Evaluating the
Key Static and Dynamic Uncertainties of Korolev Field, Kazakhstan
Zhumagulova, Akmaral1, Dennis
W. Dull2, Mark Skalinski3, Djuro Novakovic2
(1) TengizChevroil, Houston, TX (2) Chevron, Houston, TX (3) TengizChevroil,
Atyrau, Kazakhstan
Korolev Field is one of the largest oil
fields in the Republic of Kazakhstan and is among the
largest in the Chevron portfolio. Korolev field is an isolated carbonate
platform located near the giant Tengiz field with 1.5 billion STB OOIP. Korolev
field oil production comes from a Carboniferous age limestone reservoir that is
over 1 km thick. A project was undertaken to construct new earth and simulation
models for updating the reserve estimates for Korolev field. This project was
in part necessitated due to the availability of new well, geologic, and
engineering data.
The sequence stratigraphy and
depositional history of Korolev is nearly the same as Tengiz but there are some
significant differences. The Korolev platform area is proportionally much
smaller than Tengiz field and is dominated by an extensive lost circulation
zone (LCZ). Korolev porosity is lower than Tengiz while permeability is roughly
double and the bitumen content is significantly higher at Korolev.
To evaluate the uncertainty in OOIP over 1000
earth models were constructed. The workflow involved the use of Monte Carlo simulation and
Experimental Design to evaluate the key static and dynamic reservoir
uncertainties impact on OOIP and recovery. The static uncertainties include:
porosity, Swir (Bvw), permeability, and gross rock volume above the oil-water
contact. The dynamic uncertainty evaluation included: fracture density,
fracture porosity, fracture, matrix and vertical permeability, LCZ extent,
oil-water contact and permeability barriers and baffles.