The number of U.S. rigs exploring for oil and natural gas fell for a third straight week, Baker Hughes Inc. said Friday in its weekly report.

The combined count dipped by 15, the Houston oilfield services company said, bringing the total to 913.

The tally of oil rigs at work was down seven and now stands at 736, its lowest since June. The number of gas-directed rigs fell by eight, to 177.

Rig counts have been falling as U.S. oil prices have stagnated while traders weigh geopolitical issues and domestic data sending mixed clues about the market's direction.

Benchmark U.S. crude added 18 cents Friday to close at $51.47 a barrel on the New York Mercantile Exchange, a 2 cent gain on the week. Brent crude, used to price international oil, was $57.75 a barrel Friday in London.

Among major oil- and gas-producing states, Texas was the week's big loser, dropping eight rigs to 436. That included a six-rig decline in the West Texas-New Mexico Permian Basin. South Texas' Eagle Ford gained two to 65, the East Texas-Louisiana Haynesville Shale lost three to 41, and the Barnett Shale in North Texas was flat at four rigs.

Elsewhere, the counts in Alaska and Wyoming each declined by two and New Mexico and Utah each lost one.

Arkansas, California, Colorado, Kansas, Louisiana, North Dakota, Ohio, Oklahoma, Pennsylvania and West Virginia were unchanged.