Vitor Abreu, the owner of U.S. geoscience research company Act-Geo, which analyzed possible oil and gas deposits in the East Sea, said the address of the firm is that of his personal residence.

At a press conference in the central administrative city of Sejong on Friday, Abreu, who arrived in the country on Wednesday, said his team works remotely from locations all over the world as only computers, software and cameras are required for the job.

Abreu, who also serves as an adviser to the firm, said petroleum companies worldwide are reducing their workforces in line with the decrease in remaining oil deposits, but that there are still talented people outside of smaller firms.

Asked whether it is common for a small consulting firm to offer an analysis for a large-scale project, such as the one for potential deposits in the East Sea, Abreu said it is the industrial norm for a small firm to analyze data for such a major project.

Such remarks come amid growing suspicion regarding the reliability of the U.S. firm, after it gave its opinion to the state oil company that there could be up to 14 billion barrels of oil and gas in the East Sea, based on Seoul's deep sea exploration data.