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SEISMIC ANALYSIS OF THE ARBUCKLE GROUP IN THE PATTERSON AND HARTLAND FIELDS, WESTERN KANSAS
Ajobiewe, Adeniyi
Ajobiewe, Adeniyi
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Abstract
The Cambrian-Ordovician Arbuckle Group is the thickest of all candidate CO2 storage zones at the Patterson site, involving the Patterson and Hartland fields, in Western Kansas. The Arbuckle Group is laterally extensive and highly heterogenous, consisting mainly of dolomite with scattered beds containing chert and sand. The Patterson Site has been evaluated for its potential for Carbon Capture Utilization and Storage (CCUS). However, previous characterization studies of the Patterson Site have suffered the lack of available subsurface data (e.g., 3-D seismic data and well logs) targeting the Arbuckle Group. In this study, two recently acquired 3D seismic surveys along with two new deep wells were utilized to carry out seismic characterization of the Arbuckle Group employing post-stack (model-based) and pre-stack simultaneous AVO inversion methods. Two new 3D seismic surveys were acquired over the Patterson and Hartland fields, and two new wells, Patterson KGS #5-25 and Hartland KGS #6-10, were drilled for this project, adding to the only deep well in the area: the Longwood well. Each of the new seismic surveys consists of 3D pre-stack time migrated gathers and 3D post-stack PSTM data. The Patterson and Hartland post-stack seismic were tied to their corresponding well data to establish a time-depth relationship. This seismic-to-well tie process showed the Arbuckle top to be a weak reflector located at ~1024-1040 ms TWT in the Patterson seismic and ~1050 ms TWT in the Hartland seismic data. Additionally, the well tie process revealed both seismic surveys to be of reverse polarity. Seismic data were analyzed using the post-stack 3D volumes and the pre-stack gathers following methodologies commonly employed in reservoir characterization studies. Post-stack model-based and simultaneous AVO inversion methods yielded 3D impedance inversion volumes from the pre-stack time migrated seismic data. The two impedance volumes delineate the top of the Arbuckle group better than the reflection amplitude seismic which do not produce a distinct top of the Arbuckle reflection. The P-impedance volume generated through simultaneous AVO inversion showed better correlation with original P- impedance well logs, and lower RMS error than that obtained from the post-stack inversion. In most areas in the Patterson and Hartland fields, the inversion results show a lower impedance upper Arbuckle and a higher impedance lower Arbuckle zone. Measured borehole observations of porosity and density show lower densities and higher porosities corresponding with the low impedance upper Arbuckle zones, while the high impedance lower Arbuckle correlates to high borehole measured density and lower porosity values of the lower Arbuckle. Using the seismic impedance volumes of the Patterson and Hartland data, upper and lower Arbuckle thickness maps were generated to help identify areas that can potentially hold large volumes of CO2 in place. Based on the criteria of high thickness and high porosity (implied from low impedance), areas within the upper Arbuckle were identified in both fields that have good potential for CO2 storage.
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Date
2022-12-31
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University of Kansas
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Keywords
Geophysics, Geology, carbon capture utilization and storage, Pre-stack gathers, Seismic inversion