Numerical Modeling of Direct Responses from Productive Reservoirs with Vertical Fluid-saturated Meso-fractures

The work investigates seismic response from a formation with vertical fluid-saturated fractures the size of a few meters – meso-fractures – by employing the grid-characteristic method of 2D numerical modeling. The composition is determined of the response energy recorded on receiver’s horizontal and vertical components, and the impact is also determined that the seismic response experiences when the fracturing parameters vary. It has been established that the front of scattered converted waves recorded on receiver’s horizontal component is most intense and robust element of the response from a zone of meso-fractures in a reservoir. Analysis of wave processes confirms abnormally high attenuation of S-waves inside a fractured reservoir. This explains why a front of scattered converted waves emerges from only first few fracture rows; consequently, such front is little contingent on the reservoir thickness, which makes it possible to detect fracturing in thin formations. Validation is provided for direct 3C-recorded seismic responses as a tool for mapping fractured zones in a flat-layered section.