The Kirtland Formation and the underlying Fruitland Formation subcrop beneath the alluvium of the Los Pinos River, approximately six miles north of Bayfield, Colorado. Seepage of methane gas in this area has been the focus for a number of investigations. Downhole color video's showed gas production by free gas venting from carbonaceous shale/siltstone/coal zones that occur in the Transition Zone between the Kirtland and the Fruitland Formations. This zone matched the primary seepage location. The videos also showed gas production by desorption from the uppermost thick coal in the Fruitland Formation, known as coal S1. The several lower thick coal beds of the Fruitland Formation did not show gas production by desorption and did not match seepage locations. Sandstones of the Fruitland and Pictured Cliffs Formations also produced free gas by venting and did not match seepage locations.

AAPG Search and Discovery Article #90937©1998 AAPG Annual Convention and Exhibition, Salt Lake City, Utah