The ancient Sumerians, Assyrians, and Babylonians used crude oil and asphalt ("pitch") collected from large seeps at Tuttul (modern-day Hit) on the Euphrates for many purposes more than 5,000 years ago. Hydrocarbons was then used in warfare, medication (externally on wounds and rheumatism, internally as laxative) and waterproofing (for caulking boats).
Early in the Christian era, the Arabs and Persians distilled crude oil to obtain flammable products for military purposes. Probably because of the Arab invasion of Spain, the industrial art of distillation into illuminants became available in Western Europe by the 12th century.
As industries grew in the last century, the demand for lubricants increased. The supplies of natural oils and greases from beef and mutton tallow, lard and castor oil and from whales were not enough.
In 1847, James Young began retorting oil from oil shales in Scotland. Paraffin, used for candles, and kerosene (coal oil), used for lamps were some of the products.
Kerosene became cheaper than whale oil, which previously had been used in lamps.
This greatly expanded the demand for oil products initiating the first oil boom.
In 1859, "Colonel" Edwin L. Drake drilled a 59-foot well and produced oil at Oil Creek, Pennsylvania. This marked the beginning of the modern oil business where large volumes of hydrocarbons were extracted from the subsurface. Because of this discovery, so much oil was discovered and produced that the price of kerosene dropped to nearly nothing. This was the first oil bust.
The oil bust continued until the mass production of the internal combustion engine, and the development of mass-produced automobiles. The auto created another large demand for hydrocarbon products, and caused a second oil boom.
With the second oil boom, and First World War, large multinational oil companies developed. BP, Shell, Exxon, Gulf, Texaco, Mobil, Socal were known as The Seven Sisters. Thousands of "independent" oil companies were born.
The majors and some of the minor oil companies are vertically integrated. That is they explore, produce, refine, and market the products. Thus when crude oil prices are low, they make money in the refining business, when crude oil prices are high; they make money in the exploration/production business.
In 1960, the Organization of Petroleum Exporting Countries (OPEC) was founded. It was composed of countries whose economy was based on oil exports. These countries include Iraq, Iran, Kuwait, Saudi Arabia, Venezuela, Algeria, Dubai, Ecuador, Gabon, Indonesia, Libya, Nigeria, Qatar, and United Arab Emirates.
By the 1970's, OPEC countries produced 2/3 of the world’s oil. Thus they were able to control the price of crude oil. By limiting production, the price increased rapidly through the 1970's. The result was conservation, a worldwide recession, and drop in
About the same time, major oil deposits were discovered in the North Sea. The combined drop in consumption and the increase in production from the North Sea (largely from Norway) caused a major slump in oil prices and a bust in the early 1980's an. Two more oil busts happened between the mid 80’s and the end of the 20th century.
5.2 Exploring For Oil and Gas
5.2.1 Sedimentary BasinsLayers of sedimentary rock that are thickest in the middle of basins cover large areas of the continental crust. Nearly all oil and gas is found in such basins, which are formed over many millions of years by stretching of the crust combined with sagging.
The North Sea is an example.
Figure 10 Arabian-Iranian sedimentary basin (from Encyclopaedia Britannica).
There are approximately 600 sedimentary basins and about 160 of these have yielded oil, but only 26 are significant producers and seven of these accounts for more than 65 percent of total known oil. The Arabian-Iranian sedimentary basin is the main producing basin and it contains more than 20 supergiant fields. Supergiant fields are those with 5,000,000,000 or more barrels of recoverable oil. No other basin has more than one such field. Another 240 basins have been explored, but no significant commercial discoveries have been made.
5.2.2 The Job of the Geologist
The geologist's job is to observe, explore and scrupulously record any clue to the possible presence of hydrocarbons below ground. They attempt to reconstitute a scenario that may have been written long time ago by tracing the history of these
deposits and their lateral variations in order to identify places where oil might have become "trapped." To do this they examine rocks and take samples to ascertain their nature and date the strata from which they were taken.
Aside from exploration work, they are also involved in selecting the best exploration permits, locating explorations wells over these traps, and appraising fields following discovery. Geologists work with a variety of other specialists, like geophysicists, reservoir engineers, sedimentologists, biostratigraphers, structural geologists, and geochemists. Petroleum geologists, meanwhile, use all of their colleagues' data in order to describe the geometry and characteristics of the oil reservoir.
Oil companies sometimes call in outside experts, including academics and private consultants with leading edge techniques or equipment. They are used occasionally, as companies do not need them continuously.
Computer engineers help geologists in using software to visualize cross-sections, maps and other geological data.
Combined with aerial and satellite photographs, the geologist's observations then serve to formulate initial hypotheses: yes, there could be oil down there, below ground, and it could be worthwhile looking further.
5.2.3 The Job of the Geophysiscist 5.2.3.1 Introduction
The geophysicists study the physical properties of the subsoil. Varieties of methods are used at this stage, and a comparison of their results serves to enrich the geologist's findings. They initially use gravimetry, magnetometry, and later seismic surveys. The first two are regional in scale, less costly than seismic and are used to identify potentially oil-bearing sedimentary basins.
5.2.3.2 Gravimetry
Gravitometers measure the strength of the Earth's gravitational pull. These tools measure gravity, to give some idea of the nature and depth of strata depending on their density. This is not the same all over the Earth because of the different densities of the rocks. Igneous rocks like granite are denser than sedimentary rocks. Granite near the surface will have a stronger pull than the same lump deeper down, so measurements help to build up more information about the layers of rock.
5.2.3.3 Magnetometry
Magnetometers measure very small changes in the strength of the Earth's magnetic field. Sedimentary rocks are nearly non-magnetic and igneous rocks have a stronger magnetic effect. Because of these different effects on the magnetic field, measurements can be made to work out the thickness of the sedimentary layers that may contain oil. They give an idea of the depth distribution of crystalline terrains that have NO chance of containing any oil.
Magnetomer surveys are generally performed from the air.
5.2.3.4 Seismic Survey
applied to the ground or sea. These methods are more expensive than gravimetry and magnetometry; but it is essential to discovering oil and gas fields. There is more data obtained offshore than onshore. Since ships can travel easily in all directions, seismic measurement is in fact easier at sea than on land.
Oil companies rarely have the necessary equipment and personnel to conduct field measurements themselves. They therefore contract with outside geophysical service companies to conduct seismic surveys. The oil companies' in-house geophysicists oversee these campaigns.
The “shock” is caused by dropping a heavy weight, a mechanical vibrator, a bubble of high-pressure air; or by an explosion.
The shock wave is reflected or refracted by the geological strata back to the surface, where it is picked up by a highly sensitive microphone called a geophone (or hydrophone at sea). The way in which the waves are propagated varies as they pass through the different strata.
The geophysicist at the surface listens to the echo of these waves and records them.
If the point from which the sound wave was generated, and the speed at which it travels through the different rocks are known, then one can deduce the depth of the stratum from which the wave was reflected.
The geophysicist's seismic recordings are fed into powerful computers. The terrain is mapped by means of isochronic lines. Isochronic lines are points on the ground at which the waves take exactly the same time to be reflected / refracted at the surface.
By plotting all of the points identified on a grid covering the topographical map, one can map the depths of the main strata.
Geophysicists create an image of the subsurface deposits and their deformations, to help geologists identify traps. Two and three-dimensional images of the underground strata, and the resulting seismic maps and vertical sections are created. They serve to determine whether certain strata are likely to contain hydrocarbons.
In coordination with the geologist, they interpret the image to extrapolate the geometry of the trap.
5.2.4 Arriving At a Decision
Geologists, geophysicists, petroleum architects, together with drilling, production and reservoir engineers all supply data to economists and financial planners. All these results are aggregated and studied. By juggling figures, parameters and probabilities, they seek to work out a possible strategy for developing the reservoir in the event of confirmation of the presence of hydrocarbons. By collating and comparing their experience, expertise and findings, their conclusions are the result of a team effort.
If the decision is that it is worth taking a gamble, they are going to have to drill down to that zone. The best location for the siting of the drill rig is determined based on the existing state of knowledge of underground conditions and the topography of the terrain. This is generally sited vertically above the thickest part of the stratum thought to contain hydrocarbons.
5.3 World Distribution of Oil
To be published at a future date.