The drill string is made up of “joints” of drill pipe that are 20 to 40 feet in length. Each joint has a threaded male end and a threaded female end that is larger than the overall pipe diameter; these tool joints connect one joint of drill pipe to the next. Drill pipe itself comes in different diameters(typically ranging from 5(1/2)to6(5/8)inches indeep water). In addition to standard drill pipe, rig crews can use drill collarsor heavyweight drill pipe as well. Drill collars have much thicker walls than standard drill pipe. Rig crews often use drill collars to add weight to the bottom part of a drillstring. Doing this helps keep the drill string from kinking or breaking and puts more weight on the bit. Heavyweight drill pipe is of an intermediate weight; it minimizes the stress between the drill collars at the bottom of the drill string and standard drill pipe at the top.