Print this pageImproving Primary Oil Recovery from a (DOE Class 1) Fluvial-Dominated Deltaic Lacustrine Reservoir Uinta Basin, Utah
MORGAN, CRAIG D.
The Bluebell field (Uinta Basin, Utah) produces from the Tertiary Green River
and Wasatch Formations. The productive interval consists of thousands of feet of
interbedded fractured clastic and carbonate beds deposited in a
fluvial-dominated deltaic lacustrine environment. Wells are typically completed
by perforating 40 or more beds over 1,000 to 3,000 vertical feet, then acid
stimulating the entire interval. This technique is believed to leave many
potentially productive beds damaged or untreated.
With partial funding from the U.S. Department of Energy Class I Oil Program,
a research team headed by the Utah Geological Survey conducted a reservoir
characterization study and made recommendations for a field demonstration
program. The demonstration will show how to improve primary oil recovery using
better completion techniques. The demonstration consists of three parts: (1)
recomplete a well using multi-stage, high-diversion, low-friction acid
treatments over a gross interval of 1,500 feet; (2) in a second well, drill
10-foot laterals into three or more beds and stimulate each bed separately; and
(3) drill and complete a new well. The first part of the demonstration is
scheduled to begin in the fall of 1996.
The effectiveness of the first recompletion will be determined by logging
before and after the treatment. Pulsed neutron decay and dipole sonic logs will
be run before the treatment. Each acid stage will contain a different
radioactive tracer and tracer logs will be used to determine how effectively the
fluid is diverted. Dipole sonic, temperature, and spinner logs will be run after
the treatment. Predictions of producible beds from the characterization study
and the pulsed neutron decay log will be compared to actual results. The dipole
sonic logs run before and after treatment will be used to determine the increase
in open fractures and the relationship to the resulting production. The results
of the first part of the demonstration will be presented at the meeting.