Freeze and Hot Tap Case History #25

Objective: Freeze well to install another 7 1/16” gate valve.

Well Information: 30 mPa BHP. Wire line tools were hydrated in the hole approximately 150 meters down and braided line was across existing gate valve. Wireline lubricator rated for 21mPa with a 14mPa equalize loop with leaking 35mPa ball valve.

Procedure: Attempted to inject gel thru casing valves but pressure ratings of wireline surface equipment limited pumping pressures and gel could not be injected. Hot tap was performed on 14mPa equalize loop and gel was injected thru leaking 35mPa valve. Gel sealed leaking 35mPa valve, equalize loop was rigged out and installed new 35mPa ball valve behind failing 35mPa valve. Gel was then injected into well thru lubricator valve and casing valve. Gel was also injected into surface casing. Freeze plug was then formed and freeze was held thru the night. Plug was pressure tested from above in the morning and held. Pressure was bleed off above freeze plug and monitored. Once freeze plug had been verified the wireline lubricator was broken apart and the braided line was cut and wireline equipment was rigged out and another orbit valve was installed and pressure tested. Well was turned over to steamer truck crew to thaw.

Time on location: 28 hours