FIELD-BASED HYPERSPECTRAL DETECTION OF VEGETATION RED EDGE SHIFT RELATED TO HYDROCARBON MICROSEEPAGE IN MARINER FIELD, HANCOCK COUNTY, MISSISSIPPI

Mariner field is a shallow gas reservoir in Hancock County, Mississippi. The reservoir rock is a 35-40 foot unit of quartz sand at a depth of approximately 4,000 feet. The study area is located in the buffer zone of the John C. Stennis Space Center, in Hancock County, Mississippi.

The goal is to determine if an area of hydrocarbon microseepage can be located by conducting a field-based hyperspectral survey of the area. Pine needles and myrtle leaves have been collected and analyzed using a spectrometer to determine the vegetative stress, as indicated by a shift in the red edge of the spectrum to shorter wavelengths. Samples were collected along a traverse of approximately 2.5 miles, running at right angles to the strike of the field. At each location, leaves from multiple plants were collected.

Two sets of plots of the red edge wavelength against latitude, which corresponds approximately to sample locations along the traverse, were made. One shows the red edge wavelength of every leaf collected, while the second shows an average of multiple leaves collected at the same site. Both plots show considerable scatter but suggest a decrease of approximately 2 nm (nanometers) for locations near a producing gas well. When all leaves are plotted, a line delineating the highest values for the red edge location can be identified by visual examination. These highest values are interpreted as representing the healthiest vegetation. Similar decreases are suggested by both this line and the plot of average values. The decreased values are present for about 0.4 miles on either side of the well.