Pickin' up good vibrations

In oil drilling, as in most things in life, there's good vibes and there's bad vibes. The bad vibes cost money and waste time. For an oil driller, nirvana may well be a question of refocusing the inner energy and turning the bad vibes into good vibes. At least, that's what one of the scientists at CSIRO Petroleum, Dr Thomas Gabler, is aiming to achieve.

'If you drill an oil well, you generate vibrations in the drill string. And if something vibrates, it breaks. A very costly outcome, which can take days to remedy.

'All along the drill string, which can be kilometres in length, you may get bouncing, twisting and bending which can stretch and contract the drill string, causing energy loss,' Dr Gabler explains.

'Our objective is to harness these vibrations and use them to break rock, instead of minimising or eliminating them, which is generally the approach taken. The idea is not to oppose the forces, but to use them.'

The research team is working on designs for a reflector that will capture the shockwaves as they bounce up the drill string - and redirect them back down into the drill bit.

The idea has previously been explored by Russian scientists, and there is currently a collaboration between CSIRO Petroleum, Aquatic (Moscow), DDS (Belgium) - a bit manufacturer, the University of Minnesota, PDVSA (Venezuela) and PETRONAS Carigali Bhd. (Malaysia)

'We're testing the theory now and we'll model it against existing drill strings,' Dr Gabler says.

'We estimate that it may be possible to save as much as 20-30% of the energy now lost in vibration, and redirect it into rock-breaking.

'The potential savings are huge, not only through improving the drilling rate, but also in significantly less time spent changing tools. They can be in the order of 50%,' he concludes.

In other oil-well related research at CSIRO, researchers working with US firm Halliburton Energy Services' Baroid Drilling Fluids have developed new low-cost fluids that can reduce the environmental impact of drilling because they contain special polymers which 'coat' the surface of hole and prevent, or at least minimise, fluid from the drilling mud from seeping in and destabilising a wellbore.

A world patent has been filed for the formulations, which are being comercialised by Baroid as the BarOmega( (Osmotic Membrane Efficiency Generating Aqueous) drilling fluid system. The new fluids are now entering field trials in the Gulf of Mexico and the North Sea.