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A New Rock Physics Model and Its Application in Tight Reservoir
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 77th EAGE Conference and Exhibition 2015, Jun 2015, Volume 2015, p.1 - 5
Abstract
The most obvious characteristics of tight reservoirs are low porosity and low permeability. Under this assumption, we propose a new rock physics model. The total porosity is divided into the connected porosity and the disconnected porosity. This paper modified the matrix moduli using the Raymer relations to separate the porosity, and made an analysis of variation in saturated modulus and different response characteristics of the fluid with the introduction of disconnected pores. We find that the variable can build a connection between the low frequency and high frequency saturated moduli where the low and high frequency moduli are calculated by Gassmann and effective medium model respectively. And the fluid substitution based on the new rock physical model considering disconnected pores causes drastically change of elastic parameters and AVO types. The methodology consists of matching well-log data with the predicted velocities and finding the disconnected porosity required to accomplish this match. The estimated S-wave velocity is consistent with the log value. The rationality of the method is validated.