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.
Bullheading is one of the well control methods that involve pumping formation fluids back into formation into a shut-in well. You can read the basic details about bullheading from this link https://www.drillingformulas.com/bullheading-well-control-method/. For this time, this article will be focused on a calculation example for bullheading operation.
A mud gas separator or poor boy degasser or gas buster is one of the most critical well control equipment on drilling rigs. It is used to separate gas kick from drilling mud while circulating kick out of wells or circulating gas while drilling or workover operations. The mud gas separator used on drilling rigs is typically a vertical cylindrical vessel with many baffle plates inside because vertical vessels have small footprints. The drilling mud from the well goes into the mud gas separator and hits baffles. Then gas will be removed due to hitting action. The gas will go up and exist to atmosphere via a vent line at the top of the vessel. The drilling fluid drops after colliding baffles and exists the mud gas separator through the line and return to a mud pit.