A Novel Experimental Approach for Dynamic Quantification of Liquid Saturation and Capillary Pressure in Shale

2021 ◽  
pp. 108314
Author(s):  
Williams Ozowe ◽  
Rodney Russell ◽  
Mukul Sharma
Keyword(s):  
Capillary Pressure ◽  
Experimental Approach ◽  
Liquid Saturation

scholarly journals An experimental approach for determining unsaturated hydraulic properties of rock fractures

2004 ◽  
Vol 35 (3) ◽  
pp. 251-260 ◽  
Author(s):  
Hu Yunjin ◽  
Su Baoyu ◽  
Mao Genhai
Keyword(s):  
Hydraulic Conductivity ◽  
Capillary Pressure ◽  
Water Flow ◽  
Hydraulic Properties ◽  
Experimental Approach ◽  
Single Fracture ◽  
Rock Fractures ◽  
Unsaturated Hydraulic Conductivity ◽  
Connected Channels ◽  
Theoretical Saturation

An experimental approach for determining the unsaturated hydraulic properties (the relations between capillary pressure, saturation and unsaturated hydraulic conductivity) of rock fractures is developed and tested. Applying this approach to a single fracture, and with only water flowing, the capillary pressure–saturation and unsaturated hydraulic conductivity–capillary pressure relationships of the fracture during drainage and imbibition can be determined simultaneously. To facilitate the test of the validity of the experimental approach and to elucidate the characteristics of water flow in unsaturated fractures, an analogous fracture with parallel, connected channels of different apertures was fabricated. Experiments of unsaturated water flow in the analogous fracture were carried out. Some characteristics of water flow in unsaturated fractures (hysteresis between drainage and imbibition, etc.) were elucidated. Comparison of measured saturation values and theoretical saturation values corresponding to different apertures at the beginning of drainage and imbibition shows that the experimental approach presented in this paper is valid.

scholarly journals Bentonite Extrusion into Near-Borehole Fracture

Geosciences ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 495 ◽  
Author(s):  
Mohammad N. Islam ◽  
Andrew P. Bunger ◽  
Nicolas Huerta ◽  
Robert Dilmore
Keyword(s):  
Finite Element ◽  
Pressure Gradient ◽  
Capillary Pressure ◽  
Swelling Pressure ◽  
Elastic Model ◽  
Swelling Potential ◽  
Liquid Saturation ◽  
Modified Cam Clay ◽  
Swell Cell ◽  
Capillary Pressure Gradient

In this paper, we discuss laboratory experiments of bentonite swelling and coupled finite element simulations to explicate bentonite extrusion. For the experiments, we developed a swell cell apparatus to understand the bentonite migration to the near-borehole fracture. We constructed the swell cell using acrylic, which comprised of a borehole and open fracture. Initially, the borehole of the swell cell was filled with bentonite and liquid. Then, the apparatus was sealed for observations. Due to the liquid saturation increase of bentonite, its swelling pressure increased. The developed pressure caused the extrusion of bentonite into the fracture, and the flow of bentonite from the borehole decreased with time. Moreover, for the effectiveness of bentonite-based plugging, there is a limiting condition, which represents the relation between the maximum bentonite migration length with the fracture aperture. Additionally, we also performed the bentonite free swelling test to assess the swelling potential to the fluid salinity, and we observed that with the increase of the salinity, the swelling potential decreased. In addition, we present a fully coupled two-phases fluids flow (e.g., liquid and gas) and deformation flow finite element (FE) model for the bentonite column elements and swell cell model. We also combined the Modified Cam Clay (MCC) model and the swelling model for the bentonite deformation flow model. Then, we also present the validation of the bentonite model. To model other sub-domains, we used the poro-elastic model. Additionally, we obtained the transition between the wetting phase (i.e., liquid) and non-wetting phase (i.e., gas) using the Brooks–Corey model. From the finite element results, we observed that due to the liquid intrusion into the bentonite, the developed capillary pressure gradient results in a change of the hydro-mechanical behavior of the bentonite. Initially, we observed that due to the high capillary pressure gradient, the liquid saturation and the swelling pressure increased, which also decreased with time due to a reduction in the capillary pressure gradient. Thereby, the swelling pressure-induced bentonite migration to the fracture also decreased over time, and after the equilibrium state (for a negligible pressure gradient), there was no significant transport of bentonite into the fracture.

Utilization of Pore-Size Distributions to Predict Thermophysical Properties and Performance of Biporous Wick Evaporators

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Sean W. Reilly ◽  
Ivan Catton
Keyword(s):  
Pore Size ◽  
Capillary Pressure ◽  
Thermophysical Properties ◽  
Input Power ◽  
Size Distributions ◽  
Liquid Saturation ◽  
Sintered Copper ◽  
Pore Size Distributions ◽  
Flow Through ◽  
And Performance

A sintered copper porous medium is an extremely effective structure used to enhance the evaporative heat transfer properties of a heat pipe. It provides both capillary pressure to passively draw liquid in and increased surface area to more effectively heat the liquid. A biporous wick is particularly effective for this application as there are two distinct size distributions of pores; small pores to provide ample capillary pressure to drive flow through the wick and large pores to provide high permeability for escaping vapor. The modeling described in this work is based on the work of Kovalev who used a pore size distribution in order to determine the most probable liquid saturation at a given position. The model distinguishes phases by choosing a “cutoff” pore size, where larger pores were assumed to be filled with vapor and smaller pores were assumed to be filled with liquid. For a given thickness and thermophysical properties of the liquid, this 1-D model predicts the temperature difference across the wick for a given input power. The modeling proposed in this work yielded results that compare very well with experimental data collected on biporous evaporators by Semenic.

Experimental Determination of the Effective Resolution Limit in Thick Specimens at High Voltages

1975 ◽  
Vol 33 ◽  
pp. 664-665
Author(s):  
Mircea Fotino
Keyword(s):  
Experimental Approach ◽  
Chromatic Aberration ◽  
Resolving Power ◽  
Biological Research ◽  
Specimen Thickness ◽  
Resolution Limit ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
Resolution Level

The use of thick specimens (0.5 μm to 5.0 μm or more) is one of the most resourceful applications of high-voltage electron microscopy in biological research. However, the energy loss experienced by the electron beam in the specimen results in chromatic aberration and thus in a deterioration of the effective resolving power. This sets a limit to the maximum usable specimen thickness when investigating structures requiring a certain resolution level.An experimental approach is here described in which the deterioration of the resolving power as a function of specimen thickness is determined. In a manner similar to the Rayleigh criterion in which two image points are considered resolved at the resolution limit when their profiles overlap such that the minimum of one coincides with the maximum of the other, the resolution attainable in thick sections can be measured by the distance from minimum to maximum (or, equivalently, from 10% to 90% maximum) of the broadened profile of a well-defined step-like object placed on the specimen.

Malfunctional Reorganization in the Developing Limbo-Prefrontal System in Animals: Implications for Human Psychoses?

2001 ◽  
Vol 12 (1) ◽  
pp. 8-14
Author(s):  
Gertraud Teuchert-Noodt ◽  
Ralf R. Dawirs
Keyword(s):  
Prefrontal Cortex ◽  
Mental Disorders ◽  
Dentate Gyrus ◽  
Cognitive Functions ◽  
Experimental Approach ◽  
Regulatory Mechanisms ◽  
Hippocampal Dentate Gyrus ◽  
Non Invasive ◽  
Invasive Method ◽  
Activity Dependent

Abstract: Neuroplasticity research in connection with mental disorders has recently bridged the gap between basic neurobiology and applied neuropsychology. A non-invasive method in the gerbil (Meriones unguiculus) - the restricted versus enriched breading and the systemically applied single methamphetamine dose - offers an experimental approach to investigate psychoses. Acts of intervening affirm an activity dependent malfunctional reorganization in the prefrontal cortex and in the hippocampal dentate gyrus and reveal the dopamine position as being critical for the disruption of interactions between the areas concerned. From the extent of plasticity effects the probability and risk of psycho-cognitive development may be derived. Advance may be expected from insights into regulatory mechanisms of neurogenesis in the hippocampal dentate gyrus which is obviously to meet the necessary requirements to promote psycho-cognitive functions/malfunctions via the limbo-prefrontal circuit.

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