ACCIDENT
INVESTIGATION REPORT – DRILLING MUD DISCHARGE TO THE GULF DURING EXPLORATION AT
AN OFFSHORE FACILITY
INVESTIGATION
FINDINGS
On 12 FEB 2014 between 1630 hours and 1959 hours air pressure
was lost to the primary Telescopic Joint (TJ) Packer that resulted in a 128
barrel discharge of 13.5 ppg Synthetic Base Mud (SBM) into offshore waters. The Telescopic Joint allows the drilling riser
string a location to change length as the drilling vessel moves up and down. The rig was in the process of running 14"
casing. At 1630 hours, with 73 joints
ran, the Driller noticed an 8 barrel loss of mud. At 1700 hours with 83 joints ran an additional
23 barrels of mud was lost. With mud
losses not uncommon during casing running operations, rig personnel made the
decision to slow the running of the casing. This did slow down the mud loss rate and the
crew continued to run the casing in the well. At 1959 hours a third party employee was
walking through the moon pool area and noticed mud pouring from the telescopic
joint. The employee notified the
Supervisor and the secondary hydraulic packer was then manually engaged, mud
losses ceased at that time. After an
inspection by the rig personnel, it was noticed that the air supply line to the
TJ packer had ruptured.
The investigation revealed that:
1.
There was no automatic redundant back-up system
in place. The back-up hydraulic system had to be manually engaged.
2.
The air pressure alarm for the Telescopic Joint
Packer was disabled. Upon request of the Inspectors to verify the set points
for the telescopic joint air pressure alarm, it was discovered that the high
limit alarm was set at 0-psi and the low limit alarm was also set at 0-psi.
This was confirmed at the control panel in the Central Control Unit by the two
BSEE inspectors conducting the investigation.
LIST THE PROBABLE CAUSE(S) OF ACCIDENT:
1)
Pressure loss to the Telescopic Joint Packer due
to a ruptured air hose.
LIST THE CONTRIBUTING CAUSE(S) OF ACCIDENT:
1)
There was no automatic redundant back-up system
in place. The back-up hydraulic system had to be manually engaged.
2)
It was discovered during the course of the
investigation that the air pressure alarm for the Telescopic Joint Packer was
disabled. Upon request of the Inspectors
to verify the set points for the telescopic joint air pressure alarm, it was
discovered that the high limit alarm was set at 0-psi and the low limit alarm
was also set at 0-psi. This was
confirmed at the control panel in the Central Control Unit by the two BSEE
inspectors conducting the investigation.
LIST THE ADDITIONAL
INFORMATION:
1)
A back-up hydraulic packer on the telescopic
joint was temporarily utilized while the damaged airline was removed and
replaced.
2)
Upon arrival at the location, to conduct the
investigation, inspectors were unable to see any water discoloration or sheen
on the surface, possibly due to rough seas.
3)
It was noted in the Operators INC Response
Letter that the alarm was unknowingly disabled in August 2013 during a software
update of the system.
SPECIFY VIOLATIONS DIRECTLY OR INDIRECTLY CONTRIBUTING. NARRATIVE:
E-100 (W) - On 2-12-2014
at approximately 1900-hrs an incident occurred that resulted in a 128-barrel
discharge of 13.5 ppg synthetic based mud into offshore waters. This incident occurred due to a loss of air
pressure to the telescopic joint packer.
G-110 (W) - At the time
of the investigation the air pressure alarm for the telescopic joint packer was
disabled. Upon requests to verify the
set points for the telescopic joint packer air pressure alarm it was discovered
that the high limit alarm was set at 0-psi and the low limit alarm was also set
at 0-psi.
