Tension mooring type underwater drilling system and mounting method for same

Abstract

The invention discloses a tension mooring type underwater drilling system and a mounting method for the same. The system comprises a drilling ship, an underwater drilling platform, a tension mooring device, a blowout preventer unit, an upper marine riser and a lower marine riser. The underwater drilling platform is moored on a pile base of a seabed through a spiral steel wire rope strand, so that stability of the underwater drilling platform is greatly improved, and a stable mounting platform can be provided for the lower marine riser and underwater drilling equipment. The tensioning spiral steel wire rope strand can bear huge lifting tension possibly caused by uncertain pressure inside a well bore, so that the lower marine riser is prevented from tensile failure, and the safety factor of existing underwater drilling technology is greatly increased. When the system is in emergency, the upper marine riser and the blowout preventer unit can be quickly separated from a well head on the underwater drilling platform, so that the breakage state of the drilling ship and the underwater drilling platform is formed, the drilling ship can go to a safety sea area to avoid risks, and safety of the underwater drilling system is guaranteed.

Description

technical field [0001] The invention relates to an offshore oil and gas drilling technology, in particular to a tension mooring water drilling system and an installation method thereof in an ultra-deep sea environment. Background technique [0002] With the gradual depletion of oil and gas resources in land, offshore and middle-deep sea areas, in order to meet the huge demand of human beings for oil resources, the exploration and development of deep sea (500-1500m) and ultra-deep sea (above 1500m) oil and gas fields are the main growth points of the world petroleum industry . [0003] At present, the international offshore oil industry uses existing drilling ships (or drilling platforms) to conduct offshore oil drilling is a mature technology. However, this existing offshore oil drilling technology is used for ultra-deep sea oil exploration, which requires high design requirements for drilling ships (or drilling platforms) and seabed drilling equipment, and is expensive. I...

AI Technical Summary

Problems solved by technology

[0005] However, according to the existing underwater drilling technology, in the installation process of the lower riser and underwater drilling equipment, the stability of the submerged floating body is not enough, which increases the difficulty of the installation process; in addition, by using the installed lower riser as Tension struts provide stable support for the submerged floating body, which simplifies the process but brings great safety problems

In the process of deep-sea oil drilling, it is necessary to consider the problem that the uncertain pressure inside the wellbore acts on the lower riser. The huge lifting tension caused by this may cause the break of the lower riser, and the submerged floating body will rise rapidly. Drilling ships (or drilling platforms) on the sea surface collide, and the potential risks are huge

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