In the past decade, the thermal recovery technology has developed rapidly in China. Steam Stimulation has been the main approach for commercial recovery of heavy oil. The depth of most heavy oil reservoirs in China are in the range of 800-1600 m. The total Steam Stimulation operations in 1986 numbered 425 and oil production reached 1.5 x lo6 tons. In 1990 total wells for thermal recovery were over 3800, operations exceed 4600 and heavy oil production reached 8.3 x lo6 tons. In 1993, by virtue of 7800 operations in 6200 wells, 9.69 x lo6 tons of heavy oil were produced. This paper reviews the practical thermal recovery experience for different types of reservoirs and points out the prospect of development of thermal recovery technology in China.
China is rich in heavy oil resources. There are many types of heavy oil reservoirs distributed mainly in Liaohe oil area, Northeast China, Karamay oil area, Northwest China, and Shengli oil area, East China (Fig. 1).
In recent ten years, the thermal recovery technology in China has been developed rapidly. Steam stimulation has been a main approach for commercial recovery of heavy oil, and steam flooding pilot tests have been underway in different reservoirs.
The depth of most heavy oil reservoirs in China ranges in 800-1600 meters. In 1986, the total operations for steam stimulation numbered 425 and oil production was 1.5 x lo6 tons. In 1990, a total of
Fulaerji
Liaohe
Baoleng-Hengulia
DISTRIBUTIVE LOCATION 2. Baicheng OF HEAVY OIL-BITUMEN RESOURCES IN CHINA O 500km 1.. 15. Guangxi 16.Liuhuall-1 17. Qaidam 18. Qiketai 19. Fukang 0 Basin a Heavyoil A Surface Oil Sands Fig. 1. Distributive location of heavy oil-bitumen resources in China. 457 458 IMPROVED RECOVERY AND HEAVY OIL 171 p6 4600 steam stimulation operations reached in more than 3800 wells, and the annual heavy oil production had reached 8.3 x lo6 tons. Up to 1993, a total of 7800 steam huff and puff operations were completed in more than 6200 wells, and over 200 steam flooding patterns are underway. Annual heavy oil production has reached 11.39 x lo6 tons (9.69 x lo6 tons by steam stimulation, 0.46 x lo6 tons by steam drive and 1.24 x lo6 tons by conventional recovery). The heavy oil production has accounted for 8.2% of the total onshore oil production of 139.37 x lo6 tons in China. The annual heavy oil production in China is shown in Fig. 2. It is economically profitable for heavy oil recovery at the international oil price.
In recent three years, in order to improve the steam stimulation performance and solve the difficult problem in steamflooding, a lot of important technical researches and experiments were accomplished and great achievements has been made by RIPED, Liaohe oilfield, Karamay oilfield, Shengli oilfie
