Roller stem is a device that is used to carry out operations typically in deviated well bores. It helps in reducing friction against tubing walls and is more useful than conventional stem bars in these situations. The roller stem has sinker bars with milled slots to accommodate roller wheels and are available for a wide range of tubing sizes.
Roller stem is made up in short sections usually two feet in length with upper and lower thread connections. Slots cut at 45oto one another are cut in the body lengthwise.
Rollers are mounted in the slots with the use of a roller shaft placed at 90°. The rollers used have an outside diameter larger than the body of the roller stem.
This allows the tool string to have a gliding effect.
Used in wells with great degrees of deviation, slant wells and wells containing internal coated tubing.
The roller stem is normally placed midway in the tool string. In some applications placement is near the top and bottom of the tool string.
After each use inspect rollers for cracks, wear or chips.