公开(公告)号：EP0297716A1

公开(公告)日：1989-01-04

申请号：EP88304630.2

申请日：1988-05-23

申请人： WEATHERFORD-PETCO, Inc.

发明人： Langer, Friedrich H.

IPC分类号： E21B17/10

CPC分类号： E21B17/1028

摘要： A centralizer for well casing (16) functions in an annular space between the casing (16) and a wellbore (20). It comprises a pair of axially spaced-apart and aligned collars (12) adapted to encircle the well casing and a plurality of spring bows (14) extending between and secured to the collars. Each spring bow (14, 280) has two ends and an outwardly convex curved mid-portion. In a first form of the invention starting force is reduced by providing spring bows having outwardly projecting contact angle reduction members (282) that engage the upper edge of the wellbore (20) as the casing (16) is moved into the wellbore (20) to reduce the effective contact angle of the spring bows (14, 280) with respect to the wellbore (20) and thereby reduce the force required to insert the centralizer (10) into the wellbore (20). In a second form of the invention the spring bows are provided with casing abutment members (283) extending inwardly towards the centralizer's longitudinal axis. The casing abutment members (283) contact the casing (16) as the spring bows (14, 280) are moved towards the casing (16) during insertion of the centralizer (10) into the wellbore (20) to increase the restoring force of the spring bows. The spring bows may have both contact angle reduction members (282) and casing abutment members (283) to give a centralizer having a desirable combination of low starting force with high restoring force.

摘要翻译： 用于井套管（16）的扶正器在壳体（16）和井筒（20）之间的环形空间中起作用。 它包括一对轴向间隔开和对齐的套环（12），其适于围绕井套管以及在套环之间延伸并固定到套环上的多个弹簧弓（14）。 每个弹簧弓（14,280）具有两个端部和一个向外凸出的弯曲的中间部分。 在本发明的第一形式中，当壳体（16）移动到井眼（20）中时，通过提供具有向外突出的接触角减小构件（282）的弹簧弓来减小启动力，所述弹性弓形接头与井筒（20）的上边缘接合， 以减少弹簧弓（14,280）相对于井筒（20）的有效接触角，从而减小将扶正器（10）插入井眼（20）所需的力。 在本发明的第二种形式中，弹簧弓具有向内朝着扶正器的纵向轴线延伸的壳体抵接构件（283）。 当将扶正器（10）插入井眼（20）中时弹簧弓（14,280）向壳体（16）移动时，壳体抵接构件（283）接触壳体（16），以增加回弹力 春天的弓。 弹簧弓可以具有接触角减小构件（282）和壳体抵接构件（283），以给予具有低启动力和高恢复力的期望组合的扶正器。