- Timing. Timing with regard to conventional hydrocarbon accumulations is a critical factor that may be overlooked. First, when speaking of time, remember we're talking about geologic time which is measured in millions of years. What may seem an obvious sequence but is sometimes overlooked, is that the source rock must be mature in generating hydrocarbons prior to those hydrocarbons migrating. Further, the trap either structural or stratigraphic, must be formed before hydrocarbons can be migrated and stored within it. Further still, that trap, again either structural or stratigraphic, must maintain its integrity until such a time that it is produced. Timing is normally an issue that is checked-off early in an exploration plays history. This means that early prospects drilled into play will define whether or not timing has been correct, or isn't correct. If it is correct for an early play or early prospect, it will most probably be correct in later prospects drilled in that greater area.