To drill and test oil, drilling rigs are the primary equipment to be used. After some research and survey conducted on the site by geologists, and the site is declared as a great potential of oil production, permission to drill will be processed by the oil company. The geologists will predict the location of the oil trap. Once all necessary paperwork is accomplished, the drilling system is set up, and the crew shall start the drilling operation. The depths will be pre-set by the crew and a starter hole is drilled to the surface hole.
Drilling the Surface Hole
You begin by placing the drill bit in the collar and drill pipe in the hole. With the kelly attached to the turntable, drilling starts. Mud is circulated through the pipe and out of the bit as drilling continues. This is to allow the rock cuttings to float out of the hole and not hinder the operation.
As the hole gets deeper, new sections or joints are added to the drill pipes. Finally, when the pre-set depth is reached, the drill pipe, the collar, and the drill bit are removed or tripped out. The depth for drilling oil is normally between a few hundred and a couple-thousand feet deep. The crew will then cement the casing by placing steel pipes into the hole to prevent it from moving and collapsing.
When the rock cuttings from the mud show the oil sand, it would mean that the final depth is reached. Then, the crew will remove the drilling apparatus from the hole. To confirm that they have drilled on the right area, further tests will be conducted.
The next step is logging. Electrical and gas sensors are lowered into the hole, and the rock formations in the spot drilled are then measured. Another test is the drill-stem testing, which involves measure the pressures, using a special device that shows whether the reservoir rock has been reached. The characteristics of the reservoir rock will also be analyzed by taking samples of them.
The crew will then complete the well, allowing oil to flow in a controlled way into the casing. Acid is usually pumped down the well to help the flow. The oil company must follow and implement new drilling techniques to ensure that the operation is done accurately and appropriately, without damaging the environment. After the oil has flowed, the oilrig is removed from the site. Then to extract the oil from the well, the crew will set up the production equipment.
Efforts have been made by the oil industry to drill oil with new drilling technologies such as horizontal drilling techniques. Using lasers to drill, this technique is implemented specifically to reach oil under ecologically-sensitive areas.