Publications

When Eni unexpectedly encountered the gas/water contact while drilling in a new field, rapid delivery of standard configurable multi-position interval control valves (ICVs) or flow control valves (FCVs) expedited the implementation of a significantly revised completion design, enabling independent zonal production and flow control. Eni operates subsea wells in the C and D deepwater gas fields located off the Indonesian coast. Maximum well deviations reach up to seventy degrees, and all the wells are tied back to the floating production unit (FPU). C wells use intelligent completions for independent control of the production from each zone to manage reservoir pressure decline rates and minimize the effect of water coning and solids production. D wells, on the other hand, were planned with conventional wells, but the completion design had to be revised when the first well encountered the gas/water contact (GWC), which was not fully mapped; water production requires careful management and consequently, on-off valves are unsuitable for zonal flow control. Intervention-less valve actuation is another important requirement for the remote subsea fields. In D field, two multi-position FCVs were proposed in each well—an annular valve to control flow (from the upper zone) between the tubing and annulus and an inline one to control flow (from the lower zone) inside the tubing. Each valve has eight positions, including fully open and closed position. The closing line was used by both valves in the well. Production from each reservoir interval can be controlled independently and remotely, without requiring intervention with slickline, wireline or coil tubing. These valves were installed also in C wells and were therefore familiar to Eni Indonesia. Despite the disruptions caused by the COVID-19 pandemic, early intensive collaboration between ENI and SLB enabled expedited deployment of equipment and prepared competent personnel for the D development project. Local crews were trained especially for these complex operations, which were completed with zero NPT or HSE incidents. During execution phase, the use of FCVs also eliminated the need to install tubing plug to set the upper completion packer, an added benefit that saved rig time. Sand control technologies deployed across these unconsolidated formations ensure the durability of the FCVs, and the valves have easily withstood the production rates of the C wells. In D wells, however, Eni Indonesia increased its daily production target by about 45% when the ability of the wells to deliver at high flow rates became apparent. Valve installation was already complete, and erosion of the annular valve was a concern at the higher rates. Schlumberger worked closely with Eni to conduct extensive simulations that confirmed the valves’ flexibility and ability to withstand the revised flow rates. In one C well, where the wellbore condition compromised sand control effectiveness, the ICV enabled a gradual decrease of drawdown to withstand steadily rising sand production, extending the producing life of the well by about 6 months. In another well, water production has been chocked back to acceptable levels without affecting the output of the second zone. Remote monitoring of downhole pressures and temperatures and selective zonal flow control are helping maximize production cost-efficiently, with the optimal well count. The adjustable valves provide the flexibility to deal efficiently with reservoir and well performance that diverge from expectations.