Disclosed is a method for preventing sudden subsidence of an open caisson in a soft foundation, which includes the following steps: a position of the open caisson is determined; grouting is carried out to reinforce a foundation of the open caisson; an open caisson manufacturing site is leveled; sections of the open caisson are manufactured and installed; the step of sections of the open caisson are manufactured and installed is repeated until all the sections are manufactured and the open caisson subsides in place as a whole. The application is suitable for construction on soft soil, loss caused by the phenomenon of sudden subsidence may be avoided, and personal safety of constructors may be guaranteed.

A foundation for a subsea assembly is provided. The foundation includes connection points. The connection points permit other components to be connected to the foundation and permit loads to transfer from the other components into the foundation. The foundation may be a suction anchor. A method of converting an exploration well using the foundation to a production well is also provided.

A foundation for a subsea assembly is provided. The foundation includes connection points. The connection points permit other components to be connected to the foundation and permit loads to transfer from the other components into the foundation. The foundation may be a suction anchor. A method of converting an exploration well using the foundation to a production well is also provided.

A foundation for a subsea assembly is provided. The foundation includes connection points. The connection points permit other components to be connected to the foundation and permit loads to transfer from the other components into the foundation. The foundation may be a suction anchor. A method of converting an exploration well using the foundation to a production well is also provided.

A foundation for a subsea assembly is provided. The foundation includes connection points. The connection points permit other components to be connected to the foundation and permit loads to transfer from the other components into the foundation. The foundation may be a suction anchor. A method of converting an exploration well using the foundation to a production well is also provided.

A construction method of a rectangular working well includes steps of: (I) designing functional requirements for the rectangular working well; (II) constructing a caisson of an enclosing structure of the rectangular working well; (III) constructing an edge protector; (IV) excavating earthwork of the rectangular working well; (V) forming a bottom cover for the rectangular working well, and pre-embedding a sliding track, a pull ring and a back wall anchor; (VI) installing a ladder for entering the rectangular working well; (VII) preventing joint leakage; (VIII) installing a water-proof pressure plate at an entrance of the preset pipe jacking hole; (IX) constructing the sliding back wall; (X) lifting the sandwich concrete slab wall at a top of the preset pipe jacking hole; and (XI) performing pipe jacking. The structure system constructed by the present invention has many advantages such as clear function, safety, quickness, and flexible design.

A construction method of a rectangular working well includes steps of: (I) designing functional requirements for the rectangular working well; (II) constructing a caisson of an enclosing structure of the rectangular working well; (III) constructing an edge protector; (IV) excavating earthwork of the rectangular working well; (V) forming a bottom cover for the rectangular working well, and pre-embedding a sliding track, a pull ring and a back wall anchor; (VI) installing a ladder for entering the rectangular working well; (VII) preventing joint leakage; (VIII) installing a water-proof pressure plate at an entrance of the preset pipe jacking hole; (IX) constructing the sliding back wall; (X) lifting the sandwich concrete slab wall at a top of the preset pipe jacking hole; and (XI) performing pipe jacking. The structure system constructed by the present invention has many advantages such as clear function, safety, quickness, and flexible design.

A subsea assembly including; a foundation, a support device; and a subsea equipment adapter frame is provided. The foundation, support device and subsea equipment adapter frame are separate modular components that can be installed separately. The foundation may be a suction anchor. A method of installing and uninstalling the subsea assembly is also provided.

A subsea assembly including; a foundation, a support device; and a subsea equipment adapter frame is provided. The foundation, support device and subsea equipment adapter frame are separate modular components that can be installed separately. The foundation may be a suction anchor. A method of installing and uninstalling the subsea assembly is also provided.

A foundation for a subsea assembly is provided. The foundation comprises connection points. The connection points permit other components to be connected to the suction anchor and permit loads to transfer from the component connected to the connection points into the foundation. The foundation may be a suction anchor. A method of converting an exploration well using such a foundation to a production well is provided.