A. Belyashov¹ , V. Suvorov¹ , E. Melnik¹

¹Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch, Russian Academy of Sciences (IPGG SB RAS)

Abstract:

One of the problems in OSI subsurface techniques development is the uncertainty of potential target objects. In a general approach (which includes OSI modelling) the zones of explosive disintegration are presented in simplified form – as a vacuous cavity with areas of active crush around it. The real situation is described by more complicated models with presence of other disrupted areas, including spall zones and common fracturing areas, which could be detected using near-surface seismic surveys. At the Semipalatinsk Test Site, where borehole UNEs were conducted, an active seismic survey using diving waves method was carried out. In the UNEs epicenters the spall zones were detected to the average depth of 85 m. Their thickness depends from the yield of the nuclear charge. P-wave velocity was less than in the surrounding rocks with 1.0-1.5 km/s, S-wave with 0.5 km/s. Under the spall zones to the average depth of 150 m the common fracturing layer was revealed. Parameter of cracks density changes from 0.15 to 0.45. Upper se disintegrated zones may also be used as indicators of conducted UNEs. Herewith the spall zones allow to define UNE's hypocenter position and its yield. In this presentation we give methodical recommendations on active seismic technique applying during the OSI continuation period.