Estimation Update and Feedback Procedures
143
the reasons why they fail provide information for estimating the marginal probability of each geological factor. Chronostratigraphic and
organic maturation data are used to defi ne a basin’s burial and thermal
history. All these data can be used to identify a play and its geographic
boundaries. In addition, reservoir and well data retrieved within geographic play boundaries can provide the information needed to compile an exploration time series for evaluation of mature plays.
When there is not enough information to quantify every aspect
needed, we can apply experience gained from other basins, or compile
information from previous work. This type of compilation or comparative study can provide useful information in evaluating resources.
Procedure for Estimating Mature Plays
Step 1: Formulating a Play Defi nition and Its Geographic Boundary
A play has both geographic and stratigraphic limits; it is confi ned to
a basin or part of a basin, to a structural unit or part of it, and also to
one or more formations (Chapter 2). Figure 2.8 displays the areal extent
of the Beaverhill Lake oil play example, as defi ned by the play defi nition and expressed on the map by the play boundary. By defi nition, all
pools within a specifi c play form a natural geological population. The
importance of a properly defi ned play is that it will correspond to a single
statistical population and thus meet the statistical assumptions required
for the proper operation or the evaluation processes. A mixed population resulting from an improperly defi ned play defi nition, for example,
can adversely affect the quality of the fi nal resource estimates.
Step 2: Compiling Play Data
Once a play is defi ned and the play boundary has been outlined on a
map, all wells and pools within the formation(s) identifi ed by the assessment team as being part of the play are retrieved from the PETRIMES
information system (Lee et al., 1999). Each well or pool is then examined by the geologists to determine whether it is consistent with the
play defi nition. If not, revisions of the play defi nition and boundary are
made and retrieval is performed again.
Drill stem tests from exploratory wells within the polygon that
conform to the play defi nition are examined to produce a complete
exploration discovery time series. The exploration time series for the
143
the reasons why they fail provide information for estimating the marginal probability of each geological factor. Chronostratigraphic and
organic maturation data are used to defi ne a basin’s burial and thermal
history. All these data can be used to identify a play and its geographic
boundaries. In addition, reservoir and well data retrieved within geographic play boundaries can provide the information needed to compile an exploration time series for evaluation of mature plays.
When there is not enough information to quantify every aspect
needed, we can apply experience gained from other basins, or compile
information from previous work. This type of compilation or comparative study can provide useful information in evaluating resources.
Procedure for Estimating Mature Plays
Step 1: Formulating a Play Defi nition and Its Geographic Boundary
A play has both geographic and stratigraphic limits; it is confi ned to
a basin or part of a basin, to a structural unit or part of it, and also to
one or more formations (Chapter 2). Figure 2.8 displays the areal extent
of the Beaverhill Lake oil play example, as defi ned by the play defi nition and expressed on the map by the play boundary. By defi nition, all
pools within a specifi c play form a natural geological population. The
importance of a properly defi ned play is that it will correspond to a single
statistical population and thus meet the statistical assumptions required
for the proper operation or the evaluation processes. A mixed population resulting from an improperly defi ned play defi nition, for example,
can adversely affect the quality of the fi nal resource estimates.
Step 2: Compiling Play Data
Once a play is defi ned and the play boundary has been outlined on a
map, all wells and pools within the formation(s) identifi ed by the assessment team as being part of the play are retrieved from the PETRIMES
information system (Lee et al., 1999). Each well or pool is then examined by the geologists to determine whether it is consistent with the
play defi nition. If not, revisions of the play defi nition and boundary are
made and retrieval is performed again.
Drill stem tests from exploratory wells within the polygon that
conform to the play defi nition are examined to produce a complete
exploration discovery time series. The exploration time series for the