Merging active and passive seismic reflection data with interferometry by multidimensional deconvolution

Abstract

Seismic interferometry, also referred to as Green's function retrieval by crosscorrelation, is a technique with many applications, such as for the reconstruction of surface seismic, VSP, to Ocean-Bottom data using active or passive data. Due to the impurity of the Green's function retrieved in the presence of one-sided illumination or intrinsic losses, multidimensional deconvolution emerged as an alternative. Multidivisional deconvolution addresses the limitations by deconvolving the point-spread function from the crosscorrelation result, which removes the source signature, surface related multiples and takes intrinsic losses into account. The similarity of the inverse problems of interferometry by multidimensional deconvolution applied to active and transient passive data makes it an attractive framework to merge the two datasets and retrieve a broadband Green's function (reflection response). The actual merging is done in the frequency-space domain using simple weighting functions. Numerical validations were carried out to merge active and passive body waves using interferometry by multidimensional deconvolution in a simplified exploration-style environment. The results indicate that sufficient source illumination is need as well as sufficient spatial receiver sampling to ensure that wavefields are properly recorded. Also adequate length of the receiver line must be ensured to properly record the low-frequency wavefields and meet first-Fresnel-zone criterion. The retrieved broadband response is desired for imaging and reservoir characterization purposes. The active seismic survey conducted in the northern Netherlands accompanied by the passive recordings of induced seismicity in the area was an inspiration for the merging idea. Given that the conditions from the numerical models are met in the field, passive and active data can be merged. A simple model was used to investigate the faraway induced-seismicity arrivals and briefly discuss their usefulness.