Cement replacement in a laminated Albian reservoir
Well typeWater injector
Max. inclination30 deg
Pressure468 bar (6 787 psi)
DEPTH OF DEPLOYMENT14 530 ft (4 444 m)
Number of packers installed80 metal expandable sleeves
Length of drain covered590.5 ft (180 m)
In an offshore field in West Africa, an IOC was facing several challenges related to cement contamination in high temperature reservoirs. Due to the highly laminated and heterogeneous carbonated reservoir, the client had trouble with cementing in a short HPHT deviated 4½” in a 6 ½” hole. Critical for the operation was the primary isolation for diversion during acid stimulation to ensure the productivity throughout the life of the well.
A water injector well that had the ability to pre-produce was identified as the candidate well for WAI implementation.
After the conventional liner top packer was set and tested, the upper completion was then installed and also tested. Subsequently, after installation of the wellhead, the WAI’s metal expandable sleeves were expanded offline after which point the assembly could be perforated, cleaned up and the water injector pre-produced.
During the pre-production phase, it was confirmed that the well productivity was as expected, but significantly, it was producing with zero % water cut.
The IOC achieved a substantial reduction in well construction costs of 2.8 MUSD by deploying the WAI. Considering the criticality and short timeline for the candidate well, Welltec’s fast track approach ensured that the time from the first qualification to the first deployment happened in less than 9 months. By choosing the WAI, operations were simplified and several phases in the well construction, along with the use of cement, were entirely eliminated resulting in substantial financial, logistical and environmental savings.
In addition, this solution led to dramatic reductions in rig time which saved 4 days compared to the best composite well and 10 days compared to the average well whilst significantly reducing associated non-production time (NPT) risk.
WAI™ (Welltec® Annular Isolation) provides long length open hole zonal isolation, significantly reducing the free annulus space between the liner (casing) OD and the open hole ID.