The potential of microfluidics buoying up TotalEnergies’ transition

Microfluidics are the science and technique of handling fluids at micrometric scale. In our everyday lives, this is the technology used in ink-jet printer heads and urine pregnancy tests for example.

Microfluidics are the specialty of researchers of the Platform for Experimental Research in Lacq (PERL), and they study fluid flow on a very small scale in networks of micro-channels of a few micrometers in diameter. Among other things, they are used to make “microprocessors” that replace costly and bulky instruments and require less material. Generally speaking, working at micrometric scale makes it possible to work faster, at a lower cost, in a cleaner and safer environment. So this area of research, that draws inspiration from the natural world in which such techniques are mastered to perfection, is now booming.

“Microfluidics were born in the 1990s by adapting the techniques used by the electronics industry to manufacture semiconductor chips,” Enric Santanach Carreras, a Micromodel expert in the Physical-chemistry and analyses department of the PERL, reminds us. “The idea is to be able to engrave a network of channels, however many times we want, at the scale of a few tenths or hundredths of a micron. Extremely small volumes of fluids of less than a microliter will then be made to flow through this network. The chip is transparent, so we can see the fluid flowing and therefore combine measurements of physical parameters (pressures, flow-rates, temperatures, etc.) with the observation of phenomena that take place during fluid flow (saturation, diffusion, different fluid phases). Chips are designed according to the phenomenon we want to observe and are custom-made. One of the advantages is that these phenomena can be reproduced time and time again to generate big data.”

A solution for the safe operation of CO₂ storage projects

The objective of the researcher and the team at the PERL is to accompany TotalEnergies in its broad energy transition. For this reason, they are intent on demonstrating the potential of microfluidics which could serve many purposes in the company’s activities. Since mid-2019, they have been applying their expertise to CO₂ storage in depleted hydrocarbon reservoirs. TotalEnergies has long-since shown an interest in CO₂ storage, which is set to play a major role in achieving net-zero in the second half of the century.

Our work for the “Geological storage of CO₂” project focuses on the formation of CO₂ hydrates in very low-temperature wells (~-30 to -40°C) caused by gas expansion in depleted reservoirs. This is a major issue, as the presence of these hydrates can lead to a partial or total loss of injectivity in the wells and even shutdown of operations. We are already able to perform tests at 200 bar and observe CO₂ in its “supercritical” state, i.e. neither gaseous nor liquid, under our microscopes. So, we are in a position to map the Pressure-Temperature (P-T) conditions that cause hydrates to form and find strategies to prevent them in our CO₂ storage projects.”

The researchers do not intend to stop there: they have already begun work on the next stage, which is being able to operate at pressures of up to 300 bar and temperatures of -40°C to +150°C. “We will then have the necessary tools to extend the scope of studies focused on CO₂ and its storage. I'm thinking in particular of carbon capture, which raises many questions and whose efficiency needs to be improved, and also of CO₂ electroreduction with a view to converting CO₂ into products that can be used as raw materials!” says Enric enthusiastically.

_{For further information:}

• Achieving net-zero: a video of CO2 geological storage
• Fighting against greenhouse gases: inauguration of CCUS at the TotalEnergies PERL

As a reminder, the PERL microfluidics team is behind the initiative of making a blood viscosity measurement prototype for the medical sector:

• Blood viscosity: the PERL develops a measurement device for hospitals (totalenergies.fr)