Located in northern Oklahoma, The STACK play has yielded impressive results since its initial exploration in 2011. Named for its geological region, the STACK includes the Sooner Trend, Anadarko Basin, Canadian County, and Kingfisher County. The play is also aptly named since it contains multiple stacked intervals of producible formations that can be accessed from a single drilling location.
The core area of the STACK spans approximately 1,000 square miles contained in the roughly 70,000 square miles of the Anadarko Basin in Oklahoma. Advancements in horizontal drilling have extended the core area of the STACK from Canadian and Kingfisher counties to include Blaine County and Dewey County. While this has created more opportunities for families to sell their mineral rights, research continues to expand the STACK play as more wells are being drilled.
What STACK Reservoirs are Most Productive?
When analyzing the STACK play, you will find two primary reservoirs – the Meramec and the Osage. These formations have distinct targets that utilize different sequence lithostratigraphic and stratigraphic intervals based on specific characteristics. In most cases, these Mississippian units are characterized by their mixed carbonate and siliciclastic system, including interbedded lithology changes.
The Meramec reservoir was deposited approximately 320 to 360 million years ago. During this time, the mid-continent region was roughly 20 degrees south of the equator and was covered by a shallow, warm sea. As you might imagine, this environment was optimal for superficial marine water deposits throughout the Anadarko Basin. The geometry of this area was majorly influenced by paleotectonic activity that controlled the rate of erosion, structure accumulation, and sediment deposition. Today, the primary units are primarily composed of calcareous and argillaceous siltstones.
The Osage reservoir was formed during times of aerial exposure. Deposited sponge and spicules found in elevated silica marine waters led this area to be dominated by chert-rich packstones and grainstones. Osage intervals are primarily characterized by low clay content and progradational and aggradational stacking patterns. In most cases, Porosity will be higher in the Meramec than in the Osage or the approximately eight other formation targets, like the Oswego, Morrow, and Red Fork.