What Is the Steam-Oil Ratio?
The steam-oil ratio is a metric used to judge the efficiency of thermal enhanced oil recovery (EOR) techniques. Particularly, it relates to EOR methods that benefit from steam injections to retrieve oil from underground reservoirs. A low steam-oil ratio shows that fairly little steam is wanted to supply a barrel of oil, which indicates a further surroundings pleasant extraction process.
Key Takeaways
- The steam-oil ratio is a metric used to judge the efficiency of thermal enhanced oil recovery (EOR) techniques.
- The steam-oil ratio is said to extraction methods that rely on injecting steam into or around the centered oil wells.
- On account of the fairly best complexity and worth of EOR, companies is dependent upon primary and secondary recovery techniques as a substitute of EOR each and every time conceivable.
- The steam-oil ratio can lend a hand corporations come to a decision the suitable stage when thermal EOR techniques are actually no longer neatly definitely worth the costs involved.
- The steam-oil ratio tells us no longer anything else regarding the efficiency of thermal EOR compared to the use of carbon dioxide or polymers.
How the Steam-Oil Ratio Works
Steam injection EOR methods are fairly dear to use. As such, they are simplest used once the principle and secondary recovery techniques were utterly exhausted. Definitely, depending on parts comparable to the price of oil, it will not be economical to use EOR techniques the least bit. In some cases, oil wells can be abandoned because of extracting the remaining reserves by way of EOR may well be prohibitively dear.
When EOR is economically viable, oil-extraction companies will seek to maximize their return on investment via the usage of the best methods conceivable. To measure thermal EOR efficiency, one metric they can observe is the steam-oil ratio, which shows the quantity of steam required to extract a given barrel of oil. For example, suppose the steam-oil ratio is 4.5. That implies that 4.5 barrels of water—remodeled into steam and injected into the well—had been required to extract a single barrel of oil. Because of this truth, lower steam-oil ratios would mirror further surroundings pleasant extraction processes because of they would like a lot much less water to be remodeled into steam.
When conceivable, oil-extraction companies will seek to rely on primary recovery technologies, which can also be more effective and less dear than EOR. Primary recovery involves exploiting the existing disparity in energy between the surface and the oil reservoir deep underground. By the use of pumping water or gas into the well, companies can further build up the ability inside the reservoir, causing the oil to speed in opposition to the surface searching for lower energy. If essential, this process can be further aided by way of the use of a rod pump so to upload additional energy by way of mechanical way.
Steam injection will not be economical on account of the without doubt best value of transferring equipment into the world and fuel used to heat water into steam.
Benefits of the Steam-Oil Ratio
The steam-oil ratio can lend a hand companies make further surroundings pleasant natural helpful useful resource investments. As a company removes oil from a given well, it without end becomes tougher to extract. The steam-oil ratio can lend a hand corporations come to a decision the suitable stage when thermal EOR techniques are actually no longer neatly definitely worth the costs involved.
Disadvantages of the Steam-Oil Ratio
The steam-oil ratio simplest applies to thermal EOR techniques. It tells us no longer anything else regarding the efficiency of thermal EOR compared to the use of carbon dioxide or polymers. Additionally, the steam-oil ratio requires striking thermal EOR techniques in place forward of the ratio may also be made up our minds. That suggests it’s not useful for deciding whether or not or no longer thermal EOR will have to be used inside the first place.
Precise-World Examples of the Steam-Oil Ratio
The precise steam-oil ratio will depend partly on the particular way of thermal EOR employed. For instance, the cyclic steam stimulation way is usually associated with steam-oil ratios of 3 to 8. That suggests the program requires the conversion of between 3 to eight barrels of water into steam for the recovery of one barrel of crude oil. The program is usually reserved for wells with particularly heavy oil whose viscosity must be reduced by way of the steam so that you can have the same opinion in extraction.
Within the intervening time, the steam-assisted gravity drainage (SAGD) way is usually further surroundings pleasant, with steam-oil ratios inside the 2 to 5 range. That suggests SAGD usually requires converting between two to five barrels of water into steam for the recovery of one barrel of crude oil. The program consists of drilling two horizontal wells with regards to the oil reservoir, one above it and the other beneath it. The pressure of gravity then causes the less viscous oil to fall into the lowermost well, where pumps are then used to spice up it to the surface.
