Living in a material world

Nanotechnology is a wide and growing field being researched and developed by both academia and industry alike. Elia Barnett spoke with researchers at University of Houston, Rice University, and Halliburton to see how far the technology has come.

High-pressure high-temperature testing facilities with resistance measurements. Image from Dr. C. Vipulanandan.

Nanotechnology refers to a wide and growing area of scientific research with numerous applications in many disciplines. It involves controlling material properties by size and then designing around these materials. When materials are shrunk down to a scale of 1.5-300 nm in length, unique properties can emerge that are different from the larger bulk material.

Lee Hall, program manager, Nanotech Advanced Materials at Halliburton explains the reason why materials behave differently on the nanoscale: “When we shrink materials down to the nanoscale, the ratios of their surface area to their volume increase exponentially. And defects of the materials becomes fewer and less important. So when dimensions are less than or equal to let’s say wavelengths of light, the quantum properties of materials that can’t be observed in the bulk begin to dominate.”

Quantum properties that otherwise would be absorbed in the volume of the larger material come out with the increasing surface area and tiny dimensions of nanomaterials. Imagine all the materials in the world and depending on size, double each material’s potential uses. It’s like taking the periodic table and being told there’s a parallel universe for each element. Science fiction has come to life in nanotechnology.

Scientific research has gone into understanding these different properties and to explore the future applications. The potential of nanotechnology crosses over into almost every industry. Slowly the oil and gas industry has been gaining interest in tapping into nanotechnology’s prospects. In the energy capital of the world, universities are pouring resources into the nanotechnology research specifically for offshore oil and gas applications.

Academia

One area of major focus for the University of Houston (UH) is studying advancements for the oil and gas industry. Dr. C. Vipulanandan, professor and UH director of Center for Innovative Grouting Materials and Technology (CIGMAT), researches how to work with “smart cement” in downhole conditions.

The smart cement is designed as a sensor that uses electrical resistivity to monitor the strength and hardening of the cement. This is especially useful when cementing a well casing in subsea, high-pressure high-temperature (HPHT) conditions. According to Vipulanandan, contamination of the cement due to various factors such as seawater and oil-based drilling mud are common, major issues affecting offshore cementing. One of the purposes of his research addresses oil-based drilling mud (OBM) contaminated cement problems and looks at “how to detect contamination and how to minimize the contamination.”

Recently, Vipulanandan presented a paper at the OTC showing how adding nanoparticles of calcium carbonate (NCC) to the smart cement modified its behavior to protect against contamination, thus increasing its strength, decreasing its curing time and increasing the ability to monitor the cement. His research shows that the addition of 1% NCC to oil-based drilling mud (OBM) contaminated cement increased the rheological properties of the cement slurry due to its higher surface energy as a nano particle. The smart cement formula uses electrical resistivity to read the cement’s strength, curing time, and to monitor for weak points. OBM is a major concern because the contamination weakens the casing’s dry time and compromises the strength. With the addition of 1% NCC to both 3% and 1% OBM contaminated smart cement, the electrical resistivity increased allowing for more accurate readings. In fact the higher the contamination, the higher the resistivity. The results of the research found that the NCC modification resulted in considerable improvement of compressive strength and piezoresistivity of OBM contaminated smart cement both after one and 28 days of curing under water.

Rice University, located in Houston, is historically well-known for major breakthroughs in nanotechnology and its applications. Sibani Lisa Biswal and George Jiro Hirasaki, faculty in the Department of Biomolecular and Chemical Engineering both study the use of foam for enhanced oil recovery from mature oil reservoirs.

Hirasaki says that traditional oil recovery processes use the injection of water or gas to displace oil. A number of gases are used for enhanced oil recovery, including natural gas, enriched natural gas, nitrogen, carbon dioxide, and steam.

“A common feature of gas is that it has a low viscosity and density,” Hirasaki says. “This tends to result in the injected gas overriding and bypassing the more viscous oil phase.”

Application of nanotechnology helps stabilize the nanometers thick foam lamella that makes the flow of foam through porous rock act as if a viscous fluid was being injected, he says. This results in the preferential flow of oil instead of the injected gas and, thus, improves oil recovery.

In the foam state, the gas has the ability to get into the tighter pores and extract more oil from the reservoir. Biswal compared the foam’s oil recovery abilities to shampoo in which the bubbles forming have both a hydrophobic and hydrophilic side. One part of the foam attracts the oil; the other part displaces it to the surface, she says. The purpose of the understanding the behavior of films or bubbles in the foam is to find better methods to recover oil in hard to reach reservoirs.

Foam floods in microfluidic models. Images from Biswal Lab/Rice University.

Industry

All these areas of research create new possibilities for the oil and gas industry. Many of the applications are already standard downstream. What ways can nanotechnology improve conditions upstream? Halliburton is one company looking to apply the technology to its operations.

“Nanomaterials and nanostructured materials are really great candidates as fluid additives,” Hall says. “We currently have some programs that are looking at improving things like rheology control and fluid loss properties in drilling and cement, shale inhibition in drilling fluids, controlling reactivity and water transport during cement curing while improving strength.

“A little further out,” he continues. “We’re looking at delivering chemistry to targeted areas of the reservoir, tailoring all those nanomaterial surfaces to interact with specific reservoir rocks. There’s some involvement with interaction of fluids with logging tools whether they’re resistive or NMR or acoustic logging. Those are all great applications of nanotech that I think Halliburton will be looking to take advantage of in the future.”

Hall also says, for offshore conditions, nanotechnology can improve the thermal properties of drilling fluids and cements. These standard building tools for well construction are made more complicated in an offshore environment, he says. Drilling fluids and cements undergo huge temperature and pressure changes from cold sea floor to hot reservoir environments. “In similar environments, nanomaterials can retain their solid mechanical properties better than bulk materials while avoiding the thermal breakdown or side reactions normally associated with free polymer or molecular materials,” he says.

Conclusion

Most nanomaterial research is geared toward human body conditions, but HPHT environments present an exciting new opportunity in which nanomaterials can be studied. “Academia, if they are not incentivized to look at some their nanotechnologies in those environments, there’s no reason we should expect them to. If oil and gas does not reach out with challenge statements, and commensurate support and collaboration, we shouldn’t really expect that their new research and discoveries will be portable to our industry,” Lee says.

There’s an obvious gap between nanotechnology applications for oil and gas industry and the nanomaterial research. Proposing new methods is risky and requires extensive research. Lee emphasized that industry’s role is to communicate to researchers the specific conditions that need to be met in order for researchers to produce inventions that can be applied in in offshore environments.

There is a lot of potential for nanotechnology in the offshore oil and gas industry. The harsh conditions of offshore environments, coupled with the high temperatures and pressures invite new technological breakthroughs in nanomaterial research. Additionally, the cost of the nanotechnology is created around the fact that smaller doses of the material are needed in order to get the job done. Less material can lead to lower costs and higher efficiency rates. The technological advances can create a safer, high efficiency work environment. As the communication gap is bridged between academia and industry, more nanotechnology advancements and applications in the oil and gas industry will inevitably surface.