Page 403 - Hydrocarbon Exploration and Production Second Edition
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390 Managing the Subsurface
1st Exploration Well 1st Production Discover Extension Field Review Abandon
1st Appraisal Well
Estimate of UR
Exploration Appraisal Planning Production Time
Figure 16.5 Typical change of estimate of UR during the ¢eld life.
rate of movement of the HCWC can be tracked. This is useful in determining the
displacement in the reservoir, as well as the encroachment of an aquifer.
During the producing life of the field, data is continuously gathered and used to
update the reservoir model, and reduce the uncertainties in the estimate of STOIIP
and UR. The following diagram indicates how the range of uncertainty in the
estimate of UR may change over the field life cycle. An improved understanding of
the reservoir helps in selecting better plans for further development, and may lead to
increases in the estimate of UR. This is not always the case; the realisation of a more
complex reservoir than previously described, or parts of the anticipated reservoir
eroded for example, would reduce the estimate of UR (Figure 16.5).
16.1.2. The well performance
The objective of managing the well performance in the scheme shown in
Figure 16.1 is to reduce the constraints which the well might impose on the
