The Northern extension of the "COMBO" Barnett Shale is located primarily in Montague, Cooke, and Clay counties in the North Texas region. This play is unique in that the shale in the area is very rich in total organic content (TOC) and contains a relatively high concentration of carbonates throughout. This extension is primarily inside the the oil window of the Barnett, rather than predominately within the more gas-rich region, which dominates the rest of the shale's development throughout North Texas (See Figure 1). Some of the earliest technological enhancements in oil production from shale occurred in the COMBO Barnett play, prior to the expanse and relative boom of the Eagle ford shale, and many other successful unconventional oil shale plays throughout the industry, both domestic and international. The Barnett in this area is typically quite thick, with sections from 300-700 feet. In some cases, naturally occurring fractures are fairly evident and can be identified through the use of image logging, prior to the completion phase of a well. Some areas may exhibit limited natural fractures, but have very brittle rock. Vertical completions were dominate during the early development of the Barnett, constituting a vast majority of oil and gas wells in production within the region. In fact, measureable time in production for the wells in the area indicated that properly completed vertical wells had respectable economics, which were later, at times, enhanced with horizontal drilling and multi-stage frac completions and re-completions.

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