CAMSCAN subsea camera system proves vital to successful tieback

Claxton was asked by Qatar Shell GTL to mobilise one of its fleet of CAMSCAN™ subsea camera systems based in Doha to carry out a visual survey.  Inspection of the 13.3/8-in. mudline suspension hanger area at about 76 m below the drill floor was required to resume a stalled tieback operation.

Subsea camera assesses mudline suspension hanger

The well had been drilled using a conventional mudline suspension system. During cementing operations when turning back into the mudline suspension hanger left-hand threads, the 13.3/8-in. casing above the hanger started to back out. It was necessary to rotate to the right to make up the casing. This resulted in the 13.3/8-in. mudline suspension hanger running tool backing out of the hanger threads.

Despite several attempts, it proved impossible to make up the running tool back into the casing hanger, so the string of casing was pulled back to surface. Mudline hanger thread damage was suspected, so an inspection inside the mudline suspension hanger was also required to verify the issue subsea.

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Claxton’s CAMSCAN™ subsea camera system has multiple options, including slave lighting as well as a built-in LED array. 

Claxton mobilised a CAMSCAN™ system offshore at short notice. This was deployed downhole on drillpipe to inspect the mudline suspension hanger threads and the seal surfaces. The CAMSCAN™ images enabled the drilling supervisor to decide to utilise a ratch-a-latch tieback sub and this was made up to the connector successfully. The integrity of the tieback was subsequently confirmed and drilling operations  continued.

Quote from Jan Pellenbarg, Qatar Shell GTL:

I would like to thank you and the staff involved for making it possible to react so quickly, a good job done, the camera work was key to the success in recovering the well

Claxton supplies a full range of subsea camera systems – including pan and tilt downhole cameras, low light options and cost effective ‘disposable’  subsea cameras that can assist with installation verification.

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