82
Statistical Methods for Estimating Petroleum Resources
booked reserve of the Turner Valley pool did not substantially change,
whereas the Jumping Pound West pool that had fl uctuated increased
signifi cantly since its discovery. In general, fl uctuations of booked
reserves for the large pools are greater than those for small pools. From
1961 to 1980, the in-place booked reserves for the play were underestimated. Some of the booked reserves of the pools (e.g., the Jumping
Pound West Rundle pool) have doubly appreciated since their discovery, whereas others have depreciated, but the total has only appreciated by a factor of 2% to 7%.
Figure 4.14B exhibits the Jumping Pound gas play growth for the
same period. The dashed line shows changes of in-place volume
recorded in 1993. The play data, comprising 94 discoveries as of 1991,
were divided into three time windows: pre-1966 (Fig. 4.15A, left), pre1974 (Fig. 4.15A, middle), and pre-1991 (Fig. 4.15A, right).
Assessment results are summarized in Table 4.5. The fi rst column
presents the time windows. In the second column, the total number
of pools, N, is estimated using data from each time window. These
values may be over- or underestimated. The third column records
discovered reserves for specifi c years. The fourth column presents
expected potential. The fi fth column displays the total estimated
play resource distribution (Fig. 4.15B). The 0.9 probability prediction intervals are of the same magnitude. The last column presents
total play resource distribution means for the three windows, which
are quite similar.
Individual pool sizes predicted from the pre-1966 time window of
the Jumping Pound Rundle gas play are shown in Figure 4.16. The largest undiscovered pool, the Quirk Creek Rundle A, was discovered in
1967, whereas the second largest, the Clearwater Rundle A, was discovered in 1980. Although the pre-1966 time window predictions of the
largest two pools are accurate, the entire prediction is not as good as
those derived from the 1994 data set. Furthermore, no pool larger than
the Clearwater Rundle A has been discovered since then.
Swan Hills Shelf Margin Gas and Leduc Isolated Reef Oil Plays
The Swan Hills shelf margin gas pools were also divided into two time
windows: pre-1983 and pre-1994. Figure 4.17A displays the discovery
sequences for the two windows. The play resource distributions for
these two windows are shown in Figure 4.17B.
The Leduc isolated reef oil pools were divided into two time windows
as well: pre-1965 and pre-1994. Their discovery sequences are shown in
Statistical Methods for Estimating Petroleum Resources
booked reserve of the Turner Valley pool did not substantially change,
whereas the Jumping Pound West pool that had fl uctuated increased
signifi cantly since its discovery. In general, fl uctuations of booked
reserves for the large pools are greater than those for small pools. From
1961 to 1980, the in-place booked reserves for the play were underestimated. Some of the booked reserves of the pools (e.g., the Jumping
Pound West Rundle pool) have doubly appreciated since their discovery, whereas others have depreciated, but the total has only appreciated by a factor of 2% to 7%.
Figure 4.14B exhibits the Jumping Pound gas play growth for the
same period. The dashed line shows changes of in-place volume
recorded in 1993. The play data, comprising 94 discoveries as of 1991,
were divided into three time windows: pre-1966 (Fig. 4.15A, left), pre1974 (Fig. 4.15A, middle), and pre-1991 (Fig. 4.15A, right).
Assessment results are summarized in Table 4.5. The fi rst column
presents the time windows. In the second column, the total number
of pools, N, is estimated using data from each time window. These
values may be over- or underestimated. The third column records
discovered reserves for specifi c years. The fourth column presents
expected potential. The fi fth column displays the total estimated
play resource distribution (Fig. 4.15B). The 0.9 probability prediction intervals are of the same magnitude. The last column presents
total play resource distribution means for the three windows, which
are quite similar.
Individual pool sizes predicted from the pre-1966 time window of
the Jumping Pound Rundle gas play are shown in Figure 4.16. The largest undiscovered pool, the Quirk Creek Rundle A, was discovered in
1967, whereas the second largest, the Clearwater Rundle A, was discovered in 1980. Although the pre-1966 time window predictions of the
largest two pools are accurate, the entire prediction is not as good as
those derived from the 1994 data set. Furthermore, no pool larger than
the Clearwater Rundle A has been discovered since then.
Swan Hills Shelf Margin Gas and Leduc Isolated Reef Oil Plays
The Swan Hills shelf margin gas pools were also divided into two time
windows: pre-1983 and pre-1994. Figure 4.17A displays the discovery
sequences for the two windows. The play resource distributions for
these two windows are shown in Figure 4.17B.
The Leduc isolated reef oil pools were divided into two time windows
as well: pre-1965 and pre-1994. Their discovery sequences are shown in