Bill Freeman,* Shell Oil, J. Daniel Arthur,* CH2M HILL, Technical Reviewers: Bill Bryson, Kansas Corporation Commission, Jerry Mullican, Railroad Commission of Texas, Paul Roberts, Nebraska Oil & Gas Conservation Commission, Don Warner, University of Missouri-Rolla, Lori Litzen, Shell Western E&P Roger Noble, CH2M HILL Abstract The competition between ever-expanding environmental regulations and the ongoing decrease in environmental protection resources has prompted both regulatory agencies and industry to more closely examine the use of these limited resources. In the underground injection control (UIC) program, technical and managerial professionals from industry and government must at times evaluate whether or not certain ground water aquifers should be protected. If an aquifer exemption is clearly justified, the operator should not have to protect it, hence conserving valuable environmental protection resources. However, some state and federal agencies would prefer never to approve an aquifer exemption even though some are justified. This is apparent as the variations regarding how aquifer exemptions are processed by agencies seems largely to be resulting from the lack of clear guidance on aquifer exemptions and the lack of understanding for the term "reasonably expected" as intended by EPA and Congress. Because of the lack of positive instruction from state and federal agencies and a general lack of awareness on industry's part, the aquifer exemption process continues to be somewhat esoteric and often times misunderstood. The purpose of the UIC Program as mandated by Congress is to protect underground sources of drinking water (USDW) being used in public water systems, as well as to protect potential USDWs where there is a reasonable likelihood that these sources will be needed in the future. However, Congress did not intend for EPA to protect all potential USDWs. If it was reasonably expected that a potential USDW could not be used in the future as a public water system, protection of that aquifer would not be required. In fact, EPA affirmed that it would be a misallocation of resources to seek to protect as drinking water sources aquifers which in fact would not be used by public water systems. The ensure that such aquifers would not be protected, EPA developed an aquifer exemption process under 40 CFR 144.7 and 146.4 by which aquifers could be evaluated for their potential use as future public water systems. Government and Industry should utilize the aquifer exemption process as much as possible to ensure that the wise use of limited environmental protection resources is accomplished. The Clinton Administration appears to also endorse this position. In an April 1994 Letter to Congressman Earnest J. Istook on the domestic oil and gas industry, President Clinton stated: "we intend to help on the cost side… by reducing unnecessary and inefficient costs and regulations. I have challenged federal agencies to eliminate regulatory overkill and to attack regulatory barriers and subsidies here and abroad". Introduction The competition between ever-expanding environmental regulations and the ongoing decrease in environmental protection resources has prompted both regulatory agencies and industry to more closely scrutinize these scarce resources. P. 671

This study was conducted to address the problem of inconsistent barium (Ba) analyses and the need to de-fine an acceptable criteria level. The study provides both mechanistic and comparative data in support of suggested changes in the Amendment to Statewide Order 29-B. Initial non-hazardous oilfield waste (NOW) studies, which served as the basis for Ba criteria, used 1979 ERA protocol for estimating total metal contents. Three published revisions have since been made by EPA concerning Test Methods for Evaluating Solid Wastes (SW-846, 1982; SW-846, 1984; and SW-846, 1986), Sample size was the principal difference reflected in the revised protocols; sample size decreasedover time. Experiments were designed and conducted to provide a method for determining "true" total Ba for comparison to SW-846 protocol. Regression analyses comparing SW-846 Ba as the dependent variable and corresponding total Ba as the independent variable showed the data best fit a polynomial (Y = -3.29 x 10 b(X)Z + 0.43 (X) + 376) with a r2 = 86%. Multiple linear regression analyses showed SW-846 Ba levels a function of the matrix pH, salinity, oil & grease, and "true" total Ba content. A metals fractionation by sequential chemical extrac-tion technique demonstrated that Ba remains in a solid phase (barite form), evenafter being circulated down hole and subjected to extreme heat and strongly alka-line reactions. Chemical distributions varied signi-ficantly in response to mixing NOW solids with native soil and subjecting mixtures to reducing (diminished oxygen tension) conditions. Total Ba and oxygen ten-sion (redox potential) were found to have the greatest affect on Ba activity.

The Environmental Protection Agency (EPA) presented the Regulatory Determination on presented the Regulatory Determination on drilling muds, produced water and associated wastes to Congress on June 30, 1988. One conclusion was regulatory gaps were present in some State oil and gas programs that compromised environmental protection. EPA believes they have authority under Subtitle D to fill these gaps. However, the Subtitle D type waste management guidelines, as being formulated by EPA to regulate mining operations and municipal landfills, are not viable or cost effective when applied to Oil and Gas Industry (OGI) operations. The existing drilling waste management practices used by the OGI in a number of State oil and gas programs though are viable and cost effective to ensure environmental protection. These existing practices as discussed protection. These existing practices as discussed in this paper can be implemented in applicable State programs to fill regulatory gaps. 1.0 Introduction Under the Resource Conservation and Recovery Act (RCRA) passed in 1976, and amended in 1980, EPA was directed to conduct a two-year study to determine if drilling muds, produced water, and associated wastes were hazardous and should be regulated under Subtitle C. The Study was to be completed by October 1982, but was not implemented. After a lawsuit was filed by environmentalists in 1985, the study was initiated and the Regulatory Determination for OGI wastes was submitted by EPA to Congress on June 30, 1988. In the Regulatory Determination EPA stated "The Agency plans a three-pronged approach toward filling the gaps in existing State and Federal programs by: programs by:Improving Federal programs using existing authorities in Subtitle D of RCRA, the Clean Water Act, and Safe Drinking Water Act;Working with States to encourage changes in their regulations and enforcement programs to achieve more uniformity in the administration of their programs; andWorking with the Congress to develop any additional, statutory authority that may be required". EPA believes they have authority under Subtitle D of RCRA to promulgate nationwide guidelines to regulate the generation, collection, and disposal of OGI wastes. Because Industry believes OGI wastes are generally managed properly in most States, API is working to describe existing drilling operations and disposal practices in an Environmental Guidance Document that can be used by States to fill regulatory gaps. It is essential for EPA to understand that States can use these existing practices to formulate cost effective regulations in their existing programs to protect the environment, without mirroring onerous and expensive Subtitle D regulations designed for mining waste and municipal landfill disposal sites. 2.0 Scope This Paper addresses existing waste generation, collection, and disposal practices in the drilling segment of the OGI. First, drilling wastes and volumes are identified and reported, respectively. Second, waste generation sources are identified, collection practices are reviewed, and disposal practices are briefly described. practices are briefly described. P. 451