An Investigation About the Trajectory Control During the Subsea Equipment Installation Using Cable

Abstract

Nowadays, several seafloor equipments have been developed and deployed in order to enhance the production of petroleum and natural gas from reservoirs in deep and ultra-deep waters. Thus the installation and maintenance of such seafloor equipments shall be an issue. The most important seafloor equipment during the production phase is the “Wet Christmas-Tree” (X-tree), which is a set of valves that controls the pressure at well bottom. This equipment is installed by a Mobile Offshore Drilling Unit (MODU) after the drilling and completion are finished. Recently, beside the X-mas, a variety of subsea pumps, usually called as Subsea Booster System, have been deployed in the development of new reservoirs in deep-water. At the beginning, such subsea pumps and even other seafloor equipments had been installed by a MODU. But the high-cost of the MODUs is one of the main concerns about the installation and maintenance of the subsea equipments. One alternative to reduce the installation cost is to use cable system installed on a service boat instead the completion riser of a MODU. This paper presents an initial investigation for the installation of a seafloor equipment using cable. The dynamic model will be featured; the dynamic analysis will be carried out using an in house developed simulation program in time-domain. Discussion about the trajectory and control of the equipment to be installed is also included.