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Petroleum Source Rock Loggingby Submitted to the Department of Earth, Atmospheric, and Planetary Sciences on February 8, 1985 in partial fulfillment of the requirements for the degree of Master of Science ABSTRACT
Regional distributions of organic content are an important aid in developing
basin evolution and hydrocarbon generation models. An approach to evaluate hydrocarbon
source rocks using resistivity, sonic, density, neutron and natural gamma ray
logs is developed. Organic matter, as a constituent in sedimentary rocks, has
a relatively low density, slow velocity, and is high in hydrogen content. Source
rocks generally have low water content, and often exhibit abnormally high concentrations
of uranium. These effects combine to make an in-situ estimation of organic content
plausible. Evolution of kerogen to bitumen, oil, and gas systematically affects
the above properties and it is possible to obtain a qualitative assessment of
the state of maturation of a known source bed. In this thesis logs and core data from wells in two separate oil provinces are
used to test the methods of predicting total organic carbon content from log
data. Two approaches are followed. The first method treats the organic matter
as a rock constituent and calculates the log responses as a function of organic
content. Two (rock and organic matter) and three (rock matrix, water and organic
matter) component models are tested. This approach suffers because of the uncertainties
of the physical properties of the organic matter. For each log type (i.e. sonic,
gamma, resistivity,…) log values are correlated with the laboratory measured
total organic content. Bivariate regression helps to illustrate the efficacy
of the models. In the second method, multivariate equations based on linear
combinations of individual correlation coefficients are obtained. The importance
of combining several logs which are organic content predictors is demonstrated.
These equations can be used to predict total organic carbon content using only
log data, in different parts of an oil province. Return to Theses Return to ERL Home Updated: May, 1999
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