Summary
It is said that "a picture is worth a thousand words". A movie must be worth considerably more. Petroleum generation is something that perhaps everyone connected to the oil industry has thought about and many petroleum geochemists have spent their lives studying. Until now, the closest we have come to actually visualizing the process is computer models. The advent of the Environmental Scanning Electron Microscope (ESEM) has changed this. Using an ESEM and a programmable heating stage we can actually see and record the petroleum generation process under laboratory conditions. Accordingly, we have made the first ESEM movie of petroleum generation from an immature Kimmeridgian Clay core sample from the North Sea by heating the sample under the stage in the presence of water vapor to enhance the image. The result can be seen at: http://www.youtube.com/watch?v=lISNwF5tMXM. Processes observable in the movie include the creation of porosity and permeability via: (1) the conversion of solid kerogen to a mobile phase which migrates out of the pores and (2) the formation of cracks along bedding planes which can be seen to open due to pressure created by kerogen-to-gas and oil-to-gas generation. Interestingly, these processes were either not observed or are much diminished in lower TOC samples (1-2%). This emphasizes that, in addition to volumetrics, high-quality source rocks initiate many important processes necessary for viable unconventional and conventional plays, e.g. creation of porosity and permeability in the source enhancing primary migration, creating overpressuring enhancing production and possibly fracturing the source rock to facilitate migration both within and perhaps out of the source rock
