In addition to vitrinite reflectance values not being fixed for oil generation all oil-prone typeII kerogen, Lewan GeoConsulting is also aware that there are two different trends for vitrinite reflectance with thermal maturity, the common trend is the coal trend that is assumed in most models. The suppressed trend show a much lower relationship to thermal stress. Lewan GeoConsulting has experience with determining which trend a given source rock will follow based on small-scale hydrous pyrolysis. Although the cause of this suppressed trend remains controversial, the small scale hydrous pyrolysis is a quick way to determine which trend a source rock follows.
