Maintenance of well-testing equipment

Article published in the Regulator | Issue 2: 2017 

In March 2017, NOPSEMA announced at an industry conference in Perth that maintenance assurance of well-testing equipment will be a focus area for OHS inspections of mobile offshore drilling units (MODUs).

Well testing is a complex and hazardous undertaking which provides a pathway into an oil and gas reservoir, thus introducing the risk of bringing hydrocarbons onto the drilling facility where previously there were none. Well testing also presents challenges in managing contractors that are using temporary equipment packages over relatively short work campaigns, and managing multiple interfaces between the different companies and organisations involved. Given the uncertainty about how each test will eventuate, it is imperative that well testing is designed, planned, and managed effectively to safely obtain the required data without leading to a major accident event (MAE).

The titleholder is responsible for the well testing activities being conducted within their title area and has a duty to ensure the work is conducted safely and without risk. The drilling contractor, as the operator of the facility, is responsible for implementing the safety case requirements for well testing activities. In some instances, the titleholder and facility operator are the same organisation. Well testing service providers also have responsibility for safety and integrity of the plant and equipment they supply, and for their employees undertaking well testing activities. While each stakeholder has individual responsibilities under the legislation, collectively they share the responsibility for OHS during well testing.

Maintenance of well testing equipment

Maintenance of well testing equipment 2

During a recent MODU inspection, NOPSEMA identified that pressure-containing equipment supplied by the contractor to be used during well testing was not maintained or certified. This presented an immediate threat to health and safety and so NOPSEMA issued an OHS Prohibition Notice to the operator to cease well testing until the threat was removed. We also issued three OHS improvement notices to the titleholder, operator, and third-party contractor for contraventions under legislation; specifically the inadequate maintenance of safety-critical equipment which could lead to an uncontrolled hydrocarbon release and MAE.

True to the ‘Swiss cheese model’ of accident causation, none of the relevant parties identified that the equipment was not maintained or certified. NOPSEMA’s intervention was the last barrier before the equipment was to be used. Without it, there could have been an MAE. As a result of our enforcement action, all parties reviewed their maintenance assurance processes and critical interface management arrangements, and committed to improving their performance. All published notices are available at

NOPSEMA strongly encourages the industry to consider their maintenance assurance processes and procedures and to maintain oversight of critical interface management practices. Although many duty holders do not specifically carry out well testing activities, the lessons learned from this example can be applied to the industry more broadly. NOPSEMA will continue to focus on maintenance assurance of well testing equipment through its assessment, inspection and investigations.

NOPSEMA uses its OHS planned inspections to monitor duty holders’ compliance with the legislation and the commitments made in permissioning documents, such as safety cases, diving safety management systems or diving project plans. OHS planned inspections also provide us with an opportunity to gain additional assurance that the implementation of risk management systems remains effective. In 2016, NOPSEMA undertook 93 OHS planned inspections and made 1021 recommendations as a result. Inspection recommendations provide greater insight into duty holder OHS performance and are a key consideration in selecting focus areas for  future inspections.