Oil Sands

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Explore Biological Solutions to improve the Environmental Sustainability of the Oil Sands

Global Energy Context The world’s demand for energy is forecast to double by 2035 as countries develop higher living standards that increase their per capita energy consumption. Electricity, transportation, heating and cooling homes, clothing, plastics and medications all use fossil fuels. Until we find reliable, cost-effective alternative sources to keep up with our increasing demand, we will continue to rely on oil. (For more info, see: http://www.conocophillips.com/EN/about/energy/pages/petroleumhouse.aspx) There is an obvious need for lower impact and more efficient energy extraction and production. This requires investment in new technology such as synthetic biology, which has the potential to transform Oil Sands production and significantly reduce its environmental footprint.

“Energy efficiency and renewable sources of energy will certainly help to address the challenge of climate change. But fossil fuels will continue to dominate global energy systems in the near future and we must quickly transition these fossil energy systems to greatly reduced and, ideally, zero carbon emission”. - Steve Larter, Canada Research Chair, University of Calgary.

The Oil Sands and the Challenges

The Canadian oil sands, located in Northern Alberta, are the second largest energy resource in the world (after Saudi Arabia). The development of this resource is on an immense scale.

Bitumen is a heavy and viscous form of crude oil, with a consistency similar to peanut butter at room temperature. Heating (removing carbon) or diluting with lighter hydrocarbons (adding hydrogen) are two methods that reduce viscosity, but other (more environmentally friendly) approaches are considered necessary.

Breakthrough energy-saving and alternative processes are sought to reduce the environmental impact of the oil sands and to reduce costs. Biological processes are particularly attractive, since bitumen itself is the result of past biological activity.

The vast majority of the oil sands deposits are too deep to mine from the surface and the bitumen is commercially recovered through burning natural gas to produce steam (known as in-situ). The remaining 18 per cent of the oil sands lie within 75 metres of the surface and the bitumen is extracted using hot water and chemicals. Ninety percent of the water from mining operations is reused and the remaining 10 per cent (contaminated with fine clays, small amounts of hydrocarbon, and other compounds) goes to the tailings ponds to be reclaimed.

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Technical Information

In-situ: Mining: Depth: 200 metres or more 75 metres or less Temperature of bitumen: ~ 10°C ~ 10°C Pressure: 2,000 kilopascals (kPa) N/A Oxidization: Isn’t exposed to air Is exposed to air (oxidization) Naturally occurring composition: 10-15% bitumen, 3-8% water, 5-35% fine particles (less than 55 fine microns), balance is sand 7-14% bitumen, 3-8% water, 5-35% fine particles, balance is sand

WIKI Definitions

Athabasca Oil Sands:

The Athabasca Oil Sands are large deposits of bitumen, or extremely heavy crude oil, located in northeastern Alberta, Canada. These oil sands, hosted in the McMurray Formation, consist of a mixture of crude bitumen (a semi-solid form of crude oil), silica sand, clay minerals, and water. The Athabasca deposit is the only large oil sands reservoir in the world which is suitable for large-scale surface mining, although most of it can only be produced using more recently developed in-situ technology.

Bitumen:

Bitumen is a mixture of organic liquids that are highly viscous, hydrogen-deficient, black, sticky, entirely soluble in carbon disulfide, and composed primarily of highly condensed polycyclic aromatic hydrocarbons. Compared to conventional crude oil, bitumen contains too much carbon and too little hydrogen. Naturally occurring or crude bitumen is form of petroleum which is so thick and heavy that it must be heated or diluted before it will flow. At room temperature, it has a consistency much like cold molasses. Distilled bitumen is the residual (bottom) fraction obtained by fractional distillation of crude oil. It is the heaviest fraction and the one with the highest boiling point, boiling over 525 °C (977 °F).

Clostridia:

The Clostridia are a class of Firmicutes, including Clostridium and other similar genera. They are distinguished from the Bacilli by lacking aerobic respiration. They are obligate anaerobes and oxygen is toxic to them.

Cracking:

In chemistry terms, cracking is a process by which complicated organic molecules (such as kerogens or heavy hydrocarbons) are broken down into simpler molecules (e.g. light hydrocarbons) by breaking their carbon-carbon bonds. How fast the cracking process is and how long it takes for the end products to form are very dependent on the temperature and any existing catalysts. Cracking is used in petroleum to form "light" products such as LPG and gasoline. i. Hydrocracking: Hydrocracking is a high temperature, high pressure refinery process that converts high boiling range material into gasoline and diesel fuel by cracking or breaking up larger molecules in the presence of hydrogen and a catalyst (by adding hydrogen). Similar to the hydrotreater, the function of hydrogen is the purification of the hydrocarbon stream from sulfur and nitrogen hetero-atoms. The products of this process are saturated hydrocarbons; depending on the reaction conditions (temperature, pressure, catalyst activity) these products range from ethane, LPG to heavier hydrocarbons comprising mostly of isoparaffins. Hydrocracking is normally facilitated by a bi functional catalyst that is capable of rearranging and breaking hydrocarbon chains as well as adding hydrogen to aromatics and olefins to produce naphthenes and alkanes. ii. Coking:

Coking involves thermally cracking the heavy fractions (at 468-498° C) to produce distillable liquids (eg, gasoline, fuel gas) and petroleum coke and to burn off unwanted impurities.

Diluent:

A diluent (also referred to as a filler, diluent or thinner) 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 problematic, 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. One industrial application is the transport of crude oil via pipelines. Heavy crude oil/bitumen are fluids with high viscosity, especially at low temperatures. The addition of a diluent enables the diluted fluid (dilbit in the case of bitumen) to meet pipeline specifications in order for it to be efficiently transported. Typical diluent in this case is naphtha or condensate or synthetic crude oil (upgraded bitumen).

In Situ:

In situ refers to recovery techniques which apply heat or solvents to heavy oil or bitumen reservoirs beneath the earth. There are several varieties of in situ technique, but the ones which work best in the oil sands use heat (for example, SAGD).

Mining:

"Strip mining" is the practice of mining a seam of mineral by first removing a long strip of overlying soil and rock (the overburden). It is most commonly used to mine coal or oil sand. Strip mining is only practical when the ore body to be excavated is relatively near the surface.

Oil Sands:

Oil sands, also known as heavy oil, are a type of bitumen deposit. The sands are naturally occurring mixtures of sand or clay, water and an extremely dense and viscous form of petroleum called bitumen. They are found in large amounts in many countries throughout the world, but are found in extremely large quantities in Canada and Venezuela. Oil sands are often referred to as unconventional oil or crude bitumen, in order to distinguish the bitumen extracted from oil sands from the free-flowing hydrocarbon mixtures known as crude oil traditionally produced from oil wells.

Production (Upgrading):

Bituminous sands are a major source of unconventional oil. Conventional crude oil is normally extracted from the ground by drilling oil wells into a petroleum reservoir, allowing oil to flow into them under natural reservoir pressures, although artificial lift and techniques such as water flooding and gas injection are usually required to maintain production as reservoir pressure drops toward the end of a field's life. Because extra-heavy oil and bitumen flow very slowly, if at all, toward producing wells under normal reservoir conditions, the sands must be extracted by strip mining or the oil made to flow into wells by in situ techniques which reduce the viscosity by injecting steam, solvents, and/or hot air into the sands. These processes can use more water and require larger amounts of energy than conventional oil extraction, although many conventional oil fields also require large amounts of water and energy to achieve good rates of production.

This is because heavy crude feedstock needs pre-processing before it is fit for conventional refineries. This pre-processing is called 'upgrading', the key components of which are as follows:

1) removal of water, sand, physical waste and lighter products 2) density reduction though carbon rejection or hydrogen addition. 3) catalytic purification by hydrodemetallisation (HDM), hydrodesulfurization (HDS) and hydrodenitrogenation (HDN)

SAGD:

Steam Assisted Gravity Drainage (SAGD) is an enhanced oil recovery technology for producing heavy crude oil and bitumen. It is an advanced form of steam stimulation in which a pair of horizontal wells are drilled into the oil reservoir, one a few metres above the other. Low pressure steam is continuously injected into the upper wellbore to heat the oil and reduce its viscosity, causing the heated oil to drain into the lower wellbore, where it is pumped out. The basis of the process is that the injected steam forms a "steam chamber" that grows vertically and horizontally in the formation. The gases released, which include methane, carbon dioxide, and usually some hydrogen sulfide, tend to rise in the steam chamber, filling the void space left by the oil and, to a certain extent, forming an insulating heat blanket above the steam. Oil and water flow is by a countercurrent, gravity driven drainage into the lower well bore. The condensed water and crude oil or bitumen is recovered to the surface by pumps such as progressive cavity pumps that work well for moving high-viscosity fluids with suspended solids.

Tailings:

Tailings (also known as slimes, tailings pile, tails, leach residue, or slickens) are the materials left over after the process of separating the valuable fraction (bitumen) from the worthless fraction (sand). In coal and oil sands mining, the word 'tailings' refers specifically to fine waste suspended in water.

i) Tailing Ponds:

Tailing ponds are areas of refused mining tailings where the water borne refuse material is made into a pond to allow the sedimentation (meaning separation) of solid particles from the water. The pond is generally impounded with a dam, and known as tailings impoundments or tailings dams. It was estimated in 2000 that there were about 3,500 active tailings impoundments in the world. The ponded water is of some benefit as it minimizes fine tailings from being transported by wind into populated areas where the toxic chemicals could be potentially hazardous to human health; however, it is also harmful to the environment.

ii) Mature Fine Tailings (MFT):

When tailings are deposited at the disposal site, it separates and settles further to create a layer of clarified water on top that is re-used in extraction, and a dense mixture of clay, silt and water on the bottom which is referred to as mature fine tailings.