Drilling Near Nuclear Blast Cavity Called Risky Business

On a bright fall afternoon 36 years ago, the Atomic Energy Commission and a Texas oil company detonated a 40-kiloton nuclear device inside an 8,000-foot shaft on a high meadow, an effort to crack into a bounty of natural gas trapped in a dense subterranean rock formation.

Here on Colorado’s energy-rich Western Slope, the nuclear experiment yielded mixed results. A rich lode of gas was indeed shaken out of its rock casing, but the gas that rushed to the surface was too radioactive to be commercially useful.

Federal officials assured the community that the Rulison test site, named after a nearby community, was safe. Still, they forbade oil or gas drilling on 40 acres surrounding the blast. Last year, the Colorado Oil and Gas Conservation Commission added another half a mile to the federal off-limits zone.

But now, another Texas energy company has proposed drilling within the half-mile zone. The company, Presco, says it will extract the gas using a nonnuclear process called hydraulic fracing, which like the original experiment is designed to shatter underground rock and tap into embedded stores of natural gas. The company says this can be done without disturbing the radioactive material that remains buried in the blast cavity.

Presco, which is based in The Woodlands, Texas, north of Houston, insists there is no danger. One company official said that the original blast cavity was so stable “it would even be safe to drill into the cavity itself.”

But the thought of shaking the earth here again has many residents of surrounding Garfield County greatly concerned about what lies sleeping beneath the ground. The residue from the 1969 blast contains some of the most radioactive and toxic substances on Earth, including tritium, carbon-14 and krypton-85.

“Let’s see, you drill a hole, put a nuclear bomb in it, explode the bomb, then come back and frac it. Real smart,” said Scott Brynildson, tapping the side of his head through a white straw cowboy hat. “I think it’s very dangerous. They ought to leave a bad thing alone,” said Brynildson, who owns a plumbing company and grows alfalfa in the nearby town of Rifle.

His opposition to drilling on Battlement Mesa is widely shared by residents of a region that owes much of its current prosperity to a boom in oil and gas drilling.

Many people in this middle-income retirement community about halfway between Glenwood Springs and Grand Junction remember the explosion in 1969 and how a radio station in Rifle broadcast the blast countdown.

Although residents within a five-mile radius of this rural mountainside were paid to evacuate for the day, a handful remained. They said they were thrown about half a foot into the air by the blast, which registered a magnitude 5.5 on the Richter scale.

The experiment on Battlement Mesa was one of 27 nuclear blasts detonated as part of Project Plowshares, a government program that was created to harness the power of atomic weapons for civilian purposes. Plowshares was the brainchild of Edward Teller, best known as the father of the hydrogen bomb who died in 2003.

Other Plowshares projects sought to use nuclear explosions to dredge canals, carve out harbors and blast tunnels through mountains. Teller, who was on hand for the Rulison blast, later expressed disappointment that Plowshares did not succeed. The program was abandoned in the 1970s.

In coming weeks, the Colorado Oil and Gas Conservation Commission is scheduled to consider Presco’s application to drill.

Commission director Brian Macke said the agency was proceeding carefully and would consider a wide range of public health and safety issues.

The commission, which never has denied a drilling permit, already has approved about a dozen natural gas wells within three miles of the blast site, an intermediate buffer zone established by federal authorities.

Alarmed officials in Garfield County last month asked the commission to hold a public hearing to debate the issue. County officials have since voted not to oppose drilling in the half-mile zone but have asked for considerable testing of water wells.

At least one of Garfield County’s three commissioners, Tresi Houpt, is adamantly against the drilling.

“I’m not convinced that we should deviate from that half-mile radius,” she said. “Nobody knows whether they will hit radioactive gas. We’ve seen human error before in this county with respect to drilling.”

In 1969, scientists told residents that because of the density of the underground rock, the radioactive materials would remain undisturbed for eternity.

They explained that the blast created underground temperatures hotter than the surface of the sun. The searing heat melted the sandstone surrounding the blast cavity; as the substrata cooled, a puddle of glass formed and sealed the bottom of the well bore, while a chimney of collapsed rock filled in the top.

Today, the energy industry, as well as government scientists, maintains there has been no migration of radioactive material from the blast site.

They say testing of water wells shows only background levels of radioactivity, or acceptable levels of radioactive material such as tritium.

However, scientists from the Lawrence Livermore and Los Alamos national laboratories reported that lethal radioactive substances from an underground weapons test in Nevada migrated almost a mile from the blast site over a 30-year period, contradicting Department of Energy predictions that such material would move just a fraction of an inch in a decade. That 1997 study found that plutonium attached itself to particles in groundwater.

Another study from the same labs had earlier found that radionuclides -- radioactive particles -- moved more than 1,000 feet from a blast site that bomb experts said had been sealed off because of melted rock. David Smith, the studies’ lead scientist, said in an interview that similar movement might not occur at every blast site.

But for hydrogeologist John Bredehoeft, for more than 30 years the U.S. Geological Survey’s expert in tracking movement of underground water, there are too many unknowns to approve drilling at the Rulison site.

“I’m surprised that the oil and gas commission doesn’t require people stay a certain distance away,” he said. “You don’t really know what will happen. Why risk it? I would be a bit more prudent. If I were the oil and gas commission, I would try to keep people away from the blast site.”

The massive sandstone formation that contains the gas is one of the nation’s most productive gas fields. Oil and gas permits are running at an all-time high in Colorado.

About 50% of the state’s operating drilling rigs are in Garfield County.

In Parachute, a town of 3,000 a few miles from the blast site, hotels and cafes are jammed with oilfield workers. For longtime residents, it’s not difficult to pick out who’s local and who’s an outsider: The big pickups without a cattle dog in the back are the ones owned by rig workers.

The concentration of oil and gas rigs has pushed out most farming and ranching, and some have taken to referring to the area as Gasfield County. The community is accustomed to and benefits from the energy business, and few say they are against all drilling.

Jaunita Satterfield, Parachute’s town administrator, calls herself a “piece of oilfield trash from Oklahoma.” She said the town’s main concern with drilling near the Rulison site was protecting its reservoirs and water sources, which sit just below the blast zone.

Residents also worry that toxic radionuclides could make their way into the air when excess gas is burned off or “flared” from wells and drilling mud dries out.

Pat and Randy Warren live on Battlement Mesa, less than a mile from the Rulison site on a 37-acre ranch where they expect to retire. Like most families in this area, they rely on well water drawn from their property. The Warrens worry that their well could become tainted.

“Our biggest concern is they’ve never done this before,” she said, as three dogs curled around her legs while she stood on a bluff overlooking Grand Valley, a broad area bisected by a slow slice of the Colorado River. “They don’t know what will happen. If there’s something that gets in the air or water, we’re dead -- so to speak. We want to be assured nothing’s going to happen. I don’t think they can offer us that.”

Opponents to drilling say they hold out little hope for stopping the Presco plan, but some argue for postponing it until the Department of Energy completes a final report on the risks. The report is expected to be completed in 2007.

“Why not wait until we get that report?” asked Orlyn Bell, a retired state water engineer and a member of the newly formed Garfield County Energy Advisory Board.

“Why do we have to push the envelope here? Why is this place so special that we have to do that?” asked Bell who has four gas wells on his property.

Since 1972, federal inspectors have regularly sampled groundwater in the blast area, said Pete Sanders, a Department of Energy geologist who oversees the Rulison site. They are looking in particular for tritium, or radioactive hydrogen, which is highly mobile. He said more than 30 years of water tests never found harmful levels of tritium.

Sanders said it was likely that radioactive gas still existed in the cavity but noted that a sophisticated, two-year computer modeling study would be part of the federal report.

The agency has produced an interim report, based on a simpler computer model, that concludes that there would be no gas or water migration from the blast site to a well located 1,500 feet away.

Nor does the agency expect that the underground fractures from the blast site and the new wells would intersect. So far, it’s the only report that addresses the scientific questions about drilling.

“It is what it is, we are not representing it as the end-all,” Sanders said. “This is a simple, simple model. I want to stress that. We want to finish the detailed work. We will hold our judgment.”

But based in part on that preliminary hypothesis, Presco and others assert the safety of the plan, which would eventually sink multiple wells within the half-mile buffer zone right up to the final 40-acre off-limits area.

“We intend to do that in the future; we’ve never tried to hide that,” said Kim R.W. Bennetts, vice president of exploration and production at Presco. “Hopefully, a year from now we will have proven that there’s no risk.”

Bennetts is well aware of widespread public concern about the company’s plans and said Presco would conduct regular tests of drilling fluids, rock cuttings and the gas from the new well.

“We have people say we are going to unleash a nuclear holocaust in the Grand Valley,” he said. “People who are distrustful of the petroleum industry say to me, ‘Can you say to me there is absolutely 100% no risk?’ I’m a scientist, I can’t guarantee you 100% of anything.”