دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: 1. an undergauge channel or groove cut in the side of the bore- hole and parallel to the axis of the hole. A key seat results from the rotation of pipe on a sharp bend in the hole. 2. a groove cut parallel to the axis in a shaft or a pulley bore.

a out of round bore hole worn to the side, often with the side of the drill pipe in a crooked hole, that looks like a key hole. Keyseats create problems with passage of tool joints and larger pipe that does not bend as easily as smaller diameter pipe.