In geology, a petroleum play, or simply a play, is a group of oil fields or prospects in the same region that are controlled by the same set of geological circumstances.
[1] The term is widely used in the realm of exploitation of hydrocarbon-based resources.
For example, in a relatively unexplored area (such as the Falkland Islands) one might speak of the "Paleozoic play" to refer to the potential oil reserves that might be found within Paleozoic strata.
In a well-explored basin such as the Gulf of Mexico, explorers refer to the "Wilcox play" or the "Norphlet play" to collectively designate the production and possible production from those particular geological formations, of Paleocene and Jurassic age respectively.
The term is one of convenience for discussion, and may refer to geologic time intervals, rock types, structures, or some combination of them.