Directional Drilling School

In this section, you'll find a downloadable BUR Chart, a practical tool designed to support your daily work as a Directional Driller. This chart helps you estimate the build-up rate based on motor size, hole size, and stabilizer setup—making BHA design faster, more accurate, and aligned with your planned trajectory.

Build-Up Rate (BUR) Chart – What It Is and How to Use It

The Build-Up Rate (BUR) Chart, also known as the Motor Output Chart, shows the maximum angle-building capability of a motor BHA when sliding (or orienting). This chart is extremely useful for Directional Drillers to select the right BHA design for a specific well trajectory.

Why Is It Important?

Experienced Directional Drillers with years of fieldwork often develop a sense of how much angle a certain motor BHA can build. They rely on memory and past experience with combinations of:

• Bent housing angle

• Stabilizer setup

• Hole size and bit size

However, this approach only works well with familiar setups.

To reduce guesswork and improve accuracy, the BUR Chart provides a calculated reference based on:

• Motor size

• Hole size

• Number and type of stabilizers (sleeve or string)

• Stabilizer size

It gives a more realistic estimation of a BHA's ability to achieve the planned well trajectory and helps avoid designing a BHA that underperforms or fails to meet trajectory requirements.

While not a guarantee of success, this chart has been successfully used across Asia, the Middle East, and Australia, proving to be a practical guide in BHA planning.

What’s in This Book?

This book includes BUR charts for the most commonly used motor sizes in directional drilling:

• 4.75"

• 6.5"

• 6.75"

• 8.00"

• 9.625"

Each motor size is further broken down based on:

• Hole size

• Number of stabilizers

• Stabilizer types and sizes

How to Read the Chart

• The Y-axis represents the bent angle set on the motor.

• The X-axis shows the expected BUR (degrees/30 m).

• To find the BUR for a specific bent angle:

  1. Start with your desired bent angle on the Y-axis.

  2. Draw a horizontal line until it intersects the red curve on the chart.

  3. From that point, draw a vertical line down to the X-axis.

  4. The point where it meets the X-axis is your estimated BUR.

This simple process helps Directional Drillers make more informed decisions when designing the BHA to match the planned trajectory.

This is a powerful set of Directional Driller Interview Questions and Answers — an essential refresher for DDs at any level preparing for technical interviews.