This message has been cross posted to the following Discussions: Well Integrity and Drilling .
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Dear professionals,
I have an intermediate 13 3/8 in casing which failed 200 psi pressure test & returned water (test media) from the conductor pipe indicating shallow failure; i.e. 13 3/8 in casing has lost its containment. The 13 3/8 in casing is cemented to surface inside a conductor pipe however, cement level between the 9 5/8 in x 13 3/8 in casing is below surface.
The well has no what so ever other -known- leaks elsewhere, i.e. completion and production casing are integral thus, the two barriers requirement is met!
On the failure matrix we have a casing leak and on the risk register Annulus B has lost its containment, but -again- I have two independent mechanical & tested barriers in place for the leak path inside the production casing. From behind the 9 5/8 in casing cement logs showed good cement above the reservoir as well as above the DV Stage Tool (inside the 13 3/8 in casing).
I need your help to assess this well from well integrity & structural integrity viewpoints & to kindly help me identify hidden possible threats. Well type: Oil Producers or Water Injectors. Environment is offshore.
The questions I have and would appreciate your questions/discussion too are as following:
1- How would you -roughly- risk rank and/or risk assess such failure?
2- Is the failure in the 13 3/8 in casing considered as a failure in the well integrity envelop or a threat to the well structure, or both?
3- Can you please help me think of any potential failure scenarios?
4- Without knowing much about the 13 3/8 in casing integrity (remnant wall thickness, corrosion rate, nature of failure etc.) how can we assess its impact on the overall well structure & load bearing capability? Any assessment techniques in the market?
5- Can you suggest any mitigations/cure options? To me a 7 in tie back doesn't add much to the existing barriers nor addresses possible future leak behind casing which may be caused by cement failure? It may be for structural support only!
6- Anything else?
Sincere regards,
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Obadah Al Sawadi
Well Integrity Engineer
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