Full text loading...
-
Initial Results of a Pilot 4D Seismic Monitor in a Difficult Shallow Offshore Carbonate Context - Dynamic Connectivity and Implications for Development
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 76th EAGE Conference and Exhibition 2014, Jun 2014, Volume 2014, p.1 - 5
Abstract
Whereas Timelapse seismic is well known as a robust reservoir monitoring tool in deep offshore turbidites, this monitoring technique is less ubiquitous in fractured carbonate contexts. In our case, a prior 4D seismic feasibility was realized in such difficult context and predicts that the main 4D effects are linked to pressure changes (as first order effect) and then saturation effects. A pilot monitor survey was thereafter acquired over areas seen as the most “4D” sensitive zones 16 years after baseline acquisition and 10 years after production start-up. The pilot objective was to verify if 4D signal linked to depletion effects and water sweeping are detectable in the generally <5m thick fractured carbonate reservoir units. This paper shows in spite of seismically noisy context, validated 4D signals are present in the seismic monitor acquired and is interpretable. Through an integrated multi-attribute analysis of all available static and dynamic data; relative velocity/impedance changes enables the delineation of depleted zones and mapping of pressure and saturations boundaries. This has helped in the characterization of the fracture corridors, internal reservoir heterogeneities, understanding the main flow directions and identification of the swept and unswept zones which could help for future infill well placement.