Case Study

AT A GLANCE

Operator: North Sea Operator

Where: NCS
When: April, 2020
Scope: PWC® remediation to avoid costly re-sidetracking of well

Successful PWC® allowed continued drilling to access new reserves from sidetrack

CLIENT CHALLENGE

The client had already performed two  HydraHemera™ PWC® isolation plugs in the well main bore to allow the existing reservoir to be permanently isolated.

During sidetracking of well and cementing the production casing, the well experienced losses which resulted in well integrity criteria not being met. The options were to cement back the interval and drill a new sidetrackor to remediate in the 9-5/8” to allow a 7-¾” tieback liner to restore well integrity.

BACKGROUND

We are proud of our track record in Permanent P&A operations and have become recognised as market leaders in PWC® systems. Our customers around the world have been using PWC® for many years and by working closely together we have introduced forward thinking solutions to increase operational efficiency and new applications for the PWC® System. This case study showcases the flexibility of the system to new challenges within limited timeframes.            

HYDRAWELL SOLUTION

The solution chosen to salvage the well and deliver the original target production was to fix the zonalisolation challenge using a PWC® solution. HydraWell and the Operator worked closely to develop a risk assessed operational plan with the following steps successfully implemented;

• The top part of the existing 7-¾” liner was isolated with a FAS drill plug and cement. The 9-5/8” casing was perforated, and the annulus effectively washed and cemented across the 50-meter interval using the PWC® solution provided by HydraWell.
• Excess internal cement was drilled out and the top of the existing 7-¾” liner bore was polished to prepare for the tieback seals.
• A short 7-¾” tieback liner was then installed and cemented in place, covering the 9-5/8” casing perforations, thereby delivering a complete compliant isolation barrier to the reservoir.

RESULTS & BENEFITS

Our client avoided a costly abandonment and re-sidetracking of well, saving up to 10 days of rig-time.

As a result, the client delivered production much quicker and at lower risk through ability to follow original drilling trajectories. The well is secure and has NORSOK qualified barriers in place to avoid risk of hydrocarbon leaks to surface.