Above the sea surface of Bohai Bay, the construction vessel continues to operate. Recently, the 18 adjustment wells project on the C platform of Chengbei Oilfield Center has successfully completed the laying of approximately 41.6 kilometers of subsea pipelines. The new double layered mixed transportation pipeline will open up oil and gas transportation channels, injecting new energy for stable production into this oldest offshore oil field in China.

Intelligent exploration of complex sea conditions

Ten original pipeline cables are distributed in a staggered manner in the construction sea area of the project, and the underwater pipeline layout is like a woven net, making the pipe laying operation quite difficult. The CNOOC deep technical service team has implemented a high-precision differential positioning system to compare the routing data of new and old pipelines, develop a special construction plan, adjust the ship's anchorage and travel route, and install buoys to avoid pipeline collisions. The team dynamically analyzed and judged based on meteorological, tidal, and ocean current data, seized favorable construction opportunities, avoided strong winds and thunderstorms, and ensured the orderly progress of pipe laying operations.

Strictly adhere to construction quality

The pipeline laying project involves numerous procedures, and any negligence can affect the safety of oil and gas transportation. The project implements closed-loop control throughout the entire process, adhering to the principle of not entering the next process if the previous process is unqualified. Construction of windproof shelters for welding operations, strict control of preheating temperature and welding speed, and a one-time pass rate of 99.4% for subsea pipe welding. Fine control of the anti-corrosion process, including sandblasting, heat shrink tape coating, heating, and other procedures, ensures the anti-corrosion capability of the subsea pipeline in all aspects. Keywords: subsea pipeline laying, offshore oil and gas

Accurate pipe laying and positioning

During the underwater stage of the submarine pipeline, the staff monitors the tension of the tensioner in real time and dynamically adjusts the orientation of the submarine pipeline entering the water. Relying on high-precision positioning systems to guide ships along the designed route, ensuring precise positioning of each section of the sea pipe. This 14/18 inch double-layer hybrid subsea pipeline was laid and completed in nearly four months, undertaking the task of exporting oil and gas from new wells, continuously releasing oilfield production capacity, and consolidating the long-term stable production foundation of old oilfields.Editor/Min Jing