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A case example of near‐surface correction for multicomponent VSPS
Author(s) -
Zeng Xinwu,
MacBeth Colin
Publication year - 1996
Publication title -
geophysical prospecting
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.735
H-Index - 79
eISSN - 1365-2478
pISSN - 0016-8025
DOI - 10.1111/j.1365-2478.1996.tb00179.x
Subject(s) - anisotropy , gemology , economic geology , geology , azimuth , isotropy , regional geology , environmental geology , engineering geology , polarization (electrochemistry) , igneous petrology , hydrogeology , mineralogy , geophysics , optics , seismology , telmatology , physics , geotechnical engineering , chemistry , volcanism , tectonics
A deterministic near‐surface correction procedure is developed for multicomponent VSP data, shot using directional sources and recorded using three‐component receivers. The method is capable of removing unwanted effects of acquisition such as unequal source strengths or misorientations, but may also remove near‐surface multiples and anisotropy. This is of considerable benefit for obtaining accurate and consistent estimates of subsurface anisotropy from different source combinations. Application of the technique is illustrated using a dataset from the Romashkino reservoir in Russia, where three or four different directional sources are used at the same source locations. The technique corrects for the large discrepancies which exist between the estimates obtained using different source combinations. Application of the technique to three wells in the survey region reveals a nearly isotropic subsurface, except for a few isolated zones of moderate to high (2 to 8%) anisotropy which lie close to the expected depth for the reservoir. Although there is no significant correlation with the production figures for each well, the qS1 polarization azimuth within the reservoir does vary at each well location, suggesting that this may be a more sensitive indicator of reservoir Drocess.