Page 121 - test2

sought to ensure that the engine would not over‐speed after ingesting
combustible gases. 300

The design of engine shutdown mechanisms on dynamically‐positioned
rigs, such as the Deepwater Horizon, is different from the shutdown systems in
301
moored or jack‐up rigs. Instead of the single top‐level shutdown of all engines,
a dynamically‐positioned rig is typically designed to allow the rig to activate an
emergency disconnect system to separate from the wellhead and allow the rig to
escape the hazardous area in the event of an uncontrolled blowout or other
emergency. This design also allows for continued use of the engines in an
302
emergency such as a fire. Manual activation of the emergency disconnect
system, required on a dynamically‐positioned rig, can add complexity to a rig
crew’s response to a well control event and can also create a possible ignition
source during the presence of free gas on the rig.

2. Testing of the Over‐Speed Devices

A representative of Wartsila, the manufacturer of the Deepwater Horizon
engines, told the Panel that all automatic stop devices should be function tested
at least once every 1,000 hours of engine operation and that the over‐speed trip
devices be checked every 2,000 hours. He also stated that the Deepwater
303
Horizon engines were not configured to run on natural gas and that if they
ingested natural gas they would mechanically fail (but not explode).
304

The Panel found no evidence establishing whether, and how often, the
engine over‐speed devices and individual engine components were tested by the
American Bureau of Shipping (“ABS”). ABS conducted yearly inspections of the
over‐speed devices during their continuous machinery surveys. These yearly
inspections included an evaluation of approximately 20% of the over‐speed
devices on the rig, with the goal of inspecting all devices within a 5‐year period.

300 KMI_PI001156 RBS8D. The driller was responsible for shutting in the engine air intake on the
Deepwater Horizon. The driller’s other responsibilities included: drilling the well and knowing the
drilling operations; monitoring real time data of the well; insuring the safety of rig floor
personnel working in a confined space; investigating well flow issues and responding to well
control events; communicating with the Subsea Engineer; and activating the EDS if necessary.
301 A moored rig is held in place by cables attached to giant anchors; a jackup rig is towed onto
location and is supported by mechanical legs lowered to the seafloor.
302 KMI_PI001156 RBS8D.
303 BOEMRE interview of Bob Miller (Wartsila) (November 16, 2010). An “overspeed trip device”
is a safety device that is designed to restrict the uncontrolled acceleration of the engine.
304 Id.

116