Organizers expect 20 per cent fewer people to attend the three-day international conference that has the theme: Producing More With Less.
"It has clearly had some impact," said Miki Reeder, a congress vice-president.
"We are particularly focusing on technologies that reduce costs, improve recovery and decrease environmental impact."
Last week, the Paris-based Organization for Economic Co-operation and Development noted that oil prices are about 35 per cent below where they were when the previous semi-annual forecast was done in November.
The trend has seen many companies in the oilpatch announce deep spending and job cuts over the last few months.
Reeder says organizers still expect about 1,000 people to attend from 20 countries, including representatives from about 100 companies.
Industry professionals are to discuss topics such as the market access challenges facing Alberta's oilsands.
The keynote presentation to be led by an official from the China National Offshore Oil Corp. is on "how technology can lower the cost of production in a tough economic climate."
Another panel is to discuss how technology can reduce costs and improve production with less of an effect on the environment.
"Producing more with less is very topical," Reeder said. "It is still the largest gathering anywhere in the world of the heavy oil community."
Presentations on the future of solar power in oil extraction and on a timeline for when Middle East countries will begin developing their extensive heavy oil reserves are also scheduled.
It's the third time that Edmonton has held the World Heavy Oil Congress since it began in China in 2006.
Other oil-producing hosts have included Venezuela, the United States and the United Kingdom.