1- It will depend on which type of oil is being used in the dream. Cooking oil will often signify the removal of friction, or a way of combining different components. Massage oil suggests caring and pampering, whereas engine oil will highlight our ability to keep things moving.
2- Psychologically; we may recognise that a situation can only be dealt with by removing the stress, e.g. ‘Pour oil on troubled water.’
3- Consecration and dedication.