Case History: HydroPull™
Milling Bridge Plugs with Two-Phase Flow in Depleted Well
Nitrogen dampened the pulse amplitude but did not reduce the milling speed. A 2.88-in. (73-mm) HydroPull™ tool was run with a motor and mill on 2-in. (51-mm) coil to mill bridge plugs inside 5.5-in. (140-mm) casing from 7500 to 13,000 ft (2286 to 3962 m) MD on four horizontal gas well completions (5500-ft/1676-m horizontal). For the first job, a Tempress Motor Gas Separator (MGS™) tool was run below the HydroPull™ tool and above the motor. The tools were operated at 3.25 bpm (517 lpm) with 0.5 bpm (80 lpm) fluid, or gas equivalent, bypassed by the separator. Eight bridge plugs were milled in an average time of 8 minutes each. In offset jobs running a competitive vibrating tool instead of the HydroPull™ tool, the average milling time was 40 minutes per plug.