Microseismic Feasibility Study - Monitoring Gas Injection in Middle East Field

A microseismic feasibility study is presented to monitor the injection of gas in the Arab-D reservoir of an offshore Middle East field. Full waveform modeling and detection sensitivity analysis have shown that the proposed network of installing sensors at reservoir depth in observation wells has high detection capabilities. However the modeling results reveal that interferences would exist between direct and refracted/reflected waves making it difficult to identify first P-wave and S-wave arrivals from microseismic events. Large location uncertainties are also expected with the proposed network. As a result the feasibility study recommends placing in each observation well some additional shallower sensors ~400 meters above the reservoir. Based on these feasibility results a decision will be made whether to proceed with a field trial survey.