AAPG member H. Roice Nelson and his colleagues believe they have found a new type of geophysical data that will prove useful in resource exploration.
You might say the idea came like a bolt from the blue.
A few years back, a friend, Joseph Roberts, asked Nelson an old question, with a twist: “Does lightning strike twice in the same place? And if it does, could it be related to geology.”
Roberts has witnessed lightning strikes at apparently the same spot while on duck hunts a year apart. It was particularly intriguing because the hunt was on property near the Hockley Salt Dome in Harris County, Texas.
Nelson pursued the idea with another friend, Jim Siebert, chief meteorologist with Fox News in Houston, who has a background in earth science and has consulted for the industry.
They were aware of the National Lightning Detection Network, which had been recording lightning strike locations and related data since 1989, funded mainly by insurance companies.
The NLDN database indicated lightning strikes do cluster – and the patterns tend to repeat over time.
Nelson compared the strike patterns with geologic and exploration maps and found some compelling correlations, especially to telluric currents in the earth.
Nelson, Siebert and Les Denham formed a company, Dynamic Measurement LLC, and acquired rights to use the lightning data for natural resource exploration.
“This is not a magic bullet,” said Nelson, one of the founders of Landmark Graphics in the early 1980s.
“We get a new geophysical data type about every decade,” he said. “When we get one, people tend to oversell it, and it never works out that way. Each new geophysical data type eventually develops a sweet spot, where it meets an exploration need.
“We’re taking it slowly,” he added. “We’ve been working on it for five years and acquired a patent for some of the methodology.”
An Attractive Concept
A paper Nelson presented at the recent AAPG Annual Convention and Exhibition in Pittsburgh was “the first really big presentation” of the development.
Noting that Ben Franklin’s famous lightning experiments occurred along the now-famous Marcellus Shale, Nelson said the new research shows that cloud-to-ground lightning strikes appear to be controlled more by variations in telluric currents than topography or infrastructure.
“These variations are the result of geology, like faults that interrupt the currents in shallow earth,” he said.
“Slate, certain minerals, copper and rare earths are conductive. Fresh water aquifers are resistive. Geothermal hot water sources are conductive,” he said. “Oil and gas are resistive, kimberlite conductive, salts resistive.”
Nelson said maps they have generated seem to bear a relation to gravity and magnetic maps.
DML has done studies overlaying strike maps and various subsurface and exploration maps in North Dakota, Michigan, New York and Texas. The maps show many apparent relationships between lightning clusters and the subsurface, he said.
From Siebert’s viewpoint, “A meteorologist cannot understand weather patterns without understanding how the ocean currents are moving.
“Now we’re learning that a geologist cannot completely understand the subsurface without taking into account subsurface electrical currents and meteorological phenomena such as lightning,” he said.
“This is going to impact many industries, from mining to geothermal exploration to the timber industry and understanding where forest fires are more likely to be started by lightning,” he continued.
“As the technology of measuring lightning strikes advances, so will our ability to exploit it to search for natural resources,” he said, “and it will change how everybody looks for oil and natural gas.