FWI pode compensar a falta de iluminação na tomografia poço-a-poço? um estudo adicional

Abstract

In the wave first arrival travel time tomography (FATTT), there is a limiting factor for its efficiency associated with the seismic illumination. For a homogeneous medium, the seismic illumination is defined, at each point in the crosswell region, as the largest angular opening between the rays that connect the sources to the receivers. In the presence of velocity contrasts with interfaces outside the illumination, FATTT generates artifacts, which implies erroneous geology imaging. This study analyzes two synthetic two-dimensional models in the crosswell arrangement, one with interfaces completely covered by illumination and the other outside this coverage. This study investigates whether the complete waveform inversion (FWI) can compensate for the lack of illumination in FATTT. The seismic source is represented by the Ricker pulse at two peak frequencies, 100 Hz and 500 Hz. FWI is performed in two ways: using only the waves transmitted from one well to the other (FWI T) and the reflected waves that arrive at the well where the sources are located (FWI T+R). The results confirm that the FWI, in both arrangements, provides a better resolution for the case of the medium that contains the interfaces within the angular coverage when compared to FATTT. However, even in the FWI T+R array, it is impossible to image interfaces out of illumination correctly.