Locating fluid saturated zones by applying low frequency excitation and analysing a characteristic resonant response

摘要

Actively exciting and analyzing the resonance phenomena occurring in an enclosed oil, gas and or water reservoir allows its presence to be located by doing qualitative and quantitative estimates of its extent via forward modelling. Eight excitation types are covered. Nine qualitative analysis steps are presented. Several specific techniques are used to relate the actual measurement with a numerical or theoretical model based on specific physical concepts, and so arriving at relevant conclusions about the reservoir. A qualitative survey method and a quantitative method based on a numerical modelling in conjunction with the Monte Carlo method are used to relate the oscillation characteristics to fluid properties. Differentiation between fluids is included. The method is directly sensitive to the oil or gas itself, because the resonance effect is only present for a fluid. Gas bubbles can strongly influence results.