Sulfomethyl phenolic resin SMP-I, a fluid loss reducer, is widely used in oil drilling and cement slurry. Its main component is sulfomethylated phenolic resin. Through a special synthesis process, it can still maintain excellent fluidity and stability under high-temperature and high-pressure conditions. SMP-I can effectively reduce the loss of water in the mud, lower the filtration loss, thereby improving the drilling efficiency and reducing the operation cost. In addition, SMP-I also has good environmental friendliness, contains no harmful substances, and meets modern environmental protection requirements. In practical applications, SMP-I can be compatible with other additives, enhancing the overall performance of the mud, especially under complex geological conditions such as high temperature and saline-alkali conditions, where it performs exceptionally well. With the continuous increase in the demand for high-performance materials in the petroleum industry, SMP-I is expected to become an indispensable important material in future drilling operations. Through further research and development and optimization, the application scope of SMP-I will continue to expand, providing more reliable technical support for oil extraction and resource development.