Extraction of Oil and Gas processes
HOW TO GET OIL AND GAS OUT OF THE GROUND?
For many years, the most widely used technique for getting petroleum out of the ground has been the vertical well. This process is simple. First of all, a motor turns a drill bit with special teeth that can crush or break up rock to make a hole in the ground. Then, a liquid called drilling mud is pumped down the well. This carries small bits of rock or cuttings to surface, equalizes pressure, and prevents water from flowing into the well. The drill bit will then continue to drill until it has reached the required depth.
Often, wells will not encounter hydrocarbons, these are called dry holes or dusters. Likewise, some will encounter negligible quantities of hydrocarbons that are not commercial for extraction. This is always met with understandable frustration from oil companies because wells cost millions to drill. If a successful number of hydrocarbons do flow to the surface, then a firm will place a casing of concrete well into the newly drilled hole, this makes it stronger. Holes are then drilled in the casting to let in the oil. After removing the drill rig, the operator will place a pump on the wellhead, this will connect to an electric motor that forces the pump up and down to create suction that draws up the oil. The fluids recovered from a well are usually a mixture of oil, gas, and water. These must separate after coming to the surface. A well will remain in production until its accessed reservoir is exhausted. During this period, it will be subjected to ongoing maintenance checks.
The recoverable hydrocarbons in a reservoir depend on rock properties, technology and technique. Obviously, rock properties cannot change. However, the methods for identifying pools have improved, and drilling methods have advanced. This has made it easier and cheaper to access oil in a previously uneconomic well.
Perhaps the best example of this progress is horizontal drilling. This involves drilling vertically then turning 90 degrees and drilling horizontally. By ‘sucking up’ oil from a much greater area, horizontal areas require the drilling of far fewer wells. They can also get into inaccessible areas in the spacing between vertical wells. What’s more, they enable operators to drill several miles away from the reservoir they have identified. This grants them access to hydrocarbons in sensitive above-ground areas. Companies often combine horizontal drilling with a technique called hydraulic fracturing, or ‘fracking’. This involves blasting impermeable rock with a mixture of water and sand. The mixture expands and holds open existing cracks to allow the flow of newly-exposed hydrocarbons.
As this piece shows, the evolution of technology is one of the most important factors when investing in oil and gas companies. This is because any technological advantage can help to give a business a competitive advantage.