Mississippian Barnett Shale, Fort Worth basin, north-central Texas: Gas-shale play with multi–trillion cubic foot potential

TLDR

The Mississippian Barnett Shale in the Fort Worth basin of north‑central Texas functions as source, seal, and reservoir for a world‑class unconventional natural‑gas play, but its low permeability and complex lithology require artificial stimulation, and production is currently confined to the thick, organic‑rich, thermally mature northern basin where the Newark East field dominates. Attempts to expand the Barnett play beyond Newark East have been hampered by increasing oil saturation to the west and north and by the absence of lithologic barriers that would limit induced fracture growth. Newark East covers 400 mi², hosts over 2,340 wells, and contains about 2.7 tcf of booked gas reserves, with cumulative production reaching 0.8 tcf by 2003 and individual wells producing 0.5–4 mmcf/day at ~7,500 ft, yielding ultimate recoveries of 0.75–7.0 bcf per well.

Abstract

The Mississippian Barnett Shale serves as source, seal, and reservoir to a world-class unconventional natural-gas accumulation in the Fort Worth basin of north-central Texas. The formation is a lithologically complex interval of low permeability that requires artificial stimulation to produce. At present, production is mainly confined to a limited portion of the northern basin where the Barnett Shale is relatively thick (>300 ft; >92 m), organic rich (presentday total organic carbon > 3.0%), thermally mature (vitrinite reflectance > 1.1%), and enclosed by dense limestone units able to contain induced fractures. The most actively drilled area is Newark East field, currently the largest gas field in Texas. Newark East is 400 mi 2 (1036 km 2 ) in extent, with more than 2340 producing wells and about 2.7 tcf of booked gas reserves. Cumulative gas production from Barnett Shale wells through 2003 was about 0.8 tcf. Wells in Newark East field typically produce from depths of 7500 ft (2285 m) at rates ranging from 0.5 to more than 4 mmcf/day. Estimated ultimate recoveries per well range from 0.75 to as high as 7.0 bcf. Efforts to extend the current Barnett play beyond the field limits have encountered several challenges, including westward and northward increases in oil saturation and the absence of lithologic barriers to induced fracture growth. Patterns of oil and gas occurrence in the Barnett, in conjunction with maturation and burial-history data, indicate a complex, multiphased thermal evolution, with episodic expulsion of hydrocarbons and secondary cracking of primary oils to gas