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theses

This study is motivated by the need to estimate the effective porosity and mineral composition of sedimentary formations for the purpose of geologic carbon sequestration, based on common geophysical logs. Because there are generally more mineral types than the number of logs at a given site, current methods yield non-unique solutions and give ambiguous results.In this study, I develop a new method to estimate effective porosity and as many as needed mineral fractions based on three common geophysical logs: Gamma Ray Log (GRL), Density Log (DL) and Neutron Porosity Log (NPL). The method utilizes a probability approach, based on our knowledge on global mineral abundance in sedimentary rocks, mineral co-existence in different depositional environments, diagenetic (as a function of age/depth, hence temperature, pressure, preservation) constraints, in the form of several "filters" to rule out unlikely scenarios, and to give more weights to more likely scenarios.
Comparisons of the new model results with core-lab measurements demonstrate significant improvements over existing petrophysics methods in porosity estimation, and the new model offers a new possibility that existing petrophysics methods cannot offer, i.e., estimating the fractions of as many as necessary number of minerals.
This new method can be extended to other situations where a different set of geophysical logs are available. The innovation of this new method lies in the systematic approach of implementing physical constraints to eliminate or downplay unlikely mathematical solutions, these physical constraints being the basic knowledge of sedimentary and diagenetic processes.

http://dissertations.umi.com/gsnb.rutgers:12376

M.S.

Includes bibliographical references

doi:10.7282/t3-4tmb-5p55

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