Asia accounted for more than 9.2% of the world's oil production in 2014. The region was led by China and India, the world's fourth and 20th biggest oil-producing nations, respectively. In recent years, Asia's share of world oil production has been on a slow but regular decline. This is primarily a consequence of flat regional oil production during a period of rising overall global output.

In the five years from 2010 to 2014, Asian oil output rose slightly from about 8.5 million barrels per day in 2010 to just over 8.6 million barrels per day in 2014. During the same period, world oil production grew more than 5%, from about 88.1 million barrels per day to about 93.1 million barrels per day. While a number of countries in the region have discovered large new reserves, others face declining production from aging oil fields. Consequently, analysts expect recent production trends to continue for the region as a whole.

1. China

China is the biggest oil producer in the region by a substantial margin, accounting for nearly 4.6 million barrels of oil per day in 2014. It is responsible for nearly 53% of Asia's total production. According to the U.S. Energy Information Administration (EIA), Chinese oil production has grown every year since 1981 without exception. In the most recent five-year period from 2010 to 2014, production grew a total of about 4.6%.

The oil industry in China is led by several of the largest energy companies in the world: China Petroleum and Chemical Corporation, known as Sinopec; China National Offshore Oil Corporation, or CNOOC; and China National Petroleum Corporation, or CNPC. In 2014, these three companies combined to produce a total of over 1.4 billion barrels of oil in China, more than 85% of the country's total annual production. In the same year, the companies combined to produce an additional 630 million barrels of oil in dozens of countries around the world.

2. India

India accounted for production of about 978,000 barrels of oil per day in 2014, the fifth year in a row daily production neared but did not clear the 1 million barrel mark. While production growth has essentially flatlined in recent years, oil consumption in India continues to grow by leaps and bounds. National oil consumption reached nearly 3.7 million barrels per day in 2013, the most recent year for which data is available. In the five years from 2009 to 2013, Indian oil consumption grew a total of more than 19.3%, far outpacing domestic production. As of 2013, India is the fourth largest oil importer in the world.

Oil production in India is dominated by the state-owned enterprise, Oil and Natural Gas Corporation, which accounted for roughly 60% of domestic production in 2013. An additional 27% of Indian oil is produced by Cairn India Limited, the Indian subsidiary of the British oil and gas company, Cairn Energy PLC.

3. Indonesia

Indonesia comes in just behind India with production of about 911,000 barrels per day in 2014. In the 1990s, when production was at a high, Indonesia produced between 1.5 million and 1.7 million barrels per day. Since that period, however, production has followed a nearly unbroken downward trend to the current level. In 2009, the combination of declining production in aging oil fields and rising domestic demand led Indonesia to exit Organization of the Petroleum Exporting Countries (OPEC), of which it had been a member since 1962.

PT Chevron Pacific Indonesia, a subsidiary of the American energy giant Chevron Corporation, is Indonesia's biggest oil producer, accounting for about 40% of production in 2014. Indonesia's state-owned energy company, PT Pertamina, was responsible for an additional 26% of the country's production. Foreign oil companies including Total SA, ConocoPhillips Co. and CNOOC are also significant producers.

4. Malaysia

Malaysia produced about 697,000 barrels of oil per day in 2014, most of which was extracted from offshore fields. Over the course of more than two decades since 1991, production in the country fluctuated between 650,000 and 850,000 barrels per day. According to the U.S. EIA, recent downward production trends can be attributed largely to declining output on aging oil fields. The Malaysian government is responding by encouraging investment in recovery technology and new field development.

Petroliam Nasional Berhad, also known as Petronas, is Malaysia's state-owned energy corporation. It controls all oil and gas resources in the country and is responsible for development of those assets. International integrated oil and gas companies, such as Exxon Mobil Corporation, Murphy Oil Corporation and Royal Dutch Shell plc, are involved with Petronas in oil production activities in Malaysia, including partnerships in enhanced oil recovery projects on aging oil fields.

5. Thailand

Oil production in Thailand has trended upward in recent years, rising from about 390,000 barrels per day in 2010 to nearly 502,000 barrels per day in 2014. This performance continues a nearly unbroken growth trend that began in 1980 when the country produced only 1,300 barrels per day. Despite this growth, Thailand must import large quantities of oil to meet its domestic demand. In 2013, Thailand consumed nearly 1.2 million barrels of oil per day, requiring net oil imports on the order of 700,000 per day to meet demand.

Chevron is the biggest oil producer in Thailand. It operates Thailand's largest oil field, Benjamas, and has investments in many other important production sites in the country. Thailand's state-owned oil company, PTT Exploration and Production, is the country's second-largest oil producer. Other international companies involved in oil production in Thailand include Coastal Energy Company and Salamander Energy plc.

6. Vietnam

Vietnam has maintained oil production volumes between 300,000 and 400,000 barrels per day since 2000. Its daily production in 2014 amounted to about 316,000 barrels. In 2011, offshore exploration and drilling activities raised Vietnam's proven oil reserves from 600 million barrels to 4.4 billion barrels, rocketing it into third place in Asia after China and India. Industry analysts expect further discoveries as exploration of Vietnam's offshore waters continues.

Vietnam's state-owned oil and gas company, PetroVietnam Gas Joint Stock Corporation, is involved in all oil production in Vietnam via its production subsidiary, PetroVietnam Exploration Production Corporation, and its joint ventures with international oil companies. Chevron, Exxon Mobil and the Russian company, Zarubezhneft OAO, are several of the largest international producers operating in Vietnam.