The first oil wells were drilled in China in the 4th century or earlier. They had depths of up to 243 meters and were drilled using bits attached to bamboo poles. The oil was burned to evaporate brine and produce salt.
By the 10th century, extensive bamboo pipelines connected oil wells with salt springs. Until the advent of internal combustion engines in the late 19th century, the primary method for drilling rock involved muscle power be it human or animal. Rods were turned by hand, using clamps attached to the rod. The rope and drop method invented in China utilized a steel rod or piston raised and dropped vertically via a rope. Mechanized versions of this persisted until about 1970, utilizing a cam to rapidly raise and drop what, by then, was a steel cable.
9th Century and Beyond…
In the 9th century, oil fields were exploited in Baku, Azerbaijan, to produce naphtha. These fields were described by the geographer Masudi in the 10th century, and by Marco Polo in the 13th century, who described the output of those wells as “hundreds of shiploads.”
The Modern Era
The first modern oil well was drilled in 1848 by Russian engineer F.N. Semyonov, on the Aspheron Peninsula north-east of Baku, followed by Poland’s Ignacy Lukasiewicz who discovered a means of refining kerosene from the more readily available “rock oil” (“petr-oleum”) in 1852, and the first rock oil mine was built in Bóbrka, near Krosno in southern Poland in the following year. These discoveries rapidly spread around the world, and Meerzoeff built the first Russian refinery in the mature oil fields at Baku in 1861. At that time Baku produced about 90% of the world’s oil.
North American Oil Drilling
The first commercial oil well drilled in North America was in Oil Springs, Ontario, Canada in 1858, dug by James Miller Williams. The American petroleum industry began with Edwin Drake’s discovery of oil in 1859, near Titusville, Pennsylvania; like the Chinese, Drake had been boring for salt. The industry grew slowly in the 1800s, driven by the demand for kerosene and oil lamps. It became a major national concern in the early part of the 20th century; the introduction of the internal combustion engine provided a demand that has largely sustained the industry to this day. Early “local” finds like those in Pennsylvania and Ontario were quickly exhausted, leading to “oil booms” in Texas, Oklahoma, and California. By 1910, significant oil fields had been discovered in Canada (specifically, in the province of Alberta), the Dutch East Indies (1885, in Sumatra), Persia (1908, in Masjed Soleiman), Peru, Venezuela, and Mexico, and were being developed at an industrial level.
The earliest oil wells were drilled percussively (cable-tool drilling), that is, holes were drilled simply by hammering at the earth. Very soon, the limited depths which this method could attain meant that rotary drilling was introduced. Modern wells drilled using rotary drills can achieve lengths of over 12 000 meters / 38,000 feet.
Until the 1970s, most oil wells were vertical (although different lithology and mechanical imperfections cause most wells to deviate at least slightly from the vertical). However, modern technologies (directional drilling) allow strongly deviated wells which can, given sufficient depth, actually become horizontal. This is of great value as the reservoir rocks which contain hydrocarbons are usually horizontal, or sub-horizontal.
A well, therefore, which passes along a reservoir (rather than through it, as a vertical well must) can tap a larger volume with a much larger surface area (and thus a correspondingly higher production rate). Using deviated and horizontal drilling, it has also become possible to reach reservoirs several kilometers away from the drilling place (Extended Reach Drilling), allowing to produce hydrocarbons from underneath e.g. environmentally sensitive areas or offshore close to the coast line.
Historically there were two types of drill bits used in oil or natural gas drilling rigs, a drag bit, and a rock bit:
- a drag bit is used for soft rocks, like sand and clay. The drill stem is rotated, and teeth on the bit shear the rock.
- a rock bit (also called a roller cone bit) consists of teeth on wheels which turn as the drill stem is rotated. These teeth apply a crushing pressure to the rock, breaking it up into small pieces.
The original patent for the rotary rock bit was issued to Howard Hughes Sr. for his dual cone roller bit in 1909. It consisted of two interlocking wheels. Walter Benona Sharp worked very closely with Hughes in developing the Rock Bit. The success of this bit led to the founding of the Sharp-Hughes Tool Company.
In 1933 two Hughes engineers invented the tricone bit. This bit has three wheels and is still the dominant bit in the market today. The Hughes patent for the tricone bit lasted until 1951, after which time other companies started making similar bits. However, the Hughes’s market share was still 40% of the worlds drill bit market in 2000.
In today’s modern industry the two main types of drill bits are now classed as PDC (polycrystalline Diamond Compact) and Roller Cone; although the tri-cone dominates, bi-cone and mono cone bits do exist. Natural and synthetic diamonds are used in coring bits, as well as for very hard rock drilling with mud motors and turbines.
The technology of both bit types has advanced significantly to provide improved durability and rate of penetration of the rock. This has been driven by the economics of the industry, and by the change from the empirical approach of Hughes in the 1930′s, to today’s time domain Finite Element codes for both the hydraulic and cutter placement software.
Until the advent of internal combustion engines in the late 19th century, the primary method for drilling rock involved muscle power be it human or animal. Rods were turned by hand, using clamps attached to the rod. The rope and drop method invented in China utilized a steel rod or piston raised and dropped vertically via a rope. Mechanized versions of this persisted until about 1970, utilizing a cam to rapidly raise and drop what, by then, was a steel cable.
In the 1970s, outside of the oil and gas industry, roller bits utilizing mud circulation were replaced by the first efficient pneumatic reciprocating piston RC drills, and became essentially obsolete for the majority of shallow drilling, and are now only used in certain situations where rocks preclude other methods. RC drilling proved much faster and more efficient, and continues to improve with better metallurgy deriving harder, more durable bits, and compressors delivering higher air pressures at higher volumes, enabling deeper and faster penetration. Diamond drilling has remained essentially unchanged since its inception.