Oil pastel an almost impasto effect. Once applied to a surface, the oil pastel pigment can be manipulated with a brush moistened in white spirit, turpentine, linseed oil, or another type of vegetable oil or solvent. Alternatively, the drawing surface can be oiled before drawing or the pastel itself can be dipped in oil. Some of these solvents pose serious health concerns. Oil pastels are considered a fast medium because they are easy to paint with and convenient to carry; for this reason they are often used for sketching, but can also be used for sustained works. Because oil pastels never dry
Oil platform onshore. Subsea facilities are also easier to expand, with new separators or different modules for different oil types, and are not limited by the fixed floor space of an above-water installation. Offshore oil production involves environmental risks, most notably oil spills from oil tankers or pipelines transporting oil from the platform to onshore facilities, and from leaks and accidents on the platform. Produced water is also generated, which is water brought to the surface along with the oil and gas; it is usually highly saline and may include dissolved or unseparated hydrocarbons. The world's deepest oil platform is the floating