Today’s deeper drilling calls for long and heavy casing strings. Drilling a well through rock formations means using casing to keep the sides of the well from caving in and to protect the wellstream from contamination.
At a basic level, casing slips are steel wedges hinged together. Just like rotary hand slips, they are used to grip the tubular pipe and carry the weight of the whole string to keep it from falling into the well. When the tubular is suspended into the rotary, the slips will wedge between the rotary bushings and the OD of the tubular. The weight of the pipe itself is what will keep it in place.
Casing pipe, or “setting” pipe, typically involves running steel pipe into the well and cementing it into place. “Joints” that are generally 40 feet long are screwed together to form the casing strings. Casing runs from the rig floor, with casing elevators connecting one joint at a time. The casing is stabbed into the previous casing string in the well.
Landing the casing depend on the forces exerted on the casing string after the well is completed. These forces can be caused by fluid density, formation pressure, temperature and earth compaction. The casing will shrink or expand in response to these forces.
“Dies” and “slips” are often used to describe the same thing, but technically the die is a part of the slip. Dies on the inside of the slip grip the pipe and evenly distribute the force from the wedges to the surface of the pipe to avoid crushing. “Dressing the slip” involves inserting thicker or thinner dies to change the gripping size.
Keystone “CMSXL” casing slips have a 4-inch taper and a range of 6 5/8 inches through 30 inches (which can be accomplished by adding or subtracting the number of segments and installing the proper button sizes).
Keystone “CMS-3” casing slips are designed to fit spiders and bushings with a 3-inch taper. The CMS-3 has a size range of 9 5/8” through 30 inches. As with the CMSXL, by adding or subtracting segments and inserts the slips can accommodate 30-inch O.D. casing.
The Keystone CMSXL and CMS-3 casing slips have a multi-segment design to give a full wrap-around to help prevent damage to casing. Segments are made of alloy steel and are heat-treated for strength and wear resistance, then machined to strict quality controlled standards.
Tips for Safe Operation
When using manual slips, it’s important to keep safety in mind. Casing slips should not be thrown in the rotary table, especially when the string is moving as doing so can damage the equipment. Slips should be inspected before a job, and all dies should be checked for sharpness and correct size. Casing slips can break if the string exceeds the load rating.
Finally, even if different parts of various manufactures seem compatible, they may not be, so it’s best to stick to Keystone-made parts. Get a price quote from Keystone Energy Tools on quality oilfield tools today by clicking here and filling out our form.
