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Permanent Buried Receiver Monitoring of a Carbonate Reservoir in a Desert Environment
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 80th EAGE Conference and Exhibition 2018, Jun 2018, Volume 2018, p.1 - 5
Abstract
Onshore time-lapse seismic is a major challenge, particularly in the harsh desert environments encountered in Saudi Arabia. Injection of CO2 into a stiff carbonate reservoir results in weak 4D signal, which can easily be contaminated by noise generated by changing near surface conditions. Using a hybrid acquisition system, consisting of permanent buried receivers and surface vibroseis sources, the seasonal variations in data repeatability are clearly identified. Data acquired under the same conditions (e.g., both surveys during the dry season) provide the best data quality, with significant waveform variations observed when comparing surveys from different seasons (i.e., dry-wet). Buried receiver acquisition and specialized processing has resulted in outstanding final stack repeatability. For surveys acquired under dry conditions, mean NRMS values in the range of 3–5% have been reported for surveys separated by up to two years. This level of repeatability has allowed small signals due to CO2 injection to be detected, which grow with increasing injection volume and are consistent with engineering data.