Oil Sand To The Processing Plant example essay topic

Table of Contents 1) Introduction 2) History 3) Geology 4) Composition 5) Extraction Processes 6) Effects of Kyoto Introduction For hundreds of years the oil sands have been used as a source of energy and a product of bitumen. Oil sands are deposits of bitumen and have been used in a variety of ways such as boat repairing agents by the Native Americans to a major Canadian energy source. Bitumen is a heavy black viscous oil that must be rigorously treated to convert it into an upgraded crude oil before it can be refined into gasoline and diesel fuels. Oil sands, previously known as tar sands comprise the world's largest sources of bitumen. The two largest deposits are in Alberta and Venezuela.

The Alberta deposits comprise one third of the total bitumen. Oil sands are found in three places in Alberta: Athabasca, Peace River and Cold Lake regions. These three areas cover a total area of nearly 141,000 km 2. The volume of Alberta oil sands in place is an estimated 1.6 trillion barrels with an ultimate potential of 311 billion barrels and a production rate of 645,000 barrels per day. While conventional crude oil flows naturally or is pumped from the ground, oil sands must be mined or recovered using in situ (know as in-place mining). Oil sands recovery processes include extraction and separation systems to remove the bitumen from sand and water.

Oil sands currently represent 40% of Alberta's total oil production, and about one-third of all the oil produced in Canada. By 2005, oil sands production is expected to represent 50 per cent of Canada's total crude oil output, and 10% of North American production 1. Mineable bitumen deposits are located near the surface and can be recovered by open-pit mining techniques where retraction methods are economically practical... About two tones of oil sands must be dug up, moved and processed to produce one barrel of oil. Roughly 75 per cent of the bitumen can be recovered from sand. The recovery of denser heavy oils and the deeply buried bitumen of the oil sands require first the thinning of the oil to make it mobile, then the application of pressure to make it flow 2.

Recovery methods are usually used for deposits more than 400 meters and consist of cyclic steam stimulation (CSS) and steam-assisted gravity drainage (SAGD). These in-situ recovery methods include thermal injection through vertical or horizontal wells, solvent injection and CO 2 methods 3. This paper will discuss the Alberta oil sands with a focus on the Athabasca region. It will cover the history, geology, extraction and processing methods, and effects of the Kyoto. History The oil sands have existed for around 135 million years and remained unknown to man until around 260 years ago. They remained undiscovered because of both their burial in sand and because the remoteness of the Athabasca country remained made it greatly unexplored.

The Cree and Beaver Indians were the first inhabitants of the Athabasca County and hunted the forests surrounding the Athabasca River. When European settlement began fur trading took place which later led the Europeans to be introduced to the oil sands. The natives used the oil sands as a caulking compound for repairing their birch bark canoes as well as a mosquito repellent by placing the oil sands in fires. In 1719 a Native American placed the first chunk of oil sand in a non-natives hand. This man was named Henry Kelsey and he described the oil sand "that gum or pitch which flows out of the banks of that river". This was the first time the now famous oil sands were mentioned in Canadian history.

One hundred years later in 1819 Sir John Richardson a geognostician (science of the earth) came upon the oil sands. He wrote Below this, where the Washacummow (an early name for the Clearwater), in its winding course through the valley, approaches the high- bounding hills, sections of their sides, formed by the ravines which opened into the river, enabled us to observe that they were composed of sand more or less agglutinated by bitumen, which latter hardens into slaggy mineral pitch. This sandy band, form six hundred to eight hundred feet thick, rests immediately upon yellowish-grey limestone containing many bivalve shells and orthoceratites. The dip, where it could be observed, appeared to be northward. The limestone forms the channel of the river throughout and some pro tions of it decaying more rapidly then others, exhibit more plainly the shells which enter vary largely into its composition. This description shows how Richardson gave a geologic view of the oil sand as well as observing the paleontology.

In 1875 John Macoun, a botanist, was the first white man to follow the outcroppings of the oil sands from north to south 3. Earlier accounts are of voyages down-river but none followed the outcrop from north to south. They sent Macoun on an expedition to examine the rivers draining into Lake Athabasca. He recorded his observation of water naturally washing oil out of the oil sands that is the essence of today's technology for extracting bitumen from oil sands. His main impression was that the "tar" wasn't mixed with mineral-matter, but the tar flowed through it. 4.

The Geological Survey of Canada did more exploration of the region and came up with the prediction that under the oil-laden sands flowed a pure petroleum. They thought that a pool of oil had strained the sand beds where they rose out of the ground down river from Fort McMurry 3. This theory was proven wrong within 1912 and 1913 when the first 6 wells were drilled and there were no discoveries of these oil pockets. In 1882 Dr Robert Bell established the oil sands as being in the lower Cretaceous and also reported on the possibility of hot water extraction.

This hot was not attempted until 1884 by G.C. Hoffman of the Geological Survey of Canada 2. He reported that the bitumen separated readily from the sand. In 1920 the Geological Survey of Canada assigned Dr Karl Clark and his associate Sidney M. Bair to begin research on the oil sands. They began their investigations by studying the possibilities of using oil sands as a road paving material but were soon convinced that it was more important as a potential source of crude oil 4. Clark reviewed the various separation techniques that were known, including the hot water process and decided that this process held the highest potential and would be the one which was concentrated on. Clark believed that hot water, steam and air combined with the oil sand would cause the oil to rise to the surface as a separate hydrocarbon.

This theory was tested by a Calgary resident named Gordon Coulson. Coulson experimented with his wife's spin-dry washing machine and came up with the possibility of separating oil from sand by centrifuging. Although this method was efficient for primary separation it is now incorporated into the final treatment of recovered bitumen in both producing plants 2. Figure 2: Abasand plant, 1941. Figure 3: Bituminous sand being (Provincial Archives of Alberta, A 9103) unloaded. 1924 (Provincial Archives of Alberta, A 3529) The next big player in the history of the Alberta oil sands was Robert C. Fitzsimmons who was actively involved in drilling and exploration attempts at in situ production.

He constructed a small model extraction plant using hot water separation which was the first to extract bitumen from the sands 3. In 1927 the Alcan Oil Company became the International Bitumen Company. Alcan did some drilling in the 1920's and was as unsuccessful as other firms. Fitzsimmons was in control of the company and concluded that mining and surface extraction would be the best commercial process 4. He then decided to buy a small extraction plant and for $50 and produced 340 barrels of pure bitumen. This was the first commercially successful oil sand operation 2.

In 1933 the site of the International Bitumen Company is officially called Bitumount by Fitzsimmons. The Bitumount plant was improved by expansion, and a new refinery was constructed in 1936. By late summer the Abasand Oils plant was complete and was ready to operate at a rate of 250 tons per day. The Abasand process combined a solvent extraction with hot water extraction in two stage operation. Based on the previous work at the Abasand Oil plant, it was redesigned for a capacity of 400 tons per day (Figure 2). Abasand Oils began operating on a regular basis, production was quite extensive until 1941 when the plant burnt down 4. L.R. Champion bought out Fitzsimmons in 1942 and refurnished the plant with financing help from the Alberta government.

He renamed the company It was later renamed Oil Sands Ltd. This continued operations until 1949 when the provincial government took over operation the later sold the Bitumount plant who sells to Can-Amera Oil Sands. Can-Amera then sells the Bitumount plant to Royal ite Oil Company who closes down operations in 1948 2. "After years of financial jockeying and negotiations with provincial and federal government and with the support of John Howard Pew, President of Sun Oil, the Great Canadian Oil Sands group contracted in December 1962 with the Bechtel Co. of San Francisco first to study and then to construct a large-scale commercial plant in the Mildred-Ruth Lakes deposit, north of Fort McMurray. In 1962 a pilot plant was constructed.

The main plant of Great Canadian Oil Sands was built between 1964 and 1967. It was authorized to produce an initial capacity of 31,000 barrels per day and officially opened in 1967". 3 In 1974 Syncrude became a joint public-private venture, sponsored by Esso Resources, Gulf Canada, Canada Cities Service, Hudson's Bay Oil and Gas, and the Alberta and Canadian governments. Syncrude constructed a plant at a site near the Suncor plant north of Fort McMurray. It took 4 years to complete and was licensed to produce 125,000 barrels of oil per day. The plant opened in 1948 4.

Currently there are three companies working on the Athabasca oil sand and are currently involved one of the largest construction projects on the planet; The Athabasca Oil Sands Project. This is the first new fully integrated oil sands project in 25 years. When completed in early 2003, it will supply 10 per cent of Canada's oil needs. It is a joint venture between Shell Canada Chevron and Western Oil Sands L.P. Geology The oil sands of Alberta are comprised of the Peace River, Athabasca Wabasha, Cold Lake and Llyodminister (figure 1). Jardin explains the Geology as seen in figure 5.

Heavy oil sands are confined to the Mannville Group, Which is divisible into a lower and an upper unit as described by Jardine. The lower Mannville sediments are mainly comprised of non-marine sediments which are now oil reservoirs. These are seen at Peace River and Athabasca. Upper Mannville sediments contain non-marine classics with beds of marine sands and shales. These comprise of the oil bearing sands at Wab sca and Cold Lake. Correlation chart of the areas is shown in figure 5.

During the Jurassic, Western Canada was uplifted and a period of high erosion resulted. Also the Nelson and Cassiar-Omi neca batholiths of the Cordilleran Region were emplace d. This uplift continued through the Cretaceous and provided a lot of detrital sediments which was combined with sediments coming from the Eastern Canadian Shield 3. The largest delta deposited was the Athabasca. The basal Cretaceous sands were deposited in a dominantly fluvial environment, and filled in most of the irregularities of the erosional surface only.

The upper Mannville formed at the end of the lower Mannville and is represented by a short marine transgression where sands where re-worked and distributed. The remainder of the upper Mannville is dominantly non-marine through central Alberta. There are some inter-bedded marine sediments in the Lloyd minister Area. Subsidence continued and this allowed the Arctic sea to advance into northern Alberta and British Columbia. This formed a layer of marine shales that make up the Clearwater and the Sport River Formations.

The upper Mannville ends with the deposition of the partly marine Grand Rapids Sands. At the end of the Mannville the entire area began to sink. The arctic and Gulf ian seas came together and formed and epicontinental ocean where the upper Cretaceous sediments were laid down. The Athabasca is the largest deposit of the heavy oils and is described well by Jardine.

They occur in the basal Cretaceous McMurry sands of the Athabasca area. Sediments derived form the east were deposited in a broad basinal area situated between the Precambrian shield and a high ridge of resist and Devonian rocks that lay to the west. McMurray sediments on-lap the flanks on the western highland in the west and thin out to less the 15 m. The eastern edge of the deposit adjacent to the Precambrian Shield are comprised of a series of small subsidiary basins where thin sections of the McMurray sediment accumulated. The subbasins are made by removing salt by solution of the underlying Elk Point evaporites. Deposition of the McMurray changes from continental conditions to marine conditions and this allows the McMurray to be sub-divided into an upper and lower section.

The lower section is usually present in the thicker subbasins and does not contain oil. It is composed of fluvial sand and a swampy lacustrine facies. The upper unit is comprised of a fluvial facies which consists of a fluvial sheet complex, an estuarine facies which makes up most of the unit, and a marine facies. The marine facies passes upward into the Clearwater. Geographic distribution of the oil is determined by the westward thinning and disappearance of the McMurray sands. To the east there is a oil-water contact but the oil is present in a sync line.

Oil saturation disappears easterly. Vertical distribution of the oil is also complex and the lowermost sands are usually barren. The richest sands are usually in the coarse grained portions and the muddier sands are more unfilled 5. Geologists do not agree on how the oil sands became saturated. The two prominent theories are that the oil was formed locally or that it originated elsewhere. The second hypothesis describes why the sand particles are covered with water.

The oil originated elsewhere and then flowed into a water-filled sand deposit. One problem with this theory is present flow rate data. It was thought that flow rates were on the order of m / yr but Adams shows evidence that this quick flow rate would flush the Western Canada Sedimentary Basin (WCS B) of brine within 1.6 million years. This is inconsistent with the presence of highly saline brings in the basin today. Also the modeled temperature profile is characterized by cool water recharging in the foothills and elevated heat flow near the basin margins.

This poorly explains the high formation temperatures of epigenetic minerals in the deep basin. The revised model by Adams uses present day salinity profiles which are reduced to produce slower flow rates. These flow rates cannot explain the formation of the Athabasca oil sand. To explain the genesis of the Athabasca oil sands, other processes and mechanisms must be present such as tectonics, higher hydrocarbon concentrations or other mechanisms need to be included in numerical models.

Composition The oil sands are unconsolidated grains which are not cemented together but rather held together by a grain to grain contact. It can be easily crumbled by a hand and smells like freshly lain hot asphalt. The oil sands are major constituents consist of quartz rich sand, clay, water and bitumen. The ratios which these are comprised of vary at different locations as well as the amount of bitumen is saturated in the sand.

Saturation can vary from 0%-18%. More then 10% is considered rich oil sand, between 6%-10% is moderate and less then 6% is lean 2. The Alberta oil sands are hydrophilic (water wet) so each grain of sand is covered by a layer of water which is covered by oil. This feature allows the hot water separation method to work 2. Jha et al. show how the oil sands contain low molecular weights and volatile materials.

The most abundant single constituent up to C-5 compounds is neopentane followed by isobutene, methane acetaldehyde, propane and isobutene. The presence of acetaldehyde shows that there is a slow maturation process. Thermolysis studies show that the maturation process is thermal. The neopentane is an end product of microbiological degradation of petroleum and / or proto petroleum. The concentration distribution volatile content shows that the oil sands all have a common origin and a similar dia genetic history. Athabasca oil sands are exposed and susceptible to aerobic oxidation which enhances the production of hydrocarbons by factors ranging from 1.1 to 50 and the rate of oxidation products, by up to 5007.

"The sulfur content of a oil sand is believed to be determined largely buy the sulfur content of the under graded precursor oil and the extent of biodegradation which involves a preferential removal of non-sulfur components". New sulfur probably is not added to the residual oil during biodegradation's but its concentration is increased mainly because of the removal of other components 8. Extraction Processes Mining The first mining practices in the Alberta oil sands occurred in the Athabasca region close to Fort McMurry. This is because the deposits have low amounts of overburden with some outcrops actually visible at the surface. This allows for recovery by surface mining was the first practical method in retrieval 2. Areas that are economically suitable for mining usually have an overburden of 250 feet or less 10.

Surface mining is currently being used by Suncore Energy and Syncrude Limited Canada. Only 7% of the Athabasca Oil Sands deposit can be mined using the surface mining technique, as the other 93% of the deposit has more than 75 m of overburden. This other 93% will have to be mined using different mining techniques. The first step to mining is identifying area with rich amounts of bitumen by taking cores. Once this is completed the area is cleared of trees and the remaining ground cover is muskeg.

This form of peat moss ranges in thicknesses of 6 m to 20 m and must be drained by using channels and ditches before it can be removed. This process may take two or more years 2. Overburden is a layer of clay, sand, and silt which lies directly above the oil sands deposit. Overburden is used to build dams and dykes around the mine and will eventually be used for refilling mined-out areas.

Most mining is done by Syncrude and Suncore in the Fort McMurry region 10. Mining was first done in the 70's with large drag lines that scooped up the oil sands and placed them on a conveyor belt system that led to the refining plant. This operation was slow and it was costly to maintain the equipment so the companies moved toward electric shovels. Electric shovels have buckets that hold 100 tones, and are capable of filling heavy hauler trucks with a capacity of 240 to 400 tones. The mine delivers about 400,000 tones of oil sand per day to ore preparation plants 9. Another refining method used is called hydro-transport where oil sand is mixed with water at the mine site then it is shipped to a plant for further processing.

This method saves the cost of trucking the oil sand to the processing plant. The mined oil sand is processed to extract the bitumen from the sand using chemicals and hot water. This is done by first crushing the slurry and sending it through pipes where some bitumen is extracted. Next hot water and chemicals are added in giant separation cell where bitumen is extracted. The fine tailings (leftover sand and clay) are then pumped into a holding pond. New technologies have dropped the water temperature drastically from 195 oF to 75 oF and the chemical component has been dropped to a negligible amount 10.

In Situ Methods The reserves of bitumen suitable for in situ recovery methods are almost 10 times the size of those accessible by surface mining. These new in situ projects that came on stream included BP Canada / Petro-Canada Wolf Lake, Amoco Elk Point, Dome Lindbergh, Murphy Lindbergh, and Shell Peace River. Projects use ether Cyclic Steam Stimulation (CSS) or also know as "huff and puff". The "puff" portion injects steam into the well at 200 psi which condenses into water and separates the bitumen from the sand. The condensed water is then pumped out of the well in the "huff' process 10.

A new and more efficient in situ procedure used is called Steam Assisted Gravity Drainage (SAGD). SAGD has a 70% recovery rate where CSS only has a 30-35% recovery rate 10. Other advantages are that SAGD uses less steam at lower temperatures which allows SAGD to have a lower operating cost and it does not need as much specialized equipment as CSS. The SAGD process consists of two holes drilled in the oil sands with one on top of the other. The top well injects steam into the oil sand which condenses to water.

The bitumen becomes fluid and it able to be pumped by out by the second well. Each well pair can produce up to 1,000 -1,500+ bbl / d and are spaced 100-200 m apart. The Firebag site is a facility which processes the water, steam and oil. "The Firebag site consists of a well pads and associated facilities, a surface production gathering and steam distribution system, a central plant containing production treating, water recycling and steam generation facilities, and a utility corridor from Firebag to the base facility containing four connecting pipelines and a power line". (figure 9). Extraction and Upgrading The extraction process involves separating the Bitumen from the sand, clay and other materials. The oil sand is processed through apron feeders then into tumblers or conditioning drums where hot water is added to form a slurry which is less viscous.

Caustic soda is then added and this which allow the bitumen to attach to air. When air is added to the slurry, it attaches to the bitumen which is then pumped to large gravity separation vessels. Here the bitumen attaches to air bubbles and rises to the top of the separation vessel and forms a bitumen-rich froth. This froth is processed through a stripper which removes the air bubbles. From there the slurry passes through a series of vibrating screens that separate and reject any rocks or clumps of clay still in the slurry and directed to two large froth storage tanks.

Bitumen froth rises to the top and heavy particles are separated and removed to the bottom while the middle a gravity separation vessels is processed through a flotation system to optimize bitumen recovery 2. The bitumen froth is then piped into a counter-current decantation circuit where gasoline-like product called naphtha is added. This thins the bitumen froth separates the remaining solids, water and heavy asphaltenes is a three stage circuit process 14. The circuit process forms clean bitumen which is low in contaminants. It is now ready to go through a pipeline.

Figure 10: Western oil sands extraction plant. From web Figure 11: Extraction plant at Suncor Energy. From web Upgrading must then be done because the bitumen from the centrifuges is not suitable for transport until it can be broken down into lighter synthetic crude oil and vacuum gas oil by increasing the hydrogen-to-carbon ratio. This is done by removing impurities such as nitrogen, sulfur and carbon. There are two main upgrading technologies; carbon removal and hydrogen conversion.

Hydrogen conversion is more frequently used because it is more environmentally friendly, and eliminates the need for coke and produces more crude oil 16. This process can be seen in figure 12. The primary products produced from upgrading are naphtha, used for the manufacture of gasoline, middle distillates such as diesel, kerosene and jet fuel, and gas oils. By-products include sulfur, butane, fuel gas and coke 11. Kyoto Kyoto has not had a significant negative impact on the Alberta oil sands. The treaty which was passed in December 2002 commits Canada to reduce its green house gas emissions to 6% below the 1990 levels between 2008 and 2012.

Even though it takes 5 to 10 times the energy, area and water, to mine, process and upgrade the tar sands oil, than it does to process conventional oil there is still major development of the in the Alberta oil sands 11 (Ref 6). This year Suncore has committed to invest $7.11 million to develop and maintain its production of the Athabasca and Cold Lake oil sands. Other current investments into the oil sands was French oil giant Total Fina Elf SA that has bought 41.5% of a $1 billion dollar project. These investments seem to show that Kyoto has not had a major impact on development. Suncore president and chief executive officer stated that "out capital spending plan illustrates that Suncor remains keenly focused on well managed and predictable oil sands growth". 17.