Recently we had a big problem with 7 days NPT - loss of grease seal during PLT.
We rigged up WL PCE (cable cutter, triple BOP, lubricator, grease injection system and stuffing box) rated for 15K. The problem began as we start to run, the weight of the tool was not heavy enough to overcome the wellhead pressure, so we closed the downhole valve, released the pressure and ran the tool. At the halfway, we pressure up the tubing to equalize at the downhole valve (DV) and open it. Later we noticed the loss of grease from the return line and gas coming from the top of PCE. Stopped the run, closed the stiffing box but could not managed to regain the grease seal - gas was coming from the return. Pulled the tool above the DV and closed the well at the DV.
Then we checked all flow tubes, changed the grease, tested the grease injection pump but the next two runs were also unsuccessful - always the loss the grease seal... The service company at this moment cannot explain why we are losing the seal. Taking the grease as the main source of problem.
Now we planning to run the tools on slickline as the temporary decision.
Has anybody had a such problems and what was the solutions?