Underwater pipeline connection joined to a riser

A bottom-to-surface connection installation for an undersea pipe resting on the sea bottom, in particular at great depth, the installation comprising:

• I) at least one vertical riser connected at its bottom end to at least one undersea pipe resting on the sea bottom, and at its top end to at least one float;
• II) preferably at least one connection pipe also preferably a flexible pipe, providing a connection between a floating support and the top end of said vertical riser;
• and
• III) the connection between the bottom end of said vertical riser and a said undersea pipe resting on the sea bottom being provided by means of an anchor system comprising a base resting on the bottom, and wherein
• a) the bottom end of the vertical riser is connected to the end of the pipe resting on the sea bottom via at least a first flexible pipe element that is curved to form a bend;
• and
• b) said base comprises a platform resting on the bottom and a superstructure secured to said platform and holding in position both said end of the undersea pipe resting on the sea bottom and said vertical riser that is connected to said first flexible pipe element, whereby
• the end of said first flexible pipe element connected to the bottom end of the vertical riser is held in a position that is fixed relative to said base;
• and
• the axes of said ends of said undersea pipe resting on the bottom and of said vertical riser connected to said first flexible pipe element are preferably held in a common plane perpendicular to said platform.