Analysis and interpretation of seismic data from thin reservoirs: Northwest Java Basin, Indonesia
What is this?
A detailed analysis and interpretation is performed of a 2?D seismic line over a sequence of thin reservoirs in the upper Cibulakan formation in the Northwest Java Basin. Most well sites in this area are selected to be structures near fault zones as faults are assumed to be the main hydrocarbon migration paths. Amplitude variation with offset analysis is little used because of contamination by thin?layer tuning effects. Attribute analysis, impedance inversion, and full?wavefield modeling suggest that gas reservoirs are detectable even when they are less than their tuning thickness, as they correspond to acoustic impedance anomalies and low instantaneous frequency. The presence of hydrocarbons can also be detected by anomalous behavior in crossplots of acoustic impedance versus density and P?wave velocity; sandstone reservoirs show low velocity and low impedance. Two?dimensional P?velocity and density distributions resulting from impedance inversion produce synthetic elastic common?source gathers that display reflection behaviors that are qualitatively similar to the corresponding field data.