As of 2013 the Cline Shale, also referred to as the "Wolfcamp/Cline Shale", the "Lower Wolfcamp Shale",[1] or the "Spraberry-Wolfcamp shale",[2][a] or even the "Wolfberry",[4] is a promising Pennsylvanian oil play east of Midland, Texas which underlies ten counties: Fisher, Nolan, Sterling, Coke, Glasscock, Tom Green, Howard, Mitchell, Borden and Scurry counties.[1] Exploitation is projected to rely on hydraulic fracturing.[5]
an organic rich shale, with Total Organic Content (TOC) of 1-8%, with silt and sand beds mixed in. It lies in a broad shelf, with minimal relief and has nice light oil of 38-42 gravity with excellent porosity of 6-12% in thickness varying 200 to 550 feet thick.[1]
The total recovery was estimated to 30 billion barrels in 2012,[6][7] and United States Geological Survey estimated the technically recoverable reserve to 20 billion barrels in 2016, the largest USGS estimate ever[8] and nearly three times larger than that of the 2013 USGS Bakken-Three Forks resource assessment in North Dakota.[9] The field also seems to contain 16 trillion cubic feet of natural gas.[9] This is the first assessment of continuous resources in the Wolfcamp shale in the Midland Basin portion of the Permian.[9] During the 1980s, vertical wells produced oil in the Wolfcamp area.[10] However, since 2000 in North America, horizontal drilling or porpoising along with hydraulic fracturing have grown tremendously and are tapping the continuous oil reserve.[10] In Odessa, Chris Schenk, a Denver-based research geologist and assessment team member, told KWES, "This oil has been known there for a long time -- our task is to estimate what we think the volume of recoverable oil is."[10][11] According to Morris Burns, a local oil expert and former president of the Permian Basin Petroleum Association, 50% to 60% is recoverable beginning at a price range of $60 to $65 per barrel.[11] This area is the largest continuous oil discovery in the United States and encompasses the cities of both Lubbock and Midland which are 118 miles apart.[8][9][12][b]
The Cline Shale is more generally referred to as the Lower Wolfcamp Shale. The Cline is a small part of the greater Wolfcamp Shale Formation.[3][14][15][c]