18
Statistical Methods for Estimating Petroleum Resources
lognormal, gamma, or Weibull distribution. This superpopulation can be considered a geological model.
A random sample of size
•
N is drawn from the superpopulation.
This sample, which constitutes the fi nite number of pools, can
be viewed as pools in a play.
The discovery process simulation was run with various exploration
effi ciencies (see hapter 3 for discussion) to generate different exploration time series, which could be used to verify the assessment results
described in chapters 3 and 4.
The Nature of Geological Populations
Geological models have continuous population pool-size distributions that can be estimated from samples. Consequently, we must
understand the nature of geological populations to choose probability
distributions for them. In geological populations, properties such as
outlier proneness and correlation of variables can be observed through
analysis of two random variables. The Beaverhill Lake play and other
oil plays from the Western Canada Sedimentary Basin are used in the
following discussion to illustrate the nature of geological populations.
The Beaverhill Lake Play
Let us use the Late Devonian Beaverhill Lake play as an example for
estimating a mature play. Transgression began with the deposition
of the Slave Point carbonate on a broad shelf in northeastern British
Columbia, northern Alberta, and the adjacent part of the Northwest
Territories. A carbonate reef-front facies, similar to the underlying Elk
Point reef carbonate, developed in British Columbia.
Continued transgression terminated the Slave Point carbonate
platform, which was succeeded by basinal lithofacies of the overlying Waterways Formation in northern Alberta. However, in the Swan
Hills region of north–central Alberta, a shallow-water platform, protected to the north by the emergent Peace River Arch and fl anked to
the southwest by the Western Alberta Ridge, provided a setting conducive to bank development and subsequent reef growth. Emergence
of the reefs, followed by the rising water level during Beaverhill Lake
deposition, terminated the growth of some Swan Hills reefs (Hemphill
et al., 1968).
Statistical Methods for Estimating Petroleum Resources
lognormal, gamma, or Weibull distribution. This superpopulation can be considered a geological model.
A random sample of size
•
N is drawn from the superpopulation.
This sample, which constitutes the fi nite number of pools, can
be viewed as pools in a play.
The discovery process simulation was run with various exploration
effi ciencies (see hapter 3 for discussion) to generate different exploration time series, which could be used to verify the assessment results
described in chapters 3 and 4.
The Nature of Geological Populations
Geological models have continuous population pool-size distributions that can be estimated from samples. Consequently, we must
understand the nature of geological populations to choose probability
distributions for them. In geological populations, properties such as
outlier proneness and correlation of variables can be observed through
analysis of two random variables. The Beaverhill Lake play and other
oil plays from the Western Canada Sedimentary Basin are used in the
following discussion to illustrate the nature of geological populations.
The Beaverhill Lake Play
Let us use the Late Devonian Beaverhill Lake play as an example for
estimating a mature play. Transgression began with the deposition
of the Slave Point carbonate on a broad shelf in northeastern British
Columbia, northern Alberta, and the adjacent part of the Northwest
Territories. A carbonate reef-front facies, similar to the underlying Elk
Point reef carbonate, developed in British Columbia.
Continued transgression terminated the Slave Point carbonate
platform, which was succeeded by basinal lithofacies of the overlying Waterways Formation in northern Alberta. However, in the Swan
Hills region of north–central Alberta, a shallow-water platform, protected to the north by the emergent Peace River Arch and fl anked to
the southwest by the Western Alberta Ridge, provided a setting conducive to bank development and subsequent reef growth. Emergence
of the reefs, followed by the rising water level during Beaverhill Lake
deposition, terminated the growth of some Swan Hills reefs (Hemphill
et al., 1968).