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Technical paper at SPE ATCE 2008

28ASC has collaborated with Halliburton in a paper presented at the 2008 SPE Annual Technical Conference and Exhibition held in Denver, Colorado, USA between 21 and 24 September 2008.
The paper titled "Velocity Calibration for Microseismic Monitoring: Applying Smooth Layered Models With and Without Perforation Timing Measurements", was presented within the session on Reservoir characterisation using next-generation seisic and lab analyses.

The paper investigates the role of origin time in velocity calibration by designing two inversion procedures. In procedure A, T0 is calculated during the Occam’s inversion while T0 is set to its true value in procedure B. A grid search locator is applied on both inverted models to produce two locations. We constructed three synthetic P-wave velocity models and add normally distributed random noise to the synthetic arrival times of all models. The noisy synthetic data are piped through procedure A to obtain location A and through procedure B to produce location B. Graphical analysis show that location A is closer to the true shot location than location B although both are close to each other. If the data noise is removed and the test is repeated, location B is closer to the true shot than location A. It was observed that the inverted location A is better in terms of the distance from the true location if using noisy data and location B is better if using noise-free data. This indicates that uncertainties due to data noise cause our inconsistent observation and implies that perforation timing measurements are not necessary and may actually result in a less accurate velocity model.

Full abstract of this paper can be downloaded by clicking here (external link)

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