How does steam assisted gravity drainage work?
Steam assisted gravity drainage or SAGD is a method that is widely used to extract bitumen from underground oil sands deposits. This method involves forcing steam into sub-surface oil sands deposits to heat the bitumen locked in the sand, allowing it to flow well enough to be extracted.
What is SAGD used for?
Steam-assisted gravity drainage (SAGD), is a drilling technique used to extract heavy crude oil which is buried too deep or otherwise burdensome to access.
Who invented SAGD?
Dr. Roger Butler
Dr. Roger Butler, engineer at Imperial Oil from 1955 to 1982, invented the steam assisted gravity drainage (SAGD) process in the 1970s. Butler “developed the concept of using horizontal pairs of wells and injected steam to develop certain deposits of bitumen considered too deep for mining”.
Why is in situ better than mining?
More efficient water usage: In-situ operations use water for steam production, which is mostly recovered and recycled back into the process plant. Fresh water consumption rates are therefore much lower than mining operations, which require large volumes of water to slurry the oil sands.
What are the advantages of shale oil?
Shale oil production makes the United States more energy independent. Storing barrels of shale oil helps prices remain more stable. Shale oil extraction (fracking) benefits from innovative drilling techniques. Fracking causes ecological damage to the environment.
What is Subcool in SAGD?
Subcool is the temperature difference between steam saturation temperature of the injector and the production temperature of the producer. Subcool control is very important in SAGD operation. Low subcool is usually preferred to maximize production because oil viscosity is lower at higher temperature.
How are oil sands extracted?
Currently, 20% of oil sands reserves are accessible via mining techniques. Large shovels scoop the oil sand into trucks which then move it to crushers where the large clumps of earth are processed. Once the oil sand is crushed, hot water is added so it can be pumped to the extraction plant.
How does in situ mining harm the environment?
The most relevant environmental risk associated with ISR is the contamination of groundwater. During ISR, a solution is injected into an aquifer (closed area that holds water) to extract uranium from the underlying rock, which is then brought to the surface to be processed.
Is shale oil better than crude oil?
Shale oil is a substitute for conventional crude oil; however, extracting shale oil is costlier than the production of conventional crude oil both financially and in terms of its environmental impact. Deposits of oil shale occur around the world, including major deposits in the United States.
Why are the Alberta oil sands bad?
In fact, oil from tar sands is one of the most destructive, carbon-intensive and toxic fuels on the planet. Producing it releases three times as much greenhouse gas pollution as conventional crude oil does. In fact, it has become one of the fastest-growing sources of greenhouse gas emissions in that country.
What is steam-assisted gravity drainage (SAGD)?
MEG Energy uses steam-assisted gravity drainage, or SAGD, technology to recover bitumen. In SAGD operations, pairs of stacked horizontal wells are drilled into the reservoir about 400 metres beneath the surface.
What is a heavy oil gravity drainage reservoir?
By definition, a gravity drainage reservoir is one in which the other drive mechanisms are absent or very weak (little, or no, solution gas, no gas-cap or water influx). Heavy oil (°API<20) reservoirs generally meet these conditions, but the high oil viscosity seriously inhibits the process of gravity segregation within the reservoir.
What is the difference between free-free gravity and forced gravity drainage?
Free gravity drainage occurs in reservoirs with high permeability and proper oil layer thickness that have reached low pressure levels, while forced gravity drainage occurs in reservoirs with dual porosity. In these reservoirs, gas proceeds to the highly permeable area (the fracture), and oil is left behind in the low permeable areas (the matrix).
What are the methods of enhanced oil and gas recovery from reservoirs?
Amirhossein Mohammadi Alamooti, Farzan Karimi Malekabadi, in Fundamentals of Enhanced Oil and Gas Recovery from Conventional and Unconventional Reservoirs, 2018 The gravity drainage process can occur in the reservoirs in two forms: free gravity drainage process and forced gravity drainage.
