Wave-equation inversion of time-lapse seismic data sets

Example

We apply the proposed method to a North Sea time-lapse data set with two years of production between the baseline and the monitor. The shots and receivers are spaced at $25$ m, and the maximum offset is $3200$ m. First, we show how wave-equation inversion can improve time-lapse amplitude information on complete data sets. In this example, the baseline and monitor data sets have similar geometries. Secondly, we simulate an obstruction in the monitor data with a gap $400$ m wide. In this example, except at the obstruction where no sources or receivers are present in the monitor, the baseline and monitor data sets have similar geometries. Figure 1 shows the full migrated baseline stacked section. After preliminary processing of the data, we identified the reservoir location around which the target area for inversion is defined. Henceforth, we show the results only for the target area. All inversion results are obtained using the RJMI formulation.

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Figure 1. Raw baseline stacked image.

Wave-equation inversion of time-lapse seismic data sets