Social media is cool. I’m able to keep up with people in the industry, all over the world. The different methods and equipment make for some interesting conversations. I got into a discussion the other night about derrick design, the different rigs and the reasons for the designs, so I thought I’d share a little of what I’ve learned over the years.
Derricks in the drilling industry basically come in two types: internally loaded and externally loaded. Examples of externally loaded derricks would include a standard Smeal rig or an oilfield workover rig. This means that the load is dispersed to the foundation by transmitting and dividing it on the block to the load on guy wires, or hydraulic cylinders. This design is very handy, as it allows you to rig up over most any hole and allows plenty of working room. Guy wires can be either to the ground or back to the rig itself. Most smaller rigs use guys to the front of the unit, and any ground wires are just for wind stability. Pulling power is often limited by the weight of the unit. I’m sure you have seen or heard about situations that lifted the front wheels off the ground. That’s pretty much the limit, and it’s hard on equipment. Downsides include flex and overall capacity. They will flex and move as loads are increased. These derricks can be built very strong, but the engineering challenges get larger on the big units.