ONGC officials told that they strongly suspected the involvement of the banned United Liberation Front of Asom (Independent) (ULFA-I) in the abduction.
In a series of tweets on Wednesday morning, ONGC said the employees were driven away by "unknown armed miscreants" in a vehicle belonging to ONGC at gunpoint.
The vehicle was later found abandoned near the Nimonagarh jungles, close to the Assam-Nagaland border.
"All the three abducted are local residents of Assam," Sivasagar SP Amitava Sinha told IANS.
The Nagaland police and the army deployed on the Assam-Nagaland border have been put on high alert.
"Nagaland's Mon district is not far from the spot of the abduction and the car was found abandoned near the Nagaland border. So, police there have been alerted,' Sinha said.
The three employees have been identified as Mohini Mohan Gogoi,(Junior Technician, Production) from Sivasagar district, Alokesh Saikia (Assistant Junior Engineer, Production) from Jorhat district and Ritul Saikia (Assistant Junior Engineer, Production) from Golaghat district.
They are all ethnic Assamese.
"The manner in which the abduction took place bears the trademark of ULFA, which is the only militant group active in this area," said police superintendent Sinha.
In December last year, ULFA(I) and Myanmar-faction of NSCN(K) had abducted two employees of the Quippo Oil and Gas Infrastructure Limited from Kumchaikha drilling site near Innao in Changlang district of Arunachal Pradesh.
They were released in April after long negotiations conducted not so secretly. The ULFA (Ind) insisted Quipppo should only employ locals but it was not if money changed hands and if so, how much.
Public sector behemoth ONGC is India's biggest oil and gas exploration and production company.
It has been exploring and producing oil and gas in Upper Assam since the early 1960s.
The company has suffered at ULFA's hands, even loosing senior engineer B.S Raju in 1991 when he was killed in a crossfire between security forces trying to rescue him and ULFA militants.