Inpex has been forced to halt offshore drilling at its Ichthys LNG project after about 200 tonnes of large pipe fell out of control on the Maersk Deliverer drilling rig on January 22.
Since then, the $US45 billion project suffered another safety incident when a tanker loading condensate could not keep the correct position near the 336m-long Ichthys Venturer oil vessel, and an emergency disconnection was required.
The drilling incident prompted offshore safety regulator NOPSEMA to tell Inpex to stop drilling and move the rig to a safe area until the cause of the incident is identified and fixed, and all equipment involved in the incident checked for safety.
A NOPSEMA spokesperson said the regulator had inspected the drilling rig and commenced an investigation.
“There were no injuries or environmental concerns associated with the incident,” the spokesperson said.
“However, the incident had the potential to lead to a major accident event.”
A major accident event is one that NOPSEMA regards as "having the potential to cause multiple fatalities."
A long string of vertical pipe, known as a marine riser, weighing more than 200 tonnes fell toward the seabed after a locking mechanism failed. NOPSEMA’s early conclusion is that all the equipment would have fallen to the seabed if one piece of equipment has not inadvertently caught on another.
A device to stop blowouts at the bottom of the marine riser was just 4m above the seabed when the fall stopped.
Two workers were nearby when the fall occurred.
The NOPSEMA direction issued last week to Inpex and published yesterday states the incident was a “high-potential near-miss with respect to personnel health and safety.”
“NOPSEMA was not satisfied that the same failure would not reoccur…risking damage to subsea infrastructure, including wells with potential for loss of containment and personnel injury,” the direction stated.
The NOPSEMA direction also applies to the owner of the rig, Danish company Maersk Drilling.
“While the Maersk Deliver is undertaking the drilling activity, Inpex has duties as titleholder and operator to ensure the safety of its workforce and the environment,” the NOPSEMA spokesperson said.
An expensive accident
Inpex has contracted the Maersk Deliverer for almost three years from October 2020 with two option to extend for a year at the cost of $US266,000 ($345,000) a day.
A lack of safety has been expensive with idle time already worth about $6.5 million.
Boiling Cold asked Inpex if it had determined the cause of the Maersk Deliverer incident and when it expected drilling to resume. An Inpex spokesperson said it was the company’s general policy not to comment on specifics regarding its operations.
The drilling is part of Ichthys Phase 2, a multi-billion dollar expansion of wells and pipelines to keep gas flowing to the LNG plant in Darwin. Twelve to fifteen wells will be drilled, and existing wells worked over during a campaign expected to last five years, according to Inpex’s environmental plan. Each well is expected to take three to four months to drill.
Two weeks after the 200 tonnes of pipe moved out of control on the Maersk Deliverer Inpex lost control of a much larger item: a tanker.
The tanker was loading condensate from the Ichthys Venturer floating production storage and offloading vessel when it moved out of position, forcing Inpex to activate the quick disconnect mechanism on the hose that floats on the ocean between the two vessels.
The NOPSEMA spokesperson said there was no loss of hydrocarbons or injuries, and it is investigating the incident is.
Clarification 14 February 2021: Revised to clarify that the piping that fell was a marine riser not drill pipe.
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Main image: Maersk Deliverer dynamically positioned semi-submersible drilling rig. Source: Maersk Drilling