Preparation and Evaluation of Sodium Hydroxymethyl Lignosulfonate as Eco-friendly Drilling Fluid Additive

Sodium hydroxymethyl lignosulfonate (NaHLS) was prepared by hydroxymethylation of sodium lignosulfonate (NaLS) and formaldehyde to enhance the performance as drilling fluids additive. The performances of the modified drilling fluid with NaLS and NaHLS, such as rheology behavior, filtration reducer and inhibitive ability were evaluated. The results indicate that the NaHLS can enhance the viscosity at low temperature, reduce the viscosity after ageing under 180 degrees C, which is more effective than that of NaLS. And NaHLS reduces the filtration, as the thickness of the modified fluid mud-cake is much thinner than that of NaLS. Besides, the inhibitive ability of NaHLS for clay hydrous disintegration is more effective than that of NaLS. The properties make NaHLS a potentially effective drilling mud additive.