Master of Science / Geology / Matthew W. Totten / Mississippian chert reservoirs, also known as chat reservoirs among the mid-continent in Kansas and northern Oklahoma, produce an abundant amount of hydrocarbons. Since the 1920s, chat reservoirs in Kansas have yielded over 380 million bbl of oil and 2.3 tcf of natural gas. The largest Mississippian field in south-central Kansas is the Spivey-Grabs, which spans Kingman and Harper Counties. Development of the Spivey-Grabs Mississippian reservoir, and continued production within the field, has been compromised by compartmentalization within the field, resulting in unpredictable producing rates. Previous research has investigated the differences of the fluids within the separate compartments (Evans, 2011; Kwasny, 2015), and identified the existence of at least two oil types of differing viscosity (Kwasny, 2015). The objective of this research was to determine whether the compartmentalization of the reservoir is controlled by the different lithologic characteristics between the various compartments. This was accomplished by examining drill cuttings under binocular microscope, under a petrographic microscope using digital imaging software, and under the high magnification of a scanning electron microscope. Calculated rock porosity from ImageJ software showed variation among the wells selected for this study; but the porosity variation does not correlate with differences in fluid viscosity that was previously observed, i.e. heavy and light viscosity oils (Kwasny, 2015). Heavy oils were seen in wells that had both higher and lower porosity values, and the same is true for the distribution of light oils. This suggested that fluid viscosity is the major controlling factor in compartmentalization in the Spivey-Grabs and not rock properties.

Master of Science / Department of Geology / Sambhudas Chaudhuri and Matthew Totten / The current model of hydrocarbon generation involves the thermogenic maturation of organic material as a consequence of burial. This process only considers energy generated from temperature increase due to burial. The majority of organic rich source beds contain high concentrations of radioactive elements, hence the energy produced from radioactive decay of these elements should be evaluated as well. Previous experiments show that α-particle bombardment can result in the generation of hydrocarbons from oleic acid. This study investigates the effects of γ-rays in a natural petroleum generating system. In order to determine the effects of γ-rays, experiments were conducted using cesium-137 as the γ-ray source at the KSU nuclear facilities to irradiate crude oil and organic material commonly found in petroleum systems. The samples were then analyzed using Fourier Transform Infrared Spectroscopy (FTIR) and Rock-Eval pyrolysis to determine changes in the samples. The FTIR results demonstrated that γ-radiation can cause the lengthening and/or shortening of hydrocarbon chains in crude oils, the dissociation of brine (H2O (aq)), the production of free radicals, and the production of various gases. These changes that come from γ-radiation hold the possibilities to distort the configuration of organic molecules, dissociate molecular bonds, and trigger oxidation-reduction reactions, all of which could provide an important step to the onset of dissociation necessary to create hydrocarbons in petroleum systems. Further understanding the effects of γ-radiation in hydrocarbons systems could lead to more information about the radiolytic processes that take place. This could eventually lead to further understanding of oil generation in organic-rich source beds.

Master of Science / Department of Geology / Matthew Totten / Jackson County, Kansas is situated on the west side of the Forest City Basin, location of the first oil discovery west of the Mississippi River (KGS), Production in the area is predominately from the Viola Limestone, and a noticeable trend of oil fields has developed where the basin meets the Nemaha Anticline. Exploration has been sluggish, because of the lack of an exploration model. Production rates have varied widely from well to well, even when they are structurally equivalent. The goal of this study was to determine the factors controlling reservoir quality in the Ordovician-aged Viola Limestone so that a better exploration model could be developed. A two township area was studied to examine relationships between subsurface variations and production rates. In the absence of an available core through the Viola, drill cuttings were thin-sectioned and examined under a petrographic microscope to see the finer details of porosity, porosity type and dolomite crystal-size that are not visible under a binocular microscope. Production appears to be controlled by a combination of structural position and dolomite crystal size, which was controlled by secondary diagenesis in the freshwater-marine phreatic mixing zone. The best wells exhibited a Viola Limestone made up of 100% very coarsely crystalline, euhedral dolomite crystals. These wells occur on the east and southeast sides of present day anticlines, which I have interpreted to be paleo-highs that have been tilted to the east-southeast.

Master of Science / Department of Geology / Matthew Totten / Oil production in Kansas has a long history with plays being found on all sides of the state. The source of Kansas’s hydrocarbons has been traditionally thought to be outside the state due to low thermal maturity and the shallow burial of potential source rocks within Kansas. This research addresses the question regarding the source of the oil in Kansas, at least within a small geographic area of roughly 146mi[superscript]2. The Spivey-Grabs-Basil Field has been one of the more successful fields within the state of Kansas since the 1960’s. This field is compartmentalized and offers a natural laboratory in which to conduct the field’s first formal oil-source rock correlation since oils are locked into place. While the main focus of this research relies heavily on pyrolysis and GCMS for biomarker analysis, it also investigates the possibility of using rare earth element (REE) concentrations as a possible fingerprint of organic matter within a source bed. TOC values of the Chattanooga shale samples from the Spivey-Grabs-Basil filed range from 0.75 and 3.95 wt. %, well within productive capacity. Pyrograms show both the potential for additional production, and the likely previous expulsion of hydrocarbons. Biomarker concentration percentages between C[subscript]27, C[subscript]28, and C[subscript]29 steranes, as well as pentacyclic terpane ratios compared between crude oil from the Spivey-Grabs-Basil and the Chattanooga shale show a definite genetic relationship. REE values of the organic fraction of the Chattanooga inversely correlate with those of the crude oils, suggesting fractionation during oil generation. After comparison of results with the Woodford shale in Oklahoma, the conclusion of this study is that the Chattanooga shale which underlies the Spivey-Grabs-Basil oil field of southern Kansas is the probable source rock which generated the oil now being produced.

Master of Science / Department of Geology / Matthew Totten / The Woodford shale is recognized as an abundant source rock across Oklahoma and much of the midcontinent (Lambert, 1990), and up to 8% of the world’s hydrocarbon reserves are estimated to have been sourced by the Woodford and its equivalents (Fritz et al, 1991). The Woodford shale is far more complex than other Devonian black shales found in North America due to the presence of alternating bands of chert-like amorphous silica and silica-rich shale. Analysis of chert and its possible role in gas generation and storage in shales has been largely overlooked. The goal of this study is to determine if chert size, amounts, or polycrystallinity can be indicators of thermal maturity within the Woodford shale. Handheld XRF analysis was conducted on the whole rock samples, and a mudrock specific sodium bisulfate fusion was used to separate the non-clay fraction. SEM was performed on the resulting separates to study and observe changes in chert fabric, grain-size, and amount. No correlations were observed to indicate that chert is an indicator of thermal maturity within the Woodford shale. Increase in chert growth and amount was also not detected within the size fractions as thermal maturity increases. Handheld XRF proved to be a good proxy for quick, onsite analysis of silica concentrations, as well as the amount of organic matter within drill core. This could be beneficial as hydraulic fracking produces best results in areas of higher silica content, and the wells with the highest organic matter have the highest potential for petroleum accumulations.

Master of Science / Geology / Matthew W. Totten / Organic-rich shales were deposited over a large part of what is now North America during the Late Devonian. North America in the late Devonian was located in the tropics (Woodrow et al., 1973), possibly in low southerly latitudes (Heckel and Witzke, 1979; Witzke and Heckel, 1988; Streel et al., 1990). This environment creates an organic-rich environment that resulted in thick, black shales. The Devonian-Mississippian Chattanooga (Woodford) shale is known to be an important petroleum source rock in many intracratonic basins of the Midcontinent (Lambert, 1993). Geochemical analysis of the Chattanooga shale, using various techniques, provides additional information on oil-source rock potential. Handheld XRF analysis was conducted on well cuttings samples, Loss on Ignition (LOI) was performed on a subset of those samples and mapping of the organic matter results of the two methods was completed. Handheld XRF still has the prospect for providing quick analysis to infer organic matter content to be used as a determination of the quality of source rock. Although slightly reduced correlation has been found within this study compared to Willey (2015), the method has still proven viable for fracking targets to be determined on site and in a more efficient manner. Loss on Ignition results have correlated with TOC data better then XRF results, making this method the better option for evaluating source rock potential. Mapping of these results provide the first known source rock potential map across Kansas and can be used by the industry for future exploration.