Horizontal Directional Drilling – A Quick Glance
Horizontal directional drilling is a type of directional drilling, or slant drilling, used to reach natural resources such as oil and natural gas. It’s an important tool in the constant search for the resources that provide our power.
Horizontal directional drilling, in fact directional drilling, wasn’t possible until people realized that wells aren’t only vertical. It took a long time for this to come to people’s attention. In 1920 lawsuits over drilling reaching over property lines brought this to oil industry’s attention. Many well surveys were conducted. In fact new tools for surveying had to be designed to survey while a well was being drilled.
It’s easy to measure how much a well is shifted from straight vertical. This is an important step in horizontal directional drilling. All it takes is a pendulum. But another measurement is needed. That is the direction of the well (or oil reservoir) from the vertical shaft. This was first done by measuring magnetic fields, but the metal drilling equipment could influence the fields. It was later found that gyroscopic compasses designed for aeronautical navigation could perform the needed measurements.
Other new techniques were needed before horizontal directional drilling was possible. Experience was gained in vertical drilling for drilling away from the vertical . It was something to be avoided in the past, but could now be put to use. Directional drillers eventually learned techniques to bring drilling back towards the vertical. Both were used in directional drilling for properly steering the drill.
A new advancement in the 1970’s was a major leap for horizontal directional drilling. Drills were designed that were mostly stationary, but had rotating drill bits driven by circulating mud down the drill shaft (or drill string.) This allowed on the fly direction shifts merely by adding pipes at the top.
They also had to find a way to determine the drill bit’s direction for horizontal directional drilling. This was MWD, or measurement while drilling. This refers to information about the direction of the drill bit.
Today there are tools to steer the bit in three dimensions for horizontal directional drilling. They cost a great deal so aren’t in wide use. But they make it possible to automate the drilling process. The price of these will rapidly decrease because larger companies have taken up the research of making cheaper versions that can actually be implemented.
So the quest for oil continues. Now, more and more, oil companies can get the oil wherever it is. That’s the whole point of horizontal directional drilling.
