Dogleg:

While a dogleg is sometimes created intentionally by directional drillers, the term also refers to a section of the hole that changes direction faster than anticipated or desired, usually with harmful side effects.

In surveying wellbore trajectories, a standard calculation of dogleg severity is made, usually expressed in two-dimensional degrees per 100 feet [degrees per 30 m] of wellbore length.

Generally, intentional doglegs are limited to 3-3.5 degrees/ 30m.

Higher doglegs may create problems , such as key seating or damage to the drillstring.

Terms Related to Dogleg

• Crooked hole

  A wellbore drilled in excess of the maximum allowable dogleg.

• Directional drilling

  1. Intentional deviation of a wellbore from the vertical. Although wellbores are normally drilled vertically, it is sometimes necessary or advantageous to drill at an ...

• Azimuth

  (az) the compass direction of a directional survey or of the wellbore as planned or measured by a directional survey. The azimuth is usually specified ...

• Swab

  To reduce pressure in a wellbore by moving pipe, wireline tools or rubber-cupped seals up the wellbore. If the pressure is reduced sufficiently, reservoir fluids may ...

• Deflection

  A change in the angle of a wellbore. In directional drilling, it is measured in degrees from the vertical

• Dls

  Abbr. Dogleg severity

• Drift angle

  The angle at which a wellbore deviates from the vertical, expressed in degrees, as revealed by a directional survey. Also called angle of deviation, angle ...