Permian Basin There is no doubt that the 86,000-sq-mile Permian Basin, encompassing 52 counties in west Texas and eastern New Mexico, is experiencing a renaissance in drilling activity. According to the Railroad Commission of Texas (RRC), the Texas Permian Basin rig count climbed from 129 in 2005 to 355 in 2011, sustaining a dip to 103 in 2009 with no drop in crude oil production. Total Permian Basin rig count climbed to 500 in May 2012, according to a US Energy Information Administration (EIA) report, and as of late December 2012, stood at 454. The number of drilling permits issued by the RRC has exhibited a similar rise, from 4,459 in 2005, with a downdip to 3,369 in 2009 and then a steep climb to 9,347 in 2011. The price of natural gas remains depressed in the US, largely because of a glut due to a rush to exploit very tight gas resources in shale plays such as the Marcellus, Eagle Ford, Barnett, Haynesville-Bossier, Fayetteville, Woodford, and Bakken. A trend over the past few years has therefore been building towards a focus on liquids-rich plays. As a result, US production of crude oil is reaching levels not seen in 15 years, at approximately 2.1 billion bbl/year as of September 2012, according to the US Department of Energy’s (DOE) EIA. The US now produces an average of 6.41 million BOPD, a 14% increase from 2011, according to a December 2012 DOE report—around 50% of the crude oil it consumes. The two US states emerging as yielding the greatest amount of liquids are North Dakota (the Bakken) and Texas (Permian Basin and Eagle Ford). From September 2011 through September 2012, Texas onshore crude oil production increased by more than 500,000 BOPD, due to increases in Eagle Ford and Permian Basin production. The Permian Basin now accounts for more than 18% of domestic US crude oil supply. It has more than 400 active drilling rigs, by far the most of any US basin, that are drilling a large number of wells very quickly. The EIA estimates (Fig. 1) that crude oil production from the Permian Basin surpassed 1.25 million B/D in November 2012, 33% greater than the estimated 0.93 million B/D in the Western Gulf basin and 45% greater than the 0.86 million B/D in the Williston basin.