Tool joints

Drill Collar 716. Drill Pipe 735. Tool Joints 748. Heavy-Weight Drill Pipe 749. Fatigue Damage of Drill Pipe 763. Drill String Design 765. 

Drill pipe elevators for taper shoulder and square shoulder weld-on tool joints shall have bore dimensions as specified in Table 4-6. 

Tool Joint Designation Reference Drill Pipe Size and Style (All Weights and Grades) Weld On Too) Joints Elev. Marking... 

Kelly Tool Joint Tool Joint Dnti Collar Drill Collar Swivel Sub... 

Tool Joint Tool Joint Drill Collar Drill Collar... 

The drill string is defined here as a drill pipe with tool joints and drill collars. The drill stem consists of the drill string and other components of the drilling assembly that includes the kelly, subs, stabilizers, reamers as well as shock absorbers, and junk baskets or drilling jars used in certain drilling conditions. The drill stem (1) transmits power by rotary motion from the surface to a rock bit, (2) conveys drilling fluid to the rock bit, (3) produces the weight on bit for efficient rock destruction by the bit, and (4) provides control of borehole direction. 

Upset Drill Pipe for Weld-on Tool Joints (Grades D and E) [30]... 

Caution No safety factor is included in this example calculation. Additional checkup must be done if the obtained value of the torque is not greater than the recommended makeup torque for tool joints. 

The heart of any drill pipe string is the threaded rotary shoulder connection (Figure 4-133), known as the tool joint. Today, the only API standard tool Joint is the weld-on Joint shown at the bottom of Figure 4-133. 

Tool Joint dimensions for drill pipe grades E, X, G and S (recommended by API) are given in Table 4-84. Selection of tool Joints should be discussed with the manufacturer. This is due to the fact that, up to the present time, there are no fully reliable formulas for calculating load capacity of tool Joints. It is recommended that a tool Joint be selected in such a manner that the torsional load capacity of the tool Joint and the drill pipe would be comparable. The decision can be based on data specified in Tables 4-85 through 4-88. 

The tool Joint holds drill pipe together, and the shoulders (similar to drill collars) form a metal-to-metal seal to avoid leakage. The tool Joint threads are designed to be made up with drilling fluid containing solids. Clearance must be provided at the crest and root of threads in order to accommodate these solids. Therefore, the shoulder is the only seal. To keep the shoulders together, proper makeup torque is required. 

However, makeup torque applied to the tool Joint produces as axial preloading in the pin and the box as well as a torsional stress. 

In particular, makeup torque induces a tensile state of stress within the pin and compression stress in the box. Thus, when the tool Joint is exposed to the additional axial load due to the weight of the drill string suspended below the Joint, the load capacity of the tool Joint is determined by the tensile strength of the pin. 

The magnitude of the makeup torque corresponding to the maximum load capacity of the tool Joint is called the recommended makeup torque. 

The API recommended makeup torque for different types of tool Joints and classes of drill pipe is given in Table 4-89. 

Tonlonal Yield Slienfth of the Tool Joint Baaed on Tensile Yiald Strength of the Pin and Compreuive Yield Siiength of the Box - Lowest Value Prevailing. 

DRILL PIPE DATA - TOOL JOINT ATTACHED Up et... 

If weight is of paramount importance, these connections can be supplied with a smaller O.D. or shorter tottg space on box and pin. or a combination of the two to afford mux-imum wei t reduction without uciincing safety in the joint. However, where posdble, the manufacturers recommend ordering the joints shown to obtain the maximum economical tool joint service. 

Other tool joint sizes to accommodate special situations can be fuinidied on request. 

Tensile Yield Strength of the Tool Joint Pin is based on 120,000 psi Yield and the Cross Sectional Area at the Root of the Thread S/8 inch from the Shoulder. 

Torsional Yield Strength of the Tool Joint Based on Tensile Yield Strength of the Pin and Compressive Yield Strength of the Box — Lowest Value Prevailing. 

DA(LL PIPE DATA NEW TOOL JOINT DATA PREMIUM CLASS CLASS2 CLASS3 ... 

D. of tool joints Shown for class 2 drill pipe are based on drill pipe having all the wear on one side and a minimum wall thicxnass of 65%. 

---