I work in the drilling data industry and have access to data as well as anecdotal observations. But there are lots of published articles e.g. [1], [2]

[1] http://www.nytimes.com/2015/05/12/business/energy-environmen...

[2] http://www.worldoil.com/news/2015/8/12/oil-at-30-is-no-probl...