Directional drilling (or slant drilling) is the practice of drilling non-vertical bores. It can be broken down into four main groups: oilfield directional drilling, utility installation directional drilling, directional boring (horizontal directional drilling - HDD), and surface in seam (SIS), which horizontally intersects a vertical bore target to extract coal bed methane.. HistoryMany prerequisites enabled this suite of technologies to become productive. Probably, the first requirement was the realization that , or , do not necessarily need to be vertical. This realization. .
Wells are drilled directionally for several purposes: • Increasing the exposed section length through the reservoir by drilling through the reservoir at an angle.• Drilling into the reservoir w.
[pdf] 
A down-the-hole drill, usually called DTH by most professionals, is basically a jackhammer screwed on the bottom of a drill string. The fast hammer action breaks hard rock into small cuttings and dust that are evacuated by a fluid (air, water or drilling mud). The DTH hammer is one of the fastest ways to drill. .
DTH is short for “down-the-hole”. Since the DTH method was originally developed to drill large-diameter holes downwards in surface-drilling. .
A is first thought to have been used for rock drilling in 1844. Many quarries used hand held tools that required the driller to suspend himself from a rope over the. .
In DTH drilling, the percussion mechanism – commonly called the hammer – is located directly above the drill bit. The drill pipes transmit the necessary feed force and rotation to the hammer and the bit, along with the fluid (air, water or drilling mud) used to. .
DTH products can be used in the following applications:• Mining- drill and blast holes in open pit mining, where the drill operator will drill several holes, then.
[pdf] Before spending the time and energy adding drainage to an existing retaining wall, make sure the wall is worth saving. If the wall is leaning out or there are cracks in the concrete, these could be signs of irr. These openings, known as weep holes, play a crucial role. They facilitate the drainage of trapped water behind the wall, helping to avoid excessive pressure that might cause cracks or even structural failure. Without these holes, water can accumulate and gradually weaken the wall.
[pdf] 
