GULFTENE C16-18 ISOMERISED OLEFINS - NICNAS

18 and are automatically discharged overboard through a pipe set a little below the sea surface
but far above the sea floor.
While most of the drilling mud is recovered in this manner, it is inevitable that some will
remain adsorbed on the surface of the cuttings and may be entrained between the particles of
solid waste and will be discarded with these cuttings. All drilling fluid, other than that
adsorbed to the drill cuttings, is recovered and recirculated through the drill string on a
continuous basis. No whole drilling fluid is discharged overboard. At the end of the drilling
phase all the drilling fluid is recovered and returned to shore for storage until required on
another well. It is important to note that stringent procedures are used to ensure that there is
no loss of whole drilling fluid to the environment at any stage of the drilling and transport
operations. Drilling fluids adhering to the disposed cuttings may constitute up to 10% by
weight of the cuttings.
6. OCCUPATIONAL EXPOSURE
6.1 NUMBER AND CATEGORY OF WORKERS
Import and Transportation: unknown;
Drill mud preparation: 2 to 3 workers;
Drilling crew: approximately 20 workers per offshore platform.
6.2 NATURE OF WORK DONE
Dockside and Transport
Occupational exposure is not expected except in the event of a spill.
Drill Mud Preparation
Using automated systems, operators blend Gulftene 16-18 with other components to produce
the drilling mud as described in Section 5. Preparation of the mud takes about one to two
hours depending on batch size. During preparation, potential for dermal and ocular contact to
Gulftene 16-18 at 33 to 50% exists for workers sampling the drilling mud for quality control
(QC) analysis. Exposure to Gulftene 16-18 may also occur during maintenance of equipment
or in the event of a spill. Formation of aerosol and consequent inhalation exposure is
expected to be negligible given the automated addition systems and the high density of the
drilling muds.
Drilling
The large size of drilling equipment suggests that drill operators will have potential for
exposure to high volumes of drilling mud during manipulation of the drill when the drill bit is
replaced or removed from the drill hole. There is potential for skin and eye contact during
these activities. Formation of aerosol and consequent inhalation exposure is expected to be
negligible given the high density of the drilling mud.
FULL PUBLIC REPORT 26 April 2000
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