History of Gas and Oil Development of the San Juan Basin, New Mexico and Colorado

James Fassett
Independent Research Geologist

The San Juan Basin of northwest New Mexico and southwest Colorado is the second largest gas basin in the United States and contains the largest CBM field in the world. Through September 2009, cumulative gas production from nearly 40,000 wells in the basin was 45.3 TCFG; oil production was 281 MBO. The first commercial gas well in the basin was completed in 1921 at a depth of 1000 ft in the Farmington Sandstone Member of the Kirtland Formation. Because there was no large market for gas (no pipelines out of the basin then existed) further significant gas development did not take place. In the 1950s, with the completion of large pipelines out of the basin, the drilling and completion of additional gas wells exploded with gas production expanding outward from the basin's center in all directions until the limits of production were found at the periphery of the productive area by dry holes. This gas play was never based on any solid geologic information because gas production was from stratigraphic traps with no surface manifestation whatsoever, thus the discovery of this field was totally accidental. Gas development grew and matured into the 1970s, when the basin suddenly developed new life with the discovery of the enormous gas resources hidden in the coal beds of the Fruitland Formation. It is ironic that thousands of wells had drilled through Fruitland coal beds before it was discovered that CBM could be liberated by pumping water from the coal beds. Fracking horizontal wells in the organic-rich marine shales in the basin may be ushering in a resurgence of O&G production in the San Juan Basin.

AAPG Search and Discovery Article #90169©2013 AAPG Rocky Mountain Section 62^nd Annual Meeting, Salt Lake City, Utah, September 22-24, 2013