On January 15th, 2013, the first installation and operation (disconnect and reconnect) of a 3-½-in. electro-hydraulic disconnect tool (EHDT) was successfully completed with an intelligent completion.
The completion was installed in the Carapeba oil field in Campos Basin, allowing the operators to manage simultaneous production of two distinct and isolated zones by remotely monitoring and controlling flow to each individual zone. (Fig. 1)
This tool allows the secure and reliable disconnect and reconnect of the upper completion from the lower while maintaining electrical and hydraulic control line integrity. (Fig. 2) Thus, it becomes possible to change any part of the upper completion such a non-functioning safety valves, electrical submersible pump (ESP), or other component without recovering the lower completion.
In addition to the time saved on well interventions, this operational flexibility provides a significant increase in operational safety, since it allows the complete isolation of the reservoir simply by closing the interval control valves (ICVs). Remotely-controlled ICVs can also be used to prevent fluid loss and possible formation damage during well interventions.
This development aims to overcome the challenges of well interventions with wellbore equipment fixed at both ends (e.g. tubing hanger and production packer), as currently constructed in the pre-salt.
The completion design for the Pre-Salt development in Santos Basin requires a 4-½-in. electro-hydraulic disconnect tool to simplify and increase the efficiency of critical interventions in wells with intelligent completions.
It is essential to emphasize that the learning acquired in this intermediate stage with the 3-½-in. tool on the Carapeba field, will be essential to guide the continued development and qualification of the 4-½-in. tool that is currently being developed to be used in pre-salt areas.
Intelligent completion (IC) provides the ability to monitor multiple zones of a reservoir or between intervals with large difference in permeability within the reservoir of interest, through the real-time measurement of temperature and pressure values ??and to selectively and remotely control opening and closing of the reservoir sections. This functionality allows reservoir engineering better management of production which is essential for reservoirs with high geological uncertainty as heterogeneous carbonates found in the pre-salt.
However, the use of intelligent completion technology inherently creates additional difficulties for well interventions due to the need for removing the entire lower completion string (equipment below EHDT - production packer, valves, and gauges) which can result in high operational risks.
This completion configuration would require a high risk intervention combating fluid loss in each zone with the risk of solid deposition (e.g. calcite) over the lower packer, unsetting packers, and pulling the lower completion string out of the hole.
Aiming to overcome the challenges in this scenario, a project was created to develop a tool capable of disconnecting and reconnecting safely and reliably the upper completion from the lower, while maintaining the electrical and hydraulic control line integrity, yet allowing a simpler and safer intervention.