Oil Seep/Slick Identification and Characterization
Oil seeps are well known all over the world and ancient references to hydrocarbon seepages date back to earliest recorded history. Over the years. natural hydrocarbon seeps have provided a useful tool for petroleum exploration. Hydrocarbon seepages cause surface or subsurface alterations to soil, forests, lakes, rivers and sea that make it possible to detect them using different direct or indirect exploration methods.
In offshore areas such as the deep waters of Brazil, West Africa and the Gulf of Mexico, it is not uncommon for oil emanating from source rocks to bypass natural trapping mechanisms and leak upward to the seafloor and the surface of water. In addition, entrapped oil may also escape and rise to the surface via conduits such as fractures and faults. Identifying these natural seeps and slicks can prove invaluable to explorers looking for indications of a hydrocarbon source systems in frontier exploratory areas.
When analysed by high-resolution geochemistry, natural oil seeps/slicks are a unique tool for frontier basins, indicating the presence of active petroleum systems in the areas and providing an array of decisive information to oil and gas exploration. Via a combination of high-resolution geochemical methods, oil slicks and oil seeps can yield clues regarding hydrocarbon origin, type and age, as well as the thermal evolution of the source rocks. Without such systems, oil accumulations cannot occur.