Master's Theses

Department

Geosciences

Degree Name

Master of Science (MS)

Abstract

Hydrocarbons are produced from different subbasins and stratigraphic intervals in Kansas. However, the geochemical characteristics and sources of these hydrocarbons are still poorly understood. While reservoir rocks, seals, and traps that are essential for petroleum systems are well defined within the state, the possible source rocks are often considered thermally immature, raising questions about their ability to generate the volume of hydrocarbons currently being produced. This research project tries to evaluate the geochemical characteristics of hydrocarbons produced in the state of Kansas and determine if the hydrocarbons from the different subbasins and stratigraphic units are genetically related. Thirty-seven crude oil samples were collected from five subbasins namely: Central Kansas Uplift (CKU), Hugoton Embayment (HUE), Salina Basin (SLN), Sedgwick Basin (SGB), and Forest City Basin (FCB). These samples were analyzed using Fourier-Transform Infrared (FT-IR) Spectroscopy and molecular geochemistry techniques such as Gas Chromatography (GC) and Gas Chromatography-Mass Spectrometry (GC-MS). Multivariate statistical tools such as Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) were also used to investigate correlations and covariations in the geochemical properties of the samples. The FT-IR analysis showed the presence of C-H, C-O, and C≡C chemical bonds in all analyzed samples, indicating compositional similarity. Slight variations in their absorbances suggested differences in the concentration of molecules in the samples. The GC and GC-MS results showed a Pristane/Phytane (Pr/Ph) ratio of 1.0 to 2.3, Naphthenes/Alkanes (NP/AK) ratio of 0.0 to 0.5, CPI of 0.9 to 1.1, and C29/C30 hopane ratio of 0.5 to 0.6 suggesting a shale lithology for the source rock that generated the hydrocarbons. Biomarker distribution ratios such as Pr/Ph ratio (1.0 to 2.3), C19/C23 tricyclic terpanes (0.0 to 2.1), Sterane/Hopane (0.1 to 1.1), as well as Pr/n- ii C17 vs. Ph/n-C18 plot, suggest a mixed marine and terrigenous organic matter input deposited under suboxic conditions. However, organic matter input for the FCB samples is questionable due to the near absence of isoprenoids. Based on predominance of n-C15, n-C17, and n-C19 together with minimal C20+ carbon atoms, the FCB samples are interpreted to be of Ordovician age. Multivariate statistical analysis of geochemical parameters revealed that the hydrocarbons from the Central Kansas Uplift, Hugoton Embayment, Salina Basin, and Sedgwick Basin are genetically related irrespective of producing stratigraphic intervals. The hydrocarbons from Forest City Basin were interpreted to have been generated from a different source rock, thereby indicating multiple source rocks for the hydrocarbons being produced in Kansas.

Keywords

Petroleum, Geochemistry, Oil-Correlation, Biomarker, Chemometric

Advisor

Dr. Henry Agbogun

Date of Award

Spring 2025

Document Type

Thesis

Rights

© The Author

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