Staying true to their innovative ethos, 3M has developed the 3M Glass Bubbles; unicellular spheres made from soda-lime borosilicate glass. Used across a wide range of industries such as manufacturing and automation, 3M Glass Bubbles are particularly useful in the oil and gas industry.

When combined with either a water based or synthetic oil based liquid, the 3M Glass Bubbles create a lightweight drilling fluid that help maximise under-balance during the process of allowing oil and gas to enter the well, known as perforation.

One of the main problems faced during the perforation process, is the ability to overcome pressure differential between the borehole and the surrounding hydrocarbon reservoir. Maintaining a desired state of ‘under-balanced’ pressure – achieved when hydrostatic pressure inside the borehole is less than the pressure in the rock formation – will minimise reservoir damage and ensure hydrocarbons flow into the borehole. An over-balanced pressure may lead to damage of the rock matrix and the creation of a ‘low permeability crush zone’, ultimately restricting production.

A desired under-balance condition is accomplished by injecting lightweight fluids with a low density, high stability and acceptable degree of viscosity, into the well. There are several different ways to create drilling fluids with the required characteristics but these methods can be costly and dangerous to drilling operators. Alternatively, swabbing the well can achieve the necessary perforation balance but, again, this can be a dangerous process that may even lead to a ‘blowout’.

The concept of a stable high density completion fluid was piloted during work on the Bunga Raya field by Talisman and Halliburton. The joint development between Malaysia and Vietnam, proved to be problematic, as limited water injection resources in the region and high density completion fluids led to an over-balance under local conditions. This prompted action from the team at Talisman Malaysia, who under the leadership of Graeme Rae, set about developing an even lower density lightweight fluid.

After various field tests were carried out, the conclusion was determined that with the addition of 3M Glass Bubbles to a synthetic oil, a super lightweight completion fluid with the required characteristics could be produced, providing a density range of 2.7 – 5.0ppg.

Once applied to the perforation process in the BKC-18 well of the Bunga Raya field, production rates proved to be more than double that of the nieghbouring BKC-17 well, which used conventional under balance fluids. Having previously established itself in the oil exploration and production industry – notably in buoyancy modules for subsea risers and in syntactic foam insulation for deep-sea flow lines – 3M Glass Bubbles are a reliable and proven solution for drilling operators.

Graeme Rae, who at the time was head of well technology at Talisman Malaysia, said: “While this new lightweight perforation fluid is not a panacea for well completion in general, it adds to the arsenal of problem-solving solutions.

“The only variable that can be assigned to the complete success of BKC-18 and its performance compared to associated wells is the use of the low-density completion fluid”

3M Glass Bubbles have modernised the perforation process, providing drilling operators across the globe with a cost-efficient and effective solution to achieving the required under-balanced value. Due to their lightweight and spherical shape, these glass bubbles have a much lower surface area and an enhanced strength-to-weight ratio in comparison to alternative materials, allowing for a far greater survivability, necessary in the demanding downhole environment.  Many different grades of 3M glass bubbles have been used in downhole applications across the globe with densities as low as 0.25 and crush strengths as high as 19,000psi.  

3M Glass Bubbles are also an ideal solution during cementing. Their low-density offers improved performance in cement slurries, in comparison to alternative solutions. This improved performance permits cementing in a deep well in a single stage, helping save both time and expense while reducing formation damage.

To find out more about 3M Oil and Gas, please visit www.3moilandgas.co.uk

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