As the Barnett breaks the twenty thousand well threshold, and the Bakken and Eagle Ford rapidly approach ten thousand wells – we are gaining increased insights into the lifecycle of unconventional plays. Currently, the vast majority of active drilling rigs are deployed in one of about a dozen unconventional plays (Figure 1). Following historic wisdom of finding oil (and gas) where it has been found before, development activities are currently focused upon some of the oldest conventional fields (e.g. Permian 1921, Bakken 1957, Niobrara 1876) or established petroleum systems (e.g. Eagle Ford, Woodford, Marcellus). While geologically diverse, these and other analogue plays share a common trait of poor natural petroleum flow characteristics (i.e. low permeability) requiring the application of unconventional engineering techniques including one or more of: horizontal drilling, hydraulic fracturing and pad drilling support of proximal and multi-formation targets.

As the archetype unconventional play, the 33-year-old Barnett Shale development in the Fort Worth Basin defines mature production, with well spacing commonly approaching 250 feet. Other active plays combine to define a full spectrum of maturity from unconventional exploration through development. Data availability largely defines workflow focus and detail as unconventional plays evolve from prospect through optimized producing fields.

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