Abstract：
Permeability is a measure of the ability of a porous rock to allow fluids to pass through it. It is one of the key
parameters for reservoir evaluation to reflect the characteristics of reservoir seepage. Due to the comprehensive influence of
sedimentary environment, diagenesis and tectonic factors, the tight sandstone reservoirs of the Upper Triassic Chang 6 member
in the central-southern Ordos Basin have a complex pore structure and strong heterogeneity. In the core porosity and permeability
test data, the core permeability values of the same porosity value differ by one to two orders of magnitude. Permeability
prediction with methods used for conventional reservoirs cannot meet the requirements of unconventional reservoir evaluation.
Hence, this study divided the Chang 6 reservoir into four types of flow units using the Flow Zone Indicator (
FZI
) cumulative
frequency division method. The porosity and permeability of the four types of reservoirs after classification are obviously
different, and the characteristics of the pore structure and permeability of each type of reservoir are basically the same. On this
basis, a fine interpretation model for permeability of various reservoirs was established, and a multi-parameter fitting equation for
porosity and
FZI
logging response was established by using multiple linear regression modeling methods to achieve continuous
quantitative evaluation of
FZI
and to realize the continuous division of flow unit types in tight reservoirs in the area and the
logging evaluation of permeability; and we applied it to the permeability calculation of typical single wells in the study area.
The application results show that the new method calculates permeability which is in good agreement with the core analysis
data .This method effectively improves the accuracy of permeability logging evaluation. This research is of great significance
for accurately predicting the spatial distribution of permeability of Chang 6 tight sandstone reservoirs in the study area, and will
provide a theoretical basis for the detailed evaluation of the permeability of continental tight sandstone reservoirs.
