Seismic resolution enhancement for tight-sand gas reservoir characterization

Abstract

This is a case study on the application of inverse-Q filtering to improve the resolution of 3D seismic data, for the characterization of tight-sand gas reservoirs. When seismic waves propagate through multiple tight-sand layers in the subsurface media, the energy of high-frequency components is absorbed, and the wavelet shape is distorted. Stabilized inverse-Q filtering is able to simultaneously compensate the amplitude and correct the phase of seismic waveforms. After application to 3D seismic data, the frequency bandwidth has been increased by about 10 Hz, and the width of the wavelet has been narrowed, so that we are able to identify reflections of thin sand layers clearly. Due to the phase correction in inverse-Q filtering, filtered seismic traces can match the synthetic traces at well locations. Because of the high signal-to-noise ratio with the stabilization scheme, low-amplitude zones of interest corresponding to target high-fracture areas can be easily identified, and the detail within the anomalies can also be observed. Finally, spatial variations of tight-sand layers are depicted in the inversion profile with high resolution. © 2009 Nanjing Institute of Geophysical Prospecting.