High Angle Casing Exit Question #2

All,

We are preparing to mill a window in 9-5/8" casing and drill a 1100m 8-1/2" sidetrack. Casing exit is at 4840m / 82°. Whipstock is Weatherford SAQC with 2° concave.

We are thinking about the subsequent BHA runs and risks of LWD tool damage and/or concave damage.
The primary drilling assembly is RS Geopilot-DGR-ADR-Nukes-GeoTap (ie. everything) the ADR is an azimuthal directional resistivity (basically a resistivity image tool).

There are concerns about damaging LWD tools by rotating a packed hole assembly in the window & consideration is being given to running a PDM to drill a pocket of 60m deep enough to get the RS BHA completely out. The 2° QAQC has a average 4.4° dogleg but this is made up of a 10°+6°+2° dogleg over the 20m length of the window. The ADR has a rotating dogleg limit of 8°.

Anyone have any previous experience of rotating a stabilized assembly inside a whipstock of this kind? What is the risk of damaging or moving the concave? My view is that if we can mill a pocket long enough for the Geopilot we should be able to rotate at low rpm (~30) and very high flowrate to drill/pump the hole (formation is soft) to the point that the entire BHA is out of the window.

Thanks,

David Brecknock
Devon Energy

3 Answer(s)

---