After some issues getting our 13 3/8” casing strings to bottom (due to suspected ledges), we experimented with a couple of different casing shoe designs. Initially we went with conventional shoes but then moved on to eccentric pilot guide shoes and have discussed running reamer shoes, but we do not have the ability to rotate our casing string due to the design of the subsea casing hanger and wellhead system. To provide context we are drilling in about +/- 4,500’ of water building in our 17 ½” section from around 30° at +/- 6,500’ MD up to 90° by around 9,000’ MD.
1) As we cannot rotate the casing I feel we are not getting much benefit of either an eccentric nosed or reamer shoe and furthermore if the nose of the tool is orientated to the low side of the hole it may actually be a hindrance in terms of passing any obstructions. It has been suggested that orientate the nose of the shoe to the high side of the hole when we run it through the rotary as in theory it should not rotate and stay pointed to high side.
2) One of the other options we have considered is the use of an indexing or ratcheting shoe which self-orientates down the hole by setting down on bottom then picking back up. I have had some feedback from our N American drilling teams that they have had issues drilling these out, but I would like to have a broader offset.
Does anyone have any feedback on the above points that they would like to share?
Thanks for all the interesting and useful responses, I have waited until the end of this project to respond so I can provide full feedback.
Very interesting comment on whether the reamer shoe was the cause or the cure – thanks. I agree on the bullet shaped nose, and that’s what we have reverted to with no further issues. We do install 2 x centralisers behind the shoe and this is something we have done for a while, see attached photos.
I take your point regarding the use of solid bodies but we need to have decent SO as the 13 3/8” is set in the reservoir, we have used very high end bow spring type in the past but they are very expensive and we have now had success getting strings down with solids. You will see from the photos that we run bow springs on the shoe track on occasion, but if we get in any way rough these are likely to be torn off.
We run a co-pilot system so we are able to keep the drill parameters in check, like you have mentioned this is key. We had no more issues getting casings to bottom by drilling the holes correctly in the first place with sufficient flow rates to properly clean the holes.
Nice to hear from you again, I hope you are well. As above this is a great suggestion and something we continue to do.
Thanks for the comment regarding the retrievable mud motor, and interesting suggestion but one that would require some front end engineering analysis for sure.
If using eccentric nose or reamer shoes , centraliser selection is very important. I would suggest running solid body centralisers with two on the shoe joint close to the shoe, miss a joint and two installed in the middle of the third joint (collar joint of 120ft shoe track) and the rest of the centralisers installed as per program. This will help put a slight bend on the casing between the shoe joint and collar joint and keep the nose pointing up on high angle wells. Even if rotation is not possible, by selecting a Reamer Shoe with a reaming area that covers the circumference and is the same size or slightly larger than the OD of the centralisers, reaming the hole by gently reciprocating the casing will help open the hole enough to allow the centralisers to pass through.
Les Sinclair - Blackhawk Specialty Tools