Study of Deformation bands in the Rio do Peixe Basin using GPR and Petrophysical data
Deformation bands, petrophysics, geobody, GPR, GPR attributes.
The sedimentary rocks damage zones are influenced by deformation bands (DB), especially in porous sandstones. DBs can influence the fluid flow due to their sealing ability, and in some cases, they can compartmentalize fluids as well. These structures have a sub-seismic scale. The Ground-Penetrating Radar (GPR), already tested for fractures and other structures, can be a solution to map DBs in analogue reservoirs. In addition, the attribute analysis applied to this data category would allow an even more in-depth study of the architecture of these structures in the subsurface. The Rio do Peixe Basin (BRP) is one of the cases where DBs can be found in abundance in different sizes and marks. It depends on the distance from fault cores. In particular, in the Melancias outcrop the wall and floor are polished, providing a three-dimensional perspective of how these structures correlate with other and with the stratigraphy. GPR data from the Melancias outcrop were interpreted and they revealed a complex subsurface environment, in which the stratabound DBs and subsurface layers are strongly correlated, and they may be under the same tectonic regime. For the period following this qualification exam, two main focuses will be given to the research. The first one will consist in the dielectric permittivity data measurements by using the Time-Domain Reflectometry (TDR) method in the field. These measurements are important to define the origin of the dielectric permittivity origin in the GPR data. It will be important to define the origin of the contrast in the GPR data. Additionally, permeability and porosity measurements are already underway in samples with and without DBs. Hence, GPR and outcrop analysis and petrophysical measurements of porosity, permeability and dielectric permittivity will be combined to build a standard methodology capable of identifying with a greater degree of accuracy the signature of DBs in the GPR data. The second focus will be directed to a multi-attribute analysis, in which the objective is to reveal the architecture of the DBs three-dimensionally with the construction of geobodies, as well as the influence of these structures on the flow properties in the host rock. With the methodology applied to the Melancias outcrop, it is expected to later apply it to other BRP outcrops.