Will U.S. Shale Survive If Oil Hits $40?

Within a month, the U.S. oil benchmark West Texas Intermediate recorded two first-of-a-kind events. First, it fell below zero on April 20. Then, it soared up so high it is about to book its best month ever, CNBC's Pippa Stevens noted in a recent commentary. Still, many analysts and other observers remain wary of any premature optimism.  They have a good reason to be. WTI is now trading at close to $35 a barrel. That's up from less than $13 a barrel a month ago. Marked improvement is one way you could frame this--an incredible…