Posted on: 7 November 2014Share
Oil drilling is one of the most essential industries in the global economy. Ever since the first commercial oil well was drilled in 1859 in Venago County, Pennsylvania, technology has been advancing to make oil drilling safer and more efficient. Here is an explanation of four modern oil drilling methods that are in use today.
Horizontal drilling is a type of directional drilling that aims to access oil reserves with minimal impact on the surrounding environment. Horizontal drilling starts with a vertical rig, but the well is made to angle sharply horizontal once it is within the resource work. The horizontal extension from the vertical well can reach more than a mile away from the location of the vertical rig.
Because the bit must travel along a very narrow path to reach the oil once it is at an appropriate depth, advanced real-time technology is usually used to monitor the drill bit. To precipitate the drainage of the oil out of its resource rock and into the coiled tubing, a technique known as steam assisted gravity drainage is sometimes used. In this method, there are two wellbores reaching into the oil cavern, one above the other. The top wellbore emits steam that forces oil to flow into the tubing of the lower bore.
Slant drilling is the other form of directional drilling. Slant drilling is occasionally known as extended reach drilling because it can reach oil resources that are even further from the rig than horizontal drilling can. This is because instead of drilling straight down, the bore is angled 30 to 45 degrees outward in the direction of the oil deposit, reducing the amount of tubing that is required.
Slant drilling is the best method for reaching oil that is underneath areas where a vertical rig is impossible to install. Some examples include developed areas and lakes. Slant wells can reach up to five miles away from the surface perforation, and multiple bores can extend from a single rig to minimize surface disturbance.
In oil-rich areas, drillers will occasionally find that there are several oil deposits at different depths that they need to access. Installing a new rig for each of these deposits would be both damaging to the environment and highly inefficient. Instead, multilateral drilling is used to access all of the oil deposits from a single drilling rig.
Multilateral drilling is a branch drilling structure where several lengths of coiled tubing are connected to a primary well. By branching the tubing out at several depths, you avoid the problems that you would encounter by using several directional wellbores. The workers are less likely to drill into an existing wellbore because all of the tubing lengths run parallel, and the oil from every deposit can be extracted through a single well.
There are several special considerations that must be accounted for in offshore drilling that would not be encountered during onshore drilling. One of the most significant differences between onshore and offshore drilling is the type and complexity of the drilling rig. While vertical onshore rigs are fairly simple, offshore drilling requires platforms that are either anchored to the ocean floor or free-floating that also include oil storage and housing for the workers.
Wave and wind agitation and the extreme wellbore length that is required to reach the ocean floor can make it difficult to drill accuracy at deep-sea locations. To remedy this problem, a steel template is typically cemented into a recession on the ocean floor above the location where the drilling will take place. The template contains holes that the wellbores are guided through to anchor them in place and set them at the correct angle to access the oil deposits.
Oil drilling technology has made considerable leaps and bounds in improving on the traditional vertical drilling model. These drilling methods will continue to advance to reach the deepest possible oil deposits while reducing the impact of premium connection oil drilling on the environment.