Horizontal Directional Drilling
Definition - What does Horizontal Directional Drilling mean?
Horizontal Directional Drilling is the science of drilling a wellbore at a predetermined well trajectory, angle and horizontal direction so as to intersect a subsurface target. Although wellbores are usually drilled in a vertical direction, at times it is advantageous to drill them at an angle from the vertical direction. The well is drilled at a certain deviation in a horizontal direction from the vertical direction.
Petropedia explains Horizontal Directional Drilling
In Horizontal Directional Drilling (HDD), the well is drilled such that the deviation of the borehole is 90 degrees from the vertical and it looks horizontal or parallel to the formation from an elevation view. Sometimes a deviation greater than 80 degrees is also considered as horizontal in drilling terminology. Some of the advantages associated with HDD are as follows:
- Longer horizontal drain hole increases the exposure of the pay zone.
- Allows high production rates at lower drawdown (less coning).
- Naturally fractured reservoirs can be intersected effectively with HDD
- Helps in reducing vertical drilling.
- Thick oil or tight reservoirs can be easily made productive with HDD.