society > occupation and work > industry > drilling for oil or gas > drill for oil or gas [verb (transitive)] > seal (well, etc.) (2)
Oil Industry. transitive. In drilling for oil or gas: to seal (porous or unstable strata) by causing a layer of mud to be deposited on the sides…
transitive. to plug off (also back): to seal off (an oil well or a water-bearing rock formation) by inserting a plug. Also intransitive.