A Formula of Potassium Polymer Sulfonated Drilling Fluid Developed Based on Rock Microscopic Analysis

During the rapid coring drilling in the Wenchuan earthquake Fault Scientific Drilling project, the deep fault zone is characterized with extremely broken strata and strong creeping, which made the drilling tasks very difficult. The key technology to drilling success is a suitable drilling fluid system. To design such a drilling fluid system with desired properties, the mineral composition of rock samples from deep fault zone was analyzed using X-Ray Diffraction (XRD) and Fourier Transform Infrared (FTIR) absorption spectrum. Based on the results, a potassium-based polymer sulfonated drilling fluid was developed. This drilling fluid system possesses a variety of advantages including good quality of filter cake, strong anti-pollution ability, anti-collapse ability and inhibition ability, and great compatibility with treating agent. Also, the composition of this drilling fluid is simple, easy to prepare and at a relatively low cost. The study of potassium sulfonated drilling fluid system is of great significance for the rapid core drilling in deep fault zone.