Horizontal or directional drilling is it transforming the oil and gas industry. Here is more about this exciting new technology.
Horizontal or Directional drilling refers to a new type of technology that oil and gas companies are using to drill at an angle or sideways across a zone of rock that bears oil or natural gas thousands of feet below the surface.
In the past the only way to extract crude oil or natural gas from the ground was to find a pocket or gas or oil trapped beneath the surface and drill a vertical hole down through it. Once the hole had been drilled the oil company would then set a steel pipe called casing in the hole to protect it from cave-in and then send down a device called a perforating gun to pierce holes in the steel casing at the depth where oil or gas occurred.
The disadvantage of this process was that only so many feet of sandstone or other oil – gas bearing rock could be penetrated and therefore only a limited quantity could flow out from the holes that were pierced in the casing.
This meant that many low porosity oil and gas formations were barely productive. Only a few barrels of oil or a few hundred cubic feet of natural gas could flow into the well each day through the perforations and if the quantity was too small the well, which often cost several million dollars to drill, would not be profitable and have to be abandoned.
Then along came the technology of directional or horizontal drilling.
How It Works
What makes horizontal drilling work are actually several relatively new complimentary technologies. First is the issue of how to make the well deviate, or depart from a vertical position. For many years the only way to do this was an angled metal device placed in the oil well’s casing called a whipstock. Using a diamond, metal cutting drill bit a hole was drilled in the casing and then a regular rock bit was used to drill the well out sideways into the oil or gas bearing rock, up to a few hundred feet.
This enabled more of the rock formation to be penetrated and therefore more oil and gas to flow into the well. The disadvantages of this system was that it only worked out to a couple hundred feet, since there was no way to control what direction the drill bit was going, and it became hard to turn the drill pipe all the way from the surface once it reached a certain angle.