The oil and gas industry has historically used water-based muds (WBMs) and oil-based muds (OBMs) in offshore drilling operations. WBMs are less expensive and are widely used. Both the WBMs and the associated drill cuttings may be discharged from the platform to the sea provided that U.S. Environmental Protection Agency (EPA) discharge limitations are met. In some wells, however, difficult drilling conditions may force a switch from a WBM to an OBM. Neither the OBM nor the associated drill cuttings may be discharged. The OBM is hauled to shore, where it is processed for reuse, while the associated cuttings are injected in a disposal well at the platform or hauled to shore to a disposal facility. Both of these options are expensive. Synthetic-based muds (SBMs) are drilling fluids that use synthetic organic chemicals as base fluids. SBMs were developed to replace OBMs in difficult drilling situations. SBMs are more expensive than OBMs; however, they have superior environmental properties that may permit the cuttings to be discharged on-site. Like OBMs, SBMs are hauled ashore for processing and reuse after the well is drilled. The existing national effluent limitations guidelines (ELGs) for the offshore industry do not include requirements for SBM-cuttings since SBMs were not commonly in use at the time the ELGs were adopted. In late 1997, EPA announced that it would modify the offshore ELGs to include requirements for discharges of cuttings drilled with SBMs. For the first time in the history of the ELG program, EPA is following an innovative presumptive rulemaking process that will lead to development of draft regulations in one year rather than the 4- to 6-year period usually needed. With direction from the federal government to stakeholders concerning information needs for the regulatory development the industry has established several working groups to collect new scientific information on SBMs. This paper describes the presumptive rulemaking process and summarizes the findings of the work groups to date.
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