Please watch the footage below. It was a flow back after breaking out the lubricator on the rig floor.
We don’t know full details what was happened but from what we’ve seen in this VDO, it shown that the well was flowing after the wireline operation was completed. The crew broke out the connection between the wireline lubricator and the string set on the rotary table. Few seconds after the connection was removed, the well flowed back. The flow became stronger as you can see the drilling fluid was pushed out from the drillstring quickly and the rotary table started to turn black. The lubricator was pushed by hydraulic power from the mud and it was swung around. Eventually, the crew went back to connect the lubricator to the string and the well stopped flowing. It seem like the situation was under control at the end. Luckily, there was no gas or any spark that can cause fire on the rig floor.
What Could be Done Better?
These are some key learning points that we can learn from this VDO.
- A Full Opening Safety Valve (FOSV) should be installed on top of the string. If the well is flowing, the crew shut the well in by closing the FOSV. The risks to the crew will be greatly reduced.
- Under estimation of formation pressure and wellbore hydrostatic pressure. Pore pressure greater than hydrostatic pressure will create an underbalanced condition.
- Contingency well control plan should be in place prior to performing the operation. This VDO shown that there was no plan to handle the unexpected well control situation. Typically, if this case is happened, the crew should be ready to stab the FOSV so as to shut the well in.
- Ensure the connection of FOSV is the same connection as the tubular otherwise a cross over must be prepared.
What Are Your Thought about This Case?
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