Time-Lapse Seismic Signal in the Overburden of Producing Reservoir – Separating Possible Causes.
D. Rappin, Y.-M. Leroy and J. Fiore
Event name: 79th EAGE Conference and Exhibition 2017
Session: Reservoir Evaluation, Monitoring and Management
Publication date: 12 June 2017
Info: Extended abstract, PDF ( 2.52Mb )
Price: € 20
4D time-lapse seismic is a standard technology nowadays to describe reservoir property changes during field production, especially pressure variations and fluid movements. Seismic information does not directly provide these physical properties, but seismic velocity changes or impedance changes can be obtained throughout inversion processes. In this paper, we present several examples of 4D signature encountered in the overburden of different producing reservoirs, in various geological contexts. The impact in the overburden of producing reservoir is not straightforward. There are many potential causes separate or combined to explain the observed 4D time-shift. Geomechanical effects became obvious in many cases. Effective displacements, subsidence, fault activation and fracturing, can also have significant local contributions. In addition, fluid evolution in small sandy levels located in the overburden can contribute to the observed 4D time-shift. Several cases and modeling are analyzed with different complementary workflows in order to separate and determine the weight of contribution of the different causes.