In 1967, the U.S. Atomic Energy Commission detonated a 29-kiloton nuclear device about 4,200 feet below the surface of the Carson National Forest in New Mexico. It was nearly twice the size of the atomic bomb that destroyed Hiroshima.
The AEC, the U.S. Bureau of Mines and El Paso Natural Gas Co. set off this massive blast in a high, remote area of the San Juan Basin, about 60 miles east of Farmington. This was Project Gasbuggy, the first of a series of downhole experiments in the late 1960s and early ‘70s designed to enhance natural gas production from shales and tight sandstones.
Swords Into Plowshares
The Plowshare Program was the U.S. effort organized during the Cold War in the 1950s to develop techniques for the peaceful use of nuclear explosives. The name comes from Isaiah 2:4, “ … they shall beat their swords into plowshares, and their spears into pruninghooks: nation shall not lift up sword against nation, neither shall they learn war anymore.”
Theoretical physicist Edward Teller, known as the “father of the hydrogen bomb,” was a key advocate for Plowshare. He said that it would “ … prove that nuclear detonations, used carefully and wisely, can be a tool for building civilization, for improving the conditions of human existence.”
Gasbuggy, as an element of Plowshare, was actually the third historic nuclear explosion in New Mexico. The first, of course, was Trinity, the famous 1945 nuclear weapon detonation that was the key test of the Manhattan Project, whose principal laboratory was in Los Alamos. The second was Project Gnome, the first continental nuclear weapon experiment since Trinity to be conducted by the United States outside of the Nevada Test Site. It was detonated near Roswell in 1961.
In all, 35 nuclear warheads were detonated by the United States in more than two dozen experiments to evaluate civil engineering projects, including the notion of blasting a new canal in Panama or Nicaragua, and for stimulation of low-permeability gas reservoirs. (The Soviet Union had a similar project with far more tests.)
As a successor of the AEC, the U.S. Department of Energy later explained the rationale that “the relatively inexpensive energy available from nuclear explosions could prove useful for a wide variety of peaceful purposes.” Ultimately, the explosions generated widespread public opposition, and Plowshare was officially terminated in 1977.
Fracturing
Stimulation of petroleum reservoirs for improved oil and gas recovery (aka “fracturing”) has a long history. In 1865, E.A.L. Roberts, a Civil War military explosives expert, came to the area of Colonel Edwin L. Drake’s historic 1859 discovery well in Pennsylvania with cast-iron torpedoes that he filled with gunpowder and ignited with a percussion cap in wells. Later versions used nitroglycerin, which was highly volatile, but more effective. “Shooting the well” became standard industry practice. Sometimes it worked, sometimes it failed, and sometimes the shooter was killed.
In an early example of hydraulic fracturing, Stanolind Oil and Gas injected a small amount of gasoline and sand into a Kansas well in an experimental attempt to improve natural gas flow in 1947. This was soon followed by commercially successful frac treatments by Halliburton in Oklahoma and Texas. By the mid-1960s, hydraulic fracturing with huge volumes of water, sand and chemicals at high pressure was widely employed, sometimes for stimulation of tight formations. This was when operations began for a dramatic new technique: downhole nuclear detonation, “the power of the atom.”
Planning
The federally funded Livermore Radiation Laboratory in California (now the Lawrence Livermore National Laboratory) managed Project Gasbuggy for the AEC. Gasbuggy’s premise was to use a nuclear explosion to fracture and stimulate gas production and increase ultimate recovery from the Pictured Cliffs Formation, a Late Cretaceous unit that was (and still is) gas-productive in the San Juan Basin.
The PC includes massive, cross-bedded, fine-grained sandstones and thin shales. It inter-tongues with shales, siltstones and coals of the overlying Fruitland Formation. Gas was understood by the AEC and its partners to flow primarily along the PC’s natural fractures, joints and bedding planes, rather than from the low-permeability matrix.
The Gasbuggy science team predicted that gas would flow through the fractures created by the blast and the collapse chimney would become a downhole collection chamber. The PC and overlying formations were thought to be deep enough and competent to contain the explosion.
San Juan Basin petroleum pioneer Tom Dugan and Emery Arnold explained in their book, “Gas!” that “thousands of acres of marginal and submarginal acreage containing (low-permeability) reservoirs made the area a prime candidate for such an experiment.” They estimated that only 13 percent of the gas-in-place could be recovered using the conventional stimulation techniques of the day.
El Paso Natural Gas (now part of Kinder Morgan Co.) operated the drilling and post-detonation production analysis. A major gas producer in the area, El Paso had leased the federal acreage years before. They co-sponsored the experiment and drilled the wells as part of the public-private collaboration. The state built an all-weather access road.
Among the geoscientists who contributed to the planning and evaluation of Gasbuggy (in addition to the nuclear engineers, physicists and chemists, of course) was Robert Laughlin of LRL who participated in locating the site and predicting the behavior of the geologic column after the blast. Dan Miller was one of the EPNG geologists who evaluated the potential for enhanced gas recovery. Donald Meade of the AEC studied the fracture patterns and the post-explosion subsurface gas flow process. James Hamilton and others from the U.S. Geological Survey and the USBM monitored seismic activity from the test and evaluated Gasbuggy’s usefulness in stimulating gas production.
Blasting
As the AEC’s postshot geologic report explains, EPNG 10-36 (also known as San Juan 29-4 Unit 10) was completed in 1956 by El Paso as a producing gas well. At Gasbuggy, GB-1 and GB-2 were drilled before detonation to help define the hydrologic and geologic conditions of the site. GB-1 contained an array of scientific instruments during the detonation. A series of logs were run, cores were cut and analyzed, and gas production tests were made from GB-2 for comparison with post-blast rates.
The ten-ton, 13-by-1.5-foot experimental nuclear device was lowered into GB-E. At 12:30 p.m. Mountain Standard Time on Dec. 10, 1967, the bomb was detonated in the Lewis Shale about 40 feet below the Pictured Cliffs, at a depth of 4,227 feet.
Scientists and engineers, government and El Paso employees, members of Congress, and state and local dignitaries gathered at a tent on a bluff off the highway several miles from the site. They felt a sharp shock wave there; in fact, tremors were felt for miles around. Residents expressed concern about a dam bursting or an underground chain reaction.
The explosion generated extremely high temperatures that vaporized a portion of the surrounding rock downhole, creating a temporary cavity encircled by a fractured zone radiating from the blast site. Immediately after the explosion, the fractured rock above the cavity collapsed into the void, forming a rubble-filled collapse chimney about 330-feet high and 160-feet wide that extended upward from the detonation point.
The cavity cooled, and the vaporized and molten rock settled at the bottom and solidified, becoming the lower part of the collapse chimney. Some of the radioactive material with high melting points became trapped in this glassy, solidified melt.
Well GB-ER re-entered GB-E by drilling out the cement inside casing. Post-detonation, GB-2R re-entered GB-2 to a depth of 3,812 feet, where casing deformation prevented further drilling. A sidetrack hole, GB-2RS, was drilled from 2,690 to 4,600, and new wireline logs were run to compare with the pre-detonation logs.
Testing
The upper portion of the collapse chimney was penetrated by re-entry well GB-ER. There were slumped strata and some rubble-filled voids, but no large void was found at the top of the chimney, as had been seen in previous detonations. Intense fracturing in Fruitland Formation coals and the Lewis Shale was identified, and logs showed porosity increases in the Pictured Cliffs. The casing was damaged 400 feet above the center of the explosion.
Gas from the detonation zone was produced, and optimism about the project ensued. A series of tests that were conducted over about 15 months produced more than 200 million cubic feet of gas that was flared. (Burning doesn’t remove radioactivity.)
Encouragingly, the explosion stimulated gas production six to eight times over previous rates in nearby wells, though rates then declined. However, the gas contained measurable levels of radioactive material and long-term production estimates were disappointing.
The gas had a significantly lower heating value than expected, due to dilution with nonhydrocarbon gases such as CO2 and other factors. Fracturing in the PC was concentrated immediately around the detonation, where temperature and pressure effects had the greatest impact. Smaller fractures extended away from the blast, but the fracture effectiveness decreased away from detonation’s center.
Critically, radioactive contamination left the gas undesirable for commercial use without complex, expensive processing. There was some concern that radioactivity would contaminate gas from other wells, five of which, according to the Durango (Colo.) Herald years later, were producing within a mile of the site. EPNG had disconnected the flowlines to all of them before the blast, but within months they were reconnected. Cross-contamination was apparently minimal.
Public worry grew about the potential risks of radiation and the health of workers and residents nearby. Further testing was eventually halted, and Gasbuggy was generally deemed a scientific success but an economic failure. The site was demobilized and remediated in 1978.
No Nukes is Good Nukes
Two nuclear detonations, Project Rulison and Project Rio Blanco, took place in the Piceance Basin of northwestern Colorado as part of the Plowshare Program. In September 1969, the AEC exploded a 40-kiloton nuclear device at 8,426 feet to evaluate the concept of increasing gas flow from tight sandstones in the Williams Fork Formation of the Late Cretaceous Mesaverde Group near the community of Rulison. Rates were increased by the fracturing, but radioactivity made the gas commercially unviable.
By then, public opposition to the experiments was growing. Astrophysicist Carl Sagan said in 1970, “The use of nuclear explosives in programs like Project Plowshare, regardless of the intended peaceful applications, risks irreparable environmental damage and global contamination from radioactive fallout. The Earth’s ecosystems are too fragile to withstand such a gamble.”
In May 1973, the AEC detonated three smaller nukes simultaneously in one well northwest of Rifle, Rio Blanco County, Colo., over a range of depths. Again, fractures were created in tight sandstones of the Williams Fork Fm. and gas was produced, but public concerns about the health risks of radioactive gas led to discontinuation of the project.
The AEC and El Paso proposed Project Wagon Wheel, an experiment to detonate five 100-kiloton nuclear devices over a range of depths in a well south of Pinedale, Wyo., in 1968. The target was natural gas below 9,000 feet in tight sandstones of the Paleocene Fort Union Formation. Wagon Wheel met with intense opposition locally and in Washington, and in 1974 the well El Paso had drilled was used in an unsuccessful attempt at massive hydraulic fracturing instead. Project Wagon Wheel was abandoned, and Uncle Sam got out of the business of nuclear testing for stimulating gas production (and other industrial purposes).
Historic Site
Today, maintenance of the 640-acre Gasbuggy site on the Carson National Forest, just west of the Jicarilla Apache Reservation, is the responsibility of the DOE’s Office of Legacy Management. Dry hole markers, a bronze plaque, a display of casing, and a series of explanatory signs grace the grassy site.
Petroleum industry activity off the Gasbuggy site but in the vicinity includes drilling by several operators who are now developing oil and gas reserves from hydraulically fractured horizontal wells in the Mancos Shale and other Cretaceous units. The DOE retains the right to test gas, produced water and drilling/fracturing fluids from wells near Gasbuggy within a specified area of review.
Personnel of the Jicarilla Ranger District - Carson National Forest and DOE are preparing an application to nominate Gasbuggy for the National Register of Historic Places. Historically, Gasbuggy represents the first federal-private collaboration “to use the destructive power of atomic devices for peaceful purposes,” as well as the “first U.S. underground nuclear experiment for the stimulation of low-productivity gas reservoirs.”
Acknowledgements
Thanks to Rachel Miller, John Thomas and Helen Trujillo for their generous help with files, photos, artifacts and a memorable site visit in New Mexico. For a nostalgic look at Gasbuggy from the AEC’s perspective soon after the detonation, look for their short movie at: youtube.com