Overall drilling in U.S. shale basins has increased 38% from a year ago, led by 100-200% jumps in oil- and liquids-rich natural gas plays such as the Niobrara in Colorado and southern Wyoming (200%), the Eagle Ford in South Texas (126%) and the Bakken in North Dakota and Montana (105%), according to a shale basin rig count compiled by NGI's Shale Daily.

U.S. shale oil, gas and tights sands rigs at work overall increased to 942 rigs compared to 684 a year ago.

The massive move into the oil/liquids plays reflects the response to the wide spread between the higher oil and bottom-dwelling natural gas prices over the past year. On the opposite side is the 8% decline in Louisiana's Haynesville drilling, the 19% drop in the Arkoma-Woodford in Oklahoma and the 18% decline in the tight sands Green River Basin in Wyoming during the same period.

The trends are illustrated in the first of a new weekly feature in NGI's Shale Daily. Natural Gas Intelligence (NGI) has aggregated the shale basin rig data based on its own formula, using the basic weekly U.S. rig counts produced by Smith Bits, a Schlumberger company.

During the same year ending Jan. 7, 2011 drilling in the Marcellus shale basin in the Appalachian area increased 47%, while the Piceance in western Colorado and Uinta in eastern Utah tight sands plays also showed robust drilling increases of 42% and 33%, respectively. The Granite Wash in western Oklahoma and Texas registered an 89% drilling increase over the past year, also reflecting a high liquids content, while the Cana-Woodford, in central Oklahoma, had a drilling increase of 36%.

The granddaddy Barnett Shale in Texas picked up just 7% in rig activity, while the Fayetteville in Arkansas saw a 6% drilling decline.

Active rigs in the Bakken went from 77 a year ago to 158 last week; the Eagle Ford from 53 to 120; the Granite Wash from 46 to 87 and the Marcellus from 95 to 140. While the Niobrara-DJ Basin showed the greatest percentage increase, its well total was smaller, moving from 11 a year ago to 33 on Jan. 7.

In the week ending Jan. 7 the 163 rigs active in the Haynesville were the most in any shale play, ahead of the 158 in the Bakken,140 in the Marcellus and 120 in the Eagle Ford.

The overall shale rig count declined from 964 for the week ending Dec. 31, 2010 to 942 for the week ending Jan. 7, 2011 (see table at shaledaily.com).

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