S-OIL Shaheen:
heavy lifting for South Korea’s largest petrochemical project
| Sector | Oil & Gas — Petrochemical |
|---|---|
| Location | Ulsan, South Korea |
| Expertise | Heavy lifting · Tandem lifting · Crawler crane operations · Custom rigging engineering |
| Benefits | National record · Less time on site · Engineered safety · Single point of contact |
DENZAI handled the heavy lifting for the S-OIL Shaheen petrochemical project in Ulsan, South Korea — moving 127 oversized components, completing more than 60 major lifts, and setting a national record for the heaviest crawler crane lift ever performed in the country, all across 153,520 working hours without a single lost-time injury.
Project overview
The S-OIL Shaheen Project, backed by the Saudi Arabian company Saudi Aramco, is the largest petrochemical investment in South Korean history. Launched in January 2023 on an 880,000 m² site in Ulsan’s Onsan National Industrial Complex, the 9.2 trillion won (USD 6.2 billion) development will be home to the world’s largest ethylene plant of its kind, producing 1.8 million tonnes a year.
The build is split among three of Korea’s biggest contractors — Hyundai Engineering & Construction, DL E&C, and Hyundai Engineering. DENZAI International Projects was brought in to plan and carry out the heavy lifting for all three contractors, many of which had unique characteristics.
All told, the equipment going into the complex weighs about 130,000 tonnes. DENZAI operated on a crowded, fully active site where three contractors’ schedules all depended on one another, and a timeline that left almost no room to go back and redo anything.
The S-OIL Shaheen Project marked a major step forward for heavy lifting operations in Korea, combining complex site conditions with new technical milestones. We won contracts from three major Korean EPC companies and completed Korea’s first heavy lifting operation using the 2,500-tonne crawler crane.
— Jeong Won Seo, Managing Director, DENZAI International Projects Co., Ltd.
01Engineering and hardware
Every major lift started with a detailed 3D study of the site — where each crane would stand, how much clearance it had, the path the load would travel, and the route to get it there. The order of all 60-plus lifts was then planned out in advance so the cranes had to be moved and re-set as few times as possible.
Most of the big components needed custom lifting attachments and beams engineered by DENZAI. Each piece came with its own difficulties: many were unevenly weighted — some carried almost twice as much weight on one side because of attached piping and fittings — had very few points strong enough to lift from, and came in awkward shapes. To handle this, the team built a set of mix-and-match lifting beams (in 500-, 350-, and 150-tonne sizes) that could be combined into 1,000-, 700-, or 300-tonne configurations, so the rigging could be reconfigured quickly from one lift to the next rather than rebuilt from scratch each time.
One of the toughest lifts showed what that engineering could do. The Overbridge PAR-64 module — a 431-tonne section of pipe rack nearly 36 metres long — had to be threaded into a gap between two structures that were already built. The team used a two-level lifting frame fitted with nine hydraulic cylinders, each adjustable on the fly. That let them spread the weight evenly and fine-tune the module’s tilt while it hung in the air, setting it down almost perfectly level, within a third of a degree across a base roughly the size of a tennis court.
The greatest challenge was operating within a restricted space while safely and precisely lifting extremely heavy loads. Avoiding interference with surrounding structures required simulations and advance reviews of crane positioning and lifting paths.
— Ah Young Shin, Senior Technical Engineer, DENZAI International Projects Co., Ltd.
02A national record: Korea’s heaviest crawler crane lift
The single heaviest lift of the whole program — and the heaviest crawler crane lift ever performed in South Korea — was the first-stage HCR reactor: 44 metres tall and 1,160.5 tonnes. The reactor was upended from horizontal to vertical, a maneuver carried out by two cranes working together and led by a 2,500-tonne LR12500.
As the reactor was rotated upright, the load gradually shifted onto the main crane — its share climbing from 588 tonnes to the full 1,160.5 tonnes by the time the vessel stood vertical. Both cranes were kept well below their rated capacity throughout, a deliberate safety margin. The ground was checked to confirm it could bear the enormous loads, the wind was monitored against a strict limit, and the weight on each crane was tracked live from start to finish.
Over the course of the program, DENZAI completed more than 120 lifts, moved 29,415 tonnes of equipment, and worked 153,520 hours without a single lost-time injury. In November 2025, Hyundai Engineering & Construction recognised the team with an Achievement Award for finishing all the heavy lifting work incident-free.
We plan to take on larger projects moving forward, including both nuclear power plants and offshore wind.
— Jeong Won Seo, Managing Director, DENZAI International Projects Co., Ltd.
Project at a glance
| Client EPCs | Hyundai Engineering & Construction, DL E&C, Hyundai Engineering |
|---|---|
| Scope | 127 heavy items lifted; 60+ major lifts; 29,415 tonnes moved |
| Heaviest lift | 1,160.5 tonnes — 1st Stage HCR Reactor (heaviest crawler crane lift in South Korea) |
| Tallest item | 85.6 metres; 28 vessels over 40 metres requiring tandem upending |
| Crane fleet | LR12500 (2,500t), LR11350-P1800 (1,800t), LR1750 (750t) |
| Safety record | 153,520 hours, zero lost-time incidents |
| Recognition | Achievement Award from Hyundai E&C, November 2025 |
What was the heaviest lift on the S-OIL Shaheen Project?
The first-stage HCR reactor — 1,160.5 tonnes and 44 metres tall — which two cranes worked together to rotate from horizontal to vertical, led by a 2,500-tonne LR12500. It is the heaviest crawler crane lift ever performed in South Korea.
What is a tandem lift and why was reactor upending needed here?
A tandem lift uses two cranes working together to handle a load too heavy or too long for one. Upending rotates a vessel from horizontal (as delivered) to vertical (as installed); on S-OIL Shaheen the load transferred progressively to the main crane through the rotation, from 588 tonnes to the full 1,160.5 tonnes.
How did DENZAI keep the project on schedule across three contractors?
Rather than awarding three separate heavy lift contracts, the project let DENZAI run a single program across the whole job— one contractor, one engineering team, and one shared crane fleet. That removed a whole layer of coordination between parties and cut down on the number of times cranes had to be set up and taken down.
What custom rigging did DENZAI engineer for the project?
Most of the major components used custom lifting attachments and beams designed by DENZAI. These included a set of mix-and-match lifting beams that could be combined into 1,000-, 700-, or 300-tonne configurations, and a two-level frame with nine adjustable cylinders that placed a 431-tonne pipe rack module almost perfectly level — within a third of a degree.
What was the safety record on S-OIL Shaheen?
153,520 working hours with zero lost-time incidents across 60+ major lifts. Hyundai Engineering & Construction presented DENZAI with an Achievement Award in November 2025 for completing all heavy lifting works incident-free.