This excerpt taken from the SD 10-K filed Feb 26, 2009.
We own interests in properties in Oklahoma, Arkansas and southern Kansas that make up our Mid-Continent area. As of December 31, 2008, we held interests in approximately 583,333 gross (417,573 net) leasehold and option acres in these areas. As of December 31, 2008, our estimated proved reserves in the Mid-Continent area were 93.0 Bcfe, based on estimates prepared by our internal engineers. Our average daily net production for the month of December 2008 was approximately 38.8 MMcfe per day.