Experimental and analytical investigation of an immiscible displacement process in real structure micromodels

The recovery of oil from a reservoir can be accomplished with various methods, one of the most commonly applied types being waterflooding. A common theory used to describe immiscible displacement is the Buckley–Leverett theory. A brand new type of micromodel, generated and fabricated by using a micro-computer tomography (μCT) image stack of a real sandstone core, was used to conduct immiscible displacement experiments. Critical logging data were recorded, and a high-resolution camera took pictures of the displacement process. In an image processing tool (MATLAB), an algorithm was developed to evaluate the pictures of the experiment and to examine the changes in the saturations of the displacing and the displaced fluid. The main objective of the displacement experiment was to validate the new microchip in two-phase displacement experiments and to assess the feasibility of the image processing algorithm. This was performed by comparing the results of the experimental to the analytical solutions, which were derived from the Buckley–Leverett theory. The comparison of the results showed a good match between the two types of solutions. The applicability of the analytical results to the experimental procedures was observed. Additionally, the usage of the newly fabricated micromodel and its potential to visualize the fluid flow behavior in porous media were assessed

Manufacturing and characterization of femtosecond laser-inscribed Bragg grating in polymer waveguide operation in an IR-A wavelength range

Optical sensors, such as fiber Bragg gratings, offer advantages compared to other sensors in many technological fields due to their outstanding characteristics. This sensor technology is currently transferred to polymer waveguides that provide the potential for cost-effective, easy, and flexible manufacturing of planar structures. While sensor production itself, in the majority of cases, is performed by means of phase mask technique, which is limited in terms of its degrees of freedom, other inscription techniques enable the manufacture of more adaptable sensor elements for a wider range of applications. In this article, we demonstrate the point-by-point femtosecond laser direct inscription method for the processing of polymer Bragg gratings into waveguides of the epoxy-based negative photoresist material EpoCore for a wavelength range around 850 nm. By characterizing the obtained grating back-reflection of the produced sensing element, we determined the sensitivity for the state variables temperature, humidity, and strain to be 45 pm/K, 19 pm/%, and 0.26 pm/με, respectively. Individual and more complex grating structures can be developed from this information, thus opening new fields of utilization

Experimental and Analytical Investigation of an Immiscible Displacement Process in Real Structure Micromodels

The recovery of oil from a reservoir can be accomplished with various methods, one of the most commonly applied types being waterflooding. A common theory used to describe immiscible displacement is the Buckley–Leverett theory. A brand new type of micromodel, generated and fabricated by using a micro-computer tomography (μCT) image stack of a real sandstone core, was used to conduct immiscible displacement experiments. Critical logging data were recorded, and a high-resolution camera took pictures of the displacement process. In an image processing tool (MATLAB), an algorithm was developed to evaluate the pictures of the experiment and to examine the changes in the saturations of the displacing and the displaced fluid. The main objective of the displacement experiment was to validate the new microchip in two-phase displacement experiments and to assess the feasibility of the image processing algorithm. This was performed by comparing the results of the experimental to the analytical solutions, which were derived from the Buckley–Leverett theory. The comparison of the results showed a good match between the two types of solutions. The applicability of the analytical results to the experimental procedures was observed. Additionally, the usage of the newly fabricated micromodel and its potential to visualize the fluid flow behavior in porous media were assessed