Full‐waveform processing and interpretation of kilohertz cross‐well seismic data

Abstract

High‐frequency, cross‐well seismic data, from the Midale oil field of southeastern Saskatchewan, are analyzed for direct and reflected energy. The goal of the analysis is to produce interpretable sections to assist in enhanced oil recovery activities ([Formula: see text] injection) in this field. Direct arrivals are used for velocity information while reflected arrivals are processed into a reflection image. Raw field data show a complex assortment of wave types that includes direct compressional and shear waves and reflected shear waves. A traveltime inversion technique (layer stripping via ray tracing) is used to obtain P‐ and S‐wave interval velocities from the respective direct arrivals. The velocities from the cross‐well inversion and the sonic log are in reasonable agreement. The subsurface coverage of the cross‐well geometry is investigated; it covers zones extending from the source well to the receiver well and includes regions above and below the source/receiver depths. Upgoing and downgoing primary reflections are processed, in a manner similar to the vertical seismic profiling/common‐depth‐point (VSP/CDP) map, to construct the cross‐well images. A final section is produced by summing the individual reflection images from each receiver‐gather map. This section provides an image with evidence of strata thicknesses down to about 1 m. Synthetic seismograms are used to interpret the final sections. Correlations can be drawn between some of the events on the synthetic seismograms and the cross‐well image.

Fracture imaging within a granitic rock aquifer using multiple-offset single-hole and cross-hole GPR reflection data

“…Common cross-hole processing tools such as single-trace mapping techniques (Khalil et al, 1993;Lazaratos et al, 1995) that focus on layered structures can only handle horizontal to sub-horizontal reflectors correctly. The complex spatial distribution of fractures at the site and the cross-hole acquisition geometry necessitate an approach that can accurately consider all reflector dips.…”

Nondestructive imaging of small size voids at Akrotiri archaeological site, Thera Island, Greece, by seismic inversion techniques

“…From all such arrivals, the least ambiguous source of information in cross-hole surveys is direct arrivals. In recent papers (e.g., Pratt and Goulty, 1991;Khalil et al, 1993;Lazaratos et al, 1993;Schaack, 1995;Bube and Langan, 1995), reflected and other arrivals have been used in conjunction with the direct arrivals to increase the resolution and stability of the solution. In this paper, cross-hole seismic tomography and vertical seismic profiling (VSP) methods are used to investigate small size structures, such as voids, unveiled during foundation activities at an archaeological site in Greece.…”

Visco-acoustic data modeling using optimum layer approximation technique: greenwood oil field example, USA

“…The advantages of cross-hole survey over surface seismic data are overwhelming (Hu et al, 1988;Khalil et al, 1991;Justice et al, 1993;Lee et al, 1995;Raji et al, 2016). But cross-hole seismology is not completely understood (Lazaratos et al, 1993;Long et al, 2001;Raji, 2016;Raji et al 2017).…”