Group 1 - China National Offshore Oil Corporation (CNOOC) and its subsidiaries have obtained a patent for a method to assess the safety of multi-phase water-sealed oil caverns, with the patent number CN115329431B, applied for on August 2022 [1] - CNOOC was established in 1983, headquartered in Beijing, primarily engaged in oil and gas extraction, with a registered capital of 11,380 million RMB [1] - CNOOC has invested in 45 companies, participated in 5,000 bidding projects, holds 266 trademark registrations, 5,000 patents, and possesses 28 administrative licenses [1] Group 2 - CNOOC Refining & Chemical Company, established in 2005 and located in Beijing, focuses on oil, coal, and other fuel processing, with a registered capital of approximately 1,899.55 million RMB [1] - CNOOC Refining & Chemical has invested in 28 companies, participated in 4,056 bidding projects, holds 456 trademark registrations, 476 patents, and has 19 administrative licenses [1] Group 3 - CNOOC Petrochemical Engineering Company, founded in 2009 and based in Jinan, specializes in professional technical services, with a registered capital of approximately 635.19 million RMB [2] - CNOOC Petrochemical Engineering has invested in 3 companies, participated in 3,263 bidding projects, holds 376 patents, and has 9 administrative licenses [2]