Remote Sensing of Hydrocarbon-induced Rock Alterations at Cement Field, Oklahoma

This study uses satellite- and ground-based remote sensing techniques to detect hydrocarbon-induced rock alterations at the Cement oil field, Oklahoma. Hydrocarbon seepage is the escape of oil and gas from petroleum reservoirs and their upward-migration to the surface. These hydrocarbons at the surface can generate rock alterations, including mineralogical changes, bleaching of red beds, and clay mineral alterations. Surficial expressions of such alterations are distinct from adjacent rocks, and could be detected by remote sensing techniques. The Cement field is a giant oil and gas field located in the southeastern Anadarko basin in Oklahoma. The surface structure is a northwest-trending, elongate and asymmetrical anticline. This field has been reported to have heavily altered surficial rocks. Loss of iron and impregnation of sandstone by carbonate cements, and replacement of gypsum by calcite, are the major alteration phenomena in this field. Remote sensing data hold great potential to characterize rocks with great precision and fine detail. This study identified outcrops with surficial rock alterations from Landsat 8 and ASTER multispectral data, as well as Hyperion and Specim hyperspectral imagery. Published geologic maps and geochemical data were combined to show the geologic extent and various degrees of rock alterations. Petrographic analysis showed bleaching and cementation of sandstones, as well as crystallization gradient of gypsum samples. Laboratory spectroscopy was used to assist with image classification. Principal component analysis, minimum noise fraction, spectral angle mapper, and band ratios are used in image processing. Remote sensing data detected bleaching and carbonate cementation. Combining lithological, remote sensing and geochemical data, this study built a model for petroleum seepage and related rock alterations, and provides a workflow for employing remote sensing techniques in resource exploration.