Methodology And Application Of Formation Elastic Parameters Inversion And Fluid Identification

Seismic inversion could access formation lithology and physical parameters,seismic inversion generalise seismic, geological and logging information and usingmany technology. The inversion results could afford applicable basic data forreservoir prediction and characterization, thereby, increasing the exploration successrate reduce the cost of exploration and development, and improve economic efficiency.Fluid factor is an indication of the reservoir fluid, and also is an important means forfluid identification. Therefore, the thesis theme is reservoir fluid identification, themain content is formation elasticity parameters inversion and fluid identificationmethod based on petrophysical analysis, then built two different types of fluid factors:elastic modulus fluid factor, frequency-dependent fluid factor.The formation elastic parameters pre-stack seismic inversion was studied in thisresearch. In practical applications, due to production constraints, the shear wavevelocity data are often missing, which makes elastic parameters inversion very limited.To this end, we try to create an elastic parameters inversion method in the case of lackof shear wave velocity. Firstly, shear wave velocity of well position could obtain bydoing Bayesian inversion to well position pre-stack seismic data. Then, theinformation of the elastic parameters of subsurface medium could get after elasticparameters direct inversion. After that, we could do reservoir prediction anddescription based on petrophysical analysis. Elastic parameters direct inversionimproves the accuracy of the inversion results owing to avoid the error in theparameters transformation.Fluid factor could be used as an indication of reservoir fluid, and is widely usedin the identification of reservoir fluid, but the fluid factor indicating capabilityaffected by many factors, therefore, qualitative petrophysical analysis and quantitativefluid sensitivity analysis is required before building fluid factor, according to the realgeological and geophysical conditions, and then select appropriate fluid factor for the work area. In this research, firstly, according to the elastic parameters inversio n results,the bulk modulus K and shear modulus μ are combined into a sensitive parameter,known as the elastic modulus fluid factor. The new fluid factor improves the fluididentification capacity.Frequency-dependent fluid factor was built from another standpoint,hydrocarbons could be detected by using the energy attenuation while the seismicwaves propagates to the reservoir. Frequency-dependent fluid factor is not only theextension of fluid factors based on seismic amplitude, but also could cross check withother methods. By combination with seismic amplitude and frequency information,predication ambiguity could be decreased and the surveying accuracy could beimproved. In practice, the appropriate fluid factor for reservoir prediction anddescription could be selected according to the geological and geophysical conditions.