ROCK PROPERTY MODELING OF RESERVOIR SYSTEMS AND ASSOCIATED SUBJECT MATTERS

Abstract

The need to analyze subtle differences in seismic amplitude variation is gaining tremendous ground and so is the need to model the accurate medium that generates these subtle signatures. The detection of the seismic response becomes more challenging when the medium is heterogeneous and anisotropic. Due to these complications, a suitable rock physics model is required to address field complexities. In this thesis, I used rock physics modules like Differential Effective Medium (DEM) model, Gassmann’s equation etc. to model seismic responses of sandstone and carbonate reservoirs using different from of input data: well-logs and core plugs. In this thesis, I have broadly covered three main aspects of rock-physics modeling (a) velocity modeling in heterogeneous media, (b) fluid substitution using Gassmann’s equation, and (c) in-situ measurements of an orthorhombic anisotropic system. In a heterogeneous media, a supervised machine-learning tool has been used to predict velocities in carbonate and sandstone reservoirs and the prediction shows very good match for clay-mixed lithology. The predicted velocities can also be used to delineate geomechanical parameters, DHI etc. I have also studied feasibilities of Gassmann’s equations to predict fluid effects on seismic behavior in carbonates for both isotropic and fractured reservoirs. The results of Gassmann’s model are in agreement with the observed data for both low and high-pressure measurements. At last, I have designed a laboratory-based method for an in-situ measurement of orthorhombic anisotropic systems but the experiment is still underway and therefore the results of this experiment is not discussed in this thesis.