The Incredible Growth of Shale Gas – What’s Geoscience Got to do with it?
DeGolyer and MacNaughton, Dallas, TX, [email protected]
Although shale gas has been produced since the 1820s, only in the last few years has it become mainstream with the development of the Barnett, Fayetteville, and Woodford shales in Texas, Alabama, and Oklahoma, respectively. Shale gas is often considered to be a technology play given the need to drill and complete wells effectively for economic production. However, there are multiple geological, geochemical, and petrophysical parameters that must be favorable for these plays to work. Among them are thickness, gas saturation, porosity, matrix permeability, thermal maturity, gas generative potential, lithofacies types, and in-situ-stress regimes. This paper compares these parameters on a play-by-play basis and discusses the depositional, diagenetic, and structural factors that control them. In addition, existing shale gas developments are contrasted with new shale gas plays in the Marcellus (NE U.S.) and Haynesville (Texas-Louisiana). Recent work has shown that the "Barnett Model" is not the only successful play type. The combination of greater depth, higher overpressure, interparticle porosities, and much higher matrix permeabilities in the Haynesville contribute to initial well rates that are 3 to 10 times higher than Barnett wells.
AAPG Search and Discovery Article #90088©2009 Pacific Section Meeting, Ventura, California, May 3-5, 2009