 How do the break-even costs associated with shale energy development affect its overall development? The overall economics of a shale energy project, whether it's an oil or gas well, are going to depend really on two pieces. You have those costs to drill, complete, and produce from the well, and a lot of those costs are fixed. And then you have the other side, which is the revenues that you're going to earn from selling oil or gas. The costs can be fairly substantial. A single unconventional oil or gas well is going to involve millions of dollars of upfront capital investment. But the exact cost is going to vary a lot by location because there are going to be differences in geology, in the depth of the geologic formation, in the topography of where you're drilling, in the distance between the location of the well and the market sale point. All of these things are going to influence the costs of drilling an oil or gas well. And though you're generally going to be talking in the many millions of dollars. On the revenue side, the payback for those costs incurred is ultimately going to depend on what happens in commodity markets for oil and gas. And on the natural gas side, those commodity markets are going to be influenced by things that are generally happening in North America. So things like weather, demand for electricity, things that are going to affect overall natural gas demand. North America is at this point a relatively closed market for natural gas. There aren't a lot of imports and exports. And so price fluctuations in North American natural gas markets tend to reflect things that are happening in the U.S. and Canada and Mexico. Oil on the other hand, oil markets are a totally different story because oil is really a global commodity. And so if you're drilling an unconventional oil well, your revenues from that well are going to be influenced by economic and fundamental and political things happening anywhere in the globe. And because oil is such an internationally traded commodity, if there is an increase in demand or an interruption in supply halfway across the world, that is going to be felt by an unconventional oil producer in the Bakken or the Permian or some very local place in North America.