Experimental Study on Inhibition to Marine Gas Hydrate Decomposing

When drilling in marine hydrae-bearing formation,the decomposition of hydrate will lead to a series of problems,including instability of wellbore wall,degradation of drilling fluid performance,and hydrate blockage within pipeline.These problems bring great risks to safety of drilling operation.As a result,the application of properly designed drilling fluid which can minimize gas hydrate dissociation is crucial for the drilling in this type of formation.In this work,a set of gas hydrate stimulating experiment system was used to synthesize several kinds of gas hydrate samples in laboratory,and thin silicate drilling fluid was added to the system.The behavior of gas hydrate samples decomposing under different conditions(heating,depressurization)was studied.The results show that the drilling fluid can effectively inhibit gas hydrate decomposition and can be applied to drilling in oceanic gas hydrate formation.