Directional drilling maps are flat, but the Earth is an oblate spheroid. This leads to a challenge to accurately represent the wellbore position on the Earth on a piece of paper. In this section, you will learn about mapping techniques used in directional drilling, limitations and the errors of mapping techniques.
One of the most important concepts of mapping is latitude and longitude.
Latitude is a coordinate used to specify the north-south position of a location on the surface of the Earth. Latitude is an angle which starts from 0° at the equator to 90° at the Earth North-South poles. It is simply defined like this;
- 0 ° at the equator
- +90 ° at the North pole
- -90 ° at the South pole
To define latitude, it is described in degrees, minutes and seconds. Parallel line of latitude is a small circle at particular latitude which is parallel with the Equator.
Figure 1 – Latitude and Longitude Diagram
