1887
Volume 51, Issue 6
  • E-ISSN: 1365-2478

Abstract

ABSTRACT

We investigate the interactions between the elastic parameters, , and density, estimated by non‐linear inversion of AVA data, and the petrophysical parameters, depth (pressure), porosity, clay content and fluid saturation, of an actual gas‐bearing reservoir. In particular, we study how the ambiguous solutions derived from the non‐uniqueness of the seismic inversion affect the estimates of relevant rock properties. It results that the physically admissible values of the rock properties greatly reduce the range of possible seismic solutions and this range contains the actual values given by the well. By means of a statistical inversion, we analyse how approximate knowledge of the petrophysical properties and of their relationships with the seismic parameters can be of help in reducing the ambiguity of the inversion solutions and eventually in estimating the petrophysical properties of the specific target reservoir. This statistical inversion allows the determination of the most likely values of the sought rock properties along with their uncertainty ranges. The results show that the porosity is the best‐resolved rock property, with its most likely value closely approaching the actual value found by the well, even when we insert somewhat erroneous information. The hydrocarbon saturation is the second best‐resolved parameter, but its most likely value does not match the well data. The depth of the target interface is the least‐resolved parameter and its most likely value is strongly dependent on information. Although no general conclusions can be drawn from the results of this exercise, we envisage that the proposed AVA–petrophysical inversion and its possible extensions may be of use in reservoir characterization.

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2003-10-23
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