Simultaneous Subsea Vertical Connections (1991)

ABSTRACT This system connects two different equipments by mean of a connection module, containing two hydraulic connectors which are linked through a single operated flexible line bridge. The connection tool contains all levelling and positioning mechanisms necessary to perform correct connections. The connection module can be retrieved for maintenance purposes, together with all active systems. This concept allows both greater equipment usage flexibility and over all tolerances minimization. It is specially suitable to subsea completion systems, where remote connections are to be performed in very difficult operational conditions. INTRODUCTION The development of drilling and production activities in deep water offshore fields, containing the largest unexplored oil reserves in Brazil, requires connection systems which are both simple and reliable, in relation to operation and maintenance. The objective of this paper is to present a concept for a remote subsea vertical connection system. Thus, only conceptual aspects of this connection system are considered. This problem was faced when studying the connection between a christmas tree and the manifold of a deep water template manifold, which are both very complex systems. The solution was to conceive a new connection system consisting of a universal connection tool (UCT) and a connection module (CM), featuring all the active and passive mechanisms necessary to perform a correct connection. The connection module can be retrieved for maintenance purposes, together with all active systems. FEATURES OF THE SYSTEM The following topics were the main design basis of the connection system. I - All the actives components of the whole connection system are located on the universal connection tool, therefore, in case of any failure of an active or passive component, it does not become necessary to retrieve anyone of the equipments to be connected. II - This connection system simplifies the design and operation of the equipments to be connected. This occurs because the complexity of this systems is concentrated on the connection tool itself and the equipments to be connected no longer need to make simultaneous connections. III - The concept allows connections to be made under greater positional tolerances because the connection tool has a great capability to compensate for linear and angular deviations between the components to be connected. IV - This concept reduces the chances of undisered manipulation of the equipments to be connected and it eliminates the need to shut down the whole production system due to maintenance on a single connection module. V - The connection system development and tests are independent of the equipments to be connected. This facilitates the design improvement and construction of this system. VI - The concept allows the use of a universal connection tool which could be used to connect any terminals with usual size. THE SYSTEM The system consists of a universal connection tool run by a vertical string and a connection module that links the equipments to be connected. The UCT contains active and passive mechanisms which will compensate for the linear and angular disalignments and install the connection module.