Rapidly increasing costs of exploration and development are making things harder for oil and gas companies as they struggle to match output rates.
Shell and Exxon experienced lower-than-expected profits due to maintenance issues and delays in kickstarting new production projects. And the shortage also means the gap between fuel prices and crude oil grew.
The private sector has been paying increased attention to so-called “unconventional” oil and gas resources like shale reserves, moving away from oil and gas centered in the Middle East.
Exxon reported a 7.5 percent decrease in oil and gas output, but capital and exploration expenses rose 7 percent to hit $9.2 billion.
"The production decline was more than expected," said Brian Youngberg, energy company analyst at Edward Jones in Saint Louis. "It has been a recurring challenge for Exxon."
Meanwhile, Shell experienced security problems in Nigeria. Largely due to this, oil and gas production dropped to 2.982 million barrels of oil equivalent per day, down from 3.012 million boepd.