There is a big difference between the normal onshore oil drilling and the new, modernized way of oil drilling. The traditional way was to slant drill, where they would include a slant in the drill when going down, but in recent years, horizontal oil drilling has stepped into the spotlight. The fundamental difference between the two is that slant drilling (directional oil drilling) can take 2000 feet just to change direction, whereas the horizontal oil drilling methods can perform a 90 degree turn in a couple of metres. That was a massive advance in the technology of oil drilling, and it has increased productivity by 400 percent, see below.
Although the idea is modern, and its only recently started to become more mainstream, the first idea and patent to develop a horizontal oil drilling was give to Robert Lee in 1891. The drill did not make a 90 degree turn, but instead 2 holes were drilled, one vertically and one horizontally and the met. The advance in horizontal oil drilling was forced, as they needed ways of accessing harder to reach pockets of oil, to meet the rise in demand for oil and petroleum. Thats the basis of why horizontal oil drilling was formed, however we still are seeing a shortage of the liquid gold.
Images for horizontal oil drilling
Below is a pretty accurate example of what horizontal oil drilling looks like. Source is from USGS
It shows a traditional oil well next door to a horizontal drilling well.
Horizontal drilling actually costs 80 percent more than vertical drilling, but it increases efficiency by 400 percent. This is where every company will be heading, and it is needed to maintain our demand for natural gases.