Some more recent data and an excellent explanation of why the break even cost for shale oil is a moving target. Especially useful is the description of the horizontal drilling technique.
This explains why US shale oil production did not go down like the Saudis thought it would when recently (2015) they tried to pump more oil to capture market share from the US and others as world prices fell. It turned out to be hard to drive out shale oil producers.
What is the break even cost for shale oil? That depends on a number of factors, and it is a moving target.
Supply Chain and Logistics 