Petroleum is obtained by drilling holes in the earth’s crust and sinking pipes into it as shown in Fig. 51.1
Fig. 51.1. Mining of petroleum.
When the pipe reaches the oil deposit, natural gas comes out with a great pressure and for a time the crude oil comes out by itself due to the pressure of the gas over oil. This is the primary recovery process. Gradually the pressure of the gas decreases. At this stage, the crude oil is extracted with the help of lift pumps. The is the secondary recovery process.
In West Africa, Nigeria and, to a lesser extent Cote d’ Ivoire are the only countries that produce oil.
Ghana meets its oil requirements by importing refined as well as crude oil, much of the oil is imported from Nigeria