John Kemp writes in Reuters that “in the next few months, everyone in the oil market will be intently watching the volume of new drilling activity in the shale plays of the United States for any signs of a slowdown in response to the fall in oil prices.”  

“There are more than a dozen major shale plays in production. But just three account for almost all the rise in oil output since 2009 and nearly two thirds of all rigs in operation: the combined Bakken/Three Forks in North Dakota and the Eagle Ford and Permian in Texas.”  

“These three are the most mature plays and least likely to be affected by the decline in prices. Marginal plays are more likely to bear the brunt of any decline in drilling activity. Nonetheless, the big three account for so much of the shale boom that any slowdown will have to encompass them.”