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]<p>[1] <a href="http:&#x2F;&#x2F;www.nytimes.com&#x2F;2015&#x2F;05&#x2F;12&#x2F;business&#x2F;energy-environment&#x2F;drillers-answer-low-oil-prices-with-cost-saving-innovations.html?_r=0" rel="nofollow">http:&#x2F;&#x2F;www.nytimes.com&#x2F;2015&#x2F;05&#x2F;12&#x2F;business&#x2F;energy-environmen...</a><p>[2] <a href="http:&#x2F;&#x2F;www.worldoil.com&#x2F;news&#x2F;2015&#x2F;8&#x2F;12&#x2F;oil-at-30-is-no-problem-for-some-cost-cutting-bakken-drillers" rel="nofollow">http:&#x2F;&#x2F;www.worldoil.com&#x2F;news&#x2F;2015&#x2F;8&#x2F;12&#x2F;oil-at-30-is-no-probl...</a>