Well type
Oil producer
Reservoir type
Sand
Short term delivery requirement facilitated by
Welltec's manufacturing capability in Denmark
Reduction
In well construction cost
Incorporation of wab oh isolation plug resulted in
Approx. USD 2 million in cost savings per well.
Award in India
Breakthrough award & deployment for major IOC
Location
India
A NOC in India required a solution to provide permanent isolation of a depleted reservoir (if encountered) during the drilling phase on a 3 x well, side track and subsequent single zone gravel pack completion campaign. The inability to isolate the depleted zone would result in substantial increase in risk, time and cost during the gravel pack operation.
Swell type packers were not considered a viable solution due to ∆p requirements and the associated down time for swell along with the poor life of well characteristics of the swell type material. Furthermore, ECP type solutions were not considered as they require to be set with cement to safeguard against the thermal fluctuations within the application.
Two 812WAB for Zonal Isolation were mounted on a 6-5/8” casing liner. A 7-5/8” liner set above the top WAB, and a 5-1/2” liner running down to the formation isolation valve (FIV) set below the lower WAB, which then crossed over to a 6-5/8” pre-perforated liner across the lower reservoir. The assembly was run into the well, which had a total depth of approximately 17,060 ft (5,200 m). The unique ability to rotate, circulate, and work the completion string down enabled Petrobras to configure the AWA system in this way.
A 758 Welltec® Flow Valve (WFV) was installed on the 7-5/8” liner and run in the closed position, thus isolating the entire system, which is V3 qualified. The liner hanger was set and the WABs expanded—utilizing the inner string seal and seal bore—via surface control, in a fast and controlled manner into the 8 1/2” OH, providing life-of-well zonal isolation within the carbonate reservoir.
The liner was then pressure tested to 2,000 psi against the 758WFV and the FIV, providing primary well barrier integrity. Together, these two barrier elements provided reservoir isolation during the subsequent deployment of the upper completion, with the WFV opening only during the final stages of landing off the Upper Completion.
With all the elements in place and the seals engaged with the seal bore, losses were only possible down the annulus and were checked with a cup tool configured as a baffle. Once the tubing hanger had set, the FIV was pressure cycled open, and a zonal acid stimulation was completed via the ICV and ball valve. During the acid stimulation, the WAB sealing was confirmed using the ICV pressure gauges.
The Welltec Annular Barrier® (WAB) was selected and utilized as an open hole fault isolation plug, allowing the depleted reservoir to be permanently isolated enabling a routine gravel pack lower completion to be deployed. The system enables rotation and circulation of the WAB during deployment.
A solution was available for both the primary 8 ½” hole section as well as the 6” contingency hole. Across all wells, the reservoir section drilled to 8 1/2" open hole size, and the 812WAB was deployed, on drill pipe, as a life of well solution to the total losses and was applied as follows:-drill the 8 1/2" open hole. Once fault is encountered – stop drilling and POOH drill bit.
RIH with 812WAB on toe valve + float shoe – ran on drill-pipe coupled to a hydraulic release running tool. TD – p/up to neutral and apply hydraulic pressure down DP to set WAB above / across the fault drop ball and then apply release pressure liner running tool.
POOH
The set 812WAB then became the sump of the well, permanently isolating the fault and facilitating the completion of a GP lower completion above.
Collaboration between client & Welltec® resulted in HP isolation in the most extreme environment.
812WAB fault isolation solution allowed client to realize 50% CAPEX reductions, when compared with previous LCM mitigation methods, along with risk reduction for the subsequent gravel pack completion, resulting in complete pack placement.
Isolation of total losses allowed for deployment of single zone gravel pack completion.
WAB open hole isolation plug, enables CAPEX effective and reduced risk gravel pack completion via isolation of total losses.
WAB® for Well Abandonment (Welltec® Annular Barrier)
Future-proof wells for CAPEX effective P&A