Broadband Constrained Inversion Realization And Application Study

Seismic inversion, which uses the seismic data of surface observation and is constained by the known geological regular pattern and the data of well drilling and well logging, is a process to solve the space structure and physical property of subterranean formation. The technique of poststack seismic inversion, which is built on the background of the vertical incidence of reflex cofficient, is a gordian technique of reservoir description and reservoir predication. The sense of this technique rests with transforming seismic section which makes structure information known into wave impedance section which makes lithologic information known. Li Qingzhong pointed out that the wave impedance section is the optimal outcome of high resolution prospecting.According to realization means, seismic inversion can appromately divide into wave equation inversion which is based on wave propagation and the inversion which is based on Robinson convolution model. The latter includes: seismic direct inversion whose basement is deconvolution, the seismic inversion controlled by logging, the inversion which is based on models, the probabilistic simulation of seismic properties and stochastic inversion.The seismic inversion which is controlled by logging is also called recursion inversion. It is a kind of seismic inversion whose base is using reflex coefficient to recursively calculate formation wave impedance, and it completely depends on the quality of seismic data itself. The inversion result is sensitive and significant about noise of seismic data. The narrow seismic bandwidth will cause resolution relatively low. So it is difficult to meet require of reservoir description.Broadband Constrained Inversion (BCI) is a kind of poststack iteration inversion, which organicly combines seismic data, logging information and transcendental geologic knowledge. It develops from Generalized Linear Inversion (GLI). It is equal to GLI when there is no logging information and transcendental geologic knowledge; while the iteration time equals one, it is equal to deconvolution. The aim of BCI is to obtain optimal wide-band wave impedance model, which is fit for reservoir description, by synthetically using seismic, geological and logging data. This approach is the wave impedance inversion which is used most frequently at the moment, but it depends on initial model intensely and has ambiguity.The original is based on sufficiently comprehending different inversion methods and researches recursion inversion and BCI relatively ingoingly, and programs to realize the two inversions, and then applies to inversion of simple models, reservoir analytical models and actual data. Finally, the original analyses the pros and cons of the two inversions, along with effect factors and solutions of the two inversions.The original also probes into seismic wavelet extracting, logging data processing and reservoir models building simply, which are related to the inversion work, and programs to realize them, acquires right application effect.