ABSTRACT
UNCERTAINTY ASSESSMENT IN RESERVE ESTIMATION OF
A NATURALLY FRACTURED RESERVOIR
ERIÇ / OK, Ö / zlen
M.S., Department of Petroleum and Natural Gas Engineering
Supervisor : Prof. Dr. Fevzi GÜ / MRAH
December 2004, 169 pages
Reservoir performance prediction and reserve estimation depend on various
petrophysical parameters which have uncertainties due to available technology.
For a proper and economical field development, these parameters must be
determined by taking into consideration their uncertainty level and probable
data ranges.
For implementing uncertainty assessment on estimation of original oil in place
(OOIP) of a field, a naturally fractured carbonate field, Field-A, is chosen to
work with. Since field information is obtained by drilling and testing wells
throughout the field, uncertainty in true ranges of reservoir parameters evolve
due to impossibility of drilling every location on an area. This study is based on
defining the probability distribution of uncertain variables in reserve estimation
and evaluating probable reserve amount by using Monte Carlo simulation
method. Probabilistic reserve estimation gives the whole range of probable
v
original oil in place amount of a field. The results are given by their likelyhood
of occurance as P10, P50 and P90 reserves in summary.
In the study, Field-A reserves at Southeast of Turkey are estimated by
probabilistic methods for three producing zones / Karabogaz Formation, Kbb-C
Member of Karababa formation and Derdere Formation. Probability density
function of petrophysical parameters are evaluated as inputs in volumetric
reserve estimation method and probable reserves are calculated by @Risk
software program that is used for implementing Monte Carlo method.
Outcomes of the simulation showed that Field-A has P50 reserves as 11.2
MMstb in matrix and 2.0 MMstb in fracture of Karabogaz Formation, 15.7
MMstb in matrix and 3.7 MMstb in fracture of Kbb-C Member and 10.6 MMstb
in matrix and 1.6 MMstb in fracture of Derdere Formation. Sensitivity analysis
of the inputs showed that matrix porosity, net thickness and fracture porosity are
significant in Karabogaz Formation and Kbb-C Member reserve estimation
while water saturation and fracture porosity are most significant in estimation of
Derdere Formation reserves.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/2/12605713/index.pdf |
| Date | 01 December 2004 |
| Creators | Ericok, Ozlen |
| Contributors | Gumrah, Fevzi |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for METU campus |
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