Research on key technologies and new method of high precision 3D geological modeling

In order to make full use of spatial distribution information of underground lithology, properties and fluids in 3D seismic exploration data, to further improve the accuracy of 3D geological model and improve the numerical simulation effect of reservoirs, the quality of pre-stack seismic gathers and the improvement of well-seismic matching were discussed. Through the spectral equalization of different offset seismic traces, the distortion of the seismic data was corrected by the absorption of the formation by NMD the tensile effect. The consistency of seismic data in depth domain with logging curve has been improved by constructing high-precision 3D velocity model for time-depth conversion. The multi-disciplinary integrated methods of petro physics, seismic inversion, geological modeling and reservoir numerical simulation were used for cyclic feedback to optimize the accuracy of 3D geological model and to improve reservoir production history fitting. The results show that the application of spectrum equalization technique for different offset seismic traces eliminates the distortion of the long-distance seismic waveform, so that the seismic wave energy is concentrated in the effective frequency range. The new method of 3D time-depth conversion was established by combining the high-resolution velocity cube from geo-statistical inversion with the automatic meshing technique of interlayer ensures the fine matching of 3D seismic data and well logging curve in depth domain. And the deep-field seismic inversion data after time-depth conversion,the well logging curve is consistent in both depth and value.At the same time, the numerical simulation data obtained from the new geological model are highly consistent with the actual production data, and the production history is well fitted.The difference between the recalculated geological reserves and the dynamic reserves is greatly reduced. The method solved the problems of lower accuracy geological modeling and large difference between dynamic with static reserves that has long existed in gas field.