TEXAS 油田开发成本低一些(仍然需要若干M),平均产量也低一些。
http://foundationforenergyeducation.org/crude_oil_us_crude_oil_facts_and_statistics.php
http://sayanythingblog.com/entry/the-average-north-dakota-oil-well-will-pay-nearly-23-of-its-profits-in-state-taxes/
http://www.ndoil.org/image/cache/Facts_and_Figures_2011_-_online.pdf