At the time, big energy firms were eyeing the two companies, which had a leasehold on 317,000 acres in the gas-rich Marcellus Shale basin, industry and shareholder reports show.
The couple made between $10.1 million and $50.2 million when Exxon Mobil bought the companies in June 2011.
An Exxon Mobil subsidiary is now at the basin using hydraulic fracturing — commonly referred to as fracking — to break apart the shale and free the gas by injecting large volumes of water, sand and other chemicals.
Kelly and his wife, Victoria, also continue to be partners in two other natural gas companies: Campbells Gas Partners and PC Exploration Ltd., which also have land along the Marcellus Shale, records show. The couple earned between $37,000 and $100,000 from their holdings in 2011, Kelly's latest disclosure statement shows.
Both as a candidate and congressman, Kelly has taken a high-profile stand in favor of Marcellus Shale gas development.
"We are poised to be on the forefront of the new energy economy thanks not only to our rich history but also to our proximity to large deposits of natural gas known as Marcellus Shale," Kelly's campaign website said.
After he was elected, Kelly joined more than a dozen caucuses, including the Marcellus Shale Caucus, which held its organizational meeting on April 1, 2011.
Six days later, he voted for a bill to bar the Environmental Protection Agency from regulating greenhouse gases, which passed the House but not the Senate. Some scientists have warned that large quantities of greenhouse gases can be released during fracking.
The following day, April 8, an opinion piece by Kelly appeared in a local newspaper. Kelly wrote that "burdensome" regulations in Washington were impediments and emphasized the economic benefits to the region. "Reports have shown that for each mile of pipeline throughout the Marcellus Shale, nearly $1 million is poured into Pennsylvania's economy," he wrote.