The Permian-aged Wichita Albany group is a combined marine limestone and shale unit. It is found at depths of 2,013 to 2,345 metres (6,605 - 7,700 feet). First production from the Wichita Albany dates back to the 1960's when the Running W. Field was discovered in Crane County, Texas. Historical vertical development involved completing the shallower Wichita with deeper Devonian targets. Deeper targets were routinely drilled first.