Since Edward Drake completed the first successful oil in 1859 near Titusville Pennsylvania, more than 4 million wells have been drilled in the United States in search of or to extract oil and natural gas. If you count other types of wells such as test wells, injection wells, service wells, etc., the total is closer to 5 million wells.1 That is an average of 3.4 wells per hour for 163 years.
Drilling for oil accelerated in the late 19th century due to surging demand for kerosene as a fuel for lighting. That period was punctuated by the discovery of the massive Spindletop field in east Texas in 1901 which spurred a flurry of investment in the oil industry as new markets for oil products emerged such as gasoline for the automobile.
Drilling surged after the end of World War II due to pent-up consumer demand, a growing GDP and population, and the orientation of American life around the automobile and trucking. However, regulations by state governments in the major oil-producing states that capped the amount of oil that could be produced encouraged major oil companies to look for better financial returns in the 1960s. Domestic drilling declined, and investment moved overseas, especially due to the massive new discoveries in the Middle East.
The historic energy price increases associated with the Arab oil embargo in 1973 and the Iranian revolution in 1979 pushed drilling to all-time highs. However, the drilling boom was quickly followed by a drilling bust when oil prices collapsed due to a change in the way in which OPEC set production quotas. The number of wells drilled in the late 1990s was the lowest since the 1890s. Favorable prices and the advent of hydraulic fracturing (“fracking”) in the early 2000s caused another big increase in drilling efforts.
Drilling for natural gas significantly lagged oil drilling until the 1950s when advances in pipeline technology made long-distance transmission technically, and economically feasible. Quick to follow was an increase in the demand for gas in household and industrial heating, and for the generation of electricity. Between 1910 and 1955 the ratio of oil wells drilled to gas wells drilled was about 7:1. By the early 1970s that ratio dropped to 2:1, and by the early 2000s gas wells outnumbered oil wells.
Fracking is a combination of two technologies: horizontal drilling and the fracturing of geologic formations by the injection of high-pressure water and propping agents. Since Drake’s first well in 1859 through the 1990s, nearly all wells were drilled vertically. From the mid-1990s to 2020, horizontal and directional wells increased from 10% to more than 80% of all wells drilled.
The fracking boom improved domestic energy security, created lots of jobs, and enabled natural gas to displace coal in electricity generation. But fracking quickly became a divisive issue due to its prodigious use of water, its inducement of minor earthquakes and other environmental impacts, and its disruptive influence on social cohesion in some local communities.
1 WellDatabase reports 4,854,580 wells of all types drilled as of August 4, 2023, https://welldatabase.com/