The Montara Incident
On August 21 2009, the Montara-H1 ST-1 experienced a well control incident during a tie back operation which resulted in an uncontrolled release of oil and gas to surface.
The uncontrolled release continued for 74 days and an estimated 400 barrels of oil was lost per day. The well was killed on November 3, 2009 via a relief well, Montara-RW1 ST-4. The response operations continued until the well was capped on December 3, 2009.
The cause of the well control issue was due to a combination of well integrity factors including inadequate barriers being in place and an inadequate kill fluid (seawater) being used to control the reservoir pressure.
Environmental impacts appear to have been limited by oil evaporation, natural degradation, dispersant spraying and skimming.
Following this incident new safety procedures have been introduced and very stringent controls have been put in place on future drilling campaigns to ensure that there is no repeat of this type of incident.
Incident response
On 21 August 2009, PTTEP AA immediately accepted full responsibility for the costs of the response operations and clean up.
The initial emergency response activities were carried out professionally, with all 69 persons on-board the West Atlas rig safely evacuated and transported to Darwin.
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