2. Theoretical background
Crude oil, also known as petroleum, is a wide ranging term that includes many substances and forms of
liquids. The word petroleum derives from the Greek words petra, meaning rock, and oleum, denoting oil,
which combined literally means rock-oil. This term was first used by the German mineralogist Georgius
Agricola (1546a) in the treatise De Natura Fossilium.
The ancient Greek word naphtha was often used to describe any petroleum or pitch-like substance and
in older texts was often used as a synonym for petroleum, but this has now been phased out in English
language. However, some languages, such as Russian or Arabic, still use variants of naphtha as the word
This work will focus on oil, but much of the geology, physical laws and extraction techniques can also
be applied to natural gas production. However, coal is also an important fossil fuel in the global energy
system, but behaves differently due to physical differences. Even so, some discussions and methods from
crude oil analysis may be relevant for investigation of coal or other energy sources.
The naturalistic approach to science and observations of reality is based upon the position that the uni-
verse obeys certain rules and laws of natural origin. It forms the philosophical foundation of natural sci-
ence, including all forms of physics. Natural science is also the basis of applied sciences, where the scien-
tific method and knowledge is used to solve practical problems; sciences such as engineering and tech-
nology are closely related to the applied sciences. Resource physics and the study of global energy sys-
tems, such as petroleum, are examples of the application of engineering science and applied physics to
characterize and describe the utilization of resources for energy production in society.
An important part of any form of oil production modelling and hydrocarbon extraction forecasting is to
uncover mathematical models for the physical behaviour of the production processes. The mathematical
principles of the behaviour are always important and useful. The cause of the behaviour can sometimes be
satisfyingly explained by natural laws, but unfortunately not always. This dilemma is perhaps best cap-
tured by a quotation about the theory of gravity from Isaac Newton (1726):
I have not as yet been able to discover the reason for these properties of gravity from phenomena, and I do not
feign hypotheses. For whatever is not deduced from the phenomena must be called a hypothesis; and hypotheses,
whether metaphysical or physical, or based on occult qualities, or mechanical, have no place in experimental phi-
losophy. In this philosophy particular propositions are inferred from the phenomena, and afterwards rendered gen-
eral by induction.
Resource physics and analysis of global energy systems involves pure physics to a high degree, but
there are also elements of economic or political nature that affect the situation. Ultimately, physics will
dominate and determine the limitations, since neither economical incentives nor political motives are able
to bend or break the natural laws that govern reality.
Much of the work, presented here, is just statistical or data analysis in order to identify trends or cer-
tain behaviours in time series of resource data. Locating and obtaining good data is essential and some-
times quite challenging. Petroleum related trade journals and statistical yearbooks from various oil com-
panies have shown to be an important source of production data.
Much of the giant oil field data was compiled by my previous colleague Fredrik Robelius in his thesis
(Robelius, 2007). In many ways, my work on giant fields may be seen as a more detailed analysis of his
material. Furthermore, Robelius' databases have now been updated and will be developed even more in
the future, as new data and information become available. Closer description of the data and details on the
exact methodology, used in each study, can be found in papers I, II and III.