Definition - What does Deviation mean?
Deviation, also known as a deviation angle is used to refer to the inclination of a wellbore. It is basically an angle at which an oil well divagates from the vertical. Since all wells have a tendency to bend due to the cracks and dips in the rock formation, the deviation helps engineers to plan further actions. When drilling an oil well, the well can be deviated at a certain angle by using the different mechanisms such as whipstock. The deviation angle can be set to horizontal so as to get maximum exposure to the oil and gas producing zones inside the formation.
Petropedia explains Deviation
Deviation is a term which refers to the inclination of an oil well from a vertical position. Drilling engineers conduct deviation surveys to find out the deviation, i.e., the deviation angle that determines how far an oil well is leaning from the vertical position. To get the maximum exposure to the production zones in an oil reservoir, the well can be easily deviated in a horizontal direction. Different kinds of mechanisms, such as whipstock, steerable motors and even turbines are used for deviation in complex rock formations in an oil well.