Effects of complex near surface on 4D acquisition with buried source and receiver

Abstract

A seismic field acquisition test was conducted in an onshore field in Saudi Arabia. The effects of near-surface complexity (in the form of sand, karsts, topography), environmental noise as well as large surface temperature variations are illustrated and quantified by 4D attribute analysis using permanent seismic sources and buried geophones. We show that burying receivers dramatically improves the wavelet amplitude stability as well as naturally reduces the effect of man-made surface noise. The near-surface layers comprise sand from 3 m to more than 20 m thick in this area overlying layered limestones and marls with karsting of limited lateral extent from 20 m to at least 50 m deep. Data quality from the permanent sources at this depth was inadequate for imaging using such low-fold acquisition, but the best data seems to come from the deepest buried sensors at 50 m. In addition, more sensitive sensors may be used to properly record weak high-frequency signal in this buried quiet environment.