Comparative test of emulsion and pentolite based explosive seismic sources

Abstract

In land acquisition, explosive sources that release a great amount of energy at a minimum charge and environmental impact are preferred. In order to compare two explosive sources, namely emulsion and pentolite based sources, we performed a series of thirty-two isolated test shots and two surveys of two-hundred shots in parallel seismic lines. For the isolated shots we measured the top and volume of cavities to estimate its environmental impact. We also measured the three-component signals and peak particle velocities with a portable seismograph. These quantities allowed to obtaining a rough estimation of the energy equivalence for a pentolite/emulsion charge ratio of 2kg/3kg per shot. In order to obtaining a statistically meaningful comparison we performed a two-hundred shot pentolite survey, to be compared with an already done emulsion survey, with the pentolite charge determined from the isolated shot charge ratio. The pentolite and emulsion seismic lines were then processed with same parameters. The amplitude spectrum, the ratio between geological response and noise, the visual inspection of seismic resolution and lateral continuity of reflectors showed that the source energy of pentolite is relatively smaller than that of emulsion for the chosen pentolite/emulsion charge ratio.