While one well can replace 4-8 vertical wells (realistically), the cost to drill that well (about 10,000 ft. down, and about 10,000 ft. over) will run by completion roughly 8 to 10 million dollars. Break even price on most wells runs in the range of $70 to $80/bbl of oil.
IMO, the big news is NATGAS, not oil. I suspect as more and more NATGAS is developed, that the byproduct condensibles will get cheaper and cheaper (relatively), and displace at least some oil.
The real business that is going to "take it in the shorts" is coal. I see no way for coal to compete with NATGAS over the long run, for both economic and environmental considerations....which is why I am glad to see that the shale plays are basically in the heart of coal country, and can give the miners new employment as the mines shut down.