The Baker Hughes Inc. count of rigs running in unconventional basins declined by two to end at 650 on Friday (June 12). Most of the basins held steady for the week, and the declines were spread out.

The Eagle Ford Shale added one rig to end at 104, while the Marcellus Shale, Utica Shale and Permian Basin each lost one rig to end at 63, 23 and 232, respectively. The other basins/formations tracked by Baker Hughes held steady.

In the latest count, 10 horizontal rigs were laid down by drillers in the United States, while two vertical rigs were added. Meanwhile, analysts at BMO Capital Markets were putting their pencils to the task of figuring out who's drilling the most productive horizontal wells and where.

"Our analysis generally concludes that core Marcellus (Cabot Oil & Gas Corp., Rice Energy Inc.) and Eagle Ford (Pioneer Natural Resources Co., Devon Energy Corp., Marathon Oil Corp., EOG Resources Inc.) achieve the highest 12-month recoveries, while selected Utica (Antero Resources Corp.), Delaware Basin (Cimarex Energy Co., Concho Resources Inc.), and Bakken (EOG, WPX Energy Inc.) areas rank in the top quartile in terms of average well productivity," BMO's Phillip Jungwirth wrote.

"U.S. E&P well performance improved meaningfully in 2014 versus 2013, and we'd expect continued improvements in 2015 given optimization of completions and high-grading of drilling activity."

Jungwirth conceded that well costs and royalties differ across plays, adding that while the Niobrara might rank low in productivity relative to other plays, its well costs are almost half those of other shale plays.

After losing 12 rigs, the land-based North America count stands at 825 rigs running. One rig was added in the inland waters category for a total of five running, and two rigs were added in the offshore, bringing that count to 29. Seven oil-directed rigs were lost in the United states, and one natural gas-directed rig gave it up, leaving 635 oil- and 221 gas-directed rigs.

Most of the 11 returning rigs in Canada were coming back for oil: nine added for a total of 68. Gas-directed rigs gained two to land at 59. With Canada's 11 returning rigs, the North American count landed at 986 for the week.