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4D Seismic Warping in Two Steps for Overburden and Reservoir - Example of a Compacting Carbonate Field
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 76th EAGE Conference and Exhibition 2014, Jun 2014, Volume 2014, p.1 - 5
Abstract
Conventionally, the 4D warping is only performed over the reservoir interval, assuming that all 4D effects are located in the reservoir. In the case of a compacting reservoir, the overburden is affected by subsidence, hence by time shifts. For this particular situation, we present a workflow in two steps to optimize separately the 4D warping of the overburden and the warping of the compacting reservoir.
This two step approach has two advantages: First, the warping parameters can be optimized independently for each interval. The second advantage is to apply a time shift correction at top reservoir before the reservoir warping, to avoid any contamination of the reservoir warping by the overburden time shift.
This workflow is illustrated by a case study over an offshore carbonate gas field buried under a silicilastic overburden. The 1st warping step reveals that the overburden is affected by translation but only the western part is affected by vertical stretching (geomechanical arching effect). The 2nd warping step, focused on the reservoir, reveals a tilted rise of the gas-water contact, associated to a decrease in P-wave velocity.