The Greenwood gas field of Morton County, Kansas, Baca County, Colorado, and Texas County, Oklahoma, is on the west flank of the Hugoton embayment of the Anadarko basin where porous Upper Pennsylvanian (Virgil) limestone beds grade westward to impermeable limestone and clastic rocks, creating a major stratigraphic trap for gas. The Greenwood gas field is on a monoclinal feature north of the Cimarron uplift. The shallow-water environment of deposition resulted in optimum conditions for the development of porosity and permeability in the limestone reservoir beds.

The field was discovered in October 1952 after seven tests through the Virgil gas zones had failed to find this major shallow accumulation. As of the end of 1963, 275 gas wells had been drilled, proving an area of about 214,000 acres (Hilpman et al., 1964, p. 152) and recoverable gas reserves of about 1 trillion cu ft.

Development drilling has been active from 1952, and lately new extensions in Texas County, Oklahoma, have shown significant enlargement of the Greenwood gas field into the Oklahoma Panhandle.