John A. Veil
Argonne National Laboratory
Karen P. Smith
Argonne National Laboratory
NORM can be disposed of both on the lease site and at offsite commercial disposal facilities.
The total cost for disposing of NORM waste is difficult to quantify. The cost components that must be considered, in addition to the cost of the disposal operation, include analytical costs, transportation costs, container decontamination costs, permitting costs, and long-term liability costs.
Current NORM waste-disposal costs range from $15 to $420/bbl.
Since 1992, the U.S. Department of Energy (DOE) has funded Argonne National Laboratory to conduct studies evaluating issues related to management and disposal of oil field wastes contaminated with naturally occurring radioactive material (NORM).
This article is based on information from a DOE study on NORM disposal in salt caverns.1
NORM occurrenceOil and gas production and processing operations sometimes accumulate NORM at elevated concentrations in by-product waste streams. The sources of most radioactivity are isotopes of uranium-238 (U-238) and thorium-232 (Th-232) that are naturally present in subsurface formations from which oil and gas are produced.
The primary radionuclides of concern in NORM wastes are radium-226 (Ra-226) of the U-238 decay series, and radium-228 (Ra-228) of the Th-232 decay series. Other radionuclides of concern include those that form from the decay of Ra-226 and Ra-228.
The waste streams most likely to be contaminated by elevated radium concentrations include produced water, scale, and sludge.2 Spills or intentional releases of these waste streams to the ground can result in NORM-contaminated soils that must also be disposed of. Radium, which is slightly soluble, can be mobilized in the liquid contained in a subsurface formation and transported to the surface in the produced water stream.
Dissolved radium either remains in solution in the produced water or precipitates out in scales or sludges. Conditions that appear to affect radium solubility and precipitation include water chemistry (primarily salinity), temperature, and pressure.
NORM-contaminated scale and sludge can occur when dissolved radium coprecipitates with other alkaline earth elements, such as barium, strontium, or calcium.
In the case of scale, the radium coprecipitates, primarily with barium, to form hard, insoluble sulfate deposits. Scale typically forms on the inside of piping, filters, injection wellhead equipment, and other water-handling equipment. It can also form as a coating on produced sand grains.
Radium can be present in several forms in sludge. It can coprecipitate with silicates and carbonates that form in the sludge, or it can be present in pieces of barium sulfate scale that become incorporated into the sludge.
NORM-contaminated sludges can accumulate inside piping, separators, heater/treaters, storage tanks, and any other equipment where produced water is handled. The U.S. EPA estimates that about 25,000 tons of NORM-contaminated scale and 225,000 tons of NORM-contaminated sludge are generated annually by the petroleum industry.3
In addition to their radioactive characteristics, NORM wastes also have physical and chemical characteristics typical of nonhazardous oil field waste (NOW). Reference 4 assumes that a typical NOW stream going to a disposal cavern consists of accumulated heavy hydrocarbons, paraffins, inorganic solids, and heavy emulsions.
Regulatory considerationsThe most important distinction between oil field wastes and many other industrial wastes is that the former are exempted from the hazardous waste requirements of the Resource Conservation and Recovery Act (RCRA). Most oil field wastes are commonly considered to be nonhazardous oil field wastes (NOW).
EPA issued a regulatory determination on July 6, 1988, that exempted any wastes arising from the exploration, development, and production of crude oil, natural gas, and geothermal energy from regulation as hazardous wastes under RCRA Subtitle C (53FR25477).
EPA clarified the 1988 determination on Mar. 22, 1993, and exempted many other wastes that were uniquely associated with exploration and production operations from RCRA Subtitle C requirements (58FR15284). Most states have adopted similar exemptions for oil and gas wastes.
The difference between NOW and NORM waste is the presence in the latter of radionuclides above a state-specified action level. The presence of radionuclides does not change the waste's exempt status under RCRA as long as the waste itself, exclusive of the radiological components, is an exempt waste.
Therefore, most oil field NORM waste is not regulated as hazardous waste. But the term "nonhazardous" oil field waste should not be interpreted to mean that no hazardous substances are found in oil field wastes.
At least one oil and gas producing state does not follow the blanket RCRA exemption for exploration and production wastes and associated wastes. In California, each batch of waste is tested for specified parameters to determine whether the waste is hazardous. Wastes found to be hazardous must be managed at a hazardous waste-management facility, which typically is much more expensive than a NOW disposal facility.
NORM regulationsNo existing federal regulations specifically address NORM-waste handling and disposal. Therefore, individual states have taken responsibility for developing NORM regulatory programs. These programs have been evolving rapidly over the last few years.
Many states have promulgated NORM regulations, and many others are reviewing the magnitude of NORM issues within their borders and the need for specific regulations.
Existing state regulatory programs establish requirements for:
- NORM exemption standards or action levels
- Licensing of parties possessing, handling, or disposing of NORM waste
- Release of NORM-contaminated equipment and land
- Worker protection
- NORM waste disposal.
In these states, the action level is 5 pCi/g total radium if the radon emanation rate exceeds 20 pCi/sq m/sec and 30 pCi/g total radium if the radon emanation rate is below that level. Most state regulations currently approve the following disposal methods for waste exceeding the NORM action levels:
- Burial at either a licensed NORM waste or low-level radioactive waste-disposal facility
- Downhole disposal via encapsulation inside the casing of a plugged and abandoned well
- Underground injection into subsurface formations via a permitted Class II well.
Downhole encapsulation and underground injection of NORM waste typically are approved on a case-by-case basis only and, in the case of underground injection, may require modification of existing Class II permits.
NORM managementThe presence of NORM in oil and gas wastes has been known since the 1930s. NORM was not recognized as a waste management issue, however, until the mid-1980s, when the industry and regulators realized that NORM occurrence was more widespread than originally thought and that radioactivity levels could be high.
The petroleum industry adopted methods for managing and disposing of NORM-contaminated wastes that are more restrictive than past practices and are likely to provide greater isolation of the radioactivity.
Simultaneously, state agencies have promulgated NORM regulations that establish new, more restrictive standards for the management and disposal of NORM wastes. These actions have served to limit the number of disposal options available for NORM wastes, thereby increasing waste management costs.
Produced water is the largest oil and gas waste stream that contains NORM. Except at offshore platforms, which discharge produced water to the ocean, nearly all produced water is injected into the subsurface through injection wells.
At this time, the radium content of produced water going to injection wells is not regulated. Consequently, radium that stays in solution in the produced water stream does not present a significant waste management problem from a regulatory perspective and is not discussed further in this article.
Some operators dispose of NORM wastes at their own sites, although most use offsite commercial disposal facilities. Also, pipes and casing with NORM contamination may be recycled as scrap steel if NORM levels are below background concentrations.
Today, the primary method for NORM-waste disposal is underground injection.
Smaller NORM-waste quantities are disposed of at licensed radioactive waste landfills, encapsulated in the casing of a well being abandoned, or managed on lease sites through land-spreading.
Only four offsite commercial NORM-disposal companies have been identified in the U.S. Two inject NORM waste underground and the other two bury NORM waste in landfills.
Identification of disposal companies by name, in this article, does not constitute an endorsement of those companies or provide any indication of their performance capabilities. The companies are included solely to provide an indication of the commercial disposal options available to operators in mid-1998.
Underground injectionNORM-contaminated scales, sludges, and other solid wastes have also been disposed of through underground injection wells. Reference 6 discusses a NORM waste injection project in an Alaska North Slope oil field developed by two major producing companies.
About 100 tons of NORM solids were cleaned from 3,000 oil production pipes and casing. The resulting solids were processed to a particle size of less than 80 mm slurried with 10,000 bbl of water, and then injected into a Class II injection well.
Two of the four U.S. commercial offsite NORM-disposal companies use subsurface injection. Both facilities crush, mill, and slurry the NORM waste before injecting it.
Newpark Environmental Services Inc. operates a NORM-disposal facility near Winnie in East Texas. It receives most of the U.S. NORM wastes commercially disposed of. In July 1997, Lotus LLC opened a NORM-disposal facility in West Texas, near Andrews.
Other disposal contractors, such as Apollo Services and National Injection Services, will come to an operator's site and process NORM wastes so that they can be injected through the operator's own Class II injection well.
The process consists of grinding and milling the waste to a small particle size, slurrying the waste to facilitate pumping, and injecting it into formations at fracture pressure.7
Apollo Services and National Injection Services are primarily disposing of drilling wastes at offshore platforms, but both can also accommodate NORM wastes.
Landfill disposalThe other U.S. offsite commercial NORM waste-disposal option is burial in landfills. U.S. Ecology operates a low-level radioactive waste landfill on DOE's Hanford site in southeastern Washington.
The landfill is primarily designed to handle radioactive wastes other than oil field wastes, but oil field NORM waste is accepted. U.S. Ecology receives relatively little NORM waste because of its remote location from most oil-producing areas and the higher costs associated with general low-level radioactive waste-management requirements.
For example, in 1997, U.S. Ecology received less than 500 cu ft of NORM wastes.
Envirocare of Utah Inc. also operates a landfill for mixed wastes and low-specific-activity radioactive wastes in Clive, Utah. It has accepted NORM waste for disposal.
Encapsulation, downhole disposalWith the encapsulation and downhole disposal option, an operator encapsulates NORM waste either directly in the well bore or inside a section of pipe that is then sealed on both ends and lowered into a well. A plug is placed on top of the waste-containing zone.
Reference 8 discusses two encapsulation projects conducted offshore in the Gulf of Mexico.
In the first project, NORM waste was placed into eight casing joints as the pipe was being lowered into the hole.
In the second project, 31 drums of NORM waste were placed into 21 casing joints onshore and sealed on both ends. The sealed joints were transported offshore and lowered into the well bore.
In both projects, cement plugs were placed on top of the waste-containing joints.
Encapsulation works well for NORM-waste disposal, but each well can handle only a relatively small waste volume. Because of this restriction, the process is not widely used.
Land spreadingThe principle behind land-spreading is to mix NORM wastes having an activity concentration higher than the action level with clean soil so that the resulting blend has an activity concentration lower than the action level.
Some producers use land spreading on their lease sites to blend patches of high-activity NORM soils with low-activity NORM soils. At present, land spreading for disposal of NORM waste is limited. Of the states that have promulgated NORM rules, only two states, New Mexico and Texas, allow land-spreading of NORM.
Disposal costNORM-waste disposal cost has several components. In addition to the cost of the actual disposal operation, operators must consider costs associated with transportation, physical inspection, radionuclide and chemical analysis, and container decontamination.
Because of the limited number of offsite commercial disposal sites available, transportation costs from remote locations can represent a significant cost component.
To the extent possible, this article indicates if the cost figures reflect only disposal costs or include other costs as well.
In addition to direct costs, another important potential cost is long-term liability under the Superfund law. Remediation costs from environmental contamination can be substantial. The EPA estimates the average cost for cleaning up a Superfund site is about $30 million in 1994 dollars (60FR20330, Apr. 25, 1995).
Long-term liability costs are not quantified in this article because they represent a future potential cost, not an actual current cost.
Liability insurance rates paid by operators include the insurer's perception of long-term liability from all phases of the operator's business, including waste disposal. The incremental insurance costs associated with NORM-waste disposal were not identified in this study.
Historical costsAPI's 1992 survey of U.S. oil and gas industry NORM wastes included methods for disposal, costs, and NORM volumes. 9 The survey indicated that disposal costs varied greatly, depending on the specific activity of the NORM, the number of drums being disposed of, and the disposal option selected.
Table 1 [82,362 bytes] summarizes the disposal costs from the survey. The costs ranged from $49 to $3,333/55-gal drum, with an average of $544/drum or $415/bbl.
For some disposal options, various additional costs are identified, including:
- Radiological analysis-$100-500/sample
- Chemical analysis-$250-500/sample
- Pretreatment washing volume reduction-$10-25/drum
- Permitting and manifesting, administrative costs, and non-NORM waste disposal costs.
Current costsSome disposal options in use in 1992 are no longer available, particularly the commercial surface treatment facility in Louisiana. That facility was closed because the operation became unprofitable.
In general, however, NORM-waste disposal costs have decreased between 1992 and 1998.
The following sections provide current information on offsite commercial disposal and disposal services at an operator's site using an existing injection well. Table 2 [44,720 bytes] summarizes these costs.
Cost information was collected directly from disposal companies and from oil and gas operators.
Offsite commercial costsThe following costs were reported to the author in early 1998. There is no guarantee that these costs reflect the actual costs that would be charged to customers or that these companies still charge the same fees. Most commercial disposal companies will negotiate more-favorable rates for customers with large waste volumes.
Newpark Environmental Services Inc. charges $196.50/55-gal drum or $150/bbl for disposal of NORM wastes through injection. This cost includes inspection and verification of contents as well as the necessary analytical costs. The cost of decontamination is $25/drum and $150/bulk container.10 Transportation costs are not included in these figures.
Lotus LLC began accepting NORM waste in 1997. Lotus charges $132/55-gal drum or $100/bbl for disposal by injection. Gamma spectroscopy analysis costs an additional $100/sample. Transportation cost is not included but is estimated to be about $3/loaded mile for a full 72-bbl roll-off box.11
U.S. Ecology operates a low-level radioactive waste-disposal landfill that receives various types of radioactive waste, including NORM waste. Because the facility primarily receives radioactive wastes other than oil field wastes, the requirements are more stringent than those for typical NORM-disposal facilities and costs are higher.
Base disposal costs range from $500 to $550/55-gal drum or from $66.67 to $73.33/cu ft, depending on volume.
Washington State does not recognize the RCRA exemption from hazardous waste status for exploration and production wastes. Therefore, each waste stream must be analyzed for hazardous waste characteristics and radionuclides.
Transportation cost is not included but is estimated to be about $2.10/mile based on a full truck load. All waste generators shipping waste to U.S. Ecology must obtain a site-use permit from the Washington Department of Ecology, which adds to the total cost.
All shipments are subject to a minimum disposal charge of $2,500.12
Envirocare of Utah Inc. operates a landfill for mixed wastes and low-specific activity radioactive wastes that has, on occasion, accepted NORM waste for disposal. Envirocare declined to provide a standard price for disposal but indicated that it sets prices on a case-by-case basis.
According to the company contact, Envirocare is competitive when bidding on large disposal jobs but is not competitive on small jobs because its overhead costs, set for all low-level radioactive waste-disposal activities, is quite high and is constant regardless of the job size.
For large jobs, the overhead is spread over many drums of waste and is therefore low on a cost/drum basis.13
On-site commercial costsAt least two companies, Apollo Services and National Injection Services, provide NOW and NORM disposal at an operator's site. Wastes are ground up, slurried, and injected into the operator's own injection well.
The process of injecting ground and slurried NORM waste could potentially plug the receiving formation. Operators should consider the potential cost of an injection well workover when estimating total disposal costs for these companies.
As of early 1998, Apollo was primarily disposing of NORM at offshore platforms. Apollo estimates that NORM waste disposal costs range from $100 to $300/bbl, depending on volume disposed of.14
National Injection Services disposes of NOW and NORM through on-site injection. National's cost ranges from $15 to $150/bbl, depending on the nature of the materials to be disposed of.15
Actual practices, costsTo provide another perspective on NORM-waste disposal, several major U.S. oil and gas producers were asked about their NORM-disposal practices. Contact persons at these companies agreed to provide information under the condition that their companies not be identified by name. Therefore, companies are identified as Company A, Company B, etc.
Company A disposes of about 600 bbl/year of NORM waste from offshore and the eastern U.S. at a commercial injection-well facility. The cost for disposal and decontamination of containers is $150/bbl, and the cost for lab analyses, transportation, and handling adds another $30/bbl.
Company B operated its own offshore injection well for disposing of offshore NORM waste but now sends all of its NORM wastes to a commercial injection well facility.
Disposal costs range from $125 to $200/bbl. The typical cost rate for a 15-bbl cuttings box is $150/bbl. Company B does some analytical work at $100/test before shipping the waste. Transportation costs are about $25/bbl.
Company C sends much of its NORM waste to a commercial injection-well facility. In the past, Company C operated annular injection wells offshore for NORM disposal. Disposal costs at these wells ranged from $500/bbl for "trouble-free" projects to more than $2,000/bbl for "trouble-plagued" projects.
As less-expensive commercial alternatives became available, Company C opted for offsite commercial disposal.
Company C needs to dispose of a large volume of NORM-contaminated soils from remediation projects and recently opted to develop its own onshore injection well to handle these wastes. Cost figures are not yet available, but the contact person noted that capital and operating costs are high. For the process to be cost effective on a $/bbl basis, the project needs to handle a large volume of wastes.
Company D also sends most of its NORM waste to a commercial injection-well facility. During lease abandonment, Company D sometimes blends patches of NORM-contaminated soils with clean soils to reduce the aggregate NORM activity below levels of regulatory concern. In other cases, large volumes of NORM-contaminated soils are excavated and sent offsite for disposal.
Company D did not provide specific cost figures but indicated that it had received a significant discount from the disposal company's standard rates for one particularly large project.
Two companies operating in Alaska utilize different NORM-disposal methods. Company E ships all its Alaskan NORM waste to a commercial injection facility in Texas, whereas Company F grinds and slurries NORM waste and injects it into its own injection well. No cost information was available for these projects.
One disposal option that was not mentioned by any of the companies is encapsulation in pipes and casing and downhole disposal during plugging and abandonment. This practice is probably occurring, but the costs tend to be higher than other options (Table 1).
If a company has NORM waste at the same location where it is plugging and abandoning multiple wells, this option may be cost effective.
Liability costsLong-term liability costs are an important consideration for major operators. Under the Comprehensive Environmental Response, Compensation, and Liability Act (Cercla), companies that dispose of wastes into sites that later become Superfund sites have joint and several liabilities.
This means that a company contributing only a small portion of a disposal site's waste volume can potentially be held liable for a large portion of the remediation costs, if some or all of the other waste contributors are out of business or are otherwise unable to pay.
Because of this, prudent companies that have historically disposed of waste at a particular disposal site will think twice before extending their potential liability to new disposal sites, even if the new disposal sites are less costly.
AcknowledgmentsThe work described in this article was sponsored by the U.S. Department of Energy, National Petroleum Technology Office (NPTO), under Contract W-31-109-ENG-38. The authors acknowledge John Ford of the NPTO for supporting and encouraging this study.
The study on which this article is based was co-authored by David Tomasko, Deborah Elcock, Deborah L. Blunt, and Gustavious P. Williams.
- Veil, J.A., Smith, K.P., Tomasko, D., Elcock, D., Blunt, D.L., and Williams, G.P., "Disposal of NORM-Contaminated Oil Field Wastes in Salt Caverns," U.S. DOE Office of Fossil Energy, Argonne National Laboratory, Argonne, Ill., August 1998.
- Smith, K.P., Blunt, D.L., Williams, G.P., and Tebes, C.L., "Radiological Dose Assessment Related to Management of Naturally Occurring Radioactive Materials Generated by the Petroleum Industry," ANL/EAD-2, Argonne National Laboratory, Argonne, Ill., September 1996.
- Draft of Difffuse NORM-Waste Characterization and Preliminary Risk Assessment, U.S. EPA Office of Radiation and Indoor Air, Washington, D.C., 1993.
- Tomasko, D., Elcock, D., Veil, J., and Caudle, D., "Risk Analyses for Disposing Nonhazardous Oil Field Wastes in Salt Caverns," U.S. DOE Office of Fossil Energy, Argonne National Laboratory, Argonne, Ill., December 1997.
- "Cleanup and Disposal Guidelines for Sites Contaminated with Radium-226," Drinking Water and Radiological Protection Division, Michigan Department of Environmental Quality, Lansing, 1996.
- McArthur, A., Major, M., and Lowe, D.J., "NORM Disposal in Class II Wells," Paper No. SPE29713, SPE/EPA Exploration & Production Environmental Conference, Houston, Mar. 27-29, 1995.
- Sipple-Srinivasan, M., Bruno, M.S., Bilak, R.A., and Danyluk, P.G., "Field Experiences with Oilfield Waste Disposal through Slurry Fracture Injection," Paper No. SPE38254, 67th SPE Annual Western Regional Meeting, Long Beach, Calif., June 23-27, 1997.
- Scaife, W.W., Mueller, S.G., and Young, D.R., "Downhole Disposal of NORM Wastes in An Offshore Setting: Lessons Learned," proceedings of the International Petroleum Environmental Conference, Houston, Mar. 2-4, 1994.
- "Naturally Occurring Radioactive Material (NORM) Disposal Cost Study," API Publication 7100, 1st edition, API, Washington, D.C., November 1996.
- Personal communication between J. Sammons, Newpark Environmental Services, Houston, and J. Veil, Jan. 23, 1998.
- Letter from J. Kelly, Lotus LLC, Andrews, Tex., to J. Veil, Jan. 9, and personal communication between Kelly and Veil, June 3, 1998.
- Letter from C. White, U.S. Ecology, Richland, Wash., to J. Veil, January 1998.
- Personal communication between A. Rafati, Envirocare of Utah Inc., Salt Lake City, Utah, and J. Veil, Feb. 11, 1998.
- Personal communication between J. Reddoch, Apollo Services, Lafayette, La., and J. Veil, Jan. 21, 1998.
- Personal communication between W. Page and N. Guidry, National Injection Services Inc., Lafayette, La., and J. Veil, Feb. 11, 1998.
John A. Veil is manager of the water policy program for Argonne National Laboratory in Washington D.C. He analyzes a variety of water and waste issues affecting the oil and gas industry for the U.S. Department of Energy. Veil has a BA in earth and planetary science from Johns Hopkins University and two MS degrees, in zoology and in civil engineering, from the University of Maryland.
Karen P. Smith is manager of the environmental systems engineering section, Argonne National Laboratory, Lakewood, Colo.
She has 16 years' experience in petroleum geology, policy analysis, and environmental engineering. Smith has an MS in geology from Southern Methodist University.
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