It comes just weeks after the West African country’s vice president said that more needs to be done to incorporate the bootleggers into legal refining trade.
The government has been holding talks with militants to end attacks on official oil production facilities.
Attacks cut the OPEC member’s output by 700,000 barrels a day for several months last year.
But a military crackdown on thousands of illegal refineries in the southern swamplands, which process crude oil stolen from oil majors and state oil firm NNPC, has raised tensions in the last few months.
Illicit refineries process stolen crude in makeshift pipes and metal tanks hidden in oil-soaked clearings deep in the thick bush land.
Military spokesman Abubakar Abdullahi said: “Troops of joint operation Delta Safe have intensified raids operation against crude oil theft with destruction of 80 illegal refineries across Bayelsa, Delta and Rivers States.
“Our troops would not relent until our mandate is achieved.”
But vice president Yemi Osinbajo said last month that Nigeria must engage with illegal refiners by establishing modular refineries so that they can participate in legal refining.
Militants behind last year’s attacks called for more of Nigeria’s energy wealth to go to the Delta, which remains impoverished with widespread unemployment despite being the country’s oil hub.
Crude sales make up two-thirds of government revenue.