On the use of Wireline Formation Testing (WFT) data: 2. Consequences of permeability anisotropy and heterogeneity on the WFT responses inferred flow modeling

摘要

WET rests are commonly performed to sample fluids and to assess the formation pressures in reservoirs at different depths. The interpretation of these pressure values provides the fluid gradients and the location of the interfaces between these fluids. The WET data analysis can also be used to assess mobility values from the drawdown, the buildup or both, based on analytical solutions of the diffusivity equation initially developed for the well test analysis. Various publications, comparing the permeability values derived from WET data with plug measurements, Nuclear Magnetic Resonance (NMR) interpretation, and log modeling, have shown that a good match is infrequently obtained. For most authors, the discrepancy between permeability values could be related to either the uncertainly on fluid viscosity or the permeability anisotropy.