Resource Play Exploration and Exploitation: Geochemical techniques for identifying gas and oil resource plays and prospects
Daniel M. Jarvie, Humble Geochemical Services, Humble, Texas
Resource plays are basically hydrocarbon systems where the source and reservoir are the same rock unit or formation. These source-reservoir units are generally continuous and represent areas of organic matter preservation as reflected in organic richness. These plays are typically for shale gas, but may also include shale oil plays. Evaluation of these plays suggests that there are several different types of hydrocarbon system that may be described as (1) tight, high gas flow rate thermogenic, (2) fractured, lower flow gas rate thermogenic, (3) interbedded shale/tight sand or silt thermogenic gas systems, and (4) fractured, lower gas flow rate biogenic. Shale oil resources are found in at least two types of systems both being in the oil generation window: (1) highly fractured systems and (2) relatively tight systems of interbedded source and tight gas or silt zones. In either case of shale gas or oil, completion engineering is a critical component of extracting the gas or oil from these systems.
Various hydrocarbon systems are used to illustrate these play types, e.g., the high maturity thermogenic plays of the Ft. Worth, Delaware, and Arkoma basins, the low maturity thermogenic plays of the Illinois Basin, the interbedded shale/reservoirs of the Bossier Shale of the East Texas Basin, and the biogenic Antrim Shale play of the Michigan Basin. The Monterey Formation of the Santa Maria Basin and the Williston Basin Bakken Formation oil play provide examples shale oil systems.