Behind the Scenes of the Platform Holly Vibrocore Sampling Project
In June 2025, Pacific Dredge & Construction (PDC) completed a complex and rewarding offshore operation: the Platform Holly Vibrocore Sampling Project. This undertaking just off the coast of Santa Barbara, California required precise coordination, technical expertise and seamless teamwork across multiple marine specialties.
Platform Holly is located about two miles off the coast of Goleta in the Santa Barbara Channel and sits in around 211 feet of water. The site represented the last offshore oil platform in California’s state waters at the time of plugging (Los Angeles Times).
The mission was part of ExxonMobil’s decommissioning work at the South Ellwood Field, specifically around the now-defunct Platform Holly. Years of offshore drilling had left a legacy of discharged drill cuttings and shell mounds beneath the platform. These mounds, built up over decades, needed to be carefully managed to allow for sediment sampling, an essential step in environmental analysis and seabed restoration planning.
Mobilizing Marine Precision
PDC’s role in this intricate project was to provide heavy marine support using our specialized barge, the PDC 180. Outfitted with a 9-cubic-yard digging clamshell bucket, our crew carefully removed shell material from designated vibrocore sampling sites. The job required absolute control and finesse, achieved using a four-point anchor spread that kept the barge steady during excavation and sampling.
Assisting in barge movement and anchor positioning was the Wendy Jo tugboat, ensuring our team could maintain operational safety and accuracy even in dynamic sea conditions.
Teamwork at Sea
This was not a solo effort. The project was led by marine operations firm Longitude 123 Inc. with a capable cast of collaborators:
- TEG Oceanographic Services oversaw vibrocore sediment sampling
- Woolpert provided surface navigation and ROV support
- Padre Associates managed sample receiving and laboratory testing
Together we executed a well-coordinated marine operation that highlighted the best of what collaborative offshore work can achieve.
Why It Matters
Offshore decommissioning is more than just removing old infrastructure. It is about restoring marine environments, gathering data for future planning and doing so responsibly. The Platform Holly Vibrocore Sampling Project reflects this mission by balancing precision engineering with environmental care.
For PDC it also reinforced our commitment to marine innovation and cross-industry collaboration. We are proud to have played a key part in such a meaningful project and we are ready for what comes next.