Before this week, drillers added oil rigs in only four out of 25 weeks this year, cutting on average eight rigs per week for a total of 206. Last year, they cut 18 rigs per week on average for a total of 963, the biggest decline since at least 1988.

After slumping from 1609 since October 2014 amid the biggest oil rout in a generation, the rig count has started to inch up as producers boost spending after US crude prices have hovered since late May around the $50-a-barrel key level that analysts said would trigger a return to the well pad.

In the numbers released on Friday, Texas and Oklahoma had the biggest gains. Each state added four rigs, for respective totals of 198 and 58.

Texas' gains were reflected in its Permian basin, which added four rigs for 154, and the Barnett shale, which added one rig for eight.

New Mexico, which is home to the western part of the Permian, lost one rig for 19.

Elsewhere in Texas, the Eagle Ford shale shed one rig for a total of 33.

The Haynesville shale, which straddles the Texas-Louisiana border, also lost two rigs for 17.

Louisiana was shown to gain one rig this week for 42.

Meanwhile, in Oklahoma, the Cana Woodford play added two rigs for 26.

Colorado also added two rigs this week, upping its total count to 19. Its gains were reflected in its DJ-Niobrara basin, which also added two for 14.

Alaska shed a single rig for eight.

US crude futures were largely flat this week at around $48, but have jumped 26% over the past three months, making the second quarter the best in seven years. Looking forward, futures for the balance of the year were trading below $50, while calendar 2017 was under $53.

"The worst is behind us and a modest recovery in spending is now underway," analysts at Evercore ISI, a US investment banking advisory, said in a note this week, predicting North American producers would boost capital expenditures by at least 25% in 2017 and probably another 30% in 2018.

Evercore said its $50 oil price forecast implies the US oil rig count will recover to about 620 by the end of 2017.

Simmons & Co, energy specialists at US investment bank Piper Jaffray, boosted its US oil price forecast to $60 for 2017 and $70 for 2018. That should increase cash flows and allow producers to spend more on drilling, which should result in more production.

With higher prices forecast, Simmons expects total oil and natural gas rigs will increase to nearly 1100 by the end of 2018 versus its earlier projection of 850-900 rigs at that time. The total oil and gas rig count bottomed at 404 in mid May, the lowest level since at least 1940, and increased by 10 to 431 in the week ended 1 July , according to Baker Hughes data.

The rig count is one of several indicators of future production. Other indicators include drillers ability to get more out of each well and the completion of drilled but uncompleted wells or DUCs.

US crude production is expected to fall from 9.4 million barrels per day in 2015, the highest level since 1972, to 8.6 million bpd in 2016 and 8.2 million bpd in 2017, according to the latest federal estimates.