Considering the scope of work necessary to batch-complete six wells within a tight deadline, the initial outline for an offshore Vietnam completion program required multiple slickline well interventions, not only while on the rig critical path but also during simultaneous operations (SIMOPS). This high frequency of well intervention added considerable time, cost, and potential risk to the overall completion campaign, warranting incorporation of an alternative cost-effective interventionless concept.
Remotely operated barrier valves were evaluated and determined to be a low risk but high value-enabling alternative to running conventional plug-and-prong type barriers during the completion installation. The remotely operated valves' multiple open and close capabilities provided further efficiencies that could be achieved as part of the completion running phase, as well as during SIMOPS when the wells were flowed for cleanup and later suspended for four months until topsides were commissioned.
Two remotely operated barrier valves were pre-installed in their respective nipple profiles (one above the production packer and one below) and run in each of the six completions. The upper valve added value by allowing the production tubing, which included gas lift mandrels, to be pressure tested to full working pressure before setting the production packer. The lower valve facilitated circulating the well to underbalance fluid before setting the production packer and then allowed for subsequent setting and testing of the packer from above. It was later used as a deep-set barrier, allowing blowout preventer (BOP) retrieval and christmas tree installation on the rig critical path before performing further operational steps during the planned SIMOPS.
Using the remotely operated valves in the project provided significant rig time savings of 30 hours per well by eliminating 15 well interventions. This also contributed to reduced health, safety, and environmental (HSE) risks and non-productive time (NPT) potential that are historically associated with slickline-related activity.
This paper illustrates, in detail, the completion installation practice adopted and the many benefits and added value the technology provided to the overall project, both on the rig critical path and during SIMOPS.