Finding Where to Drill

• Geophysicists use satellite images to find oil deposits.Photodisc/Photodisc/Getty Images
  
  In the TV show "The Beverly Hillbillies," Uncle Jed found oil in much the same way people had for thousands of years --- seeping out of the ground. In modern world, oil isn't so easy to find. Oil companies utilize highly trained geologists, geophysicists, computers and satellites to look for new sources of oil. Geologists look for rocks that contain traces of hydrocarbons. Aerial and satellite photograph images are carefully studied to find likely places to drill. The geologists take samples of the rocks to determine the age and geological strata of the samples. To further determine the presence of oil, geophysicists use seismic waves and sensors that measure the strength of the Earth's magnetic field in the area, according to the Society of Exploration Geophysicists. The data produced by these devices helps the geophysicists get a better picture of what the geology of the area is. Because oil-drilling projects are extremely expensive, the data are studied carefully to determine whether to drill an exploratory well.
  
  

Exploration Oil Drilling

• The large and independent oil companies are constantly exploring for new oil deposits. An exploratory well is drilled using mobile equipment that drills down into the earth. Samples of the rock are tested for oil content under a black light in a process called mud logging. All the equipment needed for the exploration drilling is trucked in and assembled to make a temporary drilling platform. Diesel engines turn a drill shaft equipped with diamond rotary drill bits to make the borehole, and mud and water are pumped into the shaft to keep the bit cool and maintain the pressure in the bore hole. Because this process can take several months, living and canteen facilities are constructed on site, according to E-tech International.
  
  

Offshore Drilling

• Offshore oil rigs operate in shallow and deep water.Jupiterimages/liquidlibrary/Getty Images
  
  Much of the oil in use today comes from offshore drilling projects. Areas like the North Sea in the Gulf of Mexico hold large deposits of petroleum beneath the seabed. Some offshore wells are relatively shallow, but others are tapping deposits several miles beneath the ocean floor. Submersible drilling rigs are used in waters shallower than 80 feet in depth. The rig is towed out to the drill site, and then submerged until it rests on the seafloor. Semi-submersible drill rigs and drill ships can operate in deeper waters.
  
  

Through Tubing Rotary Drilling

• Advanced oil-drilling technology is providing methods to make existing and older oil wells more productive. Through tubing rotary drilling is a technology for sidetrack drilling from an existing bore shaft. An oil-drilling project of this type involves going down through the existing tube to a specific depth, then drilling sideways through the shaft tubing and attaching a device known as a whip stop. After the whip stop is attached, a sideways shaft can be drilled into the reservoir to pump oil up through the existing piping. This can be very beneficial in offshore oil production, because more oil can be pumped without the added cost of building another platform.