The company has recently added concept and front-end engineering to its subsea capability.
The new services, led by Phil Law and Ian Bremner, will see PDi focus initially on subsea tie-back developments.
In February the company was awarded its first concept development work for i3 Energy’s Liberator field development in the Moray Firth area of the UKCS.
Welcoming the new staff, O’Sullivan said: “The company has grown its workforce to meet rising demand for its subsea engineering and decommissioning services. We have also recently completed a rebranding exercise, which we believe is timely given we are entering an exciting expansion era in the company’s history.
“We have always had the ability to attract high calibre people and we’re delighted to have such a tried, tested and most importantly trusted team launch our concept and FEED offering. Our aim is to build on our success to date and establish ourselves as one of the leading independent engineering houses throughout the international subsea industry, providing niche subsea services ‘from design to decom’.”