Time-lapse applications of the Marchenko method on the Troll field

The data-driven Marchenko method is able to redatum wavefields to arbitrary locations in the subsurface, and can, therefore, be used to isolate zones of specific interest. This creates a new reflection response of the target zone without interference from over- or underburden reflectors. Consequently, the method is well suited to obtain a...

Discerning small time-lapse traveltime changes by isolating the seismic response of a reservoir using the Marchenko method

4D seismic studies aim to observe time-lapse changes in the subsurface between a baseline and a monitor study. These changes are generally small, and the seismic response from a deep reservoir can be concealed by reflections from shallow structures. Here, we introduce a novel way of isolating the reservoir response by means of the Marchenko...

Monitoring changes inside subsurface layers using non-physical reflections retrieved from seismic interferometry

Seismic interferometry (SI) is a principle for retrieving responses between two receivers using cross-correlation. After the retrieval, one of the receivers acts as a virtual seismic source whose response is retrieved at the second receiver. Correct response retrieval relies on assumptions, among other, of a lossless medium being illuminated...

Interferometric reservoir monitoring with a single passive source

Changes in the subsurface can be imaged by subtracting seismic reflection data at two different states, one serving as the initial survey or base, and the second as the monitor survey. Conventionally, the reflection data are acquired by placing active seismic sources at the acquisition surface. Alternatively, these data can be acquired from...