1887

Abstract

Summary

Production from oil and gas fields induces velocity changes and strains in the subsurface, which create time shifts between vintages of time-lapse seismic data. Recovering these time shifts can be useful for reservoir management, particularly through calibration of geomechanical models. and have shown that these shifts can be estimated using non-linear inversion of poststack time-lapse seismic. These existing inversions of post-stack data assume that the seismic ray paths in all vintages are vertical. However, examining pre-stack time-lapse data shows that the recorded time shifts are offset dependent. To estimate the true subsurface changes we must invert pre-stack time-lapse seismic, which requires more accurate modelling of the seismic energy propagation. This abstract introduces a new tomographic inversion of pre-stack time-lapse seismic which aims at estimating the velocity changes that explain all pre-stack time shifts. We retain the assumption of the existing post-stack methods that the ray paths do not change between vintages, but discard the assumption that they are vertical. This allows a linear tomography system to be set up and solved for velocity change. We test this method on synthetic data and compare the results with an existing post-stack approach.

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/content/papers/10.3997/2214-4609.201413456
2015-06-01
2020-08-06
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References

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