Well testing is an expensive and tedious task. Each oil or gas well must be regularly checked to verify its productivity and to measure key parameters for optimisation.
For decades, the state of the art in well testing has been the build-up test: it requires measuring the flow from a single well, shutting it suddenly, and recording how the pressure of the well changes with time.
The build-up method is well understood and provides a wealth of information, but it requires care, because a sudden shut-in is a safety risk; it is also very expensive, because of the production loss incurred during testing, which can last hours or even days. A test campaign on an oil field can easily cost millions of dollars, and must be repeated regularly - typically every month or two.
How SmartX is different
SmartX is based on the concept of sinusoidal excitation and frequency analysis. Each well has a choke valve, which is essentially a "tap" regulating the flow of oil or gas: by slightly opening and closing the valve at a certain frequency, we can cause changes in flow and pressure that we can measure, compare and analyse to obtain the most important data for production optimisation, such as productivity index, gas-oil ratio (GOR) and water cut.
SmartX is not meant to fully replace build-up testing: it is limited to the near-well region (which is why it is able to deliver results so quickly), which is indeed the most important region in any well; however, reservoir-wide properties should still be investigated with build-up, albeit much less often and with great savings.
An additional bonus is that we can test multiple wells at the same time, even if there is only one flow measurement available on a production platform. This is thanks to frequency analysis, and its uncanny ability of separating different frequency components after they have been mixed. This results in dramatically short times for testing an entire field (hours instead of days), with no significant production loss.
Does it work?
In 2013 and 2014 we ran a field test project with financing and support from Total and GDF Suez. The method proved viable and produced very interesting results. We intend to further develop the method into a software suite that oil & gas companies can deploy on their production sites, and further pursue scientific research to extend the method.
Acknowledgements
We are thankful to the IO Centre for supporting the initial development of SmartX, Total E&P Norge and GDF Suez E&P Norge for their financial and logistic support in the field testing activities.
SmartX was developed in cooperation with NTNU, especially professor Bjarne Foss from the Department for Engineering Cybernetics. SINTEF and NTNU jointly own a patent to the method.