Emissions Reductions and Energy Efficiency in Crude Bitumen and Heavy Oil
Oil sands and heavy oil greenhouse gas (GHG) emissions are comprised of both combustion emissions as well as direct emissions of methane gas. There are significant opportunities to reduce oil sands and heavy oil GHG emissions by developing new technologies for energy efficiency and emissions reduction. Venting of methane at crude bitumen and crude heavy oil facilities has been major source of GHG emissions. Approximately 80% of reported vented volumes in Alberta take place in the Bonnyville and Wainwright regions and are associated with cold heavy oil production. They occur where conservation would be prohibitively expensive using existing technologies. Solution gas vented from crude bitumen and crude oil batteries was 429 million cubic meters in 2014.
Realizing the need to find practical and cost-effective technologies that can reduce methane emissions and improve energy efficiency in the heavy oil and in situ oil sands industry, Petroleum Technology Alliance Canada (PTAC) proposed the project “Emissions Reductions and Energy Efficiency in Crude Bitumen and Heavy Oil” for ecoEII funding. PTAC and its partners Accurata Inc., Devon Canada, Husky Energy, Spartan Controls, the Saskatchewan Research Council, and Sentio Engineering were awarded $387K from ecoEII for the Project.
The initial task was a conceptual engineering study of technologies that reduce methane venting of cold heavy oil. Existing technologies were studied in order to understanding applicability, operability, and cost of implementation. A literature search was also conducted to search for new technologies. Among those identified were the SlipStream® GTS (Green Tank System), Hexa-Cover® Floating Cover, and Go Technologies High Volume Blower Compressor (HVBC). These new technologies were analyzed further by Spartan Controls, Husky Energy, and Devon Canada, respectively.
A second task investigated the use of REM Technology’s SlipStream® GTS for Cold Heavy Oil Production with Sand (CHOPS) facilities. SlipStream® GTS is designed to capture low pressure, highly variable vented hydrocarbons from oil and condensate storage tanks. When used at CHOPS facilities, it was expected that GTS would capture and combust casing vent gas, thereby reducing site GHG emissions and fuel use. Performance requirements were specified and key technical risks were identified before proceeding with the design of a functional prototype GTS system. The cost of implementing the system was estimated, and determined to be too high for market acceptance. Thus, it should not be implemented at this time, even though the system is technically feasible.
A third task involved the demonstration of Go Technologies’ HVBC at Devon Canada’s heavy oil facilities in Bonnyville-Lloydminster districts. Unlike the existing reciprocating compressors, which were not effectively capturing casing gas, Go Technologies’ HVBC was expected to handle higher volumes of casing gas while achieving lower outlet pressure. Devon Canada put in place HVBCs and achieved stable operation on two well pad sites in Bonnyville- Lloydminster districts. After a 9-month pilot period, the results were inconclusive. It was determined that improved gas measurement capabilities on site and continued monitoring would be required. Moreover, installation at alternate sites may see greater benefit from the HVBC units.
A final task involved a field demonstration of Greatario Hexa-Cover® floating tiles on tanks at heavy oil sites to assess the potential for generating carbon offsets through a reduction in onsite and upstream emissions. Husky Energy installed Hexa-Covers® in northern Alberta on a train of tanks, with a parallel train used as a control. Both trains of tanks were equipped with separate fuel gas meters, and the volume of oil and emulsion entering the tanks was also metered. The annual carbon-offset potential was estimated at 48 tonnes of CO2e emission reduction. Cost savings from reduced fuel consumption would also be realized and would provide an economic return when propane is the fuel used on-site.
Benefits to Canada
Advancements in technologies that substantially reduce methane venting in crude bitumen and heavy oil facilities would benefit the oil sands industry in Canada, as well as conventional oil and gas operations around the world.
It is expected that the Project will lead to follow-on projects that test, demonstrate and support the development of new technologies in order to reduce methane and CO2 emissions in the oil and gas sector.
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