Group 1 - The State Intellectual Property Office of China shows that China National Petroleum Corporation (CNPC) and China Petroleum Group Engineering Materials Research Institute have applied for a patent titled "A Method for Qualitative Rapid Detection of Carbon Disulfide in Oilfield Chemical Agents," with publication number CN121275728A and application date of July 2024 [1] - The patent describes a method for qualitatively and rapidly detecting carbon disulfide in oilfield chemical agents using readily available sodium sulfide as a color developer, allowing for visual identification of color changes to determine the presence of carbon disulfide [1] - This method is applicable to colorless, yellow, blue, green, and other cool or light-colored oilfield chemical agents, but not suitable for warm or dark-colored agents like red, purple, brown, or black [1] Group 2 - CNPC, established in 1990 and located in Beijing, primarily engages in oil and natural gas extraction, with a registered capital of 48.69 billion RMB [2] - CNPC has invested in 107 companies, participated in 5,000 bidding projects, and holds 1,447 trademark records and 5,000 patent records, along with 28 administrative licenses [2] - China Petroleum Group Engineering Materials Research Institute, founded in 2021 and based in Xi'an, focuses on specialized equipment manufacturing, with a registered capital of 679.11 million RMB [2] - The institute has invested in 4 companies, participated in 1,687 bidding projects, and holds 15 trademark records and 841 patent records, along with 16 administrative licenses [2]