When it comes to gas and oil production, finding new reservoirs has become increasingly difficult. As a result, the petroleum industry is refocusing its efforts on ways to maximize the production of existing reservoirs. New, more efficient ways of extracting additional hydrocarbons from reservoirs currently in production are being devised. One of the most promising of these is nanofluid use in enhanced oil recovery EOR). Nanofluids and EOR, it’s believed, make a great team in boosting oil production.
What are nanofluids?
Nanoparticles suspended in fluids compose what is known as nanofluids. Nanoparticles are 1 to 100 nanometers (nm), with one nanometer being a billionth of a meter. To put it into an everyday perspective, a millimeter is roughly the diameter of the lead in a wooden pencil and a nanometer is one-millionth of that.
Silica nanoparticles are inexpensive to create, easy to modify to suit the needed parameters, and installation has a modest capital cost. Researchers believe that Silica nanoparticles (SiNPs) have the potential to improve oil production without a negative impact to the environment.
Nanoparticles are suspended in saltwater by researchers in controlled concentrations from 0.01 to 1 weight percent. Alternatively, metal oxide nanoparticles are also suspended in saltwater by the same researchers.
Why Use Nanotechnology Enhanced Oil Recovery?
Seawater aids in producing oil in most existing reservoirs. Injected directly into the reservoirs, seawater aids in propelling the oil into the production wells. After the initial application of seawater reaches the production well, more water is injected and mostly follows the same water path so it doesn’t flush out more oil. The contrast in viscosity between oil and water, aside from the interfacial tension between water and oil phases, is the reason.
Water is thinner in consistency and less viscous so it flows easily through a reservoir. Oil has a thicker viscosity and doesn’t flow well independently. Some oil clings to rock within the reservoir or gets trapped in small remote or porous channels. While the injection of seawater is and has been an effective way of improving oil production, many believe that other methods can be devised and used to further improve oil production.
Here is where nanofluids for enhanced oil recovery is proven. When nanoparticles are added to the injected seawater, it can help flush out remaining oil deposits within the reservoir that might normally remain. The distinctive silica nanoparticles (sand) have proven effective in growing oil recovery when added to seawater injected into oil-saturated sandstone blocks. Like smaller petroleum reservoirs, the blocks when combined with other experiments help researchers comprehend how rock and oil interconnect with the nanoparticles in EOR processes making the use of nanofluids for enhanced oil recovery beneficial.
How can nanofluids maximize oil recovery?
There are several different ways in which nanofluids and EOR work together to boost oil production including, but not limited to, the following:
- By slightly increasing the viscosity of seawater, nanoparticles help push oil through reservoirs.
- By lowering the interfacial tension between seawater and oil to dislodge oil in tiny porous channels can be released from into production wells, nanoparticles push more oil out of reservoirs.
- Nanoparticles can strip oil drops and small deposits from rocky surfaces by forming wedge-films.
Nanoparticles, along with nano-gels, are used to plug up water pathways so water flow can be controlled and directed through oil-filled paths.