This type of drilling is based on the shape of the hole created or formed in the drilling operations are conducted. Based on the shape of the hole, drilling can be divided into:
- Drilling upright (straight hole drilling / vertical drilling)
- Directional drilling (directional and horizontal drilling)
1. Drilling Straight.
Drilling is also called the straight vertical drilling or Straight Hole Drilling. This means that drilling is done from the point of location on the surface, the hole is maintained vertically straight up to the target point. Digolongan drilling in drilling the straight hole drilling, is if it fulfills the requirements as shown below (shown in Figure 3.6.):
- Drilling is still in a cone with angle of 5 o, to an altitude of 10,000 ft cone. This cone is formed from the starting point on the surface to a depth of drilling to 10,000 ft with a slope cones at 5 0. During a hole formed in the drilling operation carried still is within the cone is then this drilling included drilling straight / vertical / straight hole
- Holes may be banked, the origin dog leg maximum is 3 ° per 100 ft. In fact the hole could not be maintained as possible, this is due to the condition of the rock layers that have different properties that would affect the condition of the borehole. So that the drill holes will be slightly banked or often called the dog-leg. This is allowed as long as pembelokannya not exceed 3 0 per 100 ft and addresses on the cone as described above.
If the pit is made into the cone-like Figure 3.6, the type of drilling including a group of straight hole drilling. If the dog legnya smaller than 3 ° / 100 ft, but the pit exit cone like Figure 3.6, then this type of drilling is no longer belong to a group of straight hole drilling.
Figure 3.6. Straight Hole Drilling
2. or Horizontal Directional Drilling.
In drilling a formation, always expected drilling with a hole straight / vertical, for drilling a hole straight / vertical addition to the operation easier, also generally cost becomes cheaper. However, due to certain conditions, drilling straight / vertical can not be done by drilling are therefore likely to be directed according to those conditions.
Drilling is done by directing the holes commonly called the drilling directional or horizontal drilling (and Horizontal Directional Drilling). Some of the factors that cause or horizontal directional drilling done (and Horizontal Directional Drilling) is geography, geology and economic considerations.