West Slope Colorado Oil & Gas Association Share: Oil & Gas Producers & Industry Services West Slope Colorado Oil & Gas Association Visit Website PO Box 89 Grand Junction, CO 81502 (970) 773-2198 About Map About The West Slope Colorado Oil and Gas Association exists to promote the development of oil & natural gas in Western Colorado. What's Nearby? Distance: 5 10 15 20 25 50 mi.