PWC is now a field proven method for restoring cemented isolation in casing annuli and has been successfully applied to casing exit repairs, zonal isolations as well as side-track and permanent abandonments. It is a viable alternative to section milling or cutting and pulling casing, with field history also demonstrating that it offers more reliable results than simple ‘perf and squeeze’. It is now accepted in many regulatory locations and is used by a large number of major operators around the world, but it is important to understand the limits of its application.
This paper focuses on illustrating the application envelope for PWC in well abandonment. It will examine the trade-off of service costs versus saved duration, highlighting where a low rig spread rate may drive a decision towards choosing an alternative conventional approach. Furthermore, the paper features and discusses the well parameters such as casing sizes, hole angle, rig capability and annulus content which are key parameters when designing a PWC operation.
Operators and Service Companies have undertaken a large portfolio of Computational Fluid Dynamic (CFD) modelling of PWC operations and more than 70 operations have been subjected to verification by cement quality logging. The paper considers the options for PWC barrier verification and shares when and how CFD and historical cement quality logs from the track record to date has been used to provide confidence in, and verification of, subsequent operations.
Number of Pages
Well integrity in drilling and well operations, Chapter 9, NORSOK Standard D-010, Rev 4, 2013
SPE 185938: Perforate, Wash and Cement PWC Verification Process and an Industry Standard for Barrier Acceptance Criteria, Laurent Delabroy, David Rodrigues, Espen Norum, Martin Straume, Knut Halvorsen; 2017.
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