recently, weizhou 10-3 single-point dismantling and disposal work have been completed, thus far weizhou 10-3 single-point dismantling/weizhou 11-4c platform scrap disposal project has been mechanically completed, marking the successful implementation of the first platform dismantling project in south china sea in china.
in the process of weizhou 10-3 single-point demolition, it is found that there are a plenty of cement inside each steel pile, but there is not any set of mature cement cleaning equipment within steel pile in the world. cooec has set up a special project research team to collect and study relevant information at home and abroad on one hand, and on the other hand, to sample and analyze on-site cement, and finally take high-pressure water cleaning as the final cement cleaning method of this project.
for platform demolition projects finished by cooec previously, the operation depth is generally 20 meters, while the maximum operation depth of the project is 51 meters, which is close to the limit of air diving, the operation time for divers each time is within 20 minutes, but each outlet decompression time is 1 hour, the underwater operation efficiency is extremely low.
in order to ensure the success rate of design and manufacturing, the special project research team built a simulation test platform in advance and made 16 test sample blocks with reference to cement samples. after 32 simulation tests in 2 months, the design parameters were determined. on august 20, 2019, the world's first cement cleaning equipment for steel piles was completed. in july 2020, the newly researched and developed cleaning equipment was utilized on the sea for the first time and successful, the thickness of cleaning cement was up to 20.1m, not only saving cost of around more than 4 million yuan for the project, but it is a significant breakthrough for core technology of cnooc oilfield disposal business, filling the blank of the business and laying a solid foundation for the demolition of similar structures of jinzhou 20-2nw platform in the future. in the demolition construction, the project team adopted high-pressure water cutting technology and hydraulic shear method, which maximized the green demolition and protected the marine ecology in the reduction operation area.
generally, the projected lifetime of an offshore platform is about 20 years. if it is not demolished when its operating lifetime expires, it will have a great impact on the marine environment, navigation safety and the use of other marine functions. cooec is the only company in cnooc with offshore structure demolition business. before the implementation of this platform demolition project, cooec has completed dozens of offshore platforms demolition tasks, but this one is still the first time in the south china sea.
it is reported that, there are more than 200 platforms in the china sea, seven among more than 50 platforms in the south china sea are already out of service, and more and more offshore platforms need to be demolished over time. the market for platform demolition is very promising, more than 6,500 offshore oil platforms all over the world are expected to be demolished in the future.
photo: weizhou 11-4c module hoisting