High and dry: new challenges for offshore safety
Drilling for hydrocarbons is intrinsically hazardous but correctly identifying critical safety flaws can go a long way. Dr Gareth Evans reports on how exploration and drilling in deeper water and at higher temperatures and pressures is creating new demands for offshore safety.
With the increasing trend towards drilling for and producing hydrocarbons from deeper water and in high temperature / high pressure reservoirs allowing less reliance on fixed structures and greater use of sub-sea technology, the demands of offshore safety are undoubtedly changing.
Less than a fortnight after production was shut down on Shell's Gannet Alpha platform, 112 miles east off of Aberdeen, with around 50 non-essential personnel evacuated as a precaution after natural gas was discovered escaping underwater, offshore safety is once again firmly in focus.
Drilling for hydrocarbons is, of course, an intrinsically hazardous activity, as a spokesman for the Offshore Division of the UK's Health and Safety Executive (HSE), makes clear.
"It can involve breaking the integrity of an underground reservoir of highly flammable gases and liquids at high temperature and high pressure. The most immediate risk is therefore of catastrophic fire or explosion causing loss of life, along with loss of containment leading to environmental pollution."
There are other less immediately obvious risks to contend with too, such as structural collapse - through extreme weather or ship collision - and the loss of stability or sinking, in the case of floating installations.
It all makes identifying the safety-critical elements, implementing control management systems for them and ensuring that they are checked for performance and integrity, essential in preventing a major disaster. UK health and safety law places duties on a variety of people but in essence, it means those who create the risks at the workplace are primarily responsible for controlling them.
"By law, every duty holder must have and implement a verification scheme which identifies the safety-critical elements, assigning them performance standards in terms of their functionality, availability, reliability and survivability. The assurance that safety-critical elements can meet their performance standards is provided by a third-party, an independent, competent person, normally from outside the company."
Central to this is the 'Safety Case' - a requirement for all forms of offshore installations in British waters, including drilling rigs and needing formal acceptance by the HSE.
To get that approval, the safety case must provide evidence of effective safety management systems, that hazards with a potential to cause a major accident have been identified and that any risks arising from those hazards are, or will be, adequately controlled. It also needs to be revised as necessary during the operational life of the installation.
"Inspectors from HSE's Offshore Division inspect offshore installations to assess compliance with safety case commitments, as well as to investigate accidents and complaints and for other inspection purposes," the spokesman said.
"The frequency of such inspections varies, depending on risk - larger fixed manned installations could expect two or three proactive offshore inspection visits a year."
Software and remote operation
In common with other industry sectors, digital technologies now play an increasing part in offshore production too. Statoil, for instance, recently announced it will deploy the Experion Process Knowledge System and Honeywell Distributed System Architecture at its Valemon platform in the North Sea.
Some commentators wonder if this will become a much repeated trend and usher in a future where subsea and topside operations are routinely monitored and controlled without the need for personnel on-site - and if expert knowledge systems might one day replace real-life experts in the field.
For the moment at least, according to the HSE spokesman, from a safety perspective the situation is clear.
"Software systems commonly compliment and augment other safety systems offshore and when properly designed and operated can provide additional layers of protection. Remotely operated equipment is required to meet the same standards of integrity and safety as manned equipment. Many of the offshore assets in the Southern Basin are remotely operated and only require human intervention occasionally. So, while the technology is advancing, this is not new to the UKCS."
As for future developments, he added: "It is unlikely at the moment that human intervention will ever be wholly superseded by expert knowledge systems, but technology in this industry advances rapidly."
Whatever else the coming years will hold, ageing plants and equipment are sure to feature, so what procedures and systems are in place to ensure they will meet current and future safety standards?
"In July 2010, HSE launched its KP4 programme looking at ageing installations. The issue is not a new one and we have been working with the industry to address the risks for several years. We are very clear that if installations are going to be used beyond their original anticipated design life, then operators need to look to the future and anticipate inevitable consequences.
"This is a priority for us. Ageing offshore installations run the risk of deterioration, which can have serious consequences for installation and asset integrity. This is not acceptable. The safety of 28,000 workers is dependent on systems and structures being in good working order now and in the future."
It seems that HSE will be seeking evidence and reassurance that operators are giving both ageing and life-extension proper consideration as a key - and distinct - part of their asset integrity management plans.
KP4 will run until September 2013. It will also include the development of technical information for operators on ageing installations covering three areas: structural integrity and the integrity of process plant, fire and explosion, and electrical and control systems.
Crucially, HSE have specifically set out work with the offshore industry to establish a common approach to the management of ageing installations - and the approach has clearly borne fruit.
"The industry and unions are fully behind this programme. They appreciate that well maintained, safe and efficient plants and equipment are vital to ensure the long term future of the UK offshore oil and gas industry."
A global approach
Ultimately, ensuring that this future remains a safe one largely comes down to managing offshore risk effectively and preventing disaster through the maintenance of integrity, coupled with good detection, mitigation and emergency response.
While a number of British safeguards are already in place to do that, the potential for a serious incident exists anywhere there is oil and gas drilling - and lessons learnt from around the globe inevitably influence safety offshore of the UK.
"There is a good deal of both formal and informal sharing of information. For example, although HSE does not have any regulatory involvement with the Deepwater Horizon incident, we have been watching closely to see if there are any lessons that can be learned and applied to the UK offshore industry.
"We have been in contact with regulatory colleagues in the USA. Also, due the similarities in approach and geographical proximity we liaise closely with the Norwegian PSA. There is also a lot of sharing of information between the various specialists we have in our offshore inspectorate and their counterparts in other parts of the world."
With the increasing trend towards drilling for and producing hydrocarbons from deeper water and in high temperature / high pressure reservoirs driving less reliance on fixed structures and greater use of sub-sea technology, the demands of offshore safety are undoubtedly changing, but HSE's core philosophy remains a good one.
"Our regulatory regime is one of goal-setting with continuous improvement, where the adoption of good practice is actively encouraged and promulgated."