18 October 2019
Has anybody had any good/bad experience of achieving a good cement bond/zonal isolation when cementing a 4.1/2" liner in an 8.1/2" hole?
The hole would be vertical through sands and shales at 3500m with a 300m liner including 100m liner lap, LTOBM at 1.4 sg and 140 deg C. Not too demanding and no restriction on pump rate or rotation if required.
Ed, its been a while since I have seen a 4.5” cemented liner in 8.5”, for sure 5.5” is more common and 7” much more. You will probably still run a 7” x 9.5/8” liner hanger crossed over to 4.5” with the wiper plug on a stinger positioned inside the 4.5”. I think for 4.5” x 8.5” there is a strong case for selecting solid bodied spiralled centralisers, perhaps with an 8” rather than 8.25” OD, but solid and spiralled to ensure if channeling starts it is abated but the disruption as it passes the centralisers. Rotation will help but not as much as in other liner x OH sizes. A reamer shoe will ensure the end is well centralised too. You will still have the pressure drop associated with a 7” x 9.5/8” liner hanger which is usually 8.25” inside 8.5”+. Good luck and let us know what you plan and how it goes. Too few people ask for advice/experience but never feedback the results.