The second-largest producing oil complex in the world is Mexico’s giant Cantarell oil field, in the Gulf of Mexico off the Yucatan. The field was discovered in 1976, supposedly after a fisherman named Cantarell reported an oil seep in the Campeche Bay.
Exploration yielded surprising results. It turned out that Mexico’s richest oil field complex was created 65 million years ago, when the huge Chicxulub meteor impacted the Earth at the end of the Mesozoic Era. Some 10 years earlier, Luis and Walter Alverex had suggested in their independent studies that an impact meteor was responsible for the extinction of the dinosaurs. Scientists now believe that the Chicxulub meteor impact was the culprit that killed the dinosaurs, as well as the cause for creating the Cantrell oil field.
The impact crater is massive, estimated to be 100 to 150 miles (160 to 240 kilometers) wide. The seismic shock of the meteor fractured the bedrock below the Gulf and set off a series of tsunami activities that caused a huge section of land to break off and fall back into the crater under water. The geology of the field suggests that up to 300 meters (approximately 985 feet) of coarse-grained carbonate breccia settled in the impact crater at the bottom of the Gulf, as a result of “a single giant, debris flow generated by the platform-margin collapse due to seismic shaking resulting from the meteorite impact.” In other words, the shock of the meteor’s impact broke enough soft soil off the mainland to fill in the hole some 300 meters deep with settling sediment that was jarred off from the shore.
Proponents of the abiotic, deep-earth theory of the origin of oil argue that the deep fracturing of the basement bedrock at Cantarell caused by the meteor’s impact was responsible for allowing oil formed in the Earth’s mantle to seep into the sedimentary rock that settled in the huge underwater crater. Geologists have documented that the bedrock underlying the crater shows “melt rock veinlets pointing to large megablock structures as well as a long thermal and fluid transport” as part of the post-impact history.
In other words, the bedrock at Cantarell did suffer sufficiently severe fracturing to open the bedrock to flows of liquids and gases from the deep earth below. How sedimentary rock got below bedrock is another question.
Until the 1960s, geologists considered collisions of extraterrestrial objects with the Earth as interesting, but not necessarily important. Since Cantarell was discovered, geologists have come to realize that the intense shock waves generated in meteor impact events have significantly shaped Earth’s surface, distributed its crust, and fractured its bedrock.
Over 150 individual geological structures – many masked over by subsequent sedimentary deposits – have been identified as important, ranging from circular impact bowls measuring from only a few kilometers in diameter to as much as 200 kilometers (approximately 125 miles) in diameter. Moreover, Cantarell has stimulated interest in meteor impact structures as potential locations to explore in order to find oil-producing sites.
Still, Cantarell was an accidental find, occasioned by the sighting of oil that seeped to the surface of the Gulf. Oil geologists had not predicted a meteor impact find from their theories or methodologies prior to 1976. Typical oil exploration in the continental United States has tended to stay close to the surface, dictated by the idea that sedimentary layers close to the surface of the Earth would contain the biological material needed to produce oil.
Ultra-deep drilling is a relatively new technology in the United States, permitting in the last 20 years oil exploration in deep waters more than 1,300 feet underwater off the continental shelf. Before Cantarell, it would have been hard to find a “fossil-fuel” oil geologist who thought meteor impact sites merited oil exploration, especially if the impact area was offshore.
Most “fossil-fuel” theorists continue to argue that the oil found in Cantarell is “fossil fuel.” Geologists claim that enough biological debris got carried offshore along with the Cretaceous carbonate breccia debris to cook into oil in the 65 million years since the crater hit at the end of the Mesozoic. Yet, Cantarell has caused one important concession. Geologists agree that the oil in Cantarell seeped into the field through deep rock fractures caused by the meteor’s impact.
Yet, even this is not enough to shake “fossil-fuel” logic. Oil geologists agree that the Cantrell oil did seep up through impact fissures. They disagree, however, whether the oil flowed from lower lying “source rock” possibly from the Jurassic Period (some 200 million years ago, at the middle of the Mesozoic Era), as “fossil-fuel” theorists would argue, or from deep-earth oil reservoirs of abiotic oil origins.
Typically, “fossil-fuel” theorists saw oil as trapped into source rock until the temperature and pressure conditions were right to cause anaerobic bacteria to turn the organic material into kerogen. So, the “fossil-fuel” theorists argue that at Cantrell the oil seeped up from Jurrasic “source rock” that lies below the faults.
Even though Cantarell has been producing oil since 1976, “peak-oil” theorists see the giant field as no threat to their conclusion that the world is running out of oil. Cantarell has already reached “peak production,” they argue, and is now “dying” as the giant field inevitably moves toward depletion.
Originally, the field was estimated to contain approximately 35 billion barrels of oil in place. Pemex, the Mexican company operating Cantarell, has built 26 new platforms in the Gulf, along with the largest nitrogen extraction facility capable of injecting a billion cubic feet of nitrogen per day to maintain reservoir pressure. Taking these steps, the production in Cantarell has been boosted to some 2.1 million barrels a day, from a 1994 “depletion” level of 890,000 barrels a day. With current efforts, Pemex estimates that approximately 50 percent of the Cantarell reserves will be brought to market, the rest remaining until higher prices or newer technology justifies further production.
Still, no matter how much oil Cantarell contains or how efficient Pemex is in extracting the oil, “peak-production” theorists would not be shaken, as long as the oil could eventually be projected to run out. “One more giant field pumped dry,” theorists such as Matt Simmons and Ken Deffeyes would most certainly pronounce.
Even if future exploration at Cantarell were to yield new finds, the “peak-production” paradigm would remain unshaken in the eyes of advocates. Maybe the dates for oil depletion would have to be moved out farther, but eventually “peak-oil” theorists would argue that all the oil would run out of Cantarell, regardless of how long it took, no matter how many more productive wells were found within the Chicxulub crater.
Short of finding an oil-field equivalent of “the fountain of youth,” there probably is no argument that could convince “peak-oil” believers that the world today is nowhere close to running out of oil, and maybe never will be.