--> --> Hunting “Elephants” in the Rio Grande Rift - A New Frontier

AAPG Annual Convention and Exhibition

Datapages, Inc.Print this page

Hunting “Elephants” in the Rio Grande Rift - A New Frontier


Exploration frontiers are spawned in bypassed areas when innovative ideas combine with new technology, persistence and the willingness to intelligently gamble - where and when the payoff may be large. The Rio Grande rift from Mexico, north up through New Mexico and into southern Colorado has only been sporadically and lightly explored since the early 1900's. This despite the fact that productive rift systems worldwide (constituting only 2-½ % of the world's basins), contain 12% of the world's oil and 4% of the gas reserves (Klemme, 1980), and they contain a disproportionately large percent of the worlds giant oil and gas fields. The first oil found, produced and sold from the Rio Grande rift (IP 40 bbls/day of 40 gravity oil) was produced from a single well in the Santa Fe Embayment of the rift in 1986. Unfortunately, this was at the same time oil prices plunged below $9 per barrel. Bureaucracy, over regulation, local County and State politics and environmental pressures combined with the low oil and gas prices have slowed exploration at least twice since 1985. The anatomy of this play reads like a comedy of errors, combined with unfortunate circumstances and bad timing. If a major discovery is made, the chronology of exploration and drilling should become a classic case of persistence, lessons learned and the proper use of analogs integrated with new technology for rift exploration. However, exploration has now proven the necessary factors for major accumulations of hydrocarbon are probably present in large parts of the rift. New geophysical and geochemical surveys have revealed several surprises. Large C4 microbial anomalies are found coincident with basement structural highs seen on seismic lines (and in some cases) coincide with large gravity lows. Significant shows, ranging up to minor production, have been seen in every well drilled into the Cretaceous in large parts of the rift. Current evidence combined with new industry completion technology suggests this frontier area may become a new producing oil and gas province when large untested structures on highs and transfer zones in the rift are drilled. Recent exploration is using producing rift fields around the world as analog exploration models. Known source rocks present in the rift may be sourcing Paleozoic, Mesozoic and Tertiary reservoirs. This suggests that hundred million barrel-plus oil fields could be present. The “tracks” of a potential “Elephant” are present in the rift, and should be followed for a shot at a possible “Giant”.