Investigation of Non-Linear Seismic Effects for Hydrocarbons Indication

Linear-elastic approach is commonly used in seismic methods theory. But in practice we’re often confronted with non-linear behavior of geological environment. The authors assert that oil and gas reservoirs show nonlinear properties. Thus it’s necessary to use a new model of subsurface considering the Earth’s non-linearity. The main goal of this paper is to define a level of non-linear effects and to investigate availability of non-linear properties in the problem of prognosis of hydrocarbon reservoir's properties. The special fieldwork had been realized using 2D vibroseis exploration. As a result of this investigation two main effects in hydrocarbon reservoirs were discovered:<br>- oscillations with multiple, combinative - summarized and differential - frequencies appear in the reservoir;<br>- non-linear behavior of registered signal amplitudes comparative to emitted signal amplitudes.<br>A new method for hydrocarbon indication was created on basis of these two phenomena and fieldworks.