Remote Sensing

Natural oil and gas seeps have historically provided invaluable information to oil explorationists. Foremost, they indicate the presence of generative hydrocarbon source rocks, without which there can be no accumulations. The high cost of offshore exploration has made the identification of seeps a well-accepted risk assessment methodology. The use of spaceborne synthetic aperture radar (SAR) systems is invaluable for the detection of natural oil seeps in the ocean. It is the most cost-effective tool available in the market, particularly if compared with the traditional procedures of ocean in situ sampling using ships. SAR works by emitting, and then measuring, reflected microwaves. Unlike optical sensors, microwave energy penetrates clouds, rain, smoke, dust, or haze, enabling SAR systems to collect data under any atmospheric condition.

RADARSAT-1 is the best spaceborne remote sensing technique for detecting ocean surface features in frequently cloud-covered marine areas such as the Espírito Santo, Campos and Santos basins offshore south-eastern Brazil. However, with regard to radar-imaging, the suppression of the wave backscatter is unfortunately not unique to the presence of oil. False targets include wind shadow, natural surfactants, local upwelling, shallow marine vegetation, and areas of heavy rainfall. GSI circumvents these pitfalls using a proprietary textural classification algorithm than enhances ocean surface features related to natural and man-made oil slicks in RADARSAT-1 data.