THE National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) has urged industry to increase its focus on design, preventative maintenance and management systems in order to prevent uncontrolled hydrocarbon releases.
The call comes after the rate of releases rose to 20 in 2013, up from 17 in 2012, NOPSEMA’s latest Annual Offshore Performance Report showed.
Of that 20, 13 occurred at normally attended platforms, four at floating production storage and offloading facilities and one each at pipeline facilities, mobile offshore drilling units (MODU) and platforms which were normally left unattended.
In a newsletter distributed by NOPSEMA, the regulator’s chief executive Jane Cutler said this finding was “particularly disappointing,” given a reduction in the rate of these releases recorded in 2012.
“The prevalence of inadequate design specifications and preventive maintenance among incident root causes is an opportunity for improved performance,” she said.
NOPSEMA launched three investigations of hydrocarbon leaks as dangerous occurrences – defined an incident which could reasonably have caused an accident.
An investigation into a gas release during drilling operations at the Jack Bates MODU, operated by Sedco Forex International, found that “ineffective management of the operation and the overall management of change system” had resulted in an uncontrolled hydrocarbon release.
A reduction in bottom hole pressure, known as swabbing, occurred when a gas influx from the bottom of the drill hole expanded when it approached the surface.
Corrective actions identified in the report suggested the operator revise its procedures to ensure that any changes to the sanding instructions for drillers were reviewed and approved by the toolpusher.
A low level transmitter calibration error was blamed for a gas release in a process module at Woodside Energy’s Goodwyn Alpha production facility.
The release was caused by the removal of the level switch from the stripping gas compressor lube oil seal oil pumps, a loss of seal oil levels following a loss of power, NOPSEMA said.
The third, a pin hole leak on a hydrocarbon surface flow line at Apache Energy’s Stag Central production facility in December, was likely caused by microbiological induced corrosion, NOPSEMA said.
The regulator also carried out three investigations into hydrocarbon fluid releases as reportable environmental incidents in 2013 – a step it takes in order to identify breaches of the offshore safety and environmental management legislation, it said.
The regulator found 774 litres of crude oil had leaked into the Bass Strait as a result of corrosion on the Cobia to Halibut pipeline – typical of microbiological induced corrosion.
Operator Esso Resources has since repaired the pipeline, NOPSEMA said in its report.
It had also found a defective bow thruster seal on a supply vessel, coupled with poor decision making, had resulted in 115 litres of hydraulic oil being released to sea in January 2013 at PTTEP Australasia’s Montara operations.
Ongoing minor releases from a well conductor at Apache Energy’s Stag facility caused by a residual inventory of oil established in the conductor or mudline area originating from offspec produced water being reinjected into the well was also resolved following a workover, it said.