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Selecting the right drill pipe requires more than checking its outside diameter. Pipe size, nominal weight, wall thickness, steel grade, tool joint connection, upset type and length all affect drilling performance and compatibility.
This guide introduces commonly used oilfield drill pipe specifications, including API 5DP size references, steel grades, dimensional terminology and ordering considerations. Use it as a starting point when comparing drill pipe options for your drilling operation.
Drill pipe is a hollow, high-strength steel tubular used to transmit drilling torque, circulate drilling fluid and connect the surface drilling system with the bottom hole assembly.
A complete drill pipe specification normally identifies the pipe body dimensions, nominal weight, steel grade, connection type, upset style and required length. These details should be considered together rather than selecting a pipe by outside diameter alone.
Outside diameter, inside diameter and wall thickness determine the basic dimensional characteristics of the pipe body.
E75, X95, G105 and S135 are commonly specified drill pipe grades. Grade selection depends on the required mechanical properties and drilling conditions.
Tool joint dimensions and rotary-shouldered connections must match the drilling string and the required connection standard.
The following table provides representative commonly used drill pipe body sizes and nominal weight references. Actual configurations should be confirmed against the applicable API 5DP edition, manufacturer specifications and purchase requirements.
| Nominal Pipe Size (in) | Nominal Weight (lb/ft) | Pipe Body OD (mm) | Reference Wall Thickness (mm) | Common Grade Options |
|---|---|---|---|---|
| 2 3/8 | 6.65 | 60.33 | 7.11 | E75 / X95 |
| 2 7/8 | 10.40 | 73.03 | 9.19 | E75 / X95 / G105 |
| 3 1/2 | 9.50 | 88.90 | 6.45 | E75 / X95 / G105 |
| 3 1/2 | 13.30 | 88.90 | 9.35 | E75 / X95 / G105 / S135 |
| 3 1/2 | 15.50 | 88.90 | 11.40 | E75 / X95 / G105 / S135 |
| 4 | 14.00 | 101.60 | 8.38 | E75 / X95 / G105 / S135 |
| 4 1/2 | 16.60 | 114.30 | 8.56 | E75 / X95 / G105 / S135 |
| 4 1/2 | 20.00 | 114.30 | 10.92 | E75 / X95 / G105 / S135 |
| 5 | 19.50 | 127.00 | 9.19 | E75 / X95 / G105 / S135 |
| 5 | 25.60 | 127.00 | 12.70 | E75 / X95 / G105 / S135 |
| 5 1/2 | 21.90 | 139.70 | 9.17 | E75 / X95 / G105 / S135 |
| 5 1/2 | 24.70 | 139.70 | 10.54 | E75 / X95 / G105 / S135 |
| 5 7/8 | 23.40 | 149.23 | 9.17 | E75 / X95 / G105 / S135 |
| 6 5/8 | 25.20 | 168.28 | 8.38 | E75 / X95 / G105 / S135 |
| 6 5/8 | 27.70 | 168.28 | 9.19 | E75 / X95 / G105 / S135 |
Drill pipe is available in several steel grades with different minimum yield strength requirements. The appropriate grade depends on the tensile and torsional loads, well depth, drilling environment and operating conditions.
| Steel Grade | Minimum Yield Strength | Minimum Tensile Strength | Typical Selection Consideration |
|---|---|---|---|
| E75 | 75 ksi / 517 MPa | 100 ksi / 689 MPa | Conventional drilling applications |
| X95 | 95 ksi / 655 MPa | 105 ksi / 724 MPa | Higher strength requirements than E75 |
| G105 | 105 ksi / 724 MPa | 115 ksi / 793 MPa | Higher-load drilling strings |
| S135 | 135 ksi / 931 MPa | 145 ksi / 1000 MPa | High-strength drilling applications |
The tool joint connects individual drill pipe sections and transfers torque through the drill string. Connection selection must consider thread type, pin and box dimensions, shoulder geometry, make-up requirements and compatibility with the existing drilling equipment.
Numbered connections are widely used rotary-shouldered connections. The correct NC size must be selected according to the required connection dimensions and application.
Internal Flush connections are used in certain drilling string configurations. Verify compatibility before matching replacement pipe with existing equipment.
Full Hole connections are another commonly encountered connection family. Exact connection dimensions and thread specifications should be confirmed during procurement.
For rotary-shouldered connection requirements, refer to the applicable API standards and confirm the required connection specification with your supplier.
The pipe-end upset provides additional material at the pipe ends to support the tool joint connection and the required load transfer. Common upset configurations include:
The internal diameter is reduced at the upset section. This configuration provides additional material at the pipe end while maintaining the outside profile.
The outside diameter increases at the upset section. This configuration adds material around the pipe end while maintaining the internal profile.
Both the internal and external profiles change at the pipe end. This configuration is selected according to the required pipe-end and connection design.
Drill pipe is supplied in different length ranges. The required range should be specified when preparing a purchase order. Actual available lengths and acceptance tolerances depend on the applicable standard and order requirements.
| Length Range | Common Reference Length | Metric Reference | Ordering Consideration |
|---|---|---|---|
| Range 1 (R1) | 18–22 ft | 5.5–6.7 m | Shorter drill pipe sections |
| Range 2 (R2) | 27–30 ft | 8.2–9.1 m | Common drilling string length range |
| Range 3 (R3) | 38–45 ft | 11.6–13.7 m | Longer drill pipe sections |
Length ranges shown above are general reference ranges. Confirm the applicable API requirements and actual ordered length tolerances before finalizing specifications.
A suitable drill pipe configuration should match the drilling equipment, well conditions and required operating loads. Before requesting a quotation, prepare the following information:
Drill pipe quality evaluation should cover the pipe body, tool joints, weld area, dimensions and required mechanical properties. Inspection requirements should be agreed upon before production and shipment.
Review material identification and the relevant material documentation against the purchase specification.
Check pipe body dimensions, wall thickness, length and specified tool joint dimensions.
Apply the specified inspection methods to the relevant areas according to the agreed inspection requirements.
Verify the required mechanical properties in accordance with the applicable material and product specification.
Inspect thread condition and connection dimensions against the required connection specification.
Confirm the required inspection records, test reports and product documentation for the order.
Explore more information about drill pipe selection and our available product categories.
API Specification 5DP is a key product specification for drill pipe. The applicable edition and any relevant addenda should be confirmed for each order.
Commonly specified grades include E75, X95, G105 and S135. Each grade has different minimum mechanical-property requirements and should be selected according to the drilling application.
Pipe body OD refers to the outside diameter of the tubular pipe body. Tool joint OD refers to the outside diameter of the connection component at the pipe end. They are different dimensions and should not be used interchangeably.
Consider the required pipe body dimensions, wall thickness, steel grade, drilling loads and compatibility with the existing drill string. Confirm the complete configuration rather than selecting by nominal weight alone.
Connection options depend on the pipe size, tool joint configuration and order requirements. Provide the exact connection designation or a drawing when requesting a quote.
Provide pipe size, nominal weight, steel grade, connection, upset type, length range, quantity and any inspection or documentation requirements.
Send us your required pipe size, steel grade, nominal weight, tool joint connection and quantity. Our team can review your requirements and discuss a suitable drill pipe configuration.
