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On March 18, it was learned from China National Petroleum Corporation’s Bohai Drilling Second Cementing Company that the \"Cementing flushing fluid for oil-based drilling fluids and its preparation method\", which was independently developed by this company, has recently been granted an invention patent by the **Intellectual Property Office. This technology, which solves the difficult problems related to cementing in unconventional oil and gas reservoirs, provides an independent technical solution for the efficient development of oil and gas resources in complex formations. With the continuous advancement in the exploration and development of unconventional oil and gas, the use of oil-based drilling fluids has become increasingly widespread. Common technical challenges such as the difficulty in cleaning the oil films and filter cakes adhering to the casing walls and borehole walls during cementing operations, as well as low displacement efficiency, have become more prominent. Traditional flushing fluids often have limitations such as low oil-washing efficiency, narrow application range, and poor compatibility with subsequent working fluids. To overcome this technical bottleneck, the company’s research team spent 3 years working on it and successfully developed an oil-cleaning type rinse solution with high-efficiency penetration, emulsification and solubilization capabilities, as well as wetting-reversal properties. It is understood that this product innovatively enhances the cleaning ability of oil-based drilling fluid residues through the synergistic action of various functional surfactants and treatment agents. Experiments and applications have shown that this product can effectively remove the residual oil-based drilling fluid adhering to the casing walls and wellbore walls, reverse the wetting of the wellbore walls, and significantly improve the cleanliness of the wellbore. Compared with traditional products, its content has been reduced by over 30%; the operating temperature range has been expanded to 10°C to 180°C; it possesses excellent rheological properties, and it is highly compatible with drilling fluids and cement slurry, thereby ensuring the safety and quality of cementing operations. To date, this product has been used in over 150 well operations in various unconventional oil and gas fields, including those involving shale oil in Dagang, shale gas in Sichuan and Chongqing, and shale oil in the Northeast China region; the total amount used has exceeded 300 tons, and the results of its field application have been satisfactory. (China Chemical Industry News, by Qu Zhaogui; correspondents: Ma Ruran, Li Shijie)