Abstract:TX 75083-3836, U.S.A., fax 01-972-952-9435.
AbstractThe inability to consistently discriminate biodegradation performance inhibits the development and use of Synthetic-Based Muds ( SBMs) and other non-aqueous base fluids. Government regulators and industry representatives are discussing and seeking to improve the repeatability, discriminatory power and environmental relevance of the current bottle and simulated seabed biodegradation tests. To date, the existing protocols and procedures are only moderately succ… Show more
“… 4 Chemical structures of some drilling base fluids, vegetable oil-based functional fluids, and other functional fluids. %TGP = percent of theoretical gas production in modified ISO 11734; EN = estolide number. …”
Section: 4 Drilling Base Fluidsmentioning
confidence: 99%
“…Recent work has focused on anaerobic biodegradation because anoxic conditions are expected to prevail in the centers of cuttings piles in the field. 32,33 Effluent guideline limitations established in 2001 require that SBFs to be used in offshore drilling be tested for sediment toxicity using the amphipod Leptocheirus plumulosus and for anaerobic biodegradability using a modification of ISO 11734 34 (http://web.ead.anl.gov/dwm/techdesc/discharge/index. cfm).…”
“… 4 Chemical structures of some drilling base fluids, vegetable oil-based functional fluids, and other functional fluids. %TGP = percent of theoretical gas production in modified ISO 11734; EN = estolide number. …”
Section: 4 Drilling Base Fluidsmentioning
confidence: 99%
“…Recent work has focused on anaerobic biodegradation because anoxic conditions are expected to prevail in the centers of cuttings piles in the field. 32,33 Effluent guideline limitations established in 2001 require that SBFs to be used in offshore drilling be tested for sediment toxicity using the amphipod Leptocheirus plumulosus and for anaerobic biodegradability using a modification of ISO 11734 34 (http://web.ead.anl.gov/dwm/techdesc/discharge/index. cfm).…”
Drilling muds used by the petroleum exploration and production industry have the role of lubricating and cooling the drilling bits and facilitating the transport of crushed rocks to the surface of the well. The chemical formulations of the drilling muds influence their fate when discharged into the marine environment and, along with ambient parameters, determine the biodegradability and toxicity of the muds. A case study describes the comparison of aquatic toxicity and biodegradability of two different synthetic‐based drilling mud systems (SBMs), Syndrill 80:20 and Syndrill 90:10, and also individual mud ingredients. Chronic fish toxicity was measured using a suite of biomarkers of fish health. Preliminary tests led to the selection of the drilling mud Syndrill 80:20, and toxicity testing of individual ingredients of this mud showed that the primary emulsifier was the most aggressive component among all the mud ingredients tested. The present study aimed at developing an ecologically safe, green SBM by further improvements to Syndrill 80:20 through replacement of the most aggressive emulsifier with an alternative low/non‐toxic alternative. The existing Syndrill 80:20 formulation was re‐engineered by the incorporation of two alternative emulsifiers as replacements for the existing aggressive emulsifier. The new modified Syndrill 80:20 was then evaluated for its chronic toxicity against the existing Syndrill 80:20 using a suite of biomarkers of fish health. Following exposure to the modified mud system, pink snapper (
Pagrus auratus
) demonstrated weaker biological reactions as measured by ethoxyresorufin‐
O
‐deethylase (EROD) activity, biliary metabolites, and serum sorbitol dehydrogenase (SDH) activity. Closed‐bottle biodegradation tests also indicated that the new formulation is actively biodegrading under marine anaerobic conditions. Therefore, the information on the toxicity of the re‐engineered SBM provides an initial basis for evaluating its environmental performance in marine ecosystems, and may assist regulatory authorities in gaining a better understanding of the fate of SBMs in the marine environment.
Biodegradation has been recognized as an important element of natural attenuation of increased organic loading at the seafloor from non-aqueous drilling fluids (NAF) that are associated with drill cuttings discharge. While recognized as an important characteristic of advanced NAF design, measurement of biodegradation properties of base fluids used in NAF presents a technical and regulatory challenge as applied to certain environments. In order to meet this challenge, modification of a standardized anaerobic biodegradation test has been pursued in Brazil with the goal of developing an ecologically relevant and repeatable test that can differentiate between the various NAF technologies. This paper will review the progress to date in developing this biodegradation test for use in Brazil. In particular, the sediment, which is used as the bacteria inoculums, will be compared and contrasted with other natural sediments that have successfully been used in this type of test.
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