North Dakota oil production was flat in April compared to March, while the state's natural gas output rose around 1% and hit another record high.

Despite the decent month, falling oil prices are worrying the state's oil producers, said Lynn Helms, director of the North Dakota Department of Mineral Resources. "Oil prices this last week have become a very significant concern," he said.

North Dakota, the nation's second-largest oil producer after Texas, pumped out 1.39 million barrels per day of petroleum and 2.86 million MCF of natural gas in April, according to state data released Friday. (An MCF is 1,000 cubic feet of natural gas.)

Oil and natural gas production have been on the upswing this year in North Dakota and throughout the country, with predictions of another record year for oil nationally.

But oil prices have been shaky since late May as concerns have spread about demand softness due to slowing global economic growth. West Texas Intermediate (WTI) — the benchmark U.S. oil price — was around $63 per barrel on May 21. Over the past week, WTI had dipped below $51 per barrel before firming up to around $52.50 Friday.

The rig count — an indicator of new oil wells — currently stands at 61 in North Dakota, down from 65 in May. The rig count nationally has been falling.