Projects
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2007 04 11 AN EXPLORATORY STUDY
Low Carbon Futures
Carbonate
Triangle and Conventional Heavy Oil –
Lowest GHG Production Scenario
Exploratory Study
pdf 3MB
PTAC Recovery Model
Guidelines for Recovery Technology Model Use
Guidelines for Recovery Technology Model Use
(excerpted from Section 5, pages 119-134 of the Study)
1.1 Model Objectives and Use
1.2 Input Parameters
1.3 Spreadsheet Calculations
1.4 Output Results
1.1 Model Objectives and Use
In conventional oil production, the concept of applying more than one
recovery technology, one after the other, to a reservoir is well established.
Conventional oil is generally first produced using primary production
techniques. When primary production declines and become less economic,
producers investigate the opportunity to water flood the reservoir as a
secondary recovery technology. Finally, tertiary methods may be applied when
water floods yield diminishing returns. Heavy oil and oil sands have a
shorter history and generally reservoirs have only been subject to only one
recovery technology. In the case of oil sands, primary and secondary recovery
technologies, as defined for conventional oil, are not applicable because
bitumen is not mobile at reservoir conditions. Therefore, oil sands
developments generally start with a thermal recovery technology which would
be considered a tertiary method or enhanced recovery method for conventional
oil. However, as the development of heavy oil and oil sands matures, the
concept of applying more than one recovery technology in a specific order is
likely to also be applied to heavy oil and bitumen reservoirs. In particular,
in the Lloydminster area, researchers and producers have already been
investigating for several years the concept of follow-up recovery
technologies once primary production is no longer economic.
The purpose of the PTAC recovery technology computer model is to assist
the strategic development of R&D for future recovery technologies. Reservoir
models already exist but their purpose is the identification and calculation
of the engineering parameters for a specific reservoir and recovery
technology combination. By contrast, the PTAC recovery technology model
focuses on the strategic issues that should guide future R&D such as:
- To maximize total resource recovery;
- To reduce overall energy intensity;
- To reduce greenhouse gas emissions intensity;
- To reduce water intensity; and,
- To reduce overall operating costs.
The model introduces the very important concept that future recovery
technologies may not all be designed for virgin reservoirs because, in the
next decades, the Western Canada Sedimentary Basin will host a very large
number of reservoirs partially depleted by existing commercial technologies
such as cold production, CHOPS, CSS and SAGD which all leave behind a
significant quantity of heavy oil and bitumen.
The value of developing a computer model is to automate and facilitate the
process of applying recovery technologies one after the other in the same
reservoir. Based on data input for each recovery technology, the model is
able to calculate the performance of the recovery technology and the status
of the reservoir after the application of each recovery technology and after
the application in sequence of up to three recovery technologies. In
particular, the model will calculate resource recovery, energy intensity,
greenhouse gas emissions intensity, water intensity and unit operating costs
as a function of the selected sequence of recovery technologies. This is a
unique capability that will allow R&D developers to understand the trade-offs
between recovery, energy, greenhouse gases, water and costs that are implied
in the choice of any recovery technology.
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1.2 Input Parameters
As part of this project, the PTAC recovery technology model was developed
for bitumen in carbonate formations and Lloydminster conventional heavy oil
reservoirs. Recovery technologies that are already commercial for these
reservoirs were written into the model as available choices. In addition, the
recovery technologies and options discussed earlier in this report were also
incorporated in the model. Finally, in order broaden the applicability of the
model, the capability was added to allow the user to specify up to three new
user defined recovery technologies. The ability of the model to accept user
defined recovery technologies is a strength that will allow the model to
continue to be used by researchers and developers as new technologies are
conceived, developed and refined by laboratory and field experiments.
This project did more than consider recovery technologies at a high level. It
recognized that for several recovery technologies, major options exist for
their implementation. In particular, the scenarios analyzed earlier in the
report identified the following major options:
- Choices for steam generation technology;
- Choices for fuel source; and,
- Choices for water source.
In keeping with this analysis, the model was developed to allow these
choices. In addition, the model allows choices for the source of electricity
used to power the recovery technology. The model also allows the user to
define a new fuel, a new water source, a new electricity source and a new
reservoir. Therefore, the model allows significant flexibility to the user to
analyze future scenarios that may come about from the development of new
technologies which would broaden choices for fuel, water and power.
In order to use the basic features of the model, the user makes choices
for recovery technology, steam generator, make-up water source, fuel, and
electricity source by making selections from lists available in the relevant
pull down menus. The entry screen is reproduced in Figure 26.
Advanced users may decide to specify up to three user defined processes
and one each of user defined fuel, user defined water, user defined
electricity and user defined reservoir. The relevant entry screens are
reproduced in Figures 27, 28, and 29. All inputs and outputs of the model are
based on metric units.
The major assumptions for the existing commercial recovery technologies
that were written into the model are shown in Appendix 1.
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to top 1.3
Spreadsheet Calculations
The model automatically makes all necessary unit conversions and
calculates the following:
- Oil recovery from the process and remaining oil saturation in the
reservoir;
- Energy required by the process for the following types of energy,
where relevant:
- Fuel for steam production;
- Natural gas used on lease;
- Electrical energy;
- Energy required for trucks; and,
- Total energy intensity per volume of oil recovered;
- Water required by the process including requirements for steam
production, water floods and water injection in Water Alternating Gas
(WAG) processes; the model calculates net water intensity defined as
the requirement for make up water net of recycling per volume of oil
recovered;
- Greenhouse gas produced by the process including, where
applicable, methane vent gas, CO2 from fuel combustion to produce
steam, CO2 from usage of electricity and CO2 from trucks; the model
calculates total GHG intensity per volume of oil recovered;
- Overall operating costs including costs for fuel, electricity,
trucks, water and CO2 emissions; the model calculates overall costs
per volume of oil recovered; and,
- The model performs all of the above calculations for each of up to
three recovery processes in series and presents results for each of
the process and for the total sequence of all three processes.
to top 1.4 Output Results
As discussed above, the outputs of the model are the strategic
considerations that should broadly guide the development of new recovery
technologies:
- Resource recovery;
- Energy intensity;
- Water intensity;
- GHG intensity; and,
- Overall costs.
The model screen that presents high-level outputs is reproduced in
Figure 30. The balance of output screens are presented in Appendix 1.
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