Vertical Curvature for Deviated Well
Deviated well drilling vertical curvature is the measure of how the wellbore deviates or bends in the vertical plane, typically from the surface towards the target formation. Deviated wells, which are not drilled vertically, require careful planning and measurement of both the horizontal and vertical deviations to ensure they follow the planned trajectory and reach the desired subsurface target. Here are some key aspects of vertical curvature in deviated wells:
Trajectory Control - Vertical curvature helps in defining how the wellbore moves from the vertical to its intended angle (build-up or drop-off sections). It ensures the wellbore follows a smooth trajectory.
Dogleg Severity (DLS) - The rate of change in the wellbore's angle (measured in degrees per 100 feet or meters) in any plane, including the vertical one, is critical to control stresses on the drilling equipment. High dogleg severity can cause problems like equipment failure or increased wear on drilling tools.
Build and Drop Rates - These are terms used to describe the vertical curvature during drilling. Build rate refers to increasing the angle of deviation, while drop rate refers to reducing the angle, returning the well closer to vertical.
Surveying and Measurement - Regular directional surveys are performed during drilling to monitor the vertical curvature and adjust the well's path as needed. These surveys use tools like inclinometers, magnetometers, or gyroscopic systems to measure the wellbore inclination and azimuth.
Vertical curvature is an essential part of ensuring a successful well trajectory, minimizing drilling risk, and optimizing the well's production potential.
Vertical Curvature for Deviated Well formula |
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| \( VC \;=\; ( I_d - I_o ) \; (100 \;/\; \partial L) \) | ||
| Symbol | English | Metric |
| \( VC \) = Vertical Curvature for Deviated Well | \(deg\;/\; ft\) | - |
| \( I_d \) = Desired Hole Inclination | \(deg\) | - |
| \( I_o \) = Original Hole Inclination | \(deg\) | - |
| \( \partial L \) = Course Length (Infinitesimal Change) | \(ft\) | - |
Tags: Drilling Drill Pipe