What is a deep-water Christmas tree?

The Christmas tree is one of the key production equipment in offshore oil and gas fields. It is responsible for multiple tasks such as controlling the flow of oil and gas and isolating the wellhead from the external environment. Therefore, whether the Christmas tree can be properly installed is related to the stable production of the oil field. The installation process of deep-water Christmas tree is more complicated, and it is susceptible to various harsh environmental factors such as ocean currents and waves. During the lowering process, it is necessary to remotely control the rotation of the Christmas tree and the accuracy of the deep-water Christmas tree lowering. If the strength of the drill string is insufficient or the lateral displacement of the drill string is too large during the lowering process, the lowering safety of the Christmas tree and the alignment installation with the wellhead will be affected.

In a project in the South China Sea, how to safely install a Christmas tree with a total weight of nearly 60t to the head of a deepwater well became a problem. The R&D personnel used 50 special installation tools to overcome the difficulty ingeniously.

Because the tree is equipped with underwater monitoring equipment such as wet gas flowmeters, it is not only heavy in weight, but also complex in structure. A slight collision during the movement may cause damage. Therefore, traditional moving methods such as dragging and hoisting are not effective. The R&D personnel had an idea: If a section of track can be laid to make the Christmas tree "slide", wouldn't the problem be solved? To this end, they specially designed a Christmas tree moving tool: it is like a group of small trains, just hoist the Christmas tree to it, and then slide the Christmas tree to the edge of the deck by sliding the track, the whole process is smooth and safe. At the same time, the hydraulic arm equipped with the tool can tightly "hold" the Christmas tree, thereby adding "double insurance" to the moving process.

However, after the Christmas tree reaches the water, it is difficult to accurately connect the pipeline with the Christmas tree underwater. This is mainly because the Christmas tree is located 1500m underwater, and the installation tools need to have multiple functions of water control, monitoring and underwater installation at the same time. . More importantly, if you encounter special circumstances such as ocean currents or typhoons during the installation process, the installation tools must be dropped off immediately to prevent the pipeline from breaking and avoid oil and gas leakage accidents.

In addition to the above-mentioned tools, 50 kinds of special tools such as the Wireline Tool and ITC Running Tool for tree internal components are also used in the project for the installation of Christmas trees, covering transportation, cleaning, Multiple links such as testing and recycling.