Yukie Tanino

Fluid saturation in relative permeability experiments is typically determined by volumetric or gravimetric measurements, as well as in-situ saturation monitoring (ISSM). Gravimetric measurements tend to have larger error due to grain loss. The conventional volumetric method used can be a challenge because produced volumes for oil and water must be separated and measured manually. ISSM method is also a costly technique. In this study, an UV–visible spectroscopy was used to continuously and cost effectively measure oil and water volumes. A water-oil unsteady state relative permeability was performed to investigate the feasibility of calculating oil and water volumes using UV–visible spectroscopy. UV–visible spectroscopy is a quantitative technique in analytical chemistry to determine concentrations of known solutes. A UV–visible spectroscope was located in the flow line immediately after the core holder and used to quantify fluid volumes (oil and water) produced from a core sample during unsteady state relative permeability study. A volumetric separator was also used to compare production volumes obtained from UV–visible spectroscope. The relative permeabilities were calculated using JBN method from both volumetric and UV-visible spectroscope measurements and then history matched with Sendra (PRORES AS). The final oil volume produced, oil and water relative permeability curves obtained from UV–visible spectroscope measurements were in good agreement with volumetric measurements. The Corey relative permeability curves simulated from Sendra also were closely matched with analytical relative permeability curves obtained using volume measurements from volumetric and UV–visible spectroscope data. Nuclear Magnetic Resonance (NMR) on post relative permeability experiment was also in good agreement with UV–visible spectroscope measurement. UV–visible spectroscopy was also used to measure the breakthrough time of the injected fluid. Breakthrough time estimated using in-line UV–visible spectrophotometer was 0.634 PVI compared to 0.617 and 0.673 PVI from pressure data and volumetric observations. Graphic

With recent developments in direct imaging techniques using x-ray and neutron imaging, there is an increasing need for efficient test setups to study the mechanical and/or transport behavior of porous rocks. Bespoke designs from commercial suppliers are expensive and often difficult to modify. This paper presents a novel design of a portable triaxial cell for imaging deformation (and a suggested adaptation to introduce fluid transport) through rocks/sand/soil under the triaxial states of stress representative of those encountered in the case of groundwater aquifers or subsurface hydrocarbon reservoirs. The design philosophy and the parameters are detailed so that interested researchers can use this experimental setup as a template to design and modify triaxial cells to suit their own experimental requirements. The design has been used in two imaging beamlines: Imaging and Material Science & Engineering (IMAT), ISIS facility, Harwell, Oxfordshire, UK, and BT2 of the National Institute of Standards and Technology Center for Neutron Research, Gaithersburg, MD, USA. The mass attenuation coefficients extracted from the 2D radiograms of the triaxial cell were compared with those reported in the literature. Further suggestions for the adaptation of the triaxial cells for studying the mechanics of deformation and fracture in rocks are included.

We designed a hands-on laboratory exercise to demonstrate why injecting an aqueous polymer solution into an oil reservoir (commonly known as “polymer flooding”) enhances oil production. Students are split into three groups of two to three. Each group is assigned to a packed Hele–Shaw cell pre-saturated with oil, our laboratory model of an oil reservoir, and is given an aqueous solution of known polymer concentration to inject into the model reservoir to “push” the oil out. At selected intervals, students record the oil produced, take photos of the cell using their smartphones, and demarcate the invading polymer front on an acetate sheet. There is ample time for students to observe the experiments of other groups and compare the different flow patterns that arise from different polymer concentrations. Students share their results with other groups at the end of the session, which require effective data presentation and communication. Both the in-session tasks and data sharing require team work. While this experiment was designed for a course on Enhanced Oil Recovery for final year undergraduate and MSc students in petroleum engineering, it can be readily adapted to courses on groundwater hydrology or subsurface transport by selecting different test fluids.