An article was published today (click here to view) promoting the Wolfcamp/Wolberry shale play. They say that Approach Resources calls it a "source rock that is world class and says it has mineral composition and lithology similar to the Eagle Ford."
El Paso Exploration compares the Wolfcamp with the Eagle Ford play and says it has twice the net thickness and twice the carbon content. They also say that the carbon content of the Wolfcamp is about 60% of the Bakken but has thickness that is multiples of the Bakken.
This is a good article that briefly summarizes many of the companies exploring the Wolfcamp/Wolfberry shale play.