Reservoir property estimation in the carbonate reservoir with rock property inversion- a case study

Abstract

One of the fundamental aims of the geophysics is to develop attributes which are understandable and acceptable to seismic interpreters, geologists and reservoir engineers. Elastic impedance inversion from far offset seismic reflection data can be considered as one of such desired attributes. It can used to derive elastic rock properties, which can be used for quick determination of lithology and fluid content. The role of the rock property inversion, as a tool for characterisation of carbonate reservoirs, has not been established. A carbonate reservoir in the South-West of IRAN is selected to examine the feasibility of rock property inversion for reservoir property estimation and lithological characterization. Of particular important was to apply this methodology in an area where reservoir rock is of a low reflectivity and acoustic impedance alone fails to separate high from low porosity zones. Lambda-Rho (??) and Mu-Rho (µ?) attributes were computed from both rock physics lab measurements and 2-D surface seismic survey. We show that the variation of µ? across a carbonate reservoir can be used to distinguish high porosity-permeability areas from non-reserve zones. The field data results correlate well with core sample measurements. We also show that in this case ?? cannot be reliably used to discriminate between oil and brine saturation.