Barnett Shale gas production, Fort Worth Basin: Issues and discussion

TLDR

The Barnett Shale field in the Fort Worth Basin is Texas’s most productive gas field, growing >10% annually, yet production is hindered near faults and structural flexures where abundant fractures are detrimental, and the shale is slightly overpressured and thermally mature with limestone beds formed from debris flows. The study proposes using the Barnett as an exploration model for other basins, particularly those on the Ouachita trend.

Abstract

Newark East (Barnett Shale) field, Fort Worth Basin, Texas, is currently the most productive gas field in Texas in terms of daily production and is growing at an annual rate of more than 10%. However, despite the fact that the Barnett play has been studied intensely by very capable geologists and engineers from several companies over a period of many years, there continues to be several misunderstandings concerning fundamental factors controlling the success of the Barnett play of north Texas. Barnett gas production is poorer in areas near faults and structural flexures (anticlines and synclines). Fractures, which are most abundant in these structural settings, are detrimental to Barnett production. Open natural fractures are rare in the Barnett and have little or nothing to do with Barnett productivity. In areas where Barnett Shale is thermally mature with respect to gas generation, it is slightly overpressured (about 0.52 psi/ft [11.76 kPa/m]). Limestone beds within the Barnett formation are the product of debris flows that originated on a carbonate shelf to the north of the present basin center. It appears that the Barnett can be used as an exploration model for other basins, especially analogous basins of the Ouachita trend. The history of the development of the Barnett reservoir in north Texas provides an excellent example of how persistence can lead to success in nonconventional gas plays.