Time-lapse velocity analysis — Application to onshore continuous reservoir monitoring

Abstract

In 4D seismic, the velocity model used for imaging and reservoir characterization can change as production from the reservoir progresses. This is particularly true for heavy oil reservoirs stimulated by steam injection. In the context of sparse and low-fold seismic acquisitions, conventional migration velocity analyses can be inadequate because of a poorly and irregularly sampled offset dimension. We update the velocity model in the context of daily acquisitions with buried sources and receivers. The main objective is to demonstrate that subtle time-lapse effects can be detected over the calendar time on onshore sparse acquisitions. We develop a modified version of the conventional prestack time migration to detect velocity changes obtained after crosscorrelation of the base and monitor surveys. This technique is applied on a heavy oil real data set from the Netherlands and reveals how the steam diffuses over time within the reservoir.

The appraisal of surface orbital vibrators with buried geophone array for permanent reservoir monitoring

“…Some of these challenges can be addressed by permanent reservoir monitoring, consisting of fixed source and/or receiver arrays (Meunier et al ., 2001; Hornman et al ., 2012; Berron et al ., 2015; White et al ., 2015; Bakulin et al ., 2016; Nakatsukasa et al ., 2017; Cotton et al ., 2018). To improve repeatability, permanent sensors have been utilized in both marine (van Gestel et al ., 2008) and land projects (Roach et al ., 2015).…”

Quantification of modelled 4D response and viability of repeated seismic reservoir monitoring in J-Area Field, Central North Sea

“…4D reservoir monitoring is a comparison of a baseline 2D or 3D seismic survey (ideally acquired pre-production) with a repeat 2D or 3D monitor seismic survey (acquired during production) (Landrø 2007;Eriksrud 2014;Ji 2017). The baseline and monitor survey are acquired over the same geographical location at different times with a view to understanding the changes in the reservoir over time, particularly its behavior during production (Landrø 2007;Eriksrud 2014;Cotton et al 2018). Any changes observed are hoped to be the response of geomechanical changes or rock properties changes such as densities and wave velocities to the production effects in the reservoir and not due to error in data acquisition, processing and interpretation (Fanchi et al 1999;Landrø 2007;Eriksrud 2014;Cotton et al 2018).…”

“…The baseline and monitor survey are acquired over the same geographical location at different times with a view to understanding the changes in the reservoir over time, particularly its behavior during production (Landrø 2007;Eriksrud 2014;Cotton et al 2018). Any changes observed are hoped to be the response of geomechanical changes or rock properties changes such as densities and wave velocities to the production effects in the reservoir and not due to error in data acquisition, processing and interpretation (Fanchi et al 1999;Landrø 2007;Eriksrud 2014;Cotton et al 2018). The differences between the existing Communicated by M. V. Alves Martins and repeated survey data help to measure the production effects and identify, where the changes are occurring in the reservoir (Landrø 2007;Eriksrud 2014;Cotton et al 2018).…”