The number of rigs actively searching for oil and gas in U.S. unconventional plays dropped by 1% for the week ending April 8, wiping out the 1% gain recorded for the segment during the previous week, according to NGI‘s Shale Daily Unconventional Rig Count.

Following the nine-rig gain the previous week, 12 fewer rigs were operating in the segment for the week ending April 8, leaving the total at 969 rigs. The largest decline for the week was recorded in the Marcellus Shale, where seven rigs were laid down to leave 140 rigs still in operation. The next largest declines were posted by the Arkoma-Woodford Shale in Oklahoma and the Barnett Shale in North Texas, which both lost two rigs to finish the week at 18 rigs and 69 rigs, respectively.

While most plays remained unchanged or lost at least one rig, some small upticks were recorded. The Haynesville/Bossier of East Texas and western Louisiana added two rigs to 143, while the Eagle Ford Shale of South Texas and the Piceance Basin of northwestern Colorado each added a rig to 164 rigs and 33 rigs, respectively.

NGI‘s Shale Daily Unconventional Rig Count utilizes county-level rig data provided by Smith Bits, a Schlumberger company, to more accurately target drilling levels in individual shale plays (see

Taking a look at Smith Bits overall data for rigs operating in search of U.S. natural gas, the drilling services firm reported that eight rigs dropped out of the search for the week ending April 8, leaving 892 rigs still in the hunt. Rigs targeting oil also dropped by six, from 810 to 804. The latest totals reflected an 87% gain for oil over the year-ago stats and a nearly 8% decline for natgas rigs over the corresponding week in 2010.

Smith Bits horizontal oil and gas rig count dropped by 17 from the previous week to 1,024.