New information on disposal of oil field wastes in salt caverns

Solution-mined salt caverns have been used for many years for storing hydrocarbon products. This paper summarizes an Argonne National Laboratory report that reviews the legality, technical suitability, and feasibility of disposing of nonhazardous oil and gas exploration and production wastes in salt caverns. An analysis of regulations indicated that there are no outright regulatory prohibitions on cavern disposal of oil field wastes at either the federal level or in the 11 oil-producing states that were studied. There is no actual field experience on the long-term impacts that might arise following closure of waste disposal caverns. Although research has found that pressures will build-up in a closed cavern, none has specifically addressed caverns filled with oil field wastes. More field research on pressure build-up in closed caverns is needed. On the basis of preliminary investigations, we believe that disposal of oil field wastes in salt caverns is legal and feasible. The technical suitability of the practice depends on whether the caverns are well-sited and well-designed, carefully operated, properly closed, and routinely monitored

Increased emphasis on toxics control in oil and gas industry NPDES permits

The 1987 amendments to the Clean Water Act emphasized stricter control of toxics in wastewater discharges. Although state and U.S. Environmental Protection Agency permit writers have had the authority to incorporate strict water quality-based controls in permits, they did not widely use this authority in the past. However, general permits proposed in the past year by Region VI for discharges into the territorial seas of Louisiana and by Region X for coastal and offshore discharges in Alaska are much stricter than their predecessors. The Region VI permit requires numerical produced water limits on arsenic, lead, benzene, total phenols, radium, and whole effluent toxicity. The Region X permit requires numerical produced water limits on copper, arsenic, zinc, total aromatic hydrocarbons, total aqueous hydrocarbons, and whole effluent toxicity. The additional requirements increase the cost of complying with the permit, present more opportunities for exceeding one of the permit limits, and serve as a precedent for future permits. The industry should be prepared to accept the additional costs of these requirements or develop data to convince the regulatory agencies that the increased level of monitoring and permit limits is not necessary to protect water quality. Regulatory agencies should be receptive to new data provided by the industry and flexible in setting additional toxics controls

Analysis of U.S. produced water controls -- Are they cost-effective?

The US Environmental Protection Agency (EPA) establishes controls on produced water discharges into US waters through effluent limitations guidelines (ELGs), and general and individual discharge permits. Over the past 20 years, produced water controls have become much stricter, and in some areas, no discharge of produced water is allowed. In setting discharge standards, EPA considers vast amounts of data, makes assumptions regarding which data and what approaches are representative, selects the most appropriate analytical methods, and interprets the analytical results. Despite EPA`s considerable efforts to accurately understand and characterize the economic and environmental impacts of produced water discharges before proposing and adopting ELGs and issuing permits, current US produced water controls may be overly restrictive and not cost-effective. This paper summarizes several studies that have reviewed in detail EPA`s data, assumptions, and analytical methods for earlier proposed regulations and general permits. These include the offshore oil and gas ELGs, EPA`s Region 6 general permit for coastal waters, and most recently, the proposed ELGs for the coastal oil and gas industry. By substituting different data, using revised assumptions, and reanalyzing data that are equally or more valid, the studies reach alternate conclusions on the cost-effectiveness of current produced water controls

Can nonhazardous oil field wastes be disposed of in salt caverns?

Solution-mined salt caverns have been used for many years for storing hydrocarbon products. This paper summarizes an Argonne National Laboratory report that reviews the legality, technical suitability, and feasibility of disposing of nonhazardous oil and gas exploration and production wastes in salt caverns. An analysis of regulations indicated that there are no outright regulatory prohibitions on cavern disposal -of oil field wastes at either the federal level or in the 11 oil-producing states that were studied. There is no actual field experience on the long-term impacts that might arise following closure of waste disposal caverns. Although research has found that pressures will build up in a closed cavern, none has specifically addressed caverns filled with oil field wastes. More field research on pressure build up in closed caverns is needed. On the basis of preliminary investigations, we believe that disposal of oil field wastes in salt caverns is legal and feasible. The technical suitability of the practice depends on whether the caverns are well-sited and well-designed, carefully operated, properly closed, and routinely monitored

EPA compromises consistency in its coastal oil and gas industry cost-effectiveness analysis

The US Environmental Protection Agency (EPA) conducts a cost-effectiveness (CE) analysis to estimate the cost of complying with each newly proposed set of industrial effluent limitation guidelines (ELGs). CE is defined as the incremental annualized cost of a pollution control option in an industry per incremental pound equivalent (PE) of pollutant removed annually by that control options. EPA`s guidelines for conducting the CE analysis require that all costs be expressed in 1981 dollars so that comparison to other industries can be done on a consistent basis. In the results of its CE analyses, EPA presents information showing $/PE values for all the industries for which it has done the CE analysis. These examples indicate that EPA is interested in maintaining consistency and comparability. EPA is not legally bound by the results of a CE analysis; however, if the$/PE for a proposed ELG is calculated to be significantly higher than the $/PEs for other comparable ELGs, EPA might reconsider its proposal. EPA`s approach of using an expanded pollutant list and revised weighting factors probably generates a more accurate estimate of the PEs removed for the coastal oil and gas industry, but in doing so, EPA loses the ability to equitably compare this CE analysis to the CE analyses that have been done for other industries. This shortcoming is particularly obvious since the offshore Ce analysis, evaluating a nearly identical waste stream, was completed just two years earlier. Given EPA`s concern over consistency and comparability to other industries, it may be appropriate to modify this approach for the coastal CE analysis. Another alternative that would allow EPA to reflect the newest toxicological information and still preserve consistency and comparability would be to recalculate all earlier CE analyses whenever new weighting factors are developed

Disposal of oil field wastes into salt caverns: Feasibility, legality, risk, and costs

Salt caverns can be formed through solution mining in the bedded or domal salt formations that are found in many states. Salt caverns have traditionally been used for hydrocarbon storage, but caverns have also been used to dispose of some types of wastes. This paper provides an overview of several years of research by Argonne National Laboratory on the feasibility and legality of using salt caverns for disposing of oil field wastes, the risks to human populations from this disposal method, and the cost of cavern disposal. Costs are compared between the four operating US disposal caverns and other commercial disposal options located in the same geographic area as the caverns. Argonne`s research indicates that disposal of oil field wastes into salt caverns is feasible and legal. The risk from cavern disposal of oil field wastes appears to be below accepted safe risk thresholds. Disposal caverns are economically competitive with other disposal options

Consequences of proposed changes to Clean Water Act thermal discharge requirements

This paper summarizes three studies that examined the economic and environmental impact on the power industry of (1) limiting thermal mixing zones to 1,000 feet, and (2) eliminating the Clean Water Act (CWA) {section}316(1) variance. Both of these proposed changes were included in S. 1081, a 1991 Senate bill to reauthorize the CWA. The bill would not have provided for grandfathering plants already using the variance or mixing zones larger than 1000 feet. Each of the two changes to the existing thermal discharge requirements were independently evaluated. Power companies were asked what they would do if these two changes were imposed. Most plants affected by the proposed changes would retrofit cooling towers and some would retrofit diffusers. Assuming that all affected plants would proportionally follow the same options as the surveyed plants, the estimated capital cost of retrofitting cooling towers or diffusers at all affected plants ranges from $21.4 to 24.4 billion. Both cooling towers and diffusers exert a 1$10 to 18.4 billion over 20 years. Generation of the extra power would emit over 8 million tons per year of additional carbon dioxide. Operation of the new cooling towers would cause more than 1.5 million gallons per minute of additional evaporation. Neither the restricted mixing zone size nor the elimination of the {section}316(1) variance was adopted into law. More recent proposed changes to the Clean Water Act have not included either of these provisions, but in the future, other Congresses might attempt to reintroduce these types of changes

Produced water toxicity tests accurately measure the produced water toxicity in marine environments?

U.S. Environmental Protection Agency (EPA) Region VI has issued a general permit for offshore oil and gas discharges to the Gulf of Mexico that places numerical limits on whole effluent toxicity (WEI) for produced water. Recently proposed EPA general permits for other produced water discharges in Regions VI and X also include enforceable numerical limits on WET. Clearly, the industry will be conducting extensive produced water WET testing. Unfortunately, the WET test may not accurately measure the toxicity of the chemical constituents of produced water. Rather the mortality of test organisms may be attributable to (1) the high salinity of produced water, which causes salinity shock to the organisms, or (2) an ionic imbalance caused by excesses or deficiencies of one or more of seawater`s essential ions in the test chambers. Both of these effects are likely to be mitigated in actual offshore discharge settings, where the receiving water will be seawater and substantial dilution will be probable. Thus, the additional salinity of produced water will be rapidly assimilated, and the proper marine ionic balance will be quickly restored. Regulatory authorities should be aware of these factors when interpreting WET test results

Synthetic drilling fluids - a pollution prevention opportunity for the oil and gas industry

Offshore oil and gas operators use specialized drilling fluids, referred to as {open_quotes}muds,{close_quotes} to help maintain well control and to remove drill cuttings from the hole. Historically, either water-based muds (WBMs) or oil-based muds (OBMs) have been used for offshore wells. Recently, the drilling industry has developed several types of synthetic-based muds (SBMs) that combine the desirable operating qualities of OBMs with the lower toxicity and environmental impact qualities of WBMs. This report describes the operational, environmental, and economic features of all three types of muds and discusses potential EPA regulatory barriers to wider use of SBMs