Improve the Test Method of the Degree of Sulfonation of Drilling Fluid Shale Inhibitors

Sulfonated asphaltene, an additive widely found in water base and oil base drilling fluids,is generally used to effectively plug the micro fractures, prevent sloughing shales from collapsing, and inhibit shale from becoming hydrated. It also has good lubricity, emulsifying capacity, and abilities to reduce filter loss and to stabilize mud properties at elevated temperatures. The content of sodium sulfonate in sulfonated asphaltene is an important index ofevaluating the quality of the sulfonated asphaltene; the higher the content of the sodium sulfonate, the better the quality of the sulfonated asphaltene. In laboratory studies, the ion chromatography and element analyzer were used together to establish a fast way of measuring the content of sodium sulfonate in sulfonated asphaltene. Using this method, the relative standard deviation (RSD) of the measuring result of each sample was less than 1% (n=5), indicating that this method had good repeatability. Experimental results demonstrated that this method is fast, reliable and easy to use in measuring the sodium sulfonate content in a sulfonated asphaltene.