What Are Oil Sands?

Oil sand, also known as "tar sand", "heavy oil sand" or "asphalt sand". It looks like black molasses, and its mining method is completely different from traditional oil mining. Simply put, oil sands extraction is "mining" oil, not "extracting" it. Exposed or near-surface sandstones impregnated with heavy residual petroleum are the products of asphalt-based crude oils that have lost light components during the migration process. Sandstones are mostly freshwater and brackish water facies, with the Athabasca River in Canada as the largest. They belong to the Cretaceous and cover an area of 33,400 square kilometers. Sometimes also referred to as a natural petroleum sand or sandstone impregnated with a fraction of the light ends. Can be used to refine heavy oil and asphalt.

Oil sand, also known as "tar sand", "

Oil sands extraction and separation

Oil sands mining technology

Oil sands mining is divided into open-pit mining and in-situ mining.

Syncrude Canada is the world's largest manufacturer of oil sands from oil sands. It engages in open-pit mining of oil sands in Athabasca. Its open-air mining technology of oil sands is a leader in the world.

For in-situ mining, the following methods are widely used:

(1) cyclic steam strengthening method (CSS);

(2) Steam-assisted gravity drainage (SAGD);

(3) Cold sand extraction technology;

(4) Underground horizontal well injection gas solvent extraction technology (VAPEX);

(5) Downhole in-situ catalytic upgrading technology;

(6) Hydrothermal cracking mining technology.

Oil sands separation technology

There are three main types of foreign oil sands separation technology: hot water washing method, solvent extraction method, pyrolysis carbonization method. Depending on the structure of the oil sands, the different separation methods are used. Generally, water-oiled sands are suitable for water washing and separation, and oil-oiled sands are suitable for organic solvent extraction or pyrolysis dry distillation. In China, the oil sands separation technology is still in the indoor research stage. ^[2]

Oil Sands Environmental Issues

For many critics, the environmental consequences of oil sands mining are immediately before them, and they are sufficient reasons to stop increasing oil sands production. To obtain the tar sands, mining companies used bulldozers to push out a huge open-pit mine in the wetlands. Inside the pit, the world's largest dump truck transports the black gold to a nearby separation plant, where the asphalt-containing soil is crushed and diluted, and the asphalt then floats on the surface and can be separated. This separation process consumes a lot of water and energy, and produces infamous "tailings", which are composed of the remaining sand, residual asphalt, water, clay particles and pollutants. Some of the lakes formed by these tailings have been around for decades, becoming a scar on the earth.

Oil extraction by digging oil sands accounts for more than half of the total asphalt oil production. With the depletion of shallow oil sands resources, the proportion of this oil recovery process will gradually decrease. Extraction of oil from deeper oil sands looks more elegant, but it also causes damage to the environment. The typical process is to drill the well first, then pump the steam into the ground through the wellbore, and the asphalt in the oil sands is melted by the steam, so it can be easily pumped to the surface. Heating steam requires burning a lot of natural gas, and this process emits a lot of carbon dioxide. Critics of oil sands mining say both methods threaten local rivers, poisoning fish, destroying landscapes, killing wildlife and polluting the air.

The movement against such "dirty oil" has gained momentum. Several states led by California have passed legislation aimed at preventing citizens of the state from obtaining oil produced in Alberta. Although some U.S. retailers have vowed not to buy fuel from oil sands, they have not fulfilled their promises. Environmental groups have jointly launched a "Rethink Alberta" campaign to discourage tourists from visiting the province until the province stops expanding mining of tar sands.

Poisoned wild goose

The Alberta government countered by advertising in newspapers and Times Square. The oil sands industry has also launched distinctive publicity advertisements to talk about the wonders of oil sands mines through the mouths of ordinary workers. The provincial government and oil companies often provide journalists and environmental activists with free travel to Alberta, hoping that they will see and hear that things are better than they thought, and they will give up their opposition. This candid performance usually brings more negative reports. Photos of 1600 wild duck bodies floating in a tailings pond, along with other startling scenes, make northern Alberta look like the moon's surface, and environmentalists have successfully smeared the Alberta brand. "The oil sands have become Greenlandic seals in the eyes of environmentalists," said Preston McEachern, a water environmental scientist at the Alberta government. People can easily kill this gentle animal with a stick.

David Schindler, an ecologist at the University of Alberta, has been publishing peer-reviewed research reports for a long time. These reports show that emissions from the ever-improving large chimneys, through which asphalt is converted into synthetic oil, have polluted the Athabasca River. This huge river flows through the buried area of oil sands ore. He published photos of deformed turbot and other fish in September, all from the polluted river. His research has thus received greater public attention. The photos prompted the federal government to intervene in the investigation.

Oil sand cleanup and emission reduction

Some environmental issues are easy to resolve. A long-standing idea is to create a large wildlife sanctuary in an area that could eventually be used for asphalt mining. The company is only allowed to tear an equivalent amount of land in the protected area if the developer recovers the land it has already destroyed. The Pembina Institute believes that using this method, up to 40% of the land in the area can be protected without affecting oil production. He said that there was a way to eliminate all the dirty things Dr. Schindler found in Athabasca, Hanoi, by remodeling these large chimneys and installing "simple and ready-made" gas scrubbers in the chimneys. Although there is no legal requirement to do so, many companies have installed such sulfur dioxide filtering devices in chimneys. Mandatory regulations that operators must safely handle half of their tailings in oil sands production by 2013 have been partially completed. The Pembina Institute believes that many operators are unable to meet the requirements by the deadline and that legislation is required to regulate the disposal of the other half of the tailings.