Method Of Muiltiwave Prestack Joint Inversion In Fluid-saturated Porous Media And Its Application In Reservior Prediction

Reservoir geophysics can be applied to study the physics-characteristic,space disturber,fluid attribute of reservoir by making use of seismic technology, rock-physics ,and other methods. It helps us to identify and evaluate the reservoir qualitatively or quantitatively. Nowadays,seismic technology to solved reservoir and lithology problem mostly are on the assumption that the media is symmetrical and isotropic.It takes no account of effect made by fluid and pore frame,so the methods based on this media modal usually bring on some disadvantageous factors such as inaccurate of solves, multi-solve obviously and so on. Lots of conclusion coming from study of rock-physics have proved that the Fluid-saturated Porous Media modal is more approaching to the actual rule of reservoir. The method based on this media modal maybe improve the precision of identify and evaluate the reservoir.Considering those factors above, this paper will carry out a AVA forward study and a new inversion method study which due to the precise reflection coefficient formula in Fluid-saturated Porous Media, making full use of multiwave seismic data, adapting linear inversion algorithm and considering the effect of seismic wavelet.The fluctuate equation which describe the seismic wave field promulgation rule in Fluid-saturated Porous Media relates to so many elastic parameter and most of those parameters have no clear physics mean(such as A,N,Q,R) and are difficult to observing that makes the Biot theory became inconveniently when we using. It is necessarily to build a conversion relationship formula between the elastic parameters and the common rock parameters or reservior parameters(such as P-wave velocity,S-wave velocity,density,fluid bulk modulus). On the foundation of reading a lot of literatures about rock-physcis, Bases on the Gassmann equation and Biot theory ,this paper deduced a conversion relationship formula.On the basis of the precise reflection coefficient formula and the conversion relationship formula,studied the AVA character by calculated the AVA curves of different theory modals.The forward results revealed the difference of AVA response between P wave and Shear wave and gaven a reason that why Shear wave is more sensitivity than P wave in identifing and evaluating the reservoir in the view of rock-physcis.After forward study,author places the more attention on the inversion algorithm,and proposes a multiwave joint inversion method based on waveform in Fluid-saturated Porous Media, which can be obtained P-wave velocity, S-wave velocity, density and porosity. According to furthermore computering, many lithology parameters and seismic attribute parameters can be obtained. Those obtained parameters can be use to interpretation of 2D3C and 3D3C actual seismic data.Follow the built algorithm flow,author made a practice application.In order to check the correctness ,designed a theory model to calculated applied this application.The last result proved that the application work well.After checking ,used this application processed a cross-well inline actual seismic data which come from a 3D3C survey.The inversion data substantiate the multiwave-joint-inversion method based on Fluid-saturated Porous Media is effective and applied,and also reveales the potential of Fluid-saturated Porous Media modal in lithology identification, petrophysical prediction.