I got a question asking me about what the space out means.
Space out means that you stop your drill string at the proper location where all the BOP rams (annular and pipe rams) will not close against a tool joint. Please see the figure below for more understanding.
Practically, on land or offshore (shelf), stopping your drill string with the tool joint at the rotary table is the correct and simple way to space out. The reason is that most of rigs are designed to have about 30 ft from the rotary table to top of annular preventer. Anyway, since each rig is different, you need to make sure that the drilling contractor has the correct way to space out.
Why is it important to space out?
You may heard about 3-S (Space Out, Shut down, and Shut In) for well control. This is the first important step to shut the well in effectively. If you properly space out, you will have ability to control the well in the correct way. However, if you don’t space out your drill string correctly, you may not be able to use one or more of your BOP effectively and you will be in a big trouble.
Reference book: Well Control Books