we are conducting a subsea well suspension and are having some difficulty
recovering the 10Â¾" wearbushing. We have been up to some significant
overpulls with the GE wearbushing recovery tool (up to 400 k lbf...!). We are
now looking to mobilise a spear and surface jar set-up but looking to the wider
community for any anecdotal situations with trouble recovering MS700 wearbushings
that were resolved, and how.
We'll be unlatching the BOP for a visual just to check that there is no obvious damage, but the running tool engages and disengages without issue.
Suspected formation fines jammed above the wearbushing D-ring as there is no junk/trash seal on this design of bushing.
Â± 600ft drill floor to mudline
Any thoughts appreciated.
Surface jarring assembly was what would be commonly used in this situation is my understanding where yes you jar down, where its the rebound that hopefully pops the item free.
Jarring up in 600ft!!! without an accelerator is very unwise as bits would start falling off your top drive pretty quickly as there not enough stretch in pipe to absorb the hits and why surface jar is the correct tool is my understanding.
Loads are normally set low and then increased until hopefully item pops free.
To affirm this, I'll check through my fishing notes and see if I can find any documentation, best practices etc on using a surface jar. Alternatively talk to the fishing companies leading hands.
QUOTE from my "Perpetual Diary"
*1976 Semana XXV Jueves: Offshore Mar CantÃ¡brico on board "Medusa" (Pentagone 89) Vetco 18 Â¾” SG5 seat protector jammed; 30 degrees seat angle?
Since then Shell Spain "persuaded" Vetco Offshore Inc. that indeed "trash seals" were mandatory...
Shell Spain and SERVCo spotted "pipelax" and retrieved the seat protector with rotation - to minimize friction. It took time!
No wonder that "Pay for performance" is one of the ways to force both Supplier and End User to provide/specify "proven technology" and avoid repeat mishaps, like this 38 year old lesson.
Just to update on this one, unfortunately as we were mobilising the spear and jar package (ignore my prior reference to surface jars, just a bad description on my part), the weather picked up and the sensible way forward was to get off the well while the weather was favourable, rather than risk a prolonged period waiting to recover anchors.
So, the well is now long term suspended with wearbushing still in place and assumed packed off with fines. ROV inspection showed nothing untoward.
When we come back to the well the wearbushing recovery will be the first point of action as we'll almost certainly need it to be recovered to allow the HXT to be installed for completion (though we will consider alternative tree interface options in this regard as contingency).
We've got some time to engineer a plan fully, but any further thoughts from the community would be of interest, specifically first hand experience of means to protect the wellhead H4 profile while doing open water fishing around the wellhead.
How about the following for the stuck wear bushing:
1. Perform a jetting operation
2. Spot some acid and allow it to soak, if possible
3. Try to pull
4. No joy, run a wireline or drill pipe deployed camera system, either real-time or memory, this may need to be done on drill-pipe or through drill-pipe so you can circulate to clear fluid
5. Depending on the conditions that prevail I was wondering if circulating to cold fluid could help to strink the wear bushing enough to free it.
I encounterd a similar problem in the late 90's, different WH etc but the problem was the same - we had debris 'behind' the WB (In this case I seem to remember we had swarf from a ST). We tried flushing & smacking it in various ways but in reality we were just getting more jammed. We looked at lubricants but could not see a way to deploy and all were rather nasty environmentally.
In desperation we ended up cutting it in half and pulling it in two sections. I cannot remember all the details but it was ultimately succesful. Whether you leave it for another day or do it yourself, I suggest you start looking at the radical solution!