Abstract:

In the past few years, seismic exploration of hydrocarbon is becoming more and more difficult. The main reason is complexities of the underground objects, such as structure of abrupt dip angle, overthrust, structures under volcanic rock and low-amplitude structure and so on. Volcanic rock had a serious shielding action to underlayers so that the underlying beds which had a very low signal-to-noise ratio and even had no reflection on seismic section. It badly hindered the discovery of reservoir in the underlying beds of volcanic rock. Based on the fact and refered to the research result all over the world, the authors worked out a deep and wide comprehensive seismic exploration technique to solve the problem of volcanic rock shielding. This technique makes use of the comprehensive effect of reflection wave, refraction wave and conversion wave in normal deep seismic exploration to obtain the tomography of formation under the volcanic rock. And it is applied in the Shubei area which is covered by volcanic rocks. Compared with other techniques, the results of this technique show that the overlay has a relatively high signal-to-noise ratio, and the underlayers have a clear structure images and could meet the need of geological interpretation. It could be an instrument for further exploration of hydrocarbon of these areas.

Key words: deep and wide comprehensive seismic exploration technique, areal coverage of volcanic rock, numerical simulation, wide-angle reflection wave, radial path, higher-order dynamic correction