Over the last few years there has been no shortage of discussion around hydraulic fracturing (fracking), the well stimulation technique that involves using high-pressure fluid mixtures to crack into rock formations and free the resources within. To its users and proponents, the technique, when combined with modern horizontal drilling methods, is the key to commercialising unconventional oil and gas resources on land, thus fuelling the so-called ‘shale gas revolution’ in the US, where it is now in common use, and prompting discussion and development of other fracking-intensive gas operations around the world.
To fracking’s many critics, however, it presents a totally unacceptable risk to the environment and human health, whether from air pollution, groundwater contamination or even induced seismicity. The debate over fracking has polarised opinion, with governmental approval of fracking operations provoking protests in the US, and particularly in countries like the UK, where the technique is in the early stages of its controversial deployment, beset by fierce local resistance.
Despite the recent controversy over onshore fracking, out at sea – in locations that to most are out of sight and out of mind – the oil and gas industry has been carrying out offshore fracking operations since the early 90s without any particular fuss or controversy. Certainly, the fact that the offshore environment precludes the need for tense land use debates with local government and suspicious residents will have helped keep this aspect of the fracking industry away from the glare of bad press.
Currently used primarily as an enhanced oil recovery (EOR) technique to boost the production of mature wells, the development of offshore hydraulic fracturing technologies could lead the way to future projects that employ the technique from the start to access shale gas and other unconventional reserves beneath the seabed, opening up the possibility of an offshore shale gas boom to match the ongoing onshore bonanza.
Given that this potential is unlikely to be realised for several decades, the discussion over its merits is still somewhat academic; despite Cuadrilla founder Dr Chris Cornelius’s optimistic plan to frack for shale gas in the Irish Sea and some developments in the North Sea, prohibitive costs and the need to further develop the technology make these projects a distant prospect. The debate over the industry’s use of offshore fracking for EOR, however, has implications for both the industry and the environment today.
Offshore fracking: a growth market
Just like its onshore counterpart, the established use of offshore fracking for EOR operations hinges on the combination of fracking tech with another highly developed oil and gas technology. Onshore, that technology is horizontal drilling, while in offshore environments the key technology is gravel pack completion, which is traditionally used to filter seabed sand out of well piping. The technologies together are known as a ‘Frac Pack’ completion, which uses sand and other additives in a custom-mixed fluid at high pressures to fracture rock formation and improve the productivity of the well.
The technique has been in use for more than two decades, having been deployed to improve the characteristics of wells off the Californian coast, the Gulf of Mexico, the North Sea and offshore West Africa, among other locations. With offshore operations forming only 5% of the total fracking market, it is still a niche activity, especially in comparison to the big business being done on land. Nevertheless, technological improvements, ageing wells and the need to make the most out of costly-to-develop deepwater discoveries are pushing the offshore fracking market forward.
Far the from the eyes of protestors offshore fracking seems to hold obvious appeal, but is it even possible?.
Project data reveals that the deployment of the technology for EOR can have a dramatic effect on production rates in mature fields. A case study by Schlumberger, which was a contractor on Eni’s fracking operation at the Kitina 3A reservoir off the Congolese coast in spring 2007, noted that the multi-stage fracking project at the field increased oil production by 230%, boosting recovery from 590 bbl/d to 1950 bbl/d three months after the fracking took place, as cited by About Oil.
The deepwater operations ramping up in the Gulf of Mexico are making this region a particular hotspot for offshore fracking in the short term – fracking activities in the Gulf are expected to rise by at least 10% between 2013 and the end of 2015, according to oil service company Baker Hughes, one of the largest suppliers of the specialist well stimulation vessels required to carry out Frac Pack operations.
According to a survey carried out by Offshore Magazine, oil service companies offering fracking vessels, which also include Halliburton, Schlumberger and Superior Energy Services, have increased the industry’s collective fracking fleet by nearly a third since 2007, a strong vote of confidence in the long-term health of the offshore fracking market.
Environmental campaigners respond to a new threat
In terms of the EOR application of marine fracking, the market seems to be in a stable period of growth, fuelled by big oil’s deepwater E&P efforts and so far sheltered somewhat from the storm of controversy swirling around its shore-based counterpart. That certainly doesn’t mean offshore fracking is a risk-free operation. "[Offshore is] the most challenging, harshest environment that we’ll be working in," Halliburton engineer Ron Dusterhoft told Bloomberg in August. "You just can’t afford hiccups."
The scale and sophistication of offshore fracking activities is gradually increasing to cater for large deepwater deposits that necessitate the fracking of multiple layers of rock, which requires huge volumes of water, sand and chemical additives to blast through rock and maintain the fracture. As such, concern is building about the environmental effects of fracking on surrounding waters and wildlife, especially in the US.
California has become a locus for the offshore fracking debate since an investigation by the Associated Press revealed that fracking has been used off the coast of southern California far more extensively than previously realised. For the Center for Biological Diversity, a US-based NGO that has been campaigning against offshore fracking, it is the uncertainty around the method’s use and its environmental effects that is truly worrying.
Gaps in oversight
For a start, the state body responsible for leasing land and waters to oil and gas companies for development, the California Coastal Commission, has not been monitoring the frequency of offshore fracking, meaning there is little public oversight of the practice.
"How is it that nobody in state government knew anything about this? It’s a huge institutional failure," Center for Biological Diversity attorney Kassie Siegel told the Associated Press. "Offshore fracking is far more common than anyone realised."
Furthermore, although the US Environmental Protection Agency regulates the discharge of fracking wastewater, setting limits on the amount of toxic chemicals that can be dumped in the ocean, there has been almost no research into the effect of this discharge on water quality and marine life.
"One of the key problems is nobody has really looked at the environmental impacts of offshore fracking, and we find that incredibly disturbing," said Miyoko Sakashita, the centre’s oceans director, who recently put together a report on the potential harms fracking poses to the Californian coast, including air pollution, toxic discharges and even earthquakes through induced seismicity. "Nobody knows what they’ve been discharging and in what amounts," she added.
A new bill passed by the California legislature to regulate fracking, due to come into effect at the start of 2015, is being seen as a first step towards greater transparency for companies involved in both onshore and offshore fracking in the state. Nevertheless, as offshore fracking increases in scale around the world – and the future possibility of using the technology to unlock shale gas and other unconventional hydrocarbons beneath the seabed – it’s likely that heated discussions over accountability in this controversial field will continue to escalate. When the fragile health of the world’s oceans is at stake, it would appear that out of sight does not equal out of mind, at least not for long.