There are a vast number of oil companies operating and based in Canada. However, the majority of oil production and refining in the country is carried out by less than 20 companies. The largest companies consistently compete against each other for the number one place. Research and development, or R&D, and alterations in processes, along with acquiring new technology and tools, play large roles in this competition.

Many Canadian producers are developing an interest in new energy technologies and the growing value of licensing rights. This new form of competition caused a shift in research and development toward producing patents. Oil companies sometimes utilize patents as tools to negotiate new deals.

Some of the largest and most productive oil companies in Canada are Enbridge, Inc. (ENB), TC Energy Corp. (TRP), Suncor Energy, Inc. (SU), Canadian Natural Resources, Ltd. (CNQ), and Imperial Oil, Ltd. (IMO). However, this list does not cover everything. There are more Canadian oil and gas companies worth the attention of investors.

1. Enbridge, Inc.

Enbridge is based in Calgary and is noted as one of the country's largest energy delivery companies. It had a market cap of about $61 billion (83 billion Canadian dollars) as of July 24, 2020. The company's main focus is transportation, distribution, and generation of energy throughout North America, primarily in Canada and the United States. In these two countries, Enbridge is responsible for operating one of the longest crude oil and liquid hydrocarbon transportation systems in the world. Because the company is first and foremost a distributor of energy, it owns and runs the largest natural gas distribution network in Canada. Its distribution services extend to Quebec, Ontario, and New York.

The company was first incorporated by Imperial Oil in 1949. However, Enbridge later bought its independence and began operations under its current name. It advanced several of its largest projects in the 2000s, including the Enbridge Northern Gateway Pipelines project and the Alberta Clipper pipeline project in 2006, the latter becoming operational in 2010.

2. TC Energy Corporation

TC Energy Corporation, formerly known as TransCanada, is among the top North American energy/oil companies. TC's headquarters are in Calgary, and it had a market cap of $41 billion (55 billion Canadian dollars) on July 24, 2020. The company focuses on developing energy infrastructure in North America. TC Energy is perhaps best known for the controversial Keystone XL pipeline, which was designed to transport oil from Alberta to Texas for refining and shipment. However, the company also builds and operates natural gas pipelines in Canada, the U.S., and Mexico.

3. Suncor Energy, Inc.

Suncor is one of the largest companies in Canada in terms of total revenue. It had a market capitalization of about $26 billion (35 billion Canadian dollars) as of June 2020. It was established in 1919 as the subsidiary of a company now known as Sunoco Inc. More than any other company, Suncor led the development of the Athabasca tar sands. The tar sands are an area of crude oil deposits located in the northern region of Alberta that hold a potential supply of trillions of barrels of petroleum.

The company has multiple refineries that function at high capacity, as well as upstream, midstream, and downstream operations. Suncor also operates over 1,500 gas stations around Canada. The value of the company's real estate holdings alone, where its production facilities are located, is significant.

4. Canadian Natural Resources, Ltd.

Canadian Natural Resources, or CNRL, is one of a few oil companies that is wholly Canadian. For the first 20 years of its operations, the company had little recognition. However, the development of the Athabasca sands presented a perfect opportunity and thrust it into the national spotlight. CNRL operates far beyond Western Canada. The firm has expanded its operations around the world, generating billions of dollars in Europe and even more from its light crude blocks in Africa. As of June 2020, CNRL, with a market cap of $20 billion (28 billion Canadian dollars), is one of the world's largest natural gas and crude oil producers.

5. Imperial Oil, Ltd.

Imperial Oil had a market cap of about $12 billion (16 billion Canadian dollars) on June 24, 2020. At that time, Exxon Mobil Corp. (XOM) owned approximately 70% of the company. Imperial Oil is a major producer of crude oil and natural gas. It is also a significant petroleum refiner in Canada. Furthermore, the company is a petrochemical producer and marketer for the nation, with retail and supply networks across the country. The company's headquarters are in Calgary, after moving from Toronto in 2005. It has significant holdings in the Alberta Oil Sands.