| 摘要 |
The present invention provides an apparatus and method expanding a portion of a tubular. The expansion apparatus is run into a wellbore on a working string. The expansion apparatus first comprises a rotary expander for expanding an expandable tubular. The expansion apparatus further comprises a spline assembly for coupling the rotary expander to a motor disposed on the work string. The rotary expander and spline assembly have hollow bodies that allow them to encircle the work string and rotate relative thereto. The spline assembly comprises an inner sleeve and outer sleeve. The inner sleeve is attached to the motor and the outer sleeve is attached to the rotary expander. The inner and outer sleeves are coupled to each other using a spline and groove connection. The connection allows the rotary expander to be rotated by the motor, while at the same time, allow the rotary expander to move axially relative to the motor. The rotary expander comprises two rows of rollers for expansion against the tubular. The position of the rollers on the first row is skewed in one direction relative to the longitudinal axis. The rollers on the second row are skewed in an opposite direction. When actuated, the skew angle of the rollers will cause the expander tool to move axially. Because the rollers of the two rows are placed at opposing skew angles, alternating actuation between the two rows of rollers causes the expander to move in opposite axial directions during expansion.
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