Abstract
Field operation of the Underground Test Facility (UTF) Phase A SAGD project
started in November 1987 and terminated in October 1990. In order to understand
the interactions between fluid flow and geomechanical behaviour of the
reservoir during the SAGD operation, the coupled reservoir geomechanical
simulation methodology was applied to history match the measured performance of
the project.Reservoir and geomechanical responses were available from an
extensive instrumentation program designed for this project. Reservoir
pressure, temperature, horizontal displacement, vertical strain and volumetric
strain from the coupled simulation were compared with the data obtained from
the field survey. These comparisons show that the coupled reservoir
geomechanical simulation methodology has the potential to capture both
reservoir and geomechanical responses during SAGD. In addition, the steam
chamber propagation modes, both in the field and in the simulation, were also
discussed.
Introduction
The coupled reservoir geomechanical simulation methodology (called "coupled
simulation" in this paper) has been developed and tested
successfully(1). The UTF Phase A project provided a variety of data
measured in the field during the SAGD operation which can be used to history
match the SAGD process and verify this methodology.The objective of this paper
is to establish the reservoir model and geomechanical model based on the
available and assumed reservoir properties. Then, to conduct the coupled
reservoir geomechanical simulation and compare the simulation performance with
that obtained from the field. Finally, sensitivity analyses were conducted to
examine the influence of reservoir parameters on the SAGD simulations.
Project and Reservoir Description
The UTF Phase A project is located 60 km northwest of Fort McMurray, Alberta,
Canada. Field operation started in November 1987 and terminated in October
1990. Rottenfusser et al.(2) performed a detailed reservoir
characterization. The bottom Clearwater Formation and the McMurray Oil Sands
Formation were informally divided into units of A to H. Units D, E and G
consist of the major pay zone. Unit F is located between Units E and G and is
dominantly shale, grey to light brown in colour, and thinly bedded. Unit F is
continuous across the pilot area. It separated the injectors and producers of
well pairs Al and A3. Well pair A2 was deliberately drilled so that both wells
were above the Unit F barrier(3). The effect of Unit F on the SAGD
production performance will be discussed later.
The typical reservoir properties are as follows: average porosity is 35%,
horizontal permeability is 1 to 10 darcy, bitumen saturation is about 85% and
initial reservoir pressure and temperature are 550 kPa and 8 °C, respectively.
Bitumen viscosity at reservoir temperature is 5 ? 106 cP and can be
reduced to 7 cP at 220 °C(4).
Geotechnical Instrumentation
In total, 14 dedicated thermocouples (AT series), 4 inclinometers (AGI series),
3 extensometers (AGE series) and 5 piezometers (AGP series) were installed
(Figure 1). AT1 and AT7 were also used as inclinometer wells. Piezometers were
installed in wells AT4, AT9, AT12 and AT14, and a traversing thermocouple
string was used to measure temperature in wells AGI1, AGI2, AGI3 and AGI4.
© 2009. Petroleum Society of Canada (now Society of Petroleum Engineers)
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History
- Original manuscript received:
23 June 2006
- Meeting paper published:
7 June 2005
- Revised manuscript received:
17 November 2008
- Manuscript approved:
2 December 2008
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