Our assets in Oklahoma have been owned by Alta Mesa for over 25 years and are located in the eastern portion of the Anadarko Basin referred to as the STACK. The STACK is an acronym describing both its location—Sooner Trend Anadarko Basin Canadian and Kingfisher County—and the multiple, stacked productive formations present in the area. The STACK is a prolific hydrocarbon system with high oil and liquids-rich natural gas content, multiple horizontal target horizons, extensive production history and historically high drilling success rates. The fields were originally developed by Texaco, Exxon and Conoco and have historically been shallow-decline, long-lived oil wells originally drilled on 80-acre spacing and waterflooded to varying degrees.
Beginning in the early 1990s, our STACK operations were focused on vertical wells and waterfloods. Since late 2012, however, we have concentrated on the horizontal development of the Mississippian-age Osage and Meramec formations, as well as the Pennsylvanian-age Oswego formation. Generally speaking, these formations are made up of siliceous carbonate and have highly naturally fractured reservoir and geologic systems. We intend to further develop other formations with demonstrated vertical production, using horizontal drilling, including the Pennsylvanian-age Big Lime, Prue, Skinner, Red Fork and Cherokee Shale; Mississippian-age Manning Lime; Devonian-age Woodford Shale; and Silurian-age Hunton Lime. Given the predictable geology of the STACK formations, this allows for a repeatable drilling inventory. We have more than 1,000 identified drilling locations across four benches, with multiple upside locations possible through optimized spacing and targeting of additional producing horizons.
The STACK is among the lowest cost basins in the U.S. with asset quality comparable to the Permian. Alta Mesa is an efficient operator with a proven track record and focus on continuous improvement. We have worked diligently to reduce the drilling and completion costs per well thru operating and drilling efficiencies. We have doubled our STACK acreage position to over 130,000 net highly contiguous acres since January 2015, most of which are held by production. Our contiguous acreage positions allows for efficient field development through optimal spacing and pad drilling.
While legacy infrastructure systems in this area are extensive, the Kingfisher Midstream system has been purpose-built with capacity to accommodate higher individual well rates from horizontal wells and the anticipated significant growth expected from our use of multi-well pads. Kingfisher Midstream has a modern, efficient 60 MMCF per day cryogenic plant is expected to complete expansion to 260 MMCF per day in the first quarter of 2018.