Did Time-Lapse Seismic Deliver the Anticipated Value of Information?
Delfiner, Pierre1, Frederick Lefeuvre2, Jean-Marc Rodriguez3 (1) Total E&P, Paris La Defense Cedex, France (2) Total E&P, Pau Cedex, France (3) Total USA E&P Inc, Houston, TX
Time-lapse seismic has become a key reservoir management tool.
However, as it carries a significant cost the return on investment must be
carefully evaluated. The feasibility phase involves two main questions.
Will a reliable, usable and useful time-lapse signal be present
or not? This is a technical problem solved by geoscientists. A probability of
success captures the confidence of the geoscientist in the time-lapse technique
applied to a particular field at a particular time.
Will the answer given by the measured information bring real
additional value to the field? This question requires preparing a “business
case” which compares the value of the project with and without the time-lapse
seismic information, the difference being the “Value of Information” (VOI). It
is a cooperative effort between the reservoir engineer, who is the key
“customer”, the geophysicist, the geologist, the petrophysicist,
often the driller, the economist, and the VOI expert acting as a catalyst. The
exercise involves modeling the impact of the information on field development
decisions, and the specification of various probabilities, which inevitably
have some degree of subjectivity. Therefore it would be quite informative to
compare how things turned out with what was anticipated.
Such feedback should
be available for at least two of the most recent VOI studies done at TOTAL, one
in deep offshore solve
a direct operational reservoir management problem, i.e., where
to drill a
potential
injector to stimulate production in existing wells, and
should be especially interesting.