Patent ID: 7849918
Filing Date: 2010-12-14
Classification: E21B

Abstract:
1. A centralizer for maintaining a tubular member in a substantially centralized position within a borehole, comprising: a substantially seamless material of substantially cylindrical shape, devoid of removable section, having a circumferential wall, an upper end, and a lower end; a plurality of apertures in the circumferential wall having an upper end and a lower end, wherein the apertures define an upper collar element, a lower collar element of the circumferential wall, and bow spring elements disposed between the upper collar element and lower collar element; and wherein, each bow spring element has a medial portion of the bow spring element that is expandable radially such that the circumference of the centralizer is larger around the medial portions of the bow spring elements than the around the upper collar element and the lower collar element.