Laboratory Study of Disaccharide Organic Compound Drilling Fluid for Trenchless Technology

High viscosity silt soil strata have been often encountered in trenchless engineering. Because of the high cohesion of such formations, greater shear stress is needed to destroy the soil mass, leading to many project accidents such as too large a torque placed on the drill pipe, difficulties in navigation, hole reaming and pipeline laying, delays in the construction period and cost increases, etc. A simple process to improve the drilling tools and drilling technique cannot solve these problems effectively in such strata. However, it's known that reducing the friction coefficient by changing the mechanical properties of the contact surface of borehole and drilling tool can reduce the required shear stress to overcome the problem of excessive torque. So the primary mean of handling such issues is to improve the performance of the filling liquid in the borehole-the drilling fluid. In this paper, laboratory experimental studies and molecular structure mechanism analysis of a common disaccharide organic compound were carried out on the influence of rheological parameters, lubrication coefficient, dispersion of the mud particle size, and expansibility of drilling fluid. It was found that a drilling fluid with such disaccharide organic compound can efficaciously reduce the friction, optimize rheology, enhance dispersion, etc. to reduce the high-torque engineering problem in such high viscosity silt soil strata. This drilling fluid has recently been used in practice and the application was successful.