A Weighted Closure-Phase Statics Correction Method: Synthetic and Field Data Examples

Abstract

Recorded seismograms are usually distorted by statics owing to complex geological conditions, such as lateral variations in sediment thickness or complex topographies. These distorted and discontinuous signals usually exist in either arrival times or amplitudes of waves, and they are most likely to be smeared as velocity perturbations along their associated raypaths. Therefore, statics may blur images of the target bodies or, even worse, introduce unexpected and false anomalies into subsurface structures. To partly resolve this problem, we develop a weighted statics correction method to estimate unwanted temporal shifts of traces using the closure-phase technique, which is utilized in astronomical imaging. In the proposed method, the source and receiver statics are regarded as independent quantities contributing to the waveform shifts based on their acquisition geometries. Numerical tests on both the synthetic and field cases show noticeable, although gradual, improvements in data quality compared to the conventional plus–minus (PM) method. In general, this method provides a straightforward strategy to reedit the travel times in seismic profiles without inverting for a near-surface velocity model. Moreover, it can be extended to any interferometrical methods in seismic data processing that satisfies the closure-phase conditions.