Slant drilling is such an effective method of drilling, it caused two nations to feud. In 1990, Iraq accused Kuwait of stealing 300,000 barrels of Iraqi oil a day using slant drilling.
Slant drilling, also known as directional drilling is defined as the practice of drilling non-vertical wells. It is often used in oil and gas production to exact oil or natural gas that could not be accessed by drilling vertically. The process is simple. A hole is bored into the rock using a special borer. A certain angle gives access to oil or natural gas that is at an angle to the drill. Usually special equipment is used to drill a slant well.
The most common angle for slant drilling is from 30 to 45 degrees. This can be used to extract resources from spots that can not be drilled vertically, such as under a lake or beneath a mountain. It can maximize oil and natural gas production and make drilling cheaper and easier in some instances.
Slant drilling began in 1920s, when oil companies started to possess the technology needed to slant drill. Slant drilling came into notice when oil companies noticed other oil companies were tapping their sources from under lease lines. Oil companies saw the potential of slant drilling.
It also has wonderful benefits for the environment. A slant well does a good job in not disturbing the surface. Slant drilling also keeps fragile areas from having to be disturbed. For example, slant drilling can be used in Alaska to find oil under glaciers. Without slant drilling, the glacier would have to be impacted by drilling a vertical well to the oil, or the oil would have to be left alone. Slant drilling will play a major role in more environmentally responsible drilling.
It also helps the environment by reducing the number of wells that have to be drilled to access oil. This plays a major role in protecting fragile ecosystemsm, and ensuring that drilling does not have as big of an negative impact on the environment Slant drilling also has many advantages that do not have to do with the environment. Slant drilling is often used to get out oil or natural gas that is beneath an impediment, such as a lake, a mountain or under a residential area. It is also used because it can increase the exposed section length through the reservoir, increasing production.
It can also lead to less oil rigs being on one pad, increasing the profits that come from this oil and decreasing the environmental impact that the drilling will have. Mainly this concept is being tried out on on shore rigs.
It can also help stop a blow out, caused when an original oil well fails to cap the pressurized oil. a "relief well" can be drilled from another site. slant drilling is used to access the source of the blow out to stop a spill. This well will intercept the original wellhead, relieving the spurt of the blow out. When the relief well is done being drilled, heavy fluid also known as kill fluid is pourn into the blow out via the relief well. This will stop the original well from leaking oil. The only problem with this method is that is is costly and takes time
One major disadvantage of slant drilling is it takes longer than horizontal drilling. After a certain feet of the well is drilled, a survey must be taken to plan the next course of action. These surveys must happen often and it slows down the rate of drilling. It also is very rough on drills and drill bits. With improvements in drilling methods, slant drilling is becoming more and more affordable and viable. But it is still a slow and time consuming method
Most directional drillers are given a well path to follow that is predetermined by engineers and geologists before the drilling commences. When the directional driller starts the drilling process, periodic surveys are taken with a down hole camera instrument ("single shot camera") to provide survey data (inclination and azimuth) of the well bore. These pictures are typically taken at intervals between 30-500 feet, with 90 feet common during active changes of angle or direction, and distances of 200-300 feet being typical while "drilling ahead" (not making active changes to angle and direction)
The current record for a slant drill is 10 km away from the drill site with the well only being 5,200 to 8,000 ft under the surface. Some current locations that are being drilled using this method is under the ocean near Southwest Britain, on the southwest shore of Britain, on the coast of Argentina, on the north coast of Germany, Sahhalin Island near Russia and off the shore of Qatar.
Not that slant drilling does not has its share of controversy. In 1990, Iraq accused Kuwait of stealing oil from Iraq using slant drilling. Iraq then used this as a justification for the invasion of Kuwait. This later lead to US involvement and the Gulf War. The United Nations doubts Iraq's claims because Kuwait would have to be too close to the border with specialized equipment to not be spotted in order to slant drill into Iraq. It has also caused rival oil companies to feud, when one company claims another company is tapping their oil reserve using slant drilling. This happened in the East Texas Oil Field in the mid 20th century where dishonest operators drilled under lease boundaries and stole oil from other owners. These wells were shut down and these operators faced legal action. But not before 100 million dollars worth of oil was stolen from legitimate owners.
Concerns about slant drilling have been brought up because it is a method that can be used to steal oil from legitimate owners. People are paranoid that slant drilling can rob them of their oil without detection.
It is also an option to stopping the current oil spill in the Gulf Of Mexico. BP plans to drill a relief well away from the site, pouring in kill fluid and stopping the gushing of oil from the blown well head. This is cited as BP's best option to ending the spill, but it does come with major disadvantages. It will take months for the relief well to be drilled and as more time goes on the bigger the oil spill will be, causing more economic and environmental damage.
Slant drilling has the potential to be an effective way of extracting precious oil and natural gas resources from places that can not be drilled horizontally. It can also be used as a more responsible way for oil and natural gas exploration that has minimal impact on the environment. And it continues to be an effective way to end oil spills caused to blow-outs on well heads.