Nigeria is the largest oil producer in Africa and 6th.in the world. Nigeria has refineries where crude oil is produced.These refineries are subsidiaries of Nigerian National Petroleum Corporation[NNPC].
The functional refineries at a time in Nigeria were 4 in number. One was merged to another hence we have 3 in existence currently in Nigeria. On in the north and two in the Niger deltan region.
The refineries are:

1] Port harcourt refinery the largest in Nigeria with production capacity of 210,000 barrels per day. It was established in 1989. It produces liquified petroleum gas[LPG], premium motor spirit [PMS],Dual purpose kerosine [DKP],Automative gas oil [AGO],Low Pour Fuel Oil [LPFO],and High Pour Fuel Oil [HPFO].This refinery is operated by the Port Harcourt company [PHRC] limited.

2] Warri refinery is located in Warri, Delta State and was established in 1978 with a capacity of 100,000 barrels per day.  It is the second largest in Nigeria.
3] Kaduna refinery is located in Kaduna, Kaduna state and a capacity of 100,000barrels per day also.
It is worthy of note to mention that the Dagote refinery which is under construction will soon make the number of refineries 4 in Nigeria because up till date Nigeria still largely depends on importation of fuel.
Thanks be to God almighty.
BOSIFE.