FROM time to time, Energy has touched on the topic of sand, mostly through following the progress of specialist firm SMS, Sand Monitoring Services, of Aberdeen.
In this piece, we explore some of the issues associated with sand in produced hydrocarbon streams with one of the providers of the equipment needed to deal with produced sand, UK company Cyclotech, which has been in business since 1994.
The firm’s turnover was just over £10million in 2008, and is expected to be £16million this year and more than £20million in 2010.
With founder/MD David Hadfield at the helm, Cyclotech’s stock in trade is basically the provision of technology to treat produced water and sand and to enable both “to be disposed of in a conscientious manner”.
Both are issues for the offshore industry, increasingly so in the North Sea given the maturity of the province, with prevalence of relatively unconsolidated reservoir sands such as Alba and Captain and the regulatory regime.
As far as Hadfield is concerned, there are two primary drivers – environmental legislation is tightening and the OSPAR threshold is now at a level where companies are being forced to invest money to ensure oil in produced water is at the legal minimum or better.
For readers who are unaware, OSPAR is the mechanism by which 15 governments of the western coasts and catchments of Europe, together with the European Community, co-operate to protect the marine environment of the north-east Atlantic
Hadfield points out that, as fields mature, more water is produced and, with it, more sand.
“It gets to a point in most field lives where the ability to treat both becomes a barrier to producing the hydrocarbons. There are fields out there with water-cuts … the percentage of water in the production stream from wells … in excess of 90%,” he says.
“So it is absolutely key to be able to deal with the volumes being produced and satisfy the environmental legislation to enable one to continue to produce a lot more water than oil.
“In many respects, the byproducts (water and sand) are often the tail wagging the dog. If you can’t deal with the byproducts you can’t produce the hydrocarbons. And sand, as distinct from produced water, was not originally clearly legislated for. But now that position is much clearer.”
Hadfield says that sand was relatively poorly understood for a long time – a sort of Cinderella problem that was ignored where possible.
“For a long, long time, this is an industry that has tended to embrace problems only when there has been a solution to the problem that they can afford. Solving a problem when there isn’t a solution tends to be indeterminate … expensive.”
Hadfield suggests that, at times, technology has been ahead of legislation.
“When the technology needed to effectively handle sand in reasonable volumes arrived about 10 years ago … to clean it, to allow it to be disposed of … legislation appears and things start to happen. But produced water was always the main focus, and that’s where we (Cyclotech) started.
“We provide compact cyclonic solutions … easily to retrofit … shoehorn into existing processes. They’re a lovely solution for older fields.”
Hadfield says there’s nothing new about technologies that use the centrifuge principle – they reach back to mining in the 1800s. They fit neatly with the oil&gas industry because they’re efficient – compact.
Moreover, both sand and water can be addressed using cyclone systems, so enabling both to be cleaned prior to discharge.
According to Hadfield, Cyclotech has water and sand scrubbing systems on approaching 40 North Sea installations – more in Norway than the UK. Norway has historically been a more receptive market for technology. Aside from generally being ahead in terms of regulatory regime, the Norwegians have the money to throw at new solutions.
“It’s easy to be conscientious if you can afford to be,” adds Hadfield.
“We’ve had an office in Norway since about 2000 and it accounts for 30-40% of our turnover. We have a figure of about 200 installations as being our accessible market … the bigger installations and where there are substantial volumes of produced water.”
Three such examples are Statfjord, which currently produces about 17,000 barrels of oil per day, plus 85,000 barrels of water; Gullfaks, 24,000/96,000 barrels, and Snorre, 20,000/21,000. Each is ejecting about 100 tonnes per year of sand.
It is hard to put a figure on sand production by the North Sea offshore industry, but the potential is for hundreds of thousands of tonnes of the stuff annually.
“It’s a lot of sand and much of it is invisible. It’s very damaging,” says Hadfield, pointing to the work of SMS in identifying just how damaging sand can, in fact, be.
And yet, as recently as 15 years ago, operators would not have addressed sand as a process issue. They would have lived with it as a necessary evil.