utica Shale from vibroseis data collected by Wright State University at the Gabor Gas Storage field near Canton, Ohio. I also correlate TOC measurements from wells to densities and velocities at the same depths. On the seismic data, I interpret prominent reflections from the top and bottom of the Utica Shale and an intra-Utica reflector of varying frequency content associated with a velocity/density low in well log data. I investigate the possibility that the lateral variation in frequency content and change in wavelet character of these reflections is influenced by velocity gradients, termed Wolf Ramps. A Matlab software script was written in order to approximate this behavior using synthetic wavelets, and the resulting model matched well with the seismic data. Additionally, I note a possible reverse fault within the Utica that could create fracture porosity and a migration pathway. To model the AVO response, an AVA volume was created from prestack data and reflection coefficients up to 30 degrees of incidence were calculated using the two-term Aki-Richards approximation. Large negative normal incidence reflection coefficients attenuated at higher angles of incidence (Class IV anomalies) were observed at the top of Utica reflector, a response consistent with a change from silica-rich nonsource shale to black source shale. Large positive normal incidence reflection coefficients decreasing at higher angles of incidence (Class I anomalies) were noted at the bottom of Utica reflector, consistent with a shift from low impedance source shale to higher impedance calcareous shale. To perform forward modeling, I used geophysical well logs and NS-EW vibroseis line data. Using Hampson Russell commercial software, acoustic impedance and reflectivity were computed from sonic and density logs. An average wavelet at the Utica two-way travel time was extracte (open full item for complete abstract)

Committee: Doyle Watts Ph.D. (Advisor); Ernest Hauser Ph.D. (Committee Member); David Dominic Ph.D. (Committee Member) Subjects: Geology; Geophysics

Master of Science, The Ohio State University, 2011, Geological Sciences

In Antarctica, where much of the continent is covered by ice, the use of remotely sensed geophysical data is a valuable tool for reconstructing geologic history. Data from the submarine continental shelf are fundamental for determining the structural deformation and geomorphological history of the Antarctic plate. The western Ross Sea contains a segment of the West Antarctic Rift System known as the Terror Rift. The rift lies entirely below sea level and stretches between the two volcanic provinces of Mount Melbourne and Mount Erebus. High-resolution seismic and bathymetry data from the western Ross Sea are used to analyze the structure, kinematics, and deformation history of the Terror Rift. Recent glacial history of the western Ross Sea has also been identified. A revised fault and associated volcanic edifice map of the Terror Rift in the western Ross Sea is provided. The eastern limit of faulting associated with the Terror Rift is redefined by this study. The first balanced cross sections and extension values have been calculated for the Terror Rift. Outcomes of this study provide definite constraint on the magnitude of extension since the onset of rifting in the late Neogene and define the mode of rifting.

Committee: Terry Wilson (Advisor); E. Scott Bair (Committee Member); Ian Howat (Committee Member) Subjects: Geology