Redefining the STACK Play From Sub-Surface to Commercialization: Identifying Stacked Pay Sweet Spots in the Northern Anadarko Basin

Abstract

Independent unconventional specialist companies continue to be drawn to the STACK (Sooner Trend, Anadarko Basin, Canadian and Kingfisher counties) play of northern Oklahoma. Situated in the northern portion of the Anadarko Basin, the STACK play boasts stacked pay potential from at least five major reservoir units, all of which contain varying amounts of oil and gas reserves. To date, just over 2,000 horizontal wells have been brought online in the greater STACK area, and estimated break-evens for many of these earlier wells fall below $30 per barrel. The early core of the play covers approximately 3,500 square miles in Southwestern Kingfisher County, Oklahoma and nearby areas in Canadian, Blaine and Dewey Counties. Here, operators have focused on the Mississippian age Meramec Formation, with average peak month rates approaching 800 boe/d (6:1) in early 2017. Further, estimated ultimate recoverable volumes (EURs) for Meramec horizontals are approaching 1 Mmboe (6:1), making it competitive with the prolific Bone Spring and Wolfcamp Delaware plays, which have estimated EURs around 1 Mmboe (6:1) and 1.2 Mmboe (6:1), respectively. As the STACK play develops, unconventional experts are also succeeding in secondary reservoirs that have historically been developed using conventional vertical well completions, namely the Hunton, Woodford, Osage, and Oswego. Delineation and de-risking of these additional horizontal targets has not advanced as quickly as the Meramec; however, peak month rates in these secondary reservoirs have been on par with the Meramec. Multiple horizons in the STACK play allow for stacked horizontal development–similar to what is taking place in the Permian today, where operators enjoy economic advantages from concentrated operations. In addition, operators have extended STACK success into nearby areas and renamed some areas as individual plays. This study serves to detangle the Silurian-Pennsylvanian aged stacked pays in the Anadarko Basin by standardizing the stratigraphic nomenclature, to accurately identify commercial inventory and localized well productivity by reservoir. Further, integration of geological, economic, production and completion data from each of the pay zones throughout the greater STACK area aides in identifying production drivers and inhibitors, which enables more accurate prediction of total STACK resource and future production growth potential of the STACK play and surrounding areas.

AAPG Datapages/Search and Discovery Article #90323 ©2018 AAPG Annual Convention and Exhibition, Salt Lake City, Utah, May 20-23, 2018