HEAVY CRUDE OILBy:

Muneer Basha

Introduction:

Heavy crude oil or extra heavy crude oil is any type of crude oil which does not flow easily. It is referred to as "heavy" because its density or specific gravity is higher than that of light crude oil. Heavy crude oil has been defined as any liquid petroleum with an API gravity less than 20°. Physical properties that differ between heavy crudes lighter grades include higher viscosity and specific gravity, as well as heavier molecular composition. Extra heavy oil is defined with a gravity of less than 10° API (i.e. with density greater than 1000 kg/m3 or, equivalently, a specific gravity greater than 1) and a reservoir viscosity of no more than 10,000 centipoises. With a specific gravity of greater than 1, extra heavy crude is present as a dense non-aqueous phase liquid in ambient conditions.

Heavy crude oil is closely related to natural bitumen from oil sands. Some petroleum geologists categorize bitumen from oil sands as extra heavy crude oil due to the density of less than 10 °API. Other classifications label this as bitumen differing it from extra-heavy oil. They differ in the degree by which they have been degraded from the original crude oil by bacteria and erosion. Often, bitumen is present as a solid and does not flow at ambient conditions.

The largest reserves of heavy crude oil in the world are located north of the Orinoco river in Venezuela, the same amount as the conventional oil reserves of Saudi Arabia, but 30 or more countries are known to have reserves.

Production, transportation, and refining of heavy crude oil present special challenges compared to light crude oil. Generally, a diluent is added at regular distances in a pipeline carrying heavy crude to facilitate its flow.

Economics:

Heavy crude oils provide an interesting situation for the economics of petroleum development. The resources of heavy oil in the world are more than twice those of conventional light crude oil. In October 2009, the USGS updated the Orinoco deposits (Venezuela) recoverable value to 513 billion barrels (8.16×1010 m3), making this area the one of the world's largest recoverable oil deposit. However, recovery rates for heavy oil are often limited from 5-30% of oil in place. The chemical makeup is often the defining variable in

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recovery rates. Technology utilized for the recovery of heavy oil has steadily increased recovery rates.

On one hand, due to increased refining costs and high sulfur content for some sources, heavy crudes are often priced at a discount to lighter ones. The increased viscosity and density also makes production more difficult (see reservoir engineering). On the other hand, large quantities of heavy crudes have been discovered in the Americas including Canada, Venezuela and California. The relatively shallow depth of heavy oil fields (often less than 3000 feet) can contribute to lower production costs; however, these are offset by the difficulties of production and transport that render conventional production methods ineffective. Specialized techniques are being developed for exploration and production of heavy oil.

Extraction:

Production of heavy oil is becoming more common in many countries, with 2008 production led by Canada and Venezuela. Methods for extraction include Cold heavy oil production with sand, steam assisted gravity drainage, cyclic steam stimulation, vapor extraction, Toe-to-Heel Air Injection (THAI), and open-pit mining for extremely sandy and oil-rich deposits.

Environmental Impact:

With current production and transportation methods, heavy crudes have a more severe environmental impact than light ones. With more difficult production comes the employment of a variety of enhanced oil recovery techniques, including steam flooding and tighter well spacing, often as close as one well per acre. Heavy crudes also carry contaminants. For example, Orinoco extra heavy oil contains 4.5% sulfur as well as vanadium and nickel. However, because crude oil is refined before use, generating specific alkanes via cracking and fractional distillation, this comparison is not valid in a practical sense. Heavy crude refining techniques may require more energy input[citation needed] though, so its environmental impact is presently much more significant than that of lighter crude.[citation needed]

With present technology, the extraction and refining of heavy oils and oil sands generates as much as three times the total CO2 emissions compared to conventional oil, primarily driven by the extra energy consumption of the extraction process (which may include burning natural gas to heat and pressurize the reservoir to stimulate flow). Current research in to better production methods seek to reduce this environmental impact.

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In a 2009 report, the National Toxics Network, citing data provided by the Carbon Dioxide Information Analysis Center of the government of the United States and the Canadian Association of Petroleum Producers (CAPP), found that heavy oils can have higher CO2 emissions per ton than coal. Emissions were lower than coal on a "per unit of energy produced" basis, at about 84% of those for coal (0.078/0.093) and thus higher on this basis of CO2 emissions, than conventional oil.

Environmental Research Web has reported that "because of the energy needed for extraction and processing, petroleum from Canadian oil tar sands has higher life cycle emission" versus conventional fossil fuels; "up to 25% more."

Geological Origin:

Most geologists agree that crude becomes "heavy" as a result of biodegradation, in which lighter ends are preferentially consumed by bacterial activity in the reservoir, leaving heavier hydrocarbons behind. This hypothesis leans heavily on the techniques of petroleum geochemistry. Poor geologic reservoir sealing exposes the hydrocarbon to surface contaminants, including organic life (such as bacteria) and contributes to this process.

Heavy oils can be found in shallow, young reservoirs, with rocks from the Pleistocene, Pliocene, and Miocene (younger than 25 million years). In some cases, it can also be found in older Cretaceous, Mississippian, and Devonian reservoirs. These reservoirs tend to be poorly sealed, resulting in heavy oil and oil-sands.

Chemical Properties:

Heavy oil is asphaltic and contains asphaltenes and resins. It is "heavy" (dense and viscous) due to the high ratio of aromatics and naphthenes to paraffins (linear alkanes) and high amounts of NSO's (nitrogen, sulfur, oxygen and heavy metals). Heavy oil has a higher percentage of compounds with over 60 carbon atoms and hence a high boiling point and molecular weight. For example, the viscosity of Venezuela's Orinoco extra-heavy crude oil lies in the range 1000–5000 cP (1–5 Pa·s), while Canadian extra-heavy crude has a viscosity in the range 5000–10,000 cP (5–10 Pa·s), about the same as molasses, and higher (up to 100,000 cP or 100 Pa·s for the most viscous commercially exploitable deposits). A definition from the Chevron Phillips Chemical company is as follows:

The "heaviness" of heavy oil is primarily the result of a relatively high proportion of a mixed bag of complex, high molecular weight, non-paraffinic compounds and a low proportion of volatile, low molecular weight compounds. Heavy oils typically contain very little paraffin and may or may not contain high levels of asphaltenes.

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There are two main types of heavy crude oil:

Those that have over 1% sulfur (high sulfur crude oils), with aromatics and asphaltenes, and these are mostly found in North America (Canada (Alberta, Saskatchewan), United States (California), Mexico), South America (Venezuela, Colombia and Ecuador) and the Middle East (Kuwait, Saudi Arabia).

Those that have less than 1% sulfur (low sulfur crude oils), with aromatics, naphthenes and resins, and these are mostly found in Western Africa (Chad), Central Africa (Angola) and East Africa (Madagascar).

Companies and organizations:

Major petroleum companies

Super majors

BP Chevron ConocoPhillips ExxonMobil Royal Dutch Shell Total

National oil companies

ADNOC CNOOC CNPC Iraq National Oil Company Indian Oil Corporation Kuwait Petroleum Corporation Nigerian National Petroleum Corporation NIOC ONGC Orlen PDVSA Pemex Pertamina Petrobras Petronas

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Qatar Petroleum Rosneft Saudi Aramco Sonangol Sonatrach

Other:

Anadarko Apache BG Group Cenovus Energy Devon Eni Galp Energia Gazprom Hess Husky Energy Imperial Oil Lukoil Marathon Oil Nippon Oil Occidental OMV PetroChina Reliance Industries Repsol YPF Sinopec Statoil Suncor Energy Surgutneftegas TNK-BP

Major services companies:

AMEC Baker Hughes CGGVeritas CH2M HILL

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China Oilfield Services Enbridge Ensco GE Oil & Gas Halliburton Naftiran Intertrade National Oilwell Varco Petrofac Saipem Schlumberger Snam Technip TransCanada Transocean Weatherford Wood Group

Other:

International Association of Oil & Gas Producers International Energy Agency International Petroleum Exchange OPEC Society of Petroleum Engineers World Petroleum Council

Data:

Natural gas Consumption Production Reserves Imports Exports Price

Petroleum

Consumption Production

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Reserves Imports Exports Price (Price of gasoline and diesel)

Exploration and production :

Exploration:

Core sampling Geophysics Integrated asset modelling Petroleum engineering Reservoir simulation Seismic to simulation Petroleum geology Petrophysics Reflection seismology (Seismic inversion) Seismic source

Drilling:

Blowouts Completion (Squeeze job) Differential sticking Directional drilling (Geosteering) Drilling engineering Drilling fluid Drilling fluid invasion Drill stem test Lost circulation Measurement Tracers Underbalanced drilling Well logging

Production:

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Agreements

o Concessionso Production sharing agreements

Artificial lift

o Pumpjacko Submersible pump (ESP)o Gas lift

Downstream

Enhanced oil recovery (EOR)

o Steam injectiono Gas reinjection

Midstream Petroleum product Pipeline transport Refining Upstream Water injection Well intervention XT

History:

1967 Oil Embargo 1973 oil crisis 1979 energy crisis 1980s oil glut 2000s energy crisis Founders History of petroleum Nationalization Seven Sisters Standard Oil Oil market timelines

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Provinces and fields

List of natural gas fields List of oil fields East Texas Gulf of Mexico Niger Delta North Sea Persian Gulf Prudhoe Bay Oil Field Russia Venezuela Western Canadian Sedimentary Basin

Other

Acronymns Peak oil

o Mitigationo Timing

People Petrocurrency Petrodollar Petroeuro Shale gas Swing producer Unconventional oil

Heavy crude oil:

o Oil sandso Oil shale

What is Crude Oil?

Crude oil, commonly known as petroleum, is a liquid found within the Earth comprised of hydrocarbons, organic compounds and small amounts of metal. While hydrocarbons are usually the primary component of crude oil, their composition can vary from 50%-97%

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depending on the type of crude oil and how it is extracted. Organic compounds like nitrogen, oxygen, and sulfur typically make-up between 6%-10% of crude oil while metals such as copper, nickel, vanadium and iron account for less than 1% of the total composition.

Crude Oil Formation:

Crude oil is created through the heating and compression of organic materials over a long period of time. Most of the oil we extract today comes from the remains of prehistoric algae and zooplankton whose remains settled on the bottom of an Ocean or Lake. Over time this organic material combined with mud and was then heated to high temperatures from the pressure created by heavy layers of sediment. This process, known as diagenesis, changes the chemical composition first into a waxy compound called kerogen and then, with increased heat, into a liquid through a process called catagenesis.

Crude Oil Extraction:

The most common method of crude oil extraction is drilling. Geologists will first identify a section of land they believe has oil flowing beneath it. There are a number of ways this can be accomplished, the most frequently used methods are satellite imagery, gravity meters, and magnetometers. Once a steady stream of oil is found, underground the drilling can begin.

Drilling is not an overly complicated process however a standard method has been developed to provide maximum efficiency. The first step of the process involves drilling into the ground in the exact location where the oil is located. Once a steady flow has been identified at a particular depth beneath the ground a perforating gun is lowered into the well. A perforating gun has explosive charges within it that allow for oil to flow through holes in the casing. Once the casing is properly perforated a tube is run into the hole allowing the oil and gas to flow up the well. To seal the tubing a device called a packer is run along the outside of the tube. The last step involves the placement of a structure called a Christmas tree which allows oil workers to control the flow of oil from the well.

Oil Sands:

Oil can also be extracted from oil sands, often called tar sands. Oils sands are typically sand or clay mixed with water and a very viscous form of crude oil known as bitumen. The extraction process for oil sands is quite different from drilling due to the high viscosity of this extra-heavy oil. Rather than using drills, crude oil is extracted from oil sands

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through strip mining or a variety of other techniques used to reduce the viscosity of the oil. This process can be far more expensive than traditional drilling and is found in high abundance only in Canada and Venezuela. As oil demand continues to rise, and reserves become depleted, oil sands could provide one of the last viable methods for extracting crude oil from the Earth.

Worldwide Oil Production:

While just about every country in the world depends on oil, not all countries produce it. The top five oil producing countries are: Saudi Arabia, Russia, United States, Iran, and China. It is important to note that the term production here refers to crude oil extracted from oil reserves. The top five oil consuming countries are: United States, China, Japan, Russia, and Germany.

At the current rate of consumption it is estimated that worldwide reserves will become extinguished by 2039. Scientists and engineers are working hard to find ways of more efficiently extracting and processing crude oil to delay what could become a global energy crisis.

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