The small group of Shell to Sea and Rossport Solidarity Camp protestors stopped workers from entering or exiting the building from about 7.30am.
A Shell spokeswoman confirmed there were company personnel already in the building and that some work continued.
The protestors were peacefully removed, without incident, shortly before noon, after a team of IRMS (Integrated Risk Management Services) security guards arrived. Earlier, retired Garda Supt Pat Doyle, now working for IRMS, had negotiated with the group.
Second pic: Viewing a facsimile of the Book of Kells with the Provost of TCD, Dr. John Hegarty, Librarian Robin Adams, and Chancellor of the University Dr. Mary Robinson; 3rd pic: With Dr. Hegarty and Harpist Siobhan Armstrong playing a 15th century harp; 4th pic: face to face with a portrait of Queen Elizabeth I.