Oklahoma's governor expressed condolences after the passing of Lew Ward, an oil pioneer she said helped vault the state to a lead production position.

Lew Ward, who founded Ward Petroleum Corp. in the 1960s in Enid, Okla., died at age 85. Since its inception, the company has drilled more than 900 wells in shale basins in the state. Gov. Mary Fallin said it was his leadership that's positioned Oklahoma as a lead oil producer in the United States.

"As founder of Enid-based Ward Petroleum Corp., he devoted his career to developing oil and gas resources that continue to fuel our nation," she said in a statement.

The U.S. Energy Information Administration raised its estimate for daily oil production from Oklahoma by 100,000 barrels after revisiting data reported by energy companies working in the state.

Oklahoma is one of the top 5 oil production states in the nation, accounting for an average of between 3 percent and 4 percent of the total output in the United States.

When U.S. crude oil prices soared above $110 per barrel two years ago, Oklahoma had one of the fastest growing economies in the country. With oil below $50 per barrel, Fallin this year said the state is struggling to fill a $1 billion budget gap.

Apart from the economy, the state has experienced a string of minor tremors associated with practices tied to hydraulic fracturing. The state has limited the disposal of wastewater into underground wells in an effort to curb seismic activity. Five minor tremors were recorded by the U.S. Geological Survey in Oklahoma in the past 24 hours.