In this article, we will show you how to calculate weight of casing or conductor in lb/ft based on known value of pipe OD and ID. When working in drilling operations, accurately knowing the weight of the casing or conductor pipe is essential for ensuring safety and efficiency. This weight is typically measured in pounds per foot (lb/ft). While standard specifications provide this information, there are instances when you only have access to the pipe’s outer diameter (OD) and inner diameter (ID). In such cases, you can calculate the weight using a straightforward formula.

**The Formula for Calculating Pipe Weight**

To calculate the weight of the casing or conductor pipe per unit length (lb/ft) based on the pipe’s outside and inside diameters, you can use the following formula:

$Pipe weight (lb/ft)=9.4248×(OD²−ID²)×Carbon Steel Density (lb/in³)$Where:

OD= Outside diameter of the pipe (in inches)

ID= Inside diameter of the pipe (in inches)

Carbon Steel Density (lb/in³)= Density of the steel used in the pipe, typically around 0.282 to 0.291 lb/in³

This formula accounts for the pipe’s cross-sectional area and the density of the carbon steel material to estimate the pipe weight per foot. This is not suitable for drill pipe or heavy weight drill pipe which has tool joints.

### Understanding the Components of the Formula

**9.4248**: This constant converts the result into lb/ft.**(OD² – ID²)**: Represents the difference in the cross-sectional area between the outside and inside of the pipe.**Carbon Steel Density**: Pure carbon steel generally has a density of around 7.8 g/cm³, which translates to approximately 0.284 lb/in³. However, due to variations in alloying elements, the density can range from 0.282 to 0.291 lb/in³. For practical calculations, using a density value of 0.288 to 0.291 lb/in³ provides a reliable estimate.

**Example Calculation**

Let’s illustrate this with an example:

**Pipe OD**= 7 inches**Pipe ID**= 6.184 inches**Carbon Steel Density**= 0.288 lb/in³ (for this calculation)

**Applying the formula:**

**Pipe weight (lb/ft)=9.4248×(7²−6.184²)×0.288**

The estimated pipe weight is 30 lb/ft.

**Practical Use of This Calculation**

This formula is invaluable when you need to quickly estimate the weight of casing or conductor pipe but don’t have detailed specifications on hand. For instance, if you’re working on-site and need to confirm transportation requirements, this calculation helps you plan efficiently. It’s also helpful when designing drilling programs or planning lifting operations, as accurate pipe weights are critical for safety. By understanding and applying this formula, you can ensure accurate weight estimations, leading to safer and more efficient drilling operations.