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Casing string damage
12 July 2009
Does anybody have any images of casing damage caused by installing manual casing slips. In effect inducing a degree of point loading on the casing body with high string weight. Usually when it's been thought that "it would be a good idea" to get rid of the hydraulic or air operated casing slips before picking up the casing hanger. I've heard of cases of the joint in the rotary being crimped and in worst case scenarios the manual slip hinge pins breaking and parts dropping down hole. I need this to graphically illustrate to inexperienced crews that it not "a good idea" to use hand slips with high string weights.

In the absence of any images, then other pieces of "evidence" will be most welcomed, including any reports of tubular damage/failure caused by this.


Ron Mackay
rp² Well Performance Co-ordinator
1 answer(s)
Marathon Oil
Total Posts: 7
Join Date: 12/12/05
Hi Ron,

We had a similar experience when running 7in 13Cr tubing on a platform campaign last year where we were running 2 x 11mm x 11mm control lines as part of the completion. FMS slips were used to run the completion, but the night shift chose to remove them and change out to casing type slips once the SSSV was picked up, even though there was no requirement to do this as the SSSV would pass through the FMS. The requirement to leave the FMS in place and the reason for doing this was clearly detailed in the completion programme, but unfortunately this was completely ignored.

The beauty of the FMS ensures that the slips are placed uniformly around the pipe upon setting each time, plus the guard prevents damage to the control lines.

Now what happened next was some slip segments were removed from the casing type slips to allow extra clearance for the control lines - FATAL MISTAKE! This resulted in the slips being set ununiformly from that point onwards and crimping the tubing which went unnoticed. This continued until a bang was heard near when setting the last joint prior to picking up the tubing hanger. This bang was actually a slip segment hinge pin shearing and unfortunately a potion of this pin went down hole. The joints were all pulled back to the SSSV, all were crimped and had to be replaced. We then proceeded with the operation but could not get a seal when landing the hanger in the wellhead.

Scoring was observed on the hanger when pulled back to surface, so we had to suspend the completion via an RTTS packer, nipple down the HP riser & BOPs to inspect the wellhead which was now scored and had to be dressed up in situ as best we could. Due to the action of turning to set the RTTS packer, the eccentric clamps for the gauge cable were no longer aligned casuing us to take overpulls and loosing some portions of clamps when the entire string was removed from the well. This misjudgement ended causing us a weeks downtime, not to mention the increased HSE exposure of unplanned operations and moving heavy equipment.

In a nutshell my advisce to you would be to LEAVE THE FMS IN PLACE AS LONG AS PRACTICALLY FEASIBLE!!! Do not remove any segments from slips unless an instruction has came from your tubular running vendors onshore management.

Hope this helps? I do not wish you or anyone else to go through the pain I went through.

Sorry I do not have any pictures of the event but hopefully you can picture the event by my discription above..

Best Regards,
Mark Urquhart
Completion Engineer
Marathon Oil UK Ltd
[email protected]
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