Aadnøy has been in the oil industry for 40 years. He started as a trainee with Phillips Petroleum in Odessa Texas in 1978. He worked for Phillips Petroleum both in Texas and Norway until 1980 when he became leader of drilling research at Rogaland Research, which is now IRIS/NORCE. He was project manager when Ullrigg was built and he laid the foundation for the research profile by initially focusing on automatic drillpipe handling.
The evolution within drilling and well technology started at about 1980, and Bernt Aadnøy has contributed continuously working on wellbore stability, torque and drag modelling, well integrity, long horizontal wells and also well design and modern completion design. Current focus is smart well technology. Over the years he has published nearly 250 scientific publications and authored or coauthored eight books.
At the University of Stavanger Aadnøy has built a masters program within drilling and well engineering with international reputation. He has supervised more than 200 bachelor students and master thesis, as well as a number of PhDs. He was adjunct professor at the University of the Faroe Islands from 1998 to 2003 building up a petroleum engineering program related to deep water exploration. In 2009 he was visiting professor at the University of Calgary in Canada and in 2012 he was a visiting professor at the Federal University of Rio de Janeiro in Brasil. Today he is also adjunct professor at NTNU in Trondheim.