Petroleum play

Petroleum play is an industry term that refers to the exploration and extraction of oil reserves from a region. The normal steps in the play cycle are:
#Initial observations of a possible oil reserve
#Testing and adjustments to initial estimates of extraction
#High success in locating and extracting oil from a reserve
#Lower success as the reserve is depleted
#Continued decrease in further exploration of the region

A particular stratigraphic or structural geologic setting is also often referred to as a play. 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, explorationists 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.

A play may also refer to a broad category of possible reservoirs or rock types, as in the "turbidite play" of offshore Angola or the carbonate play in the East Java Sea, or to the structural geology of the setting, as in the "sub-upthrust play" of Wyoming. Sometimes the word play is applied to a geographic area with hydrocarbon potential, as the South Texas play or the Niger Delta play, but usually "play" is used with the sense of restricting discussion to exploring a particular geologic setting. Thus, one might have both the Wilcox play and the Norphlet play (among others) in partially overlapping areas of the coast of the Gulf of Mexico; the "Gulf of Mexico deep-water play" might or might not include elements or particular locations appropriate to either the Wilcox or the Norphlet, or both. The term is one of convenience for discussion, and may refer to geologic time intervals, rock types, structures, or some combination of them.