Applications of Nanotechnology in the Oil and Gas Industry
Written and Edited by Sriniketh Sukumar
Nanoparticles augment nature. It provides us with the unique opportunity to rearrange structures and systems of substances on an atomic level. Materials optimized in this way are called nanomaterials, and are typically less than 100 nanometers in size (in at least one dimension). Nanomaterials exhibit various interesting properties as predicted by the laws of quantum mechanics.
Nanotechnology is without a doubt, the buzzword of engineering today, as it helps engineers optimize resources and increase process efficiency. It combines the principles of physics, chemistry and even biology to make strides in innovation and technology in virtually applied scientific field. Oil and gas, is, of course, no exception. While all the areas of the petroleum profession have benefited from this development in technology, the effects are most significant in drilling fluids.
Smart Fluid Design
Nanofluids are fluids used in exploration that include at least one additive that is a nanomaterial. Nanofluids in their colloidal state can overcome the drilling and production related functionality limitations of bulk materials, because these ultra-fine particles have a very low concentration requirement and unrestricted access to the internal and external surfaces of near wellbore formations, which can allow them to exercise their full functionality in preventing problems related to drilling and production, and not just control them.
This is achieved through nanoparticles’ extremely high surface area to volume ratio, which allows a very low concentration of nanoparticles to achieve the same effects as bulk materials. This property can be visualized by taking a cube, with side of length s. It’s total surface area (TSA) would then be 6s2, and its volume would be s3. If we slice this cube in half, its TSA of the two resulting cuboids is equal to 8s2, and if we cut this in half once again, the TSA becomes 10s2, all while the volume remains the same! This effect is seen in all shapes, and is of huge importance in chemical reactions, because a much greater number of particles are available to react, which means greater outputs can be achieved for the same amounts as inputs.
Below are some specific places where this principle, and others like it can be applied to drilling and production operations.
|Problem encountered in drilling and production||Solution using smart fluids|
|Shallow water flow problem in deep water drilling: (that is, when the flow of water and entrained sand from sub-seafloor strata up by the drill bit or surface casing) which requires additional casing string, thereby increasing cost. It can also trigger various other borehole problems, like instability and mud loss.||Nanoparticles are available in large numbers and can ‘fit’ into the pores and intergranular contact surfaces, thereby increasing bonding strength and resistance to stress and stability of the borehole, and reduce porosity and permeability.|
|Unconsolidated formation: Poor cohesion of sand and deep-sea formations render them mechanically weak, and the degree of unconsolidation is proportional to the borehole stability||Nanomaterials with gluing and cementing properties can access pores and intergranular gap easily by forming bonded networks of particle around the borehole wall. This can help to reduce borehole instability.|
|Lost circulation due to poor consolidation of formation and high porosity or due to improper mud weight in formation||Nanoparticles can effectively seal the porous and permeable zones, as well as strengthen formation, eliminating losses in formations with narrow mud weight windows and also enhance improving the hydraulic barriers within the formation matrix|
|Torque and drag increase when shifting from vertical to horizontal drilling in hydraulic fracturing and related increases in friction||Nanomaterials ability to form very thin films, and so nanofluids can significantly reduce friction and resistance between mechanical parts of the well, and allow for the easy sliding of the drill string along the nanocoated surface, like along a series of ball bearings.|
|Gas hydrates presence make drilling operations very difficult, especially in deep water, due to the formation of gas hydrate bearing zones, which are dangerous due to its effects on hole and equipment stability. If the thermodynamic conditions change during drilling, the gas hydrates can dissociate, and expand (1 unit of solid gas hydrate can expand into 170 units of gas). Needless to say, there is an imminent danger of blowout in wells containing natural gas hydrates.||Tailor made smart fluids can help prevent formation instability or changes to the mud quality, which help to maintain thermodynamic stability and ultimately help to prevent hydrate dissociation, or regain the initial integrity of the matrix. It can also maintain the density and overall quality of drilling muds.|
One example of a useful nanomaterial is ceramic, which is manufactured on a nanoscale, and produces much lighter and buoyant, but at the same time a stronger proppant that can travel more than 180 feet in shale and other tight sand reservoirs, while being able to withstand high pressure. Traditionally, a proppant is a sand or similar particulate material suspended in a fluid medium and is used in hydraulic fracturing to keep fissures open. Ceramic nanoparticles are applied in hydraulic fracturing, such that these particles can be carried deeper into the formation without being crushed or settles out. This signifies a huge potential in developing smart fluid systems to reduce the cost of production, which is a rampant problem in oil and gas production today.
Nano particles clearly represent the future pathway for petroleum engineering, as well as all other applied scientific fields, as their properties like size and tensile strength are of enormous benefit to us all.