Experimental Study on Low Temperature Performances of a Nano-SiO_2 Drilling Fluid for Drilling in Gas Hydrate Bearing Sediments

With more and more attention to nature gas hydrate exploration and development,more and more attention also has been paid to drilling technology in gas-bearing hydrate formation. According to drilling characteristics in hydrate formation and based on existing nano-materials,through a large number of experiments a new nano-Si O2 drilling fluid has been established for drilling in gas-bearing hydrate formation: seawater + 2% Nano-Si O2+ 3% bentonite + 1% Na-CMC + 3% SMP-2 + 1% PVP( K90) + 2% KCl,subsequently low temperature traditional performance and hydrate formation inhibition of this drilling fluid have been evaluated. Experimental results show that,this drilling fluid has optimum density,good low temperature rheology and shale hydration inhibition,and is able to effectively inhibit free gas from hydrate dissociation reformat hydrate in drilling fluid circulation system for a long time.Therefore,this drilling fluid is beneficial to keep borehole safety and successful drilling operation while drilling in gas-bearing hydrate formation.