The future of stacked horizons in oil and gas got a little brighter in October when Newfield Exploration Co. (NYSE: NFX) announced the “Stack” play in Kingfisher County, Okla., an extension to the north and east of its legacy position in the Cana Woodford in Kingfisher and Canadian counties, the latter of which provides the “Cana” in the Cana Woodford name.
The Stack now joins the SCOOP in an iconic lexicon of newly branded Anadarko Basin plays, demonstrating that Oklahomans certainly know how to market geology.
The Stack is a name, Newfield says, that originates from the “stacked” formation potential that describes opportunity in the multi-layered Anadarko Basin. A main Stack target is the upper Meramec Formation in the lower Mississippi Lime, which is stratigraphically separated from the underlying Woodford shale by the intervening Osage. The vertical column resides from 8,000 to 11,000 feet below surface across the play and includes in ascending order the Hunton, Woodford, a thin Osage section, and the lower and upper Meramec. Specific hydrocarbon targets are found in 700 feet of oil-saturated limestone with the Meramec accounting for up to 475 feet of that column.
Carbonates are traditionally a hard rock to crack in oil and gas exploitation since conduit channels are naturally cemented. The Meramec is no exception with Newfield estimating porosity at 3% to 6%. Natural fractures, or faults, serve as storage space for oil migrating into the formation from source rock like the underlying Woodford shale.
Elsewhere, operators have found success in carbonate plays like the legacy Austin Chalk and, more recently, the Buda or Marmaton by drilling horizontally to intersect as many fractures as possible. And that is what Newfield is doing. The company has adapted a horizontal approach it pioneered in the Arkoma Woodford dry gas play known as SXL drilling, or super-extended laterals , to its Stack objectives.
The company is also targeting the underlying Woodford via the SXL technique with lateral lengths up to a Bakken-like 10,000 feet, which is comforting news for geo-steering service providers.
The Meramec is part of the lower Mississippi Lime, which developed in a sub-tropical shallow shelf environment roughly 350 million years before present. An ensuing collision of the South American plate forced downwarping during later Mississippi times, generating a deeper basin into which sediments flowed, creating the Barnett and Fayetteville shales in the overlying upper Mississippi.
Consequently, the Stack reflects a shelf