Presentation by Concerned Citizens for Nuclear Safety (CCNS) and
Southwest Research and Information Center (SRIC):

TECHNICAL TESTIMONY OF DR. JOHN BREDEHOEFT; March 16, 1999.

Dr. Bredehoeft received a Ph.D. in Geology, University of Illinois, 1962; a M.S. in Geology, University of Illinois, 1957; and a B.S.E. in Geological Engineering, Princeton University, 1955. Since 1995, Dr. Bredehoeft has worked for a consulting firm, the Hydrodynamics Group. Previously, Dr. Bredehoeft worked for 32 years with the U.S. Geological Survey. He has worked on a wide variety of ground water problems, including contaminant transport. Dr. Bredehoeft has published more than 100 scientific papers, has received numerous scientific awards. For 10 years, Dr. Bredehoeft was a member of the National Academy of Sciences/National Research Council Committee on WIPP.

THE HARTMAN SCENARIO
The Hartman Scenario is described as follows: A dry hole was drilled and completed in the Bates lease (in southeastern New Mexico) in 1954. Texaco began a waterflooding operation in 1964 near the Bates well. [Waterflooding is a common process used in oil production in which liquid is injected into rocks to increase the amount of oil that can be extracted and brought up to the surface.] Later, Texaco enlarged its operations. In its waterflooding, Texaco injected liquids at very high pressures. These high pressures can cause hydraulic fractures underground which allow fluid to move very rapidly.

In the early 1990s, Mr. Hartman drilled a well a 100 feet away from the Bates dry hole. When he reached the Salado Formation at 2,200 feet, the well blew out and water flowed out of the well for 4 days (35,000 barrels of water). The most likely explanation, and the explanation accepted by the court in the lawsuit in which Hartman was awarded damages, was that Texaco's waterflooding operation had fractured an anhydrite marker bed in the lower Salado and water had moved from the Texaco well over two miles to the Hartman well.

HYDROFRACTING is a technology that increases the well bore permeability. If the pressure is high enough, the rock pressure is overcome and the rock is cracked and a fluid filled fracture is opened up. The overburden can actually be lifted up and pumping in more fluid can extend the crack. [The overburden is the rock layers above the fractured rock.] It is not necessary to have very large cracks to increase the permeability dramatically (tenths of an inch or less). Hydraulic fracturing is a common way to increase permeability. It increases the production capacity of a well and hydraulic fracturing is done thousands of times every year.

Hydrofracting can also be used to measure the stress state of the earth and to give information about the state of stress along earthquake faults. In Colorado, Dr. Bredehoeft and others started earthquakes by injecting fluid. They also stopped earthquakes stopping the injection.

INJECTION WELLS AT WIPP
Water injection wells for secondary recovery of oil or for brine disposal are very common in the oil business. Drilling is allowed right up to the Land Withdrawal Area boundary. [WIPP is a square piece of land consisting of 10,400 acres, or 16 square miles (4 miles on each side).] The WIPP boundary is two miles from the waste panels (about the distance the Hartman water traveled). At Hartman, the surface pressure measurement was1,000 psi at the land surface and the water flowed for 4 days. The permeability is more than 5 times the permeability of the marker bed at WIPP. If you had a hydrofract at WIPP similar to the Hartman Scenario, it is reasonable to extend the hydrofract for several miles. There will be a lot of waterflooding and injection around the site boundary in the future. This could move a lot of water into the repository. The 4 days of Hartman flow would inundate 10% of WIPP. There is already some brine injection near WIPP.

MODELING
In Hartman, Dr. Bredehoeft used a 2-dimensional model because flow away from the Texaco well was radial in nature and a 1-dimensional model would not capture the flow field. If the permeability is equal, the water will go everywhere in all directions, but if the permeability varies, it will flow in preferential flow patterns. The marker beds are about 1 meter thick with less permeable salt on either side. Almost all of the water (99.9%) goes into the marker bed with the rest going into the salt. When the water encounters the WIPP repository, which is at a lower pressure, the repository becomes a fluid sink. If the DOE is still mining the repository when this occurs, the pressure underground will be the same as atmospheric. Waterflooding of the repository could occur during the operational period. The injection rates in southeastern New Mexico are increasing. If, at the upper end, the water that entered the repository would overwhelm the backfill and flood the repository. This water could break through anywhere--even in an active room. Waterflooding of mines is a common occurrence.

CONTAMINANT TRANSPORT
If borehole plugs or shaft seals do not meet permeability standards, water could move contaminants up drillholes and shafts. In the long term brine could corrode the steel drums. This corrosion of the steel drums creates hydrogen gas. Hydrogen gas is highly flammable. The hydrogen gas would pressurize the repository and make it easier to transport contaminants to the accessible environment. The pressure would fracture the marker beds near the repository and gas and fluid could move out into the marker beds.

The Environmental Protection Agency (EPA) discounted the Hartman Scenario in the Compliance Certification process. The EPA never agreed that the Hartman Scenario was a hydrofract and said there was a low probability of this occurring at WIPP. Dr. Bredehoeft believes the weight of evidence shows that the Hartman Scenario was a hydraulic fracture. The other consultants, especially those in the lawsuit, and even the DOE's Dennis Powers, all agreed that the Hartman Scenario was a hydrofract. Natural brine pockets in the Castile Formation are only pressurized at 8/10 of lithostatic pressure, but the surface pressure of 1,000 psi at Hartman is approximately equivalent to lithostatic. These very high pressures are not the same as pressures in a naturally occurring brine pockets.

SUMMARY
A blowout in Hartman's well in the lower Salado was associated with anhydrite marker beds. Fluids moved a few miles. A similar situation could occur at WIPP and could move very substantial amounts of fluid in a very small timeframe in terms of the amount of drilling around the site boundary. Such a situation could occur during WIPP's operation thereby endangering workers, or during the closure period after waste operations stop.

HIGHLIGHTS OF CROSS EXAMINATION OF DR. BREDEHOEFT

EPA said Dr. Bredehoeft's model was unrealistic and they could not replicate it. Also, the DOE claims that for the Hartman Scenario to occur at WIPP there would have to be a hole in the casing at Marker Bed 139 to allow water to get into this marker bed. But oil and gas wells surrounding the WIPP site are finished much lower than the WIPP horizon [Marker Bed 139].

NEFF Federal Well #3 is a water-injection well near WIPP. The DOE argued that NEFF injects at 7,000 feet, so water would have to come up 5,000 feet or there would have to be a hole near the WIPP horizon in order for water injection to affect the WIPP repository. However, the New Mexico oil and gas regulators found that NEFF #3 injection activities would affect potash reserves, which are at 1,300 feet. The EPA also said there was a low probability of this event happening. Dr. Bredehoeft did not calculate the probability of this event happening, only what the effects would be if it occurred. Wells near WIPP are supposedly finished to higher standards than the wells in the older well fields. However, waterflooding still occurs frequently in southeastern New Mexico. It would be prudent for NMED to be notified when there will be waterflooding or brine injection near WIPP.

There are significant geological differences between the area where Hartman's well is and WIPP. However, the Salado Formation and its marker beds are located both at WIPP and at Hartman's well. The Salado Formation is where the blowout occurred.

There are disagreements between Dr. Bredehoeft and the EPA on how far a hydrofract would go. The EPA uses BRAGFLO to calculate the extent of the fractures. [BRAGFLO is a numerical computer model, developed by Sandia Labs for DOE, used to predict pressures in the repository. BRAGFLO has only been used for WIPP modeling; it has never been used by industry.] Dr. Bredehoeft compared BRAGFLO with the Linear Elastic Fracture Model (LEFM) and showed that BRAGFLO underestimated fracture magnitude by a factor of 3 to 5. LEFM is an accepted model used by the oil industry.

Blowouts still occur in southeastern New Mexico despite regulations and monitoring. In particular, many leaks are associated with water flooding. Oil operators in one field put together a committee to deal with blowouts because it is such a widespread problem. The leaks usually are of large quantities of fluid.

If injection is made at high pressure and the fluid encounters a marker bed, a crack can be created, which increases the permeability of the marker bed by 5 orders of magnitude. If pumping continues, the fracture may extend almost indefinitely.

Naturally occurring brine reservoirs exist in the Salado Formation, but they are no more than a 1,000 gallons. These naturally occurring brine reservoirs could not have accounted for all the fluid that blew out the Hartman well.

A study undertaken 7 to 8 years ago modeled the rise of water levels that were occurring in the Culebra south of WIPP. This study concluded that the probable cause of the rise of water levels was a nearby water injection well.

Marker bed 139 is connected to the WIPP repository by means of the Disturbed Rock Zone (DRZ).

Even the DOE's Performance Assessment (PA) indicated that borehole plugs would degrade fully within 200 years. At that time, what is left of the borehole plugs will have the permeability of silt.

There are several formations below the Salado that produce oil and gas near the WIPP site. Since 1990, 140 oil and gas wells have been drilled within two miles of the site boundary and 47 more are planned for that area. Twenty-seven of the wells are within 2 miles of the waste panels, which is about the distance the brine traveled from the Texaco well to the Hartman well.

NEFF Federal #3 is about 1.5 miles from the site boundary and it is not the only injection well near the site. There are 4 brine injection wells within 4 miles of the boundary, and one is operating above lithostatic pressure. NEFF Federal #3 is operating above lithostatic pressure at about 500 feet below the repository.

It is estimated that gas generation from the drums will take several hundred years or more before it could create fractures and push brine and contamination out into the marker beds. But if large quantities of fluid entered the repository very quickly, increased gas generation could occur narrowing the timeframe for contamination of the marker beds.

There is only limited information on the permeability structure of the Culebra. One way to fill in the information blanks is to use the Monte Carlo Method. [The Monte Carlo Method is used in modeling to allow random chance to occur.] The Monte Carlo Method does not work well for one cell, but works well if there are many cells. The Monte Carlo Method is a commonly used procedure, but needs confidence limits put around the conditions.

The casing material in the boreholes is steel and can be corroded by the salt. This may open up pathways through which fluid can escape. If a leak occurs between the outer casing and the formation at a pressure about 1,410 psi on the land surface, the leak could create a hydrofract in the range of 300 to 400 feet below the repository. The leak could cause hydrofracturing in any marker bed above that level. The leak does not have to be located exactly at Marker Bed 139 in order to reach that marker bed.