What Is a Submarine Pipeline?

Submarine pipeline is a pipeline that continuously transports a large amount of oil (gas) on the sea floor through closed pipelines. It is the main component of the offshore oil (gas) field development and production system. .

There are several types of subsea pipelines:

(1)

The submarine pipeline design follows the "Submarine Pipeline System Specification" (SY / T 10037-2010). In order to design a safe and reliable submarine pipeline, the following information and data need to be obtained:

(1) Transportation fluid: including oil and gas category, flow rate, composition, density, viscosity, dew point, temperature, pressure, specific heat capacity and thermal conductivity.

(2) Engineering geology: types and mechanical characteristics of seabed soil, vertical and horizontal friction characteristics of seabed, composition of surface soil structure on the seabed, seabed landforms, longitudinal profile of submarine pipeline paths, and seismic intensity

(3) Oceanographic data: water depth maps, currents, waves, tides, ice, water temperature, salinity of seawater, distribution of animals and plants in the sea area, and visibility of seawater.

(4) Meteorological data: wind direction and speed, temperature, pressure, and visibility.

(5) Other information: charts of the sea area, submarine cables or pipes to be crossed, underwater obstacles, waterways, fishing areas, and relevant government regulations. ^[1]

In order to ensure the safe operation of the submarine pipeline during the designed life, the pipeline system should fully prevent internal and external corrosion caused by the transport medium and seawater.

(I) Outer coating

Engineering practice has proven that the outer coating can provide effective corrosion protection in an actual seawater environment. The outer coatings for submarine pipelines are coal tar enamel, asphalt enamel,

The advantage of submarine pipelines is that they can be transported continuously, hardly affected by environmental conditions, and will not force oilfields to reduce or stop production due to the limitation of the capacity of offshore oil storage facilities or the untimely receipt of shuttle tankers. Therefore, the oil transfer efficiency is high and the oil transportation capacity is large. In addition, the submarine pipeline has a short construction period, fast commissioning, convenient management and low operating costs.

Disadvantages are: pipelines are on the sea floor, most of them need to be buried in a certain depth in the sea bottom soil, inspection and maintenance are difficult, and some pipe sections (especially risers) in tidal range or wave breaking zone are affected by wind, waves, tide, ice Large, sometimes it can be damaged by floating objects and ships hitting or anchoring in the sea. ^[2]