Medical technology could help protect oil wells from damage

Technology adapted from drug delivery systems could help prevent damage to oil wells, according to a team of British engineers.

Product development firm Cambridge Consultants has created a remote real-time monitoring system that checks the quality of water reinjected into oil wells to spot particles of sand, wax or oil that could block pores in the rock.

The company says the current method of lab analysis of water is too slow to identify all potential issues before they cause irreversible damage to a well and the new technology would enable operators to instantly decide whether water removed from wells can be reinjected or must be replaced.

‘When we’ve shown this technology to the industry, this is the application they keep coming back with where they really want to use it, which is monitoring not just the quality of the water but of the production fluids,’ Cambridge Consultants’ associate director of oil and gas, Dr Frances Metcalfe, told The Engineer.

‘The characteristic of what comes out of the ground change over the lifetime of the well and if it’s not working, and you want to be able to react to things as soon as possible if they’re likely to affect production in anyway.’

She added that the technology might also enable more well operators to reuse water they would otherwise dispose of for fear of damaging their wells.

‘Water’s more freely available for offshore wells. But in, for example, the Gulf States where water is in short supply then you really want to be able to use as much of it as you can.’

The technology uses sensors to measure how a particular light pattern is scattered by particles and droplets in the water, which can range from tens of microns to under one micron in diameter. This data is then used to calculate the size, shape and distribution of the particles.

The challenge for Cambridge Consultants was determining the precise colour, direction and polarisation of light to use in the pattern to create the right scattering to give robust and routine readings in a harsh environment.

To do this they adapted an iterative process originally used to determine the light pattern needed to characterise the contents of drug delivery devices.

‘We’ve got a track record of doing some quite sophisticated signal processing using Bayesian [probability] analysis to work whether the information you want to know is in the pattern you’ve measured,’ said Metcalfe.

‘And more importantly it can help you in the design of the sensors and knowing what pattern of light you need to shine on the cloud of particles to measure what you want to know about it.’

Cambridge Consultants claims the technology has the potential to be affordable enough to allow numerous devices to be deployed at multiple locations.

The firm says such a system could also include a local alarm that would flag up a potential problem and send a control signal to fix an issue or turn off a valve.