Objective: Hot tap the tubing below the bridge plug and inject gel to freeze the well to allow for the removal of the drill collars.
Well Information: 12MPa gas well. After success UBD operations to deepen a well, the floats did not hold pressure to allow for the trip out with the drill string. After several attempts to set a plug in the “Q” nipple just above the float sub, a bridge plug was set in the last joint of pipe above the drill collars and the drill string was snubbed out to the drill collars.
BHA: bit, bit sub with duel floats, 3m drill collar, “Q” nipple, 6 drill collars, 73mm tubing to surface.
Procedure: Confirm location of bridge plug in the last joint of tubing with plumb bob on trip out of the hole. Install safety valve in tubing and set first drill collar in slips. Install hot tap clamp and drill assembly on tubing below bridge plug. Pressure test and drill ¾” hole in tubing. Rig out drill and install gel injection equipment. Pump twice the volume of the drill collars capacity. Install cribbing and supply dry ice to area below the tubing to drill collar crossover. Freeze the gel, pressure test and break out the tubing. Install 2’pup and safety valve swivel joint and Kelly hose. Pull 2 drill collars, set ice cribbing, thaw top ice plug while freezing next plug. Pressure test through Kelly hose. Break connection and lay down double stand. Install crossover, 2’pup, safety valve, swivel joint and Kelly hose. Pull 2 drill collars and repeat freeze procedure. Repeat total procedure unit the bit is clear of the blind rams. Secure well with blind rams.
Time on location: Spot equipment and set up 2 hours, next day 13 hours of execution of freeze plugging procedure.