We plan to Coil Tubing milling 7" cement retainer, this will be through 3-1/2" tubing milling BHA. The motor will be less than 3 in. The cement retainer was set but no cement, so the milling will be through the ID of the retainer.
Does anyone has success for the same job? Any issue related with the small motor stabilization? And also proper milling type?
Any information would be appreciated.
I don´t have any BHA information to pass on, however I would suggest you sit down with the supplier of the cement retainer (CR) and compile a drawing of how the mill will contact and mill through the CR. As the plug will be +/-6.00” and you mill will be less than 3.00” it´s very likely that you will not be milling through the centre of the CR as the milling BHA will be laying on the low side of the liner/casing. This may result in milling through a small portion of the plug and its slips and who knows what the result will be.
I would always start with a simple drawing to replicate the situation and if you have the time and ability, a workshop mock up using some liner and tubing and a BHA or replica BHA to then discuss the way forward before going to the well.Regards