Sampling can be done manually or automatically, it can be done in the tankers or in the pipeline. It is important that the product that enters the sampling bottle remains undisturbed by the sampling process itself and thus the type of bottle used must be adequate for crude oil (simple plastic bottle will not be suitable). Oil contains both particles and water which are not found homogeneously throughout the crude oil and thus it is important to sample the oil in a manner that will best be representative of the oil in place. Sampling should thus be carried out at the top, middle and bottom of the tank