Cabot Oil & Gas ( COG ) had some interesting comments about the Bossier Shale and the Haynesville Shale on their latest conference call 10/30/08. They are basically comparing the two formations which are on top of each other. Please note: the Cotton Valley formation is on top of that.
This is a lengthy read but well worth it! In short, they think the Bossier Shale is better then the haynesville shale despite the haynesville getting more press.

David Heikkinen - Asking the Questions on the Conference Call
Basically just thinking about the Bossier versus the Haynesville and trying to frame up depositional environment and consistency in the Bossier shale as you move into your acreage, I know there isn't the Haynesville and County Line, but just trying to understand consistency and kind of properties? And then next on the Lime, normally it's too tight, so is there a cutoff as far as what you're seeing with the horizontal Lime well that you drilled, just trying to understand that too?
Dan Dinges - President & CEO giving the Answers
David, we have drilled numerous deep data points that are giving us Bossier/Haynesville shale information. We are seeing the Haynesville shale, you will extend overall of Cabot acreage. It is not as thick as we would see over in Louisiana. But the properties, the gas content, so on are the same. More importantly from our perspective is that we are seeing what we're calling the middle and upper Bossier as very thick, very gas charged. We are producing a well right now from the upper Bossier shale at nearly 3 million a day.
We talked about it earlier at Trawick at the last conference call that well is actually improving. We're confident that our horizontal Bossier shale which is in the middle Bossier interval is drilled in shale that is rich in silica and quartz and in carbonate, low in clay content. This shale should stimulate very effectively, probably better fract if the efficiency that you might see in the more play rich Haynesville shale.
And I think some of the anecdotal evidence that we've seen from some of the other operators suggests that this middle and upper Bossier which may not be getting the big press that we're seeing from Louisiana is going to be a significant contributor to the entire Bossier shale play in East Texas. So right now we're very optimistic on what we've seen so far both from rock properties in the Bossier and Haynesville shale as well as the production and test rates and gas contents that we've seen to-date.
David Heikkinen
So really, just trying to summarize you guys testing the Bossier and favoring it, it's really the economics of the Bossier because it's thicker and the Haynesville thinned out. It's not that you're not seeing Haynesville. It's just thinner so your economics are better in the Bossier on your acreage probably than they would be in the Haynesville?
Dan Dinges
Well, we have seen some data that suggests now from vertical wells and I think that these are horizontal plays, we have seen some data from vertical wells from the big thick Haynesville shale, big thick 200 feet thick or more that the initial rates after frac are not all that big. I mean a million a half a day.
So you can say that where we're drilling, although it is thinner, the similar type of rates had been established by up in the Minden area with a well that was drilled by the former operator of the property that was bought. So we think that there's still a lot of upside left in the Haynesville even though it is thinner over in the Minden area.
David Heikkinen
Okay. So maybe I'm reading too much into your decision to test the Bossier and the Lime first. It sounds like you're going to test the Haynesville on your acreage as well as beyond just the vertical well?
Dan Dinges
Absolutely we are.
David Heikkinen
So can you give any thicknesses as far as what the Haynesville and Bossier are on your acreage as you move to the South?
Dan Dinges
We're seeing the Bossier and we don't break it out into the so-called Haynesville. I don't buy the terminology. It's all Bossier. It's between 750 and 1000 feet thick and it's all gas charged.