How to turn carbon into gold for China's first million ton CCUS project?

Recently, at the 51st Geneva International Invention Exhibition, Sinopec Shengli Oilfield's independently developed CCUS (Carbon Capture, Utilization, and Storage) key technology equipment won the highest honor of the Special Commendation Gold Award. Li Yang, academician of the CAE Member and secretary-general of the International CCUS Innovation Cooperation Organization, said that this marks that China's CCUS full chain key technology and equipment have reached the international leading level.

CCUS， It is to inject the captured carbon dioxide into the ground, partially for storage, and partially for deep integration with underground oil to extract more crude oil. This process is repeated repeatedly to ultimately achieve complete storage.

From basic research to applied research, and then to engineering practice, scientific researchers at Shengli Oilfield have been working tirelessly for 59 years, breaking foreign technological monopolies, filling technological gaps, achieving multiple breakthroughs from 0 to 1, and ultimately achieving China's first million ton CCUS project.

Breaking the foreign blockade and pioneering core technology

In 1967, 27 year old Cao Yinsheng was commissioned to begin research on carbon dioxide oil displacement. Faced with differences in domestic and foreign oil reservoirs and technological blockades abroad, the first batch of researchers had no experience to draw on. Cao Yinsheng and his colleagues continuously explored and finally found the three major factors that affect the efficiency of carbon dioxide flooding: crude oil properties, pressure, and temperature.

Water injection oil recovery "is a traditional oil production method. Due to the inability to inject water and extract oil, over 90% of the reserves in the low-permeability reservoir of Shengli Oilfield, which is over 1 billion tons, are still dormant underground.

On the road of in-depth research on carbon dioxide oil displacement, the relay baton is in the hands of Zhang Chuanbao and his team. At the end of 2007, the Gao 89-1 block of Shengli Oilfield became the first "experimental field", where they conducted pilot tests on near miscible flooding using carbon dioxide. The conclusion of the experiment is that mixing carbon dioxide with crude oil is the key to improving oil displacement efficiency.

How much pressure is required for crude oil and carbon dioxide to form a mixture underground? In 2013, in the Fan 142 block of similar oil reservoirs, researchers focused their efforts on seven wells in the experimental area. Over a period of 46 months, Zhang Chuanbao's team gradually increased the reservoir pressure from 17 megapascals to 40 megapascals. Eventually, carbon dioxide and oil were successfully mixed, and the daily production of a single oil well increased from 1 ton to 6 tons.

As a result, Shengli Oilfield has pioneered the core technology of "CO2 high-pressure mixed phase drive" in China and achieved breakthroughs in field applications.

Break through technical barriers and solve the difficult problem of "not being able to bypass"

Carbon dioxide can drive oil, but how to safely and efficiently inject it underground has become an unavoidable problem.

The on-site practice data of Shengli Oilfield shows that the efficiency of carbon dioxide flooding is 40% higher than that of water flooding, and the storage rate can reach 60% to 70% at once, ultimately reaching 100%.

As of now, the CCUS project in Shengli Oilfield has injected over 1.3 billion cubic meters of carbon dioxide and stored it all underground. The daily oil production in the block has increased from 220 tons to 460 tons, and the unit energy consumption and oil production cost have significantly decreased. This provides mature and replicable technologies and solutions for the large-scale application of CCUS and the achievement of China's "dual carbon" goals.