Seismic vibrators bounce soundwaves underground. The echo helps locate crude oil.
STEVE AUSTIN | 2009/10/08
Many of us are aware of the value of oil and very aware of the oil price rise. Oil drills and oil exploration float to mind every time the oil prices go north. But are we aware of the process behind the hydrocarbon reaching the surface? Here it is:
It starts with a company obtaining licence to explore oil in a specified area which could be sea, land, forest or ice.
The first thing the company strives to do is create a comprehensive picture of area above and below the oil. So, the first step is survey.
The company may use Aerial survey: Aerial photographs and satellite pictures to get the data. Magnetic survey: establish the force of gravity. Seismic survey: detailed analysis of the underlying rocks using sound. Then the exploration process:
Shock waves are sent into the ground using vibrator trucks, and the time taken for the reflection of the sound is calculated using devices called geophones. Earlier dynamite charges were used in place of the vibrator trucks to collect the data, but the use has been banned for environmental reasons.
The data collected from the geophones called geophone data are converted into seismic lines by modern computers. These data are used by the geologist to create a 3-D computer model of the dynamics and geometries of the rocks below the earth. Geophysicist help interpret the seismic data to create a detailed picture of the under rock/undersea. Now the geologist and geophysics work together to establish the precise location of oil site to drill the holes.
After this comes the drill for oil. Drilling is a very expensive operation but is the best way to find oil. This is the stage when theory is put to practical test. The drill helps understand the composition of the rocks and the fluid present in the rocks. This information called well logs help data interpretation and the crucial decision of whether to continue the exploration or abandon it.
Even with all the modern tools, oil exploration has a high failure rate, and hence oil producers look to expand existing wells as it is more cost effective. But nothing beats the discovery of an oil rich well, luck favoured.
Next time you go to fill gas, you'll know how it came to be there. Won't you?
Published on 2009/10/08 by STEVE AUSTIN