NEW SEISMIC ATTRIBUTES ASSISTED INTERPRETATION OF SUBTLE STRATIGRAPHIC TRAPS IN NILE DELTA, EGYPT.

摘要

The offshore Nile Delta basin is considered as one of the most promising province in Egypt with an excellent potential gas and condensate reserves for future exploration. Most of the discoveries in Nile Delta were driven by the detection of direct hydrocarbon indicator (DHI), where depend on AVO class (III), such as the reservoirs in the Upper Miocene and Middle to Upper Pliocene. The exploration in our concessions from many decades depend on traditional AVO class (III), we urgently need to add more reserves in the area specially there are some gas potential in Lower Pliocene without DHI supported that have been successfully tested; Lower Pliocene sand did not show any response in all the seismic volumes (full, near and far). The AVO analysis of this sand reservoir referred as AVO class (II-p). Other case of subtle Lower Pliocene reservoir shows AVO class (I) which was tested by three wells. Using the Enhance AVO Pseudogradient equation to create new attribute cube could be extract all the anomalies and identify AVO classes for each anomaly. In this cube the AVO class (I) appears as negative, while the other classes are positive. The difference between class (III) and classes (II, II-p) is done by high positive response compare with week response for classes (II, II-p). After knowing the AVO class we can use new equation to create new attribute cube (new model) which can be used to differentiate between the gas and water anomalies for all AVO anomalies. This method (new model) was successfully proven in Petrobel’s concessions, where it helps us to discover subtle anomalies and open the gate for further exploration activities in the area.