One of the essential tools in any drilling operation is the slip. This device is used to suspend the drill pipe as it enters the rotary. While many drilling rigs rely on workers to manually lift and lower slips, automatic slip-lifting devices are an attractive alternative. In this article we will give an introduction to the traditional slip and explain the advantages of going for the automated version.
What Are Slips?
During drilling operations, slips are used to grip and suspend a drill string in the rotary table. Traditional slips are able to accomplish this through the following:
· The slip is composed of a series of hinged wedges that encircle the drill string. The inside of the wedges are coated with teeth that grip onto the pipe.
· The outsides of the wedges are then tapered to match that of the rotary table.
The drill string is then lowered after the slip is properly placed, allowing the inside teeth to grip the string. The resulting force then pulls the wedges down to lock the drill pipe in place. Workers remove the slips by grabbing the slip handles while the driller lifts the pipe out of the rotary table. Once the slips are fully removed, they are set aside.
Disadvantages and Risks with Manual Slip Lifting
· Increased Accident Risk: As with any drilling procedure, manual slip lifting increases the risk of injury. Accidents include slipping, exposure to “pinch points,” and back injuries due to incorrect lifting techniques.
· Cluttered Drilling Floor: Traditional slips require two or three workers to operate in an already crowded area with other equipment.
· Increased Down Time: The manual lifting of slips is not an easy task. The handling of many drill strings can add up to a significant portion of the overall project time.
Automatic Slip Lifts and Their Advantages
Also known as power slips, automatic slips can be air or hydraulic powered. Most are operated remotely on the drilling floor or driller’s cabin by use of a valve, pedal or control. Similar to manual slips, most automatics can handle drill pipe, collars, casing and tubing. They offer numerous advantages for any oilrig:
· Design: Some automatic devices are designed to not go beyond the length of the rotary table. This results in a less cluttered drill floor for workers. Furthermore, the remote operation of automatic slips removes workers from other immediate hazards surrounding the operation.
· Reduced Labor: Automatic slips rely heavily on gravity to be set into the rotary. While extensive prepping is required before the slips are ready for use, workers will not need to worry about lifting during operations. The elimination of risk for back injuries increases the safety of the drilling floor.
Keystone’s Slip Lifting Device
Keystone’s lifting devices can be used with drill collars, casing slips and rotary. Their models are available to work with square-drive and pin-drive master bushings.
Summary
Drilling crews looking to decrease costs will certainly benefit from automatic slips. Both hydraulic and air powered models decrease labor costs while increasing safety. Reduced downtime increases the overall efficiency of the drilling project. When considering the overall drilling process, it’s reassuring to know some devices are available to make things a bit easier.
