Gas hydrates drilling procedure

Abstract From the Canadian patent

When drilling through hydrate-containing strata instead of, increasing the density of the drilling mud to reduce or prevent melting of the hydrates, the density of the mud is maintained at a level sufficiently low to promote melting of the hydrates. The gas generated by the melting hydrates rises to the surface with the drilling mud which is diverted by a rotating diverter at the wellhead to a degasser where the gas is separated from the mud, and the mud is returned to the mud tanks for re-use. If the drill string is to be removed temporarily the mud, density is increased to stop hydrate melting.