【History of Haichuan Pipelines】The world’s first undersea pipeline

This post was last edited by Zhongyuanren on 2020-8-24 02:54 for resource sharing. Fish can always compile this information into a book of world records.

Once in operation, submarine pipelines are not constrained by water depth or topographical conditions, allowing for continuous transportation of oil and gas with high efficiency. The technical requirements for submarine pipelines are the same as those on land. Due to the difficulties in repair, the properties of crude oil must be taken into account during design. Additionally, based on information regarding the weather, sea conditions, terrain, and geology surrounding the pipeline, its route, specifications, and structure should be carefully selected to ensure safe operation. There are three methods for laying submarine pipelines: ① Submarine towing method. After being prefabricated on land, the pipeline is lowered into the water; a certain number of buoys are placed along the pipeline to keep it afloat above the seabed, after which a winch or tug boat is used to pull the pipeline to its installation location. This method is suitable for laying short pipelines in shallow seas and pipelines crossing narrow waterways. Some oil fields in the Beihai Sea use this method to lay pipelines between platforms. ②Floating method. The pipes are first welded together on land into multiple long pipe strings, which are then towed to the installation site at sea. After being connected with barges, the buoys are removed, allowing the pipes to sink to the desired depth. The advantages are low drag and simple equipment. But it is too affected by the climate, and once work begins it cannot be stopped; it can only be used for laying pipelines with short construction periods and small scales. ③Lay laid by a pipe-laying ship. The ship is equipped with equipment such as an anchoring system, welding station, flaw detection station, tensioner, and cradle. During pipeline laying, the ship is positioned along the laying route and anchored in place. The prefabricated pipe sections are lengthened on board and then lowered into the water from the support frame; the pipe-laying ship moves forward gradually through its anchoring system, advancing after each section has been welded. This is the currently standard pipe-laying method. By 1982, there were approximately 70 pipe-laying ships in the world, capable of working at depths of up to 200 meters and laying pipes with a diameter of 1120 mm. Laying of submarine pipelines: To prevent erosion by ocean currents, ensure the stability of the pipelines, and avoid damage to them caused by ships anchoring or fishing boats, the pipelines must be buried at a depth of three times their diameter below the seabed surface, or at a depth of 2 meters. The common method is to use an underwater trencher mounted on a pipe to flush away the soil beneath the pipeline with high-pressure water, allowing the pipe to sink into the trench due to its own weight; thereafter, high-pressure water is used to flush the soil back and fill the space again. Sometimes it is naturally filled in by the action of ocean currents.

It’s also some information found on the Internet; it has been compiled into a summary post. Those who are interested and in need can take a look. ============================= 【History of Haichuan Pipes】 The summary post is being updated continuously, providing information on the development of various types of pipes. https://bbs.hcbbs.com/thread-3068575-1-1.html (Source: Huahai Chuanliu – Haichuan Chemical Industry Forum Website)

There are always some new and interesting things to see =============================

Electric heating for submarine pipelines – I didn’t know about this before

Gaps will be dug in the sea and filled, and cement blocks will be placed near the jacket.