On September 10, 2026, accompanied by the rumbling sound of the derrick legs being raised and lowered, the drilling rig “Haiyang Shiyou 941”… The vessel slowly departed the company’s berth, successfully completing this series of repair and modification works and smoothly proceeding to its next drilling assignment.

Drilling Rig Business Card

“Haiyang Shiyou 941” is a benchmark‑class drilling rig operated by CNOOC Oilfield Services Co., Ltd. Measuring 100 meters in length and 76 meters in breadth, it is a JU2000E‑type enhanced jack-up offshore drilling platform designed by Friede & Goldman, Ltd. of the United States and certified to both CCS and ABS class notations. 

The scope of this maintenance project includes: replacement of the sprinkler piping on the sixth floor of the living quarters along with associated ancillary works; replacement of the drilling torque beam; digital upgrading of the drill floor; refurbishment of coatings; coating of three pile legs; and repair of rack components. The work covers a wide area and presents significant challenges, with extensive three-dimensional, cross‑disciplinary operations and the application of highly demanding processes such as welding of ultra‑high‑strength steel, thereby imposing exceptionally stringent requirements on quality, technical standards, and safety management. 

Plan ahead and make the first move. 

Prior to the platform’s arrival at the shipyard, company leadership attached great importance to the project and explicitly instructed the Production Department, Business Development Department, Quality Management Department, Technical Department, Safety and Environmental Protection Department, and the four major production workshops to jointly establish a single‑vessel management task force well in advance. They set “safety first, adherence to the schedule, cost control, and customer satisfaction” as the overarching guiding principles throughout the entire process, proactively developed construction plans and a comprehensive project safety management framework, and rigorously conducted specialized training for all levels of management and the construction teams. By approaching this maintenance assignment with high standards and stringent requirements, they laid a solid foundation for the smooth execution of the project.

Tackle tough challenges and deliver a powerful “combination punch.” 

To ensure that all work during the repair process progresses safely and efficiently according to schedule, the single‑vessel management project team engaged in constructive dialogue with the shipowner’s team, continuously refining construction procedures around the core project scope, clearly defining each milestone, and coordinating human, material, and technical resources. The team made every effort to implement specialized plans for quality and technology, as well as robust safety‑management measures. On this basis, the project team adhered to the production objectives of “expediting the dock‑out period, ensuring quality, and honoring the warranty period,” strictly upholding safety red lines, rigorously managing project timelines, and consistently improving quality. It worked tirelessly to overcome numerous challenges, including a tight contractual repair schedule, insufficient scaffolding labor, stringent requirements for rapid shift changes, multiple safety‑control priorities, and complex three‑dimensional concurrent operations. In addition to surmounting these difficulties, the project team effectively mitigated the adverse impacts of two typhoons on working conditions and fully supported the shipowner in carrying out two “drilling‑encounter” support missions, ensuring both safety and orderliness while maintaining seamless coordination.

Technological breakthroughs have tackled the “hard nuts to crack.”

During the dock‑out period, marine damage was revealed on the platform’s No. 2 and No. 3 leg support pads, making maintenance and repair of the sealed internal spaces within the pile shoes a significant challenge. For the first time, the company employed advanced water‑jet cutting technology, drilling three process holes in each pile shoe base plate, thereby creating favorable conditions for the orderly execution of the dock‑out plate‑replacement work. The hull workshop rose to the occasion, meticulously coordinating procedures, optimizing resource allocation, and organizing a highly skilled team to tackle the task in rotating shifts. Nondestructive testing of the pile pockets and process holes achieved a first‑pass acceptance rate exceeding 96%, ultimately ensuring that the “Haiyang Oil 941” platform exited the dock on schedule. In the repair project involving a total of 288 rack teeth across the three legs, the workshop overcame challenges such as the need for multiple lifts and lowers when entering and exiting the dock, which precluded continuous operations. Dedicated personnel were assigned to provide end‑to‑end oversight and rigorous quality control at every stage. All welds underwent RT and PAUT phased‑array inspections, with a 100% first‑time pass rate, fully demonstrating the company’s robust technical expertise and exceptional construction management capabilities.

The platform’s pile‑leg scaffolding project totals 75,000 cubic meters, encompassing three pile legs, the derrick, the living‑quarters side walls, four cranes, and 20 ballast tanks. With its extensive scope and significant construction challenges, this marks the company’s first large‑scale scaffolding undertaking. The painting workshop rose to the occasion, coordinating labor resources and optimizing material allocation. Adhering to a phased, area‑specific approach, it completed the main scaffolding structure within 25 days, thereby providing robust assurance for the efficient sequencing and timely advancement of subsequent construction phases.

Quality is our promise, earning “true trust.” 

Ultimately, under the meticulous organization and on-site management of the single-vessel management team, the repair work on the vessel “Marine Oil 941” was completed on schedule and to the highest quality standards. The exceptional repair expertise and the high‑quality, efficient service earned the client’s utmost praise and unwavering trust.