| 主权项 |
1. A self-locking centralizer for mounting to the exterior surface of a downhole well tubular, comprising:
a cylindrical body having an exterior surface and stabilizing fins extending outward from the exterior surface; the body having a hollow interior with an interior surface, and a first edge and a second edge formed between the interior and exterior surfaces; a first ramp formed on the interior surface, proximate to the first edge; a second ramp formed on the interior surface, proximate to the second edge; a helical interior channel on the interior surface extending between the first and second ramps; a first aperture extending between the exterior surface and the first ramp; a second aperture extending between the exterior surface and the second ramp; an expandable spring member having a first tab at one end and a second tab at its opposite end; the expandable spring member located in the channel; a first retaining pin removably located in the first aperture for engagement with the first tab, said first tab having a first position wherein said first tab is engaged by said first retaining pin, and said first tab having a second position wherein said first tab is loaded against said first ramp to limit rotation between said centralizer and said exterior surface of said downhole well tubular; and, a second retaining pin removably located in the second aperture for engagement with the second tab, said second tab having a first position wherein said second tab is engaged by said second retaining pin, and said second tab having a second position wherein said second tab is loaded against said second ramp to limit rotation between said centralizer and said exterior surface of said downhole well tubular. |
