Oil Exploration and Drilling - How is Oil Found?
Oil Exploration and Drilling
How is it they are able to find oil? What mechanical or scientific methods do they employ? These are questions that I have had, but never pursued the answer till now. I tried to find some basic answers to these questions which you can read here. I am going to keep this as simple as possible so I don't overload my brain.
In the beginning
Oil has been in use since ancient times. It had been found flowing from the ground and was used first for medical purposes. It was later used for building then found to be useful as a fuel source.
In 347AD, the Chinese are supposed to have drilled holes in ground using bamboo to extract oil. Marco Polo had recorded visiting the Persian city of Baku, on the shores of the Caspian Sea in modern Azerbaijan, he saw oil being collected from seeps for use in medicine and lighting..
Marco Polo had reported seeing oil being collected from pools seeping out of the ground while in Persia.
Pictured is an ancient Roman oil lamp.
Modern method of finding oil
Oil accumulates between layers of the subsurface or in porous rock among other things. So the job is to find the right convergence that would be necessary to form an oil pool.
Geologist can study aerial photographs and images from satellites to find data that would indicate possible locations to explore.
There was a time that the oil wells were just drilled in random locations or around established oil wells. These were called Wildcat Wells.
A newer method of locating oil is to use Vibrator or Thumper trucks to cause vibrations in the earth which are listened to by geophones. The data is processed by computers into dimensional displays that are seismic lines. This data is studied by the geologist to determine locations where oil may be found.
When a likely location is found, then the drilling is done. After the well has been drilled, a measuring device is lowered into the hole and information is gathered about the properties of the earth such as density, type of rock present and what fluids the rocks may contain.
If the hole looks promising, then the drilling for oil process continues. If its not a good location, then the hole is filled and they move on.
Finding oil underwater
The same principles for finding oil underwater are the same as finding it on land. In this case a ship is used which shoots compressed air into the water to create the vibrations somewhat like the Vibration trucks would produce. The ship trails hydrophones behind them. There could be up to 3000 hydrophones on a 3000 meter cable.
- How gas is made
Ever wonder how gas is made? Here is a brief run down on how crude oil is made into gas. Watch the Video of a refinery in Pennsylvania that gives you a walk through tour.
Setting up the oil rig
When a site has been selected for further drilling, the oil company must go through its legal channels to make sure they can drill legaly at that location. Once that's done, they must clear the area and level it, build access roads and drill a well for water if no other source is available.
A hole called a celler is dug at the location of the drilling hole. The workers then start drilling the hole most likely with a drill on a truck. The first hole is lined with a large-diameter conductor pipe. Other hole are drilled to use for storage of equipment. When this is completed, the rig equipment is then set up.
Once the rig is set up, they drill to a pre-set depth which is above where they think the oil is. Casing pipes are put into the holes and cemented to prevent the hole from collapsing.
When they reach the depth they are going for, they lower a perforating gun into the hole which will blow holes into the casing to allow the oil to flow in. A smaller diameter pipe is run into the well to allow a method to retrieve the oil.
When the oil is flowing, the oil rig is removed and the production equipment is set up. The production equipment will extract the oil from the well.