Dilbit (diluted bitumen) is a bitumen diluted with one or more lighter petroleum products, typically natural-gas condensates such as naphtha. Diluting bitumen makes it much easier to transport, for example in pipelines. Per the Alberta Oil Sands Bitumen Valuation Methodology, "Dilbit Blends" means "Blends made from heavy crudes and/or bitumens and a diluent, usually natural-gas condensate, for the purpose of meeting pipeline viscosity and density specifications, where the density of the diluent included in the blend is less than 800 kg/m3." [1] If the diluent density is greater than or equal to 800 kg/m3, the diluent is typically synthetic crude and accordingly the blend is called synbit. [2]
Bitumen and heavy oils are often produced from remote deposits such as the Athabasca oil sands in Alberta, Canada and the Orinoco tar sands in Venezuela. Before 1980, most produced bitumen was transported by truck, but trucking is seasonally restricted and relatively inefficient and expensive compared to pipeline transport. However, bitumen in its undiluted state is too viscous and dense to be transported by pipeline. To create a fluid capable of transportation by pipeline, bitumen must be mixed with a fluid that has much lower viscosity and will keep bitumen from precipitating out of the mixture. By 1985, Alberta Energy Company was operating dual pipelines to transport diluent from Edmonton to the Cold Lake oil sands and dilbit from Cold Lake to Edmonton. [3] Dilbit is now also transported by rail. [4]
The most common diluent used to dilute bitumen is natural gas condensate (NGC), especially the naphtha component. [5] Due to insufficient quantity of natural gas condensate in Alberta, bitumen shippers also use refined naptha and synthetic crude oil (SCO) as diluent, and import a considerable amount from the U.S. [6] Although SCO requires a higher volume percentage to achieve the same viscosity, at least one study found that SCO provides better blend stability than NGC. [7] Shippers dilute bitumen before shipment in order to meet viscosity and density requirements found in common carrier pipeline tariff rules. A National Energy Board study assumed a standard dilbit containing 33% condensate (resulting in product with "21.5 °API and sulphur content of 3.3 percent") and synbit containing 50% SCO. [8] [9] [10] [11] By selecting different diluent types and blend ratios, bitumen shippers attempt to lower component costs, increase blend value, and maintain pipeline transportability. The blend ratio may consist of 25 to 55% diluent by volume, depending on characteristics of the bitumen and diluent, pipeline specifications, operating conditions, and refinery requirements. [3]
Froth treatment which removes heavy constituents rather than adding lighter ones is another method. [12]
Diluent can be removed from dilbit by distillation and reused. Alternatively, the entire dilbit can be refined. Dilbit and synbit are typically processed by refineries as heavy or medium crudes, respectively. [8] Since dilbit contains hydrocarbons at extreme ends of the viscosity range, it can be more difficult to process than typical crude oil. [13]
The Kalamazoo River oil spill was a major spill from a ruptured Enbridge dilbit pipeline in 2010. [14] Cleanup took five years. The EPA ordered Enbridge to dredge the heavy bitumen out of hundreds of acres of Talmadge Creek and the Kalamazoo River.
Unlike conventional crude, unstabilized dilbit floats briefly in water but heavier components sink as light components evaporate. The remaining bitumen can make cleaning up a dilbit spill more difficult than a conventional oil spill, particularly if dredging is considered too ecologically damaging. [15] During the 2010 Kalamazoo River oil spill, the heavier components combined with silt and sank to the bottom of the water column, making cleanup difficult. [16] Cleanup of the spill was still underway three years after the event, and officials at the Michigan Department of Natural Resources' Fishery Division stated that it will "be many more years before the agency can measure the full impact on fish and other animals' reproductive cycles." [17] However, studies show that dilbit does not increase the risk of corrosion occurring within a pipeline or otherwise increase the risk of a release occurring. [18] [19] [20] [21]
In 2013, opening on the Keystone XL pipeline proposal, the EPA recommended to the State Department that pipelines that carry dilbit (such as the proposed Keystone XL) should no longer be treated just like pipelines that carry any other oil. "We have learned from the 2010 Enbridge spill of oil sands crude in Michigan that spills of diluted bitumen (dilbit) may require different response actions or equipment from response actions for conventional oil spills. These spills can also have different impacts than spills of conventional oil. ... We recommend that the Final EIS more clearly acknowledge that in the event of a spill to water, it is possible that large portions of dilbit will sink and that submerged oil significantly changes spill response and impacts. We also recommend that the Final EIS include means to address the additional risks of releases that may be greater for spills of dilbit than other crudes. For example, in the Enbridge spill, the local health department issued voluntary evacuation notices based on the level of benzene measured in the air." [22]
Pipelines are a major source of dilbit transportation and of revenue in Canada and the United States. [23] The effects of dilbit spills on freshwater ecosystems is an active area of research, and much remains unknown.
In coastal marine ecosystems, such as those found in British Columbia, Canada, dilbit floats on the surface because it is too light to sink, unless it is significantly weathered. [24] Weathering breaks down the lighter components. Dilbit is harmful to a wide range of marine animals, including sea otters, baleen whales, fish embryos, and juvenile salmon. [24]
The effects of dilbit on freshwater ecosystems have come into focus in the late 2010s, particularly by researchers at the Experimental Lakes Area and Queen’s University, both in Ontario, Canada. Environmental factors such as temperature and light change dilbit’s physical properties, so whole-lake ecosystem experiments are crucial in understanding the potential effects of dilbit leaks and spills. [25] Oil spills were simulated in limnocorrals, which are effectively giant test tubes in a lake. [25] The results of these studies show greater than 70% reduction in most phytoplankton and zooplankton in response to oil spills, although nano- and microphytoplankton populations recovered as the oil sank to the bottom of the lake. [26] Total insect emergence also decreased with increasing dilbit concentration, and the oil likely drove water strider immobility and death. [27]
Bitumen is an immensely viscous constituent of petroleum. Depending on its exact composition it can be a sticky, black liquid or an apparently solid mass that behaves as a liquid over very large time scales. In American English, the material is commonly referred to as asphalt. Whether found in natural deposits or refined from petroleum, the substance is classed as a pitch. Prior to the 20th century, the term asphaltum was in general use. The word derives from the Ancient Greek word ἄσφαλτος (ásphaltos), which referred to natural bitumen or pitch. The largest natural deposit of bitumen in the world is the Pitch Lake of southwest Trinidad, which is estimated to contain 10 million tons.
Calhoun County is a county in the U.S. state of Michigan. As of the 2020 Census, the population was 134,310. The county seat is Marshall. The county was established on October 19, 1829, and named after John C. Calhoun, who was at the time Vice President under Andrew Jackson, making it one of Michigan's Cabinet counties. County government was first organized on March 6, 1833. Calhoun County comprises the Battle Creek Metropolitan Statistical Area and is included in the Kalamazoo-Battle Creek-Portage Combined Statistical Area.
Oil sands, tar sands, crude bitumen, or bituminous sands, are a type of unconventional petroleum deposit. Oil sands are either loose sands or partially consolidated sandstone containing a naturally occurring mixture of sand, clay, and water, soaked with bitumen, a dense and extremely viscous form of petroleum.
The Athabasca oil sands, also known as the Athabasca tar sands, are large deposits of bitumen, a heavy and viscous form of petroleum, in northeastern Alberta, Canada. These reserves are one of the largest sources of unconventional oil in the world, making Canada a significant player in the global energy market.
Natural-gas condensate, also called natural gas liquids, is a low-density mixture of hydrocarbon liquids that are present as gaseous components in the raw natural gas produced from many natural gas fields. Some gas species within the raw natural gas will condense to a liquid state if the temperature is reduced to below the hydrocarbon dew point temperature at a set pressure.
Enbridge Inc. is a multinational pipeline and energy company headquartered in Calgary, Alberta, Canada. Enbridge owns and operates pipelines throughout Canada and the United States, transporting crude oil, natural gas, and natural gas liquids, and also generates renewable energy. Enbridge's pipeline system is the longest in North America and the largest oil export pipeline network in the world. Its crude oil system consists of 28,661 kilometres of pipelines. Its 38,300 kilometre natural gas pipeline system connects multiple Canadian provinces, several US states, and the Gulf of Mexico. The company was formed by Imperial Oil in 1949 as the Interprovincial Pipe Line Company Limited to transport Alberta oil to refineries. Over time, it has grown through acquisition of other existing pipeline companies and the expansion of their projects.
A diluent is a diluting agent. Certain fluids are too viscous to be pumped easily or too dense to flow from one particular point to the other. This can be troublesome, because it might not be economically feasible to transport such fluids in this state. To ease this restricted movement, diluents are added. This decreases the viscosity of the fluids, thereby also decreasing the pumping/transportation costs.
The Enbridge Pipeline System is an oil pipeline system which transports crude oil and dilbit from Canada to the United States. The system exceeds 5,000 kilometres (3,100 mi) in length including multiple paths. More than 3,000 kilometres (1,900 mi) of the system is in the United States while the rest is in Canada and serves the Athabasca oil sands production facilities. Main parts of the system are 2,306-kilometre-long (1,433 mi) Canadian Mainline and 3,057-kilometre-long (1,900 mi) Lakehead System. On average, it delivers 1.4 million barrels per day of crude oil and other products to the major oil refineries in the American Midwest and the Canadian province of Ontario. The Canadian portion is owned by Enbridge, while the U.S. portion is partly owned by that company through Enbridge Energy Partners, LP, formerly known as Lakehead Pipe Line Partners and Lakehead Pipe Line Company.
Heavy crude oil is highly viscous oil that cannot easily flow from production wells under normal reservoir conditions.
Petroleum production in Canada is a major industry which is important to the overall economy of North America. Canada has the third largest oil reserves in the world and is the world's fourth largest oil producer and fourth largest oil exporter. In 2019 it produced an average of 750,000 cubic metres per day (4.7 Mbbl/d) of crude oil and equivalent. Of that amount, 64% was upgraded from unconventional oil sands, and the remainder light crude oil, heavy crude oil and natural-gas condensate. Most of the Canadian petroleum production is exported, approximately 600,000 cubic metres per day (3.8 Mbbl/d) in 2019, with 98% of the exports going to the United States. Canada is by far the largest single source of oil imports to the United States, providing 43% of US crude oil imports in 2015.
The Ministry of Energy is a Cabinet-level agency of the government of the Canadian province of Alberta responsible for coordinating policy relating to the development of mineral and energy resources. It is also responsible for assessing and collecting non-renewable resource (NRR) royalties, freehold mineral taxes, rentals, and bonuses. The Alberta Petroleum Marketing Commission, which is fully integrated with the Department of Energy within the ministry, and fully funded by the Crown, accepts delivery of the Crown's royalty share of conventional crude oil and sells it at the current market value. The current ministry was formed in 1986, but ministries with other names dealing with energy resources go back to the Ministry of Lands and Mines in 1930.
Albian Sands Energy Inc. is a mining company which operates the Muskeg River Mine and Jack Pine Mine, an oil sands mining project located 75 kilometres (47 mi) north of Fort McMurray, Alberta, Canada. It is a joint venture between Shell Canada (10%), CNRL (70%) and Chevron Canada (20%).
The Enbridge Northern Gateway Pipelines were a planned-but-never-built project for a twin pipeline from Bruderheim, Alberta, to Kitimat, British Columbia. The project was active from the mid-2000s to 2016. The eastbound pipeline would have imported natural gas condensate, and the westbound pipeline would have exported diluted bitumen from the Athabasca oil sands to a marine terminal in Kitimat for transportation to Asian markets via oil tankers. The project would have also included terminal facilities with "integrated marine infrastructure at tidewater to accommodate loading and unloading of oil and condensate tankers, and marine transportation of oil and condensate." The CA$7.9 billion project was first proposed in the mid-2000s but was postponed several times. The project plan was developed by Enbridge Inc., a Canadian crude oil and liquids pipeline and storage company.
The Long Lake oil sands upgrader project is an in situ oil extraction project near Anzac, Alberta, 40 km (25 mi) southeast of Fort McMurray in the Athabasca oil sands region of Alberta.
The Kalamazoo River oil spill occurred in July 2010 when a pipeline operated by Enbridge burst and flowed into Talmadge Creek, a tributary of the Kalamazoo River near Marshall, Michigan. A 6-foot (1.8 m) break in the pipeline resulted in one of the largest inland oil spills in U.S. history. The pipeline carries diluted bitumen (dilbit), a heavy crude oil from Canada's Athabasca oil sands to the United States. Cleanup took five years. Following the spill, the volatile hydrocarbon diluents evaporated, leaving the heavier bitumen to sink in the water column. Thirty-five miles (56 km) of the Kalamazoo River were closed for clean-up until June 2012, when portions of the river were re-opened. On March 14, 2013, the Environmental Protection Agency (EPA) ordered Enbridge to return to dredge portions of the river to remove submerged oil and oil-contaminated sediment.
Talmadge Creek is a tributary of the Kalamazoo River. It is located in Calhoun County, Michigan, near the county seat of Marshall.
Western Canadian Select (WCS) is a heavy sour blend of crude oil that is one of North America's largest heavy crude oil streams and, historically, its cheapest. It was established in December 2004 as a new heavy oil stream by EnCana, Canadian Natural Resources, Petro-Canada and Talisman Energy. It is composed mostly of bitumen blended with sweet synthetic and condensate diluents and 21 existing streams of both conventional and unconventional Alberta heavy crude oils at the large Husky Midstream General Partnership terminal in Hardisty, Alberta. Western Canadian Select—the benchmark for heavy, acidic crudes—is one of many petroleum products from the Western Canadian Sedimentary Basin oil sands. Calgary-based Husky Energy, now a subsidiary of Cenovus, had joined the initial four founders in 2015.
The 2013 Mayflower oil spill occurred on March 29, 2013, when the Pegasus Pipeline, owned by ExxonMobil and carrying Canadian Wabasca heavy crude from the Athabasca oil sands, ruptured in Mayflower, Arkansas, about 25 miles (40 km) northwest of Little Rock releasing about 3,190 barrels of oil. Approximately 3,190 barrels of oil and water mix was recovered. Twenty-two homes were evacuated. The United States Environmental Protection Agency (EPA) classified the leak as a major spill.
Bitumen froth treatment is a process used in the Athabasca oil sands (AOS) bitumen recovery operations to remove fine inorganics—water and mineral particles—from bitumen froth, by diluting the bitumen with a light hydrocarbon solvent—either naphthenic or paraffinic—to reduce the viscosity of the froth and to remove contaminants that were not removed in previous water-based gravity recovery phases. Bitumen with a high viscosity or with too many contaminants, is not suitable for transporting through pipelines or refining. The original and conventional naphthenic froth treatment (NFT) uses a naphtha solvent with the addition of chemicals. Paraffinic Solvent Froth Treatment (PSFT), which was first used commercially in the Albian Sands in the early 2000s, results in a cleaner bitumen with lower levels of contaminates, such as water and mineral solids. Following froth treatments, bitumen can be further upgraded using "heat to produce synthetic crude oil by means of a coker unit."
Railbit is a common blend of bitumen and diluent used for rail transport. Railbit which contains approximately 17% diluents or less. compared to 30% in dilbit. Dilbit can be transported through pipelines but railbit cannot. To prevent solidifying in lower temperatures, both raw bitumen and railbit require insulated rail cars with steam-heated coils. Because it has a smaller percentage of diluents, railbit crude requires special capacity rail unload terminals capable of loading railbit and of handling larger unit trains. By the fall 2013 approximately 25% had that capacity. The U.S. State Department in their 2014 Final Supplemental Environmental Impact Statement (SEIS) regarding the proposed extension to the Keystone Pipeline, acknowledged that,
[R]aw bitumen by rail could provide better netbacks than dilbit by pipeline. Dedicated rail cars, DRUs, and/or rail terminal equipment are needed to effectively transport rawbit, which explains why most producers opt for pipelines given current infrastructure. There are increasing reports of producers doing increased testing of the potential to ship rawbit.
{{citation}}
: CS1 maint: unfit URL (link)On December 2, 2009, Purvin and Gertz reported that Alberta produces about 80,000 bbls/d of natural gasoline (primarily pentane and hexane) and another 65,000 bbls/d of Naphtha from its indigenous natural gas. These hydrocarbons have been added to bitumen (typically a 10–12 API product) to produce a pipelinable product called dilbit (19–21 API). In recent years the indigenous supply of natural gasoline not been sufficient to meet the demand. To meet bitumen producer's requirements, about 40,000 bbls/d of natural gasoline has been imported into Alberta, primarily using rail road tank cars. The National Energy Board ("NEB") tracks these volumes and in a recent publication shows that it expects the demand for natural gasoline to grow by about 27,000 bpd each year for the next ten years.
Oilsands operators have been importing diluent since about 2004 as the required volumes of pentanes plus and condensate have significantly outpaced domestic production capacity, says the CERI study. In 2010, an estimated 260,000 bbls per day of diluent was required while total Canadian domestic production was about 160,000 bbls per day, indicating that close to 40 per cent (100,000 bbls per day) of the required diluent needed to be imported, says the study.
The DilBit blend is typically made up of three parts bitumen and one part condensate. SynBit blend is comprised of roughly fifty percent synthetic and fifty percent bitumen.
Bitumen and Heavy Crude Oil must be diluted to meet pipeline viscosity and density specifications. Two blend type conventions
•upgraded light synthetic blends (SYNBIT, ~50/50 ratio) or
•heavy and bitumen diluted with condensate (DILBIT, ~25/75 ratio)
We assumed that the bitumen delivered to the Alberta upgrader would be diluted with C5+ condensate with a blend ratio of 26% C5+ and 74% bitumen needed to achieve the pipeline viscosity specification of 350 cst and 940 kg/m3 density.Athabasca bitumen has a density of 8.4 API and 4.8 weight % sulfur. SCO has a density of 35 API and 0.1 weight % sulfur.
Tar sands oil has to be diluted to make it liquid enough to flow through a pipeline. But once it's back out in the environment, the chemicals that liquefied it evaporate. That leaves the heavy stuff behind.
the Alberta systems (with a large percentage of dilbit lines) experienced comparable internal corrosion failure rates than the U.S. systems (predominantly conventional crude lines).
Under pipeline operating conditions[, d]ilbit is no different than other crude oils