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.

GAS PROCESSING IN NIGERIA [OML 53, located onshore in the north eastern Niger Delta]

OML 53

OML 53 covers an area of approximately 1,585km2 and is located onshore in the north eastern NigerDelta. The Jisike oil field, located in the northwestern area of the block, is currently the only producing field on OML 53.

Existing infrastructure at Jisike comprises flow-lines, phase one separation facilities and a flow station with a design capacity of 12,000 bopd and 8 MMscfd. Oil production is sent for further processing at the nearby Izombe facilities on OML 124 from where it is exported via pipeline to the Brass oil terminal. The block also contains the large undeveloped Ohaji South gas and condensate field, the development of which will be coordinated with the SPDC operated Assa North field on adjacent OML 21, together referred to as the ANOH project which is set to be one of the largest greenfield gas condensate development projects in Nigeria to date. The expectation is that future gas production from the ANOH project will supply the domestic market, for which significant work on commercialisation terms and development concepts has been undertaken. There is also shallow oil development potential at Ohaji South that could be pursued as a separate standalone project in the near term. Prior to initiating development of the ANOH project, Seplat expects to focus efforts on increasing oil production at the Jisike field and development of the shallow oil reservoirs in Ohaji South. Pursuant to the Joint Operating Model, Seplat is designated operator of OML 53.