Exxon Mobil announced today it bought Phillips Resources of Warrendale and TWP Inc. of Butler.

The purchase price for the two companies is $1.69 billion, adding 317,000 acres of leased land to Exxon’s natural gas operations.

Phillips Resources and TWP are reported to have held combined reserves equivalent to 228 billion cubic feet of gas at the end of 2010.

All 200 employees at the two companies are expected to keep their jobs.