Drilling waste discharges in the marine environment : a risk based decision methodology

摘要: Offshore drilling operations generate rock cuttings and spent fluids wastes during the well phase. The contain toxic substances that are harmful to marine ecosystem. Discharge limitations restrictive guidelines in different jurisdictions of world under development. Pollution prevention by encouraging synthetic based (SBFs) place traditional oil has been supported recent years. Despite having environmentally benign characteristics. SBFs associated still have a certain amount pollutants due barite contamination with formation oil. -- main aim this study was develop risk management framework for determining best waste discharge scenario disposal environment. specific objectives research were: (1) development probabilistic contaminant fate modeling methodology using fugacity aquivalence approaches; (2) an ecological assessment concepts; (3) human health cancer non-cancer methodologies (4) fuzzy composite programming integrating environmental risk, cost estimates technical feasibility various treatment options; (5) application developed hypothetical case study. Fate performed concepts. A chemical approach employed modeling. steady state non- equilibrium water sediment interaction model inputs used determine concentrations column pore water. uncertainty variability were expressed statistical distributions. estimated Latin Hypercube sampling (LHS) Monte Carlo (MC) simulations. followed lognormal parameters distribution known conditions performing multiple regression analyses. highest 95th percentile as predicted concentration (PEC). uncertainties PEC coefficients models. values converted into exposure (EC) adjusting bioavailability probability exposure. whole community defined endpoints. toxicity analyses on lognormally distributed no effect (PNEC). lowest 10th PNEC distributions safety level or criteria value. Bootstrapping original data values. hazard quotients (HQ/RQ) calculated dividing EC CHARM model's convert HQ/RQ each contaminant. determined individual assuming statistically independent events. consumption contaminated seafood. estimates. chronic daily intake rate (CDI) established fish ingestion rates, lipid content, bioconcentration factors, duration, frequency, averaging time. LHS MC simulations estimate CD I. Arsenic only proven carcinogen stream. index risks simple addition given scenario. (CP) developed. costs treatment, fluid loss damages estimated. solid control devices also studied from performance viewpoint. reductions, saving indices grouped CP methodology. double weighting scheme CP. final utility centroidal system improvement through Chen Yager ranking methods, respectively alternative. applied East Coast Canada. Five scenarios, alternatives including 10.0%, 8.5%. 7.0%, 5.5% 4.0% attached base wet cuttings, selected analysis. 4% option found be first trial when equal weight allotted one-third weight. 7.0% second 5.5%, 8.5% 10.0%. respectively. sensitivity analysis four schemes account subjectivity. It concluded alternative other better options and/or (approximately 5-6% dry cuttings). This introduced new concept within conflicting objectives. provided decision support selection any regulatory constraints.