Type of Operation

Description

Drilling

While drilling shallow surface hole without a BOP, a high pressure low volume formation is penetrated. The crew shut the diverter, evacuated the rig, and all of the mud is expelled from the hole followed by a steady blow from a non-hydrocarbon gas. After 45 minutes the flow stopped and the well is static.

Drilling

During tripping operations, the hole is not kept full due to errors in the trip sheet. Well bore gases begin flowing to the surface resulting in an unexpected blowout. When the flow is noticed the annular is closed. The well flows uncontrolled initially. Flow is diminishing as the annular element closes. When the annular element is fully closed the well is brought under control. Note: There was no equipment failure. The well flowed for the duration of time that it took for the annular element to close and seal.

Completion

While performing a completion on a land well, coiled tubing is used to drill out frac plugs following stimulation operations. While pulling out of the production casing after drilling multiple plugs, the coil becomes stuck and subsequently parts at the surface. The check valves in the coiled tubing BHA fail and water and gas begin flowing from the coiled tubing. After six minutes of uncontrolled flow, the slip rams and then shear rams are closed and the well successfully shut in.

Workover

A rod pumped well was shut in for 5 months before operations began to repair tubing in the well. The crew did not fill the tubing or annulus with fluid before pulling rods and did not install a rod BOP. While pulling rods the well is swabbed in and oil and water flow in an uncontrolled manner from the tubing. The well died after 15 minutes of flow.