On The Prediction of Repeatability Noise in Marine Time-Lapse Surveys

It is well established today that most of the repeatability damage in marine time-lapse seismic stems from the inevitable positioning errors made during the redeployment of sources and receivers. However, despite several works on this important topic we still lack a consistent framework tying such errors with what we call "repeatability noise" in a quantitative – and therefore predictive way. The stakes are high, since having control over the expected levels of 4D noise in a time-lapse survey – for instance trough sound navigation specifications – is paramount for making the most out of our monitored reservoirs at reasonable cost. Recent research has started to lift the veil on this issue by providing a new way to look at the 4D problem from the perspective of perturbation theory, leading among other results to the introduction of the SDR attribute as a true, unbiased measure of time-lapse repeatability. Building on this framework, this paper presents the main ideas of a working methodology allowing the 4D prediction problem to be tackled properly.