The U.S. oil rig count declined for the third time in four weeks as crude traded below $80 a barrel for the third straight week, Bloomberg reported Nov. 21.

Rigs targeting oil fell by four to 1,574 this week, Baker Hughes Inc. (NYSE: BHI) said on its website Nov. 21, down from the 2014 peak of 1,609 six weeks ago. Those drilling for natural gas increased by five to 355, the Houston-based field services company’s website. The total count rose by one to 1,929.

A $30-a-barrel slide in oil is threatening to slow a drilling boom in U.S. shale plays that has propelled domestic crude production to the most in at least three decades and brought retail gasoline prices below $3 a gallon for the first time since 2010. Drillers from Apache Corp. (NYSE: APA) to Hess Corp. (NYSE: HES) have announced plans to cut their rig counts in some North American oil fields.

U.S. benchmark West Texas Intermediate crude for January delivery declined 4 cents to $75.81 a barrel on the New York Mercantile Exchange. The front-month contract is down 30% since reaching $107.73 on June 20.

Nineteen shale regions in the U.S. are no longer profitable with oil at $75 a barrel, data compiled by Bloomberg New Energy Finance show. Those areas, including parts of the Eaglebine and Eagle Ford in Texas, pumped about 413,000 barrels a day (bbl/d), according to the latest data available from Drillinginfo Inc. and company presentations.

Domestic oil output slipped 59,000 bbl/d in the week ended Nov. 14 to 9 million after reaching the highest level since at least 1983, Energy Information Administration (EIA) data show.

The Response

Hess, based in New York, said in a conference call Nov. 10 that it’ll cut its rig count to 14 next year in response to the lower oil prices. Apache, with headquarters in Houston, will reduce spending in North America by 25 percent next year, a company statement issued yesterday shows.

As competitors curb spending for 2015, Encana Corp. (NYSE, TSE: ECA) said it’ll boost activity as it doubles the number of rigs targeting oil in Texas’s Permian Basin. “This as an environment to accelerate,” Doug Suttles, the company’s CEO, said in a Nov. 17 interview at his Calgary office.

While rigs have fallen, their productivity has surged to record levels across all major oil fields, with oil output per rig expected to rise to a record 543 bbl/d in North Dakota’s Bakken formation in December, the EIA said.

U.S. gas stockpiles dropped 17 billion cubic feet last week to 3.594 trillion, according to the EIA. Supplies were 6.4% below the five-year average and 5.3% under year- earlier inventories.

Natural gas for December delivery dipped 17.1 cents to $4.318 a barrel per million British thermal units on the Nymex, up 17% in the past year.