Patent ID: 8167034

Claim:
A device for centering a casing within a wellbore, comprising: a generally tubular body made of metal and having an outer surface for facing the wellbore and an inner surface opposite the outer surface; a plurality of protrusions disposed on the outer surface and each protrusion forms a cavity on the inner surface, wherein the plurality of protrusions is generally positioned along a line and individual protrusions have a first thickness between the inner and outer surfaces; and a gap region disposed between adjacent protrusions on the outer surface and generally along the line, wherein the gap region has a second thickness between the inner and outer surfaces and the second thickness is greater than the first thickness, and wherein the portions of the protrusions adjacent to the gap region are each rounded to reduce the formation of voids or snagging upon filling the gap region with cement within the wellbore such that the cement provides structural support and compensates for the reduced thickness of the protrusions.