Comparing Stochastic Simulation Algorithms by Measures of Local Accuracy and Precision

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Abstract/Contents

Abstract
There are a large number of geostatistical approaches to model the spatial variability of petrophysical properties. For a given problem, different approaches may be appropriate depending on the goals of the study. An important question occurs: among many geostatistical methods, which one is the "best" for a particular problem at hand?The conventional approach to test an estimation algorithm is to consider cross validation and look at summary statistics such as mean absolute error, mean squared error, or the correlation coefficient between the estimated values and the true values. The cross plot of the true values versus the estimated values reveals the "goodness" of the estimation technique.In the context of stochastic simulation, these measures are on longer relevant since we have a distribution of simulated values. So, an approach that can measure the "goodness" of the multiple realizations is needed. This study presents a new approach based on the "leave-one-out" cross validation method. The first step is to build multiple realizations at the location where a true value is temporarily removed. Secondly, a local conditional cumulative distribution function (ccdf) model is built and four measures, i.e., accuracy (A), precision (P ), goodness(G) and uncertainty(U) are specifically designed to establish the "goodness" of this local ccdf model. The advantages and weaknesses of these new measures are demonstrated by comparing them to the conventional cross validation tools. Furthermore, this study describes the methodology to understand strengths and shortcomings of different geostatistical simulation approaches and to assess them in relative accuracy, precision, and uncertainty.

Description

Type of resource text
Date created May 1997

Creators/Contributors

Author Mo, Yexiang
Primary advisor Deutsch, Clayton V.
Degree granting institution Stanford University, Department of Petroleum Engineering

Subjects

Subject School of Earth Energy & Environmental Sciences
Genre Thesis

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User agrees that, where applicable, content will not be used to identify or to otherwise infringe the privacy or confidentiality rights of individuals. Content distributed via the Stanford Digital Repository may be subject to additional license and use restrictions applied by the depositor.

Preferred citation

Preferred Citation
Mo, Yexiang. (1997). Comparing Stochastic Simulation Algorithms by Measures of Local Accuracy and Precision. Stanford Digital Repository. Available at: https://purl.stanford.edu/sv516tq4696

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Master's Theses, Doerr School of Sustainability

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