We came up with the idea of milling seats with the production pipe, removing the mill ate toe, pulling back to the heel and landing the string. Work began to develop above the mill: a disconnect system with metal on metal BPV. It consisted of a dual flapper floats that could pass the disconnect ball, a sliding sleeve with the same flow path as the tubing, which would be ball-activated once wellhead was installed.
Piston rigged up a HALO equipped Rigless Snubbing Unit, snubbed it in the hole, washed the sand and milled the seats to the toe. We dropped the disconnect ball, pulled back to heel land string and rigged out. The average milling time for the entire lateral was 24-28 hours. W.O.B. while milling was 2dan with 130 rpm, and cost savings averaged to $300,000 per well. This process is now a standard completion design for that oil company.