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Exploration and production geoscientists use a number of characteristics reflecting such properties of reservoirs under study as structure, lithology, porosity, permeability, etc. Reliability of estimating these parameters defines effectiveness of reservoir development actions. Measuring elastic properties of formation allows computation of a number of parameters characterising reservoir's lithological properties and filtration characteristics. The information about distribution of elastic properties allows estimation of reservoir structure and elaboration of the optimal strategy for reservoir development. Certainty and reliability of the geoinformation may be dramatically increased using integration of methods, studying elastic properties of reservoir in different frequency bandwidths using seismic waves of different types - longitudinal, shear, converted. From this point of view, the integration of fullwave sonic log, multiwave VSP and surface seismic data may provide the effective solution for the task of investigating reservoir elastic properties. Integration of information obtained using these methods allows building of a single model that includes features of different ranks. Observations, which use elastic waves of different types, make it possible to additional calculate such integrated parameters as Poisson ratio and to increase certainty of estimation of such characteristics as lithology and porosity. Seismoacoustic measurements data, supplemented by log interpretation results, core analysis, hydrodynamic study results, provide a means to dramatically increase quality and certainty of the study. Geological prerequisites Structure of most hydrocarbon reservoirs demonstrates the significant variation of acoustic properties laterally. Even for such tectonically calm region as West Siberia, many oilfields demonstrate that reservoir formations penetrated by development wells have non-comparable properties because of structural and lithological changes. In many cases non-predictable changes in structure of the pay interval are associated with pinch-outs, lithologic replacements and small-amplitude faults. It is quite obvious that no one single method out of the geoscientist's arsenal cannot solve the problem of generating the detailed model of the reservoir being applied alone. This paper describes the approach to reservoir characterisation based on integrated use of fullwave sonic log, 3C Vertical Seismic Profiling and 3C Surface Seismic. The physical basis of this technology is the existing correlation between geological characteristics of the rocks (lithology, porosity) and elastic properties of geological section (longitudinal and shear waves velocity, Poisson ratio) [1]. On the other hand, estimation of correlations between the target parameter (porosity, clay content) and elastic characteristics using core and log data analysis is the basis for performing integrated multiwave projects for reservoir study purposes in each particular case. The elaborated correlations are also the basis for the integrated interpretation of multiwave data.

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