Chapter 11: Airborne Hyperspectral Detection of Natural Offshore and Onshore Hydrocarbon Seeps
Alfredo Prelat, Sepalika Gunaratne, Laura Huebner, Clint Freeman, Allan Cook, Christopher Soriano, 2013. "Airborne Hyperspectral Detection of Natural Offshore and Onshore Hydrocarbon Seeps", Hydrocarbon Seepage: From Source to Surface, Fred Aminzadeh, Timothy B. Berge, David L. Connolly
Download citation file:
Hydrocarbon seeps occur naturally in many places, including onshore, offshore, and along the coast of Santa Barbara and Ventura counties in southern California. Existing seep-mapping projects include Santa Barbara County’s Natural Seep Inventory and the University of California Santa Barbara’s Bubbleology Coal Oil Point interactive explorer. Organic compounds typically associated with reservoir hydrocarbons are often recognized at or near the surface. Direct and indirect detection of these compounds and their associated (alteration) phenomena are a primary means of establishing the presence of an active or previously active petroleum system. Surface hydrocarbons can be detected by hyperspectral remote-sensing techniques. Hyperspectral data were collected over the Santa Barbara area onshore and offshore by gravity and magnetic surveys. The hyperspectral sensors collected data spanning the visible, near-infrared, shortwave-infrared, and thermal-infrared portions of the electromagnetic spectrum. Images were viewed using false-color infrared composite with different enhancement levels for preliminary hydrocarbon identification at various locations in the imagery. Spectral signatures from the airborne hyperspectral data, combined with field spectroradiometer measurements of known seeps, were used to create a spectral library. Numerical classification techniques identified known and previously unknown occurrences of hydrocarbons. Magnetic and gravity surveys were acquired simultaneously and were used to map major geologic trends and structures in relation to the presence of seeps. The occurrence and distribution of detected seeps provided direct evidence of the presence of an active petroleum system.
Figures & Tables
With the increased resolution power of many geophysical methods, we are seeing direct evidence of seeps on a wide variety of data, including conventional seismic. New methods and technology have also evolved to better measure and detect seeps and their artifacts and reservoir charge and to map migration and remigration routes. In addition, detection of seepage is important for minimizing the risks associated with shallow gas drilling hazards, ensuring platform stability, and preventing well blow-outs.