The client had an existing installed distribution system with spare capacity for an additional two wells, however, the field expansion plan called for four new wells for water injection to increase production rates. The task was therefore to split the control system for two wells into four. The complexity came about due to the requirement to control the water injection isolation valve since pipeline feeds from the manifold were also to be split, with the flow to two wells being governed by a single isolation valve which would need to be controlled by either of the tree control modules. The isolation valve therefore needed to have two hydraulic supplies, either of which could operate the valve irrespective of whether the other supply was installed or not. This system needed to offer a reliable solution for the life of the field. Viper Innovations was tasked with delivering the full system, including all electrical and hydraulic flying leads, and supporting the site receipt testing, load out, installation and commissioning.
The systems engineers at Viper set about identifying the best approach to meet the hydraulic and electrical distribution requirements, including electrical, hydraulic and communications analyses for the entire distribution system to confirm that the existing equipment had the spare capacity for the additional wells. A brainstorming session drawing on the experience of the engineering team at Viper resulted in the selection of a shuttle valve as the best solution to allow two control modules to operate a single valve. The Viper engineers were aware of an existing field proven valve that was suitable for use in a seawater environment (eliminating the complexity and cost of providing an oil filled enclosure), however this valve would be critical to the reliability of the system and it was therefore determined that it should be separately recoverable to allow for replacement in the event of failure. The elegant solution identified was to mount the shuttle valve on a custom designed manifold on one of Viper's V-LOCK hydraulic stab plates. The plates were configured with two inputs and a single output. The output coupling utilised vented poppets to ensure that the isolation valve would close in the event that the plate was removed. The use of the field proven V-LOCK plate would ensure a reliable operation for the life of the field. The distribution unit was designed and built against a challenging schedule and was installed and commissioned late in 2013, less than 18 months from contract award.