Alert 09 – 04 Explosion/Flash Fire on Rig Floor Following Gas Release

Alert 09 – 04 Explosion/Flash Fire on Rig Floor Following Gas Release


Following a logging run on drill pipe the drill string was pulled out of the hole (POOH). During the trip out, the well did not take the correct amount of fluid while pulling through the horizontal section. Instead of returning to bottom, the decision was made to continue POOH. After laying down all the logging tools, the drill string was run into the hole to TD in order to clean out the well. The driller then pulled back to 4303 m to circulate, during which time he observed a flow increase, so he shut in the well. The decision was made to circulate out any influx using the Driller’s Method. During this circulation returns were lost and the BOP was opened to observe the well. Mud and gas came through the table so the BOP was closed again. Gas alarms sounded. Pumping was resumed. After a time of pumping, pressure gauges read “0.” The BOP was opened again to observe the well. Again, mud and gas came through the table and gas alarms sounded. An explosive flash fire then occurred. Eight persons were injured. All were evacuated to hospital.