Multiple 1214WAB® enable cementless zonal isolation in deep water, sub sea well
- Well Type Producer
- Reservoir Type Carbonate
- WAB subjected to rigorous 'life of well' testing to enable removal of cement across 12 1/4 section
- Multiple 1214WAB facilitate open hole isolation across the 12 1/4" open hole section
- Wireless gauges confirm the setting & sealing within the open hole section
- V0 Liner Hanger protection provided by additional 1214WAB set within 13 3/8 casing
- Location Brazil
As wells get deeper and well trajectories get more complex, the challenge to establish effective cement for a barrier between reservoirs increases. An operator in Latin America was challenged by high cement losses in a number of zones in the formation, which made it difficult to deliver barrier isolation between zones to prevent co-mingling production/injection. The operator decided to install Welltec Annular Barriers (WAB’s) for Zonal Isolation (ZI) between three distinct reservoir sections on this carbonate reservoir well.
The WAB’s required qualification to meet the challenging environment conditions and prove life-of-well reliability to the local governmental agency. As well as meeting the ISO standards, individual components were subjected to repeated cyclic testing, replicating 30 years life of well simulation with a methodology defined as 'Accelerated Life Testing'.
Four WAB’s were installed within the deep water, pre salt, subsea well, run on the 9 5/8” production liner within a 12 1/4" hole to approx. 20,000 ft TVD. The liner was deployed safely and circulated to total depth (TD). A dart was dropped to shut off the shoe, then the liner hanger was set and the WAB's expanded quickly under surface control. The shallowest WAB was set within the 13 3/8" casing.
Since the 9 5/8" production liner was not cemented, the WAB's will provide the barrier elements between the reservoir units over the life of the well. The three lowermost WAB’s were installed to provide barriers between three, distinctive reservoir units. The 9 5/8” was subsequently perforated with large diameter TCP guns and the zones stimulated with a shallow hydrocarbon zone tested to surface.
WAB expansion and sealing verification was delivered via battery powered, zonal annular pressure and temperature sensors positioned between the 9 5/8” and the 12 1/4” annulus. The Delta P across the WAB’s was recorded during both the acid stimulation (designed up to 5,000 psi) and subsequent water injection, in all cases showing no leaks.
- The operation was successful with the WAB’s preventing ﬂuid communication within the different reservoirs units.
- It is the world’s first deployment of a cementless liner installed across multiple reservoir units meeting well barrier policy.
- Tangible, high value cost savings were achieved with the removal of the cementing and clean out runs.
- Significant, intangible benefits were delivered via achieving effective barriers between the reservoir units, ultimately delivering increased production from nearby wells and increasing overall recoverables.
The avoidance of cement represents a breakthrough in cost, efficiency and increased performance in well design.