Offsite oil field waste disposal varies across U.S.

John A. Veil
Argonne National Laboratory
Washington, D.C.

• These drilling mud disposal pits are in Ector County, Tex. (photo courtesy of Russ Hickerson).
• These disposal pits in Ector County, Tex., are filled with solids and then covered by soil (photo courtesy of Russ Hickerson).

Cost and availability of offsite commercial oil field waste disposal vary considerably across the U.S. and substantially depend on such factors as the disposal method, the state in which the disposal company is located, and the degree of competition in the area.

U.S oil and gas exploration and production generate millions of barrels of nonhazardous oil field wastes annually. In most cases, operators can dispose of oil field wastes at a lower cost on site than offsite and, thus, will choose on site disposal. However, significant quantities of oil field wastes are still sent to offsite commercial facilities for disposal.

The two major U.S. offsite disposal trends are as follows:

1. Nine oil and gas-producing states (Arkansas, California, Louisiana, New Mexico, Oklahoma, Pennsylvania, Texas, Utah, and Wyoming) have numerous commercial disposal companies that handle oil field wastes exclusively. These companies use the same disposal methods as on site disposal. In addition, the Railroad Commission of Texas has issued permits to allow oil field wastes to be disposed of in several salt caverns. Disposal caverns, an innovative disposal option utilizing salt caverns, are currently cost-competitive in the Texas waste disposal market. However, disposal cavern costs are likely to rise in the near future as the Railroad Commission of Texas adopts regulations governing cavern disposal. It is unclear how the increased costs will affect the competitiveness of disposal caverns in the future, since costs at competing waste disposal facilities are unlikely to remain static.
2. Twenty-two other oil and gas-producing states (Alabama, Alaska, Arizona, Colorado, Florida, Illinois, Indiana, Kansas, Kentucky, Maryland, Michigan, Mississippi, Missouri, Montana, Nebraska, Nevada, New York, North Dakota, Ohio, South Dakota, Virginia, and West Virginia) have few or no disposal companies dedicated to oil and gas industry waste. The only offsite commercial disposal companies available handle general industrial wastes or are sanitary landfills. In those states, operators needing to dispose of oil field wastes offsite must send them to a local landfill or out of state.

Oil field wastes

As companies explore for and produce oil and gas, they generate various nonhazardous liquid, semisolid, and solid wastes. When on site disposal is allowed, it is generally the least expensive disposal option. Consequently, the majority of nonhazardous wastes are disposed of on site.

The term "on site" includes waste disposal on:

• The same lease as the oil and gas operation generating the wastes
• A location off the lease owned by the same company that operates the well generating the wastes.

Offsite commercial disposal companies handle wastes if state regulations preclude on site disposal or if operators elect to avoid the responsibility of on site waste disposal.

According to an API production waste survey, in 1985 U.S. oil and gas exploration and production generated more than 360 million bbl of drilling wastes, more than 20 billion bbl of produced water, and nearly 12 million bbl of associated wastes.^{1 2} Current exploration and production activities could generate comparable quantities of these oil field wastes.

The API estimate indicates that significant volumes of oil field wastes are sent to offsite commercial disposal facilities each year.1 This includes 28% of drilling wastes, less than 2% of produced water, and 52% of associated wastes.

Recently, Argonne National Laboratory completed a survey of 31 oil and gas-producing states and compiled the number, location, type, and cost of commercial oil and gas waste disposal facilities in those states (Fig. 1 [148,483 bytes]).³ This article summarizes that survey.

Waste type

Most oil field wastes that arise from or are associated with oil and gas exploration and production are considered to be nonhazardous by virtue of being specifically exempted from federal hazardous waste requirements. ⁴ Nonhazardous oil field wastes can be assigned to several categories such as drilling wastes, produced water, and associated wastes.

Drilling wastes include drilling muds, drill cuttings, wash water, and other related wastes.

Associated wastes are small-volume wastes that are generated as a result of activities related to oil and gas exploration and production but are not drilling wastes or produced water. According to Reference 1, nearly half of the associated wastes in 1985 consisted of well treatment fluids such as workover and completion fluids.

Other waste classes that contribute significantly to associated waste volume include oil debris and contaminated soils (11%), produced sands (11%), and tank bottoms (10%).

Disposal options

Several methods for disposing of oil field wastes are available to operators. Whether on site disposal or offsite commercial disposal, the actual disposal method will commonly be one of the following:

• Underground injection such as in disposal wells, enhanced oil recovery wells, annular injection, and salt caverns
• On site burial such as in pits, and landfills
• Land treatment such as by land spreading, land farming, and road spreading
• Evaporation
• Surface discharge
• Recycling.

Operators select a disposal option after considering waste characteristics, federal and state regulations, and commercial offsite disposal availability and cost. Disposal availability is not the same in all states, and therefore, the distribution of selected disposal options varies.

Reference 3 summarizes information from References 1, 2, and 5 about disposal options available in different states.

Regulatory considerations

Because of the federal exemption from the hazardous waste requirements of the Resource Conservation and Recovery Act (RCRA) for oil field wastes, ⁴ the waste management requirements faced by most operators will be state requirements. Reference 5 provides a thorough overview of waste management requirements in 17 states with oil and gas production.

As of 1992, all of the 17 states surveyed allowed most types of oil field wastes to be disposed of on site by a variety of methods. Not every state allows all disposal methods but each state allows several disposal options.

For example:

• Kansas does not allow land spreading of drilling wastes.
• Louisiana does not allow pits in coastal areas.
• Michigan and North Dakota prohibit annular injection.

Most states follow the U.S. Environmental Protection Agency's (EPA's) determination to exempt oil field wastes from hazardous waste requirements. California is an exception to this policy. It does not offer a blanket exemption from hazardous waste requirements.

California requires testing all wastes. The wastes that test as hazardous, regardless of their source, must be handled as hazardous wastes.

The Interstate Oil & Gas Compact Commission (Iogcc) has developed waste management guidelines for state oil and gas regulatory programs that recognize and support on site disposal of nonhazardous oil and gas wastes.⁶ Individual states are not bound by the Iogcc guidelines, but the guidelines serve as a good indication of the practices allowed by states.

Reference 6 contains general and administrative criteria and technical criteria for on site pits, land spreading, burial and landfilling, road spreading, tanks, and offsite commercial and centralized disposal facilities.

Availability, cost

Table 1 [9,782 bytes]Table 1 (cont. [4,998 bytes]) lists the availability and disposal costs at offsite commercial disposal facilities in 31 states with oil and gas production. These 85 facilities accept wastes that are oily or solid wastes. This would include oil-based drilling wastes and associated wastes.

The inclusion of disposal companies in Table 1 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 commercial disposal options available to operators in the 1996-1997 time frame.

Also from Reference 3, Table 2 [9,417 bytes] provides a partial list of offsite commercial disposal facilities that accept produced water, and Table 3 [6,199 bytes] lists offsite commercial disposal facilities that accept water-based drilling wastes.

Data for Table 1 were collected in two steps. First, representatives of state oil and gas regulatory agencies were contacted to determine if a list of permitted commercial disposal companies was available. If such a list existed, each company on the list was contacted by telephone.

If a state agency had no list of commercial disposal companies, state officials were asked to describe how operators in that state disposed of their nonhazardous oil field waste.

Commercial disposal companies were asked what wastes they accepted, what disposal method they employed, and how much they charged for disposal, exclusive of transportation costs.

The majority of companies surveyed willingly provided information. A few companies elected not to participate, primarily out of concern that the cost information might be used to their competitive disadvantage.

Disposal facilities use any of three cost rates: $/bbl, $/cu yard, or $/ton. For 85 disposal facilities, overall costs range from $0 to $57/bbl, $4.20 to $50/cubic yard, and $12 to $100/ton.

Land spreading operations have a significant share of the commercial disposal market, with costs ranging from $5.50 to $57/bbl. Landfills and pits represent another important disposal option, with costs ranging from $0.50 to $36/bbl. Only one landfill/pit facility charged less than $2.25/bbl.

Two facilities evaporate the liquid fraction of the waste and send the solids to a landfill. They charge $2.50-2.75/bbl. Several facilities treat the wastes before reusing or disposing of them. These facilities charge $0-12/bbl, although only one facility charges less than $3/bbl.

Several facilities incinerate wastes, with costs ranging from $10.50 to $38/bbl. Finally, the four cavern disposal facilities charge from $1.95 to $6/bbl.

Disposal costs for produced water, rain water, and other types of dirty-water wastes range from $0.01 to $8/bbl, although most costs fall in the $0.25-1.50/bbl range. Disposal costs for water-based drilling wastes range from $0.20 to $14.70/bbl, $5 to $37.50/cubic yard, and $15 to $55/ton.

Acknowledgment

This work was sponsored by the U.S. Department of Energy, Office of Fossil Energy, under Contract W-31-109-Eng-38.

References

1. Wakim, P.G., API 1985 Production Waste Survey, Statistical Analysis and Survey Results, API, Washington D.C., October 1987.
2. Wakim, P.G., API 1985 Production Waste Survey, Part II Associated and Other Wastes, Statistical Analysis and Survey Results, API, Washington D.C., June 1988.
3. Veil, J.A., "Costs for Offsite Disposal of Nonhazardous Oil Field Wastes: Salt Caverns versus Other Disposal Methods," Argonne National Laboratory, Washington D.C., for U.S. Department of Energy, April 1997.
4. Federal Register notices at 53 FR 25477, July 6, 1988 and 58 FR 15284, Mar. 22, 1993.
5. Oil and Gas Exploration and Production Waste Management: A 17-State Study, DOE/FE-62017-H1, ICF Resources Inc., Washington D.C., for U.S. Department of Energy, and Interstate Oil and Gas Compact Commission, Oklahoma City, Okla., June 1993.
6. IOGCC Environmental Guidelines for State Oil & Gas Regulatory Programs, Interstate Oil and Gas Compact Commission, Oklahoma City, Okla