Characterization of a Linear Shaped Charge with Increased Standoff Capability

Abstract

In response to the blowout scenario in the Gulf of Mexico event in 2010 and the loss of lives and equipment, Shell International Exploration and Production Inc. started work on designing an Emergency Severance Tool (EST) to rapidly sever the marine riser assembly that connects the drilling rig on the surface with the blowout preventer on the seabed. LLNL proposed a concentric array of linear shaped charges to sever a 9.5†diameter by 3.25†wall steel drill collar located inside a 18.75†diameter marine riser assembly. The charges had to penetrate a thin layer of steel and up to 240mm of drilling mud (density ~ 2g/cc) prior to severing the drill collar. A linear shaped charge was designed based on ALE3D simulations, with the objective of maintaining severance capability at a standoff of up to 16â€. This initial simulation-based design was tested in two characterization experiments which compared jet behavior in air with jet behavior in drilling mud. Both tests were fully instrumented to measure charge performance, jet speed, shape, and penetration for comparison with preshot simulations. A new high level of performance for a linear shaped charge was validated.