GREENOIL (R): an environmentally safe drilling fluid

Based on the need of having an environmentally safe alternative for drillin g operations in sensitive environments, the present work summarizes the res ults of the environmental evaluation of GREENOIL(R), the drilling fluid for mulated by PDVSA-Intevep. The evaluation consisted in determining the biode gradability and toxicity of the fluid and drilling cuttings, which allow pr edicting the persistence of an organic compound in both aerobic and anaerob ic environments, and determining fluid and drilling cutting concentrations that might cause lethal effects to the exposed organisms. Toxicological eva luation was performed following acute toxicity bioassays (Lethal Mean Conce ntration, LC50), using aquatic bioindicators, representative of Venezuelan marine environments. Biodegradability tests were carried out under aerobic and anaerobic conditions, using microorganisms from waste treatment plants and from natural environments (Orinoco Delta and Lake Maracaibo, Venezuela) . In all cases, international standard protocols were followed to ensure re liability and reproducibility of results obtained. Results indicate that bo th GREENOIL(R) fluid and drilling cuttings are considered non toxic, accord ing to US Environmental Protection Agency (EPA) criteria. Biodegradability tests show that both fluid and drilling cuttings are biodegradable under ae robic and anaerobic conditions, therefore they will not persist in sensitiv e environments. GREENOIL(R), under these conditions, proves to be an enviro nmentally safe drilling fluid.