David G. Hill¹, Charles R. Nelson²

(1) Gas Technology Institute, Chicago, IL
(2) TICORA Geosciences, Inc, Arvada, CO

ABSTRACT: Multi-Basin Comparison of Gas Productive Naturally Fractured Shale Plays

Shale is the most commonly occurring type of sedimentary rock and worldwide is recognized as being the most important petroleum source rock type. A significant volume of natural gas is being commercially produced from naturally fractured shale plays in several U.S. basins. These fractured shale gas reservoirs currently supply 1.9 percent (0.38 Tcf) of total annual U.S. dry natural gas production and contain 2.3 percent (3.9 Tcf) of total U.S. proved natural gas reserves. The gas-in-place resource estimates for the five main U.S. gas shale plays total 581 Tcf, and the recoverable resource estimates for these five plays range from 31 to 76 Tcf. From an economic perspective the key advantages of shale gas plays are moderate exploration costs, high success rates and slow production decline rates.

Shale gas production in the U.S. has historically been associated with the Devonian age Ohio shale in the Appalachian Basin. Today, the roster of commercially productive shale gas plays also includes the Antrim Shale in the Michigan Basin, the New Albany Shale in the Illinois Basin, the Barnett Shale in the Fort Worth Basin, and the Lewis Shale in the San Juan Basin. Experience over the past twenty years has demonstrated that every gas shale play is unique and must be examined, explored and exploited differently. This paper presents a comparison of the geologic properties of these five gas productive naturally fractured shale plays. Shale gas resources also exist in many other basins and considerable potential may exist for significant new play discoveries.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado