| As the focus of oil and gas exploration gradually shifted to complex areas,a method of high resolution is needed to guide the exploration and reservoir prediction.Full waveform inversion is based on wave-equation modelling and the amplitude and phase information of the seismic information is fully utilized,so it has a higher resolution than the conventional inversion.As a result,the reservoir prediction based on the full waveform inversion is more and more popular.Wave-equation modelling is foundation of full waveform inversion method of reservoir,so the paper firstly introduces the basic theory of wave equation of acoustic in frequency domain and wave equation of elastic in frequency domain explicitly.Using them as bases and studies the theory of full waveform inversion of acoustic wave in frequency domain and the theory of full waveform inversion of elastic wave in frequency domain.And the simulation of simple model and complex model are carried out and the effect is good.On this basis this paper proposes a new algorithm—FCG(Fast Conjugate Gradient),it is applied to the full waveform inversion of acoustic wave in frequency domain and improves the convergence speed.The inversion of density is always a critical and difficult problem for full waveform inversion method of reservoir,this paper studies full waveform inversion of acoustic wave with variable density in frequency domain and studies the factors influencing the inversion of density particularly and finally gets appropriate strategy for the inversion of density,on this basis,the paper studies reservoir prediction using full waveform inversion and test of simple model is carried out.The example analyses show full waveform inversion which utilizes full wave field acquired to inverse high-precision formation density and bulk modulus could provide effective basis for reservoir prediction.Finally,all the contents of this paper are summarized. |
