
Oil, gas and coal are fossil fuels that are essential to our every day living. Our vehicles, electricity, products manufactured, food consumed and even the homes we live in depend on these fuels. Without them we would not have electricity, lighting, transport or even the communication networks we do today. Accessing oil, gas and coal reserves requires drilling into the earth to access the natural reserves in the ground. Directional drilling is the term for well drilling that follows a non-vertical direction. A well to access gas, oil or coal is dug that is intended to meet up with a reserve that is not directly underneath the surface drill site. It is considered better practice to drill in this manner for environmental and financial reasons. Directional drilling is commonly used in off shore drilling rigs. These types of drills are considered more cost effective than traditional horizontal drilling due to the ability to access further reserves without needing to install more wells. It also reduces risks associated with larger numbers of drill rigs in a small area such as damaging sensitive environmental areas or even contaminating ground water reserves.
Typically, directional drilling uses one central well pad with a number of different wells drilled off this at different directions. Well sites can be placed at a significant distance from the reserves, housing, farms and from sensitive ecological sites. In addition, this kind of drilling enables access to otherwise inaccessible spots such as reserves underneath protected areas such as lakes, environmentally sensitive regions and even cities or towns. This manner has been found to reduce the disturbance of the surface and reduces the number of central well pads required to drain oil or gas reserves.
According to the United States Environmental Protection Authority (USEPA), the four major directional drilling techniques are short, medium, long and in-mine. These differ depending on the drilling method used and the distance drilled. Short drilling is limited to 1500ft (450m) and is characterized by a curved drill guide and flexible drill pipe. Medium drilling has a larger drill radius than short directional drilling, up to 500 ft (150m) yet has the same length limit. Medium also has the advantage of being able to use conventional drilling technology with a steerable compressive drill pipe. Long directional drilling has a drill radius of up to 2800ft (850m) and can reach lengths of over 1500 ft. Conventional directional drilling equipment can be used with horizontal drilling not able to be done until a distance of over 4400ft (1300m) is reached. In-mine drilling reaches a distance of over 5000ft (1500m) and makes use of existing underground drilling technology that have position systems and steerable motors.
A single surface site allows for a number of different wells to feed of the main drill rig which significantly reduces the environmental impact that drills have. In addition, the cost of installing a number of different rigs at the surface to access the reserves does not have to be done, meaning there is a reduction in the number of workers required to man the rig and drills. Visit UEA for more information about directional drilling.










