Abstract Carbonate reservoir rocks are normally mixed-wet or oil-wet, leading to low oil recovery... more Abstract Carbonate reservoir rocks are normally mixed-wet or oil-wet, leading to low oil recovery efficiency using water-based oil recovery methods. It is critical to understand the molecular composition of the organic material coating the surface of carbonate reservoir rock in order to design better enhanced oil recovery (EOR) methods. Herein, we extracted organic compounds from a carbonate reservoir rock and characterized their composition using high resolution mass spectrometry (HRMS). In contrast to conventional interpretation that the mixed-wet or oil-wet nature of carbonate reservoir rocks arises from the adsorption of carboxylic acids, our results demonstrated that the organic species strongly bound to carbonate reservoir rock surface are dominated by N-containing species, including a group of “sticky molecules”. Each of these molecules can form multiple hydrogen-bonds, therefore they might act as a “double-sided tape” which binds crude oil strongly to the carbonate rock surface. Furthermore, we applied atomic force microscopy (AFM) techniques to a model mineral surface with regions of positive change and negative charge which was contacted with the crude oil produced from the formation where the rock was sampled. It was found that only the organic molecules with positive charge in the oil were adsorbed onto the mineral. This supports HRMS results which suggest that the organic materials strongly bound to the carbonate reservoir rock surface are dominated by basic N-containing molecules. Overall, these findings suggest that, beside fatty acids, these “sticky molecules” might also play an important role in controlling the wetting state of carbonate reservoir rock.
TRANSDUCERS 2007 - 2007 International Solid-State Sensors, Actuators and Microsystems Conference, 2007
... A DEPLETION LAYER ACTUATOR James HT Ransley1*, Colm Durkan1, and Ashwin A. Seshia1 1 Cambridg... more ... A DEPLETION LAYER ACTUATOR James HT Ransley1*, Colm Durkan1, and Ashwin A. Seshia1 1 Cambridge University Nanoscience Center, Cambridge, CB3 0FF, UNITED KINGDOM (*Corresponding author: Tel : +44-1223 ... 0 2 2 2 3 129.0 12 2 1 a L wEh dx dx ud wh E V L E ...
In this article, we describe nanometer scale characterization of piezoelectric thin films of Lead... more In this article, we describe nanometer scale characterization of piezoelectric thin films of Lead-Zirconate-Titanate (PZT). Using the electric field from a biased conducting atomic-force microscopy (AFM) tip, we show that it is possible to form and subsequently image ferroelectric domains. Using a sphere-plane model for the tip-sample system we calculate the distribution of electric potential, field and polarization charge, and find good agreement with the experimental values. We also discuss the effects of surface contaminants on domain formation.
An analysis of polycrystalline Au thin-film interconnects of widths ranging from 850 to 25 nm, an... more An analysis of polycrystalline Au thin-film interconnects of widths ranging from 850 to 25 nm, and lengths ranging from 1 microm to 20 nm which have been electrically stressed to the point of failure is presented. A new method for testing failure of interconnects is proposed, based on a quantity we call the failure current density. The mean time to failure for fixed current density and also the failure current density are seen to decrease with decreasing wire width contrary to expectations. The failure current density for a given wire width increases as the length decreases. An analysis of the temperature and stress profiles based on calculations of a simple model is presented which shows that the length dependence is due to thermal stresses rather than electromigration, and the width dependence is due to enhanced electromigration due to surface diffusion.
The authors report the electrical characterization of gold and gold-palladium nanowires failed by... more The authors report the electrical characterization of gold and gold-palladium nanowires failed by electromigration. Nanogaps 1–2nm in size are reliably made from metal nanowires by controlling the electromigration failure process, opening up the possibility of using these metal nanowires with nanogaps for molecular conduction studies and large-scale molecular junction device fabrication. Nanogaps are formed by applying a voltage sweep to the wires at a ramp rate of 4mV∕s. The interplay between Joule heating and electromigration means that reliable nanogaps can be formed without the need of a feedback circuit, rendering the technique relatively simple to implement.
Page 1. CURRENT AT THE NANOSCALE An Introduction to Nanoelectronics Colm Durkan Page 2. ... Page ... more Page 1. CURRENT AT THE NANOSCALE An Introduction to Nanoelectronics Colm Durkan Page 2. ... Page 4. CURRENT AT THE NANOSCALE An Introduction to Nanoelectronics ColmDurkan University of Cambridge, UK ICP Imperial College Press Page 5. ...
Abstract Carbonate reservoir rocks are normally mixed-wet or oil-wet, leading to low oil recovery... more Abstract Carbonate reservoir rocks are normally mixed-wet or oil-wet, leading to low oil recovery efficiency using water-based oil recovery methods. It is critical to understand the molecular composition of the organic material coating the surface of carbonate reservoir rock in order to design better enhanced oil recovery (EOR) methods. Herein, we extracted organic compounds from a carbonate reservoir rock and characterized their composition using high resolution mass spectrometry (HRMS). In contrast to conventional interpretation that the mixed-wet or oil-wet nature of carbonate reservoir rocks arises from the adsorption of carboxylic acids, our results demonstrated that the organic species strongly bound to carbonate reservoir rock surface are dominated by N-containing species, including a group of “sticky molecules”. Each of these molecules can form multiple hydrogen-bonds, therefore they might act as a “double-sided tape” which binds crude oil strongly to the carbonate rock surface. Furthermore, we applied atomic force microscopy (AFM) techniques to a model mineral surface with regions of positive change and negative charge which was contacted with the crude oil produced from the formation where the rock was sampled. It was found that only the organic molecules with positive charge in the oil were adsorbed onto the mineral. This supports HRMS results which suggest that the organic materials strongly bound to the carbonate reservoir rock surface are dominated by basic N-containing molecules. Overall, these findings suggest that, beside fatty acids, these “sticky molecules” might also play an important role in controlling the wetting state of carbonate reservoir rock.
TRANSDUCERS 2007 - 2007 International Solid-State Sensors, Actuators and Microsystems Conference, 2007
... A DEPLETION LAYER ACTUATOR James HT Ransley1*, Colm Durkan1, and Ashwin A. Seshia1 1 Cambridg... more ... A DEPLETION LAYER ACTUATOR James HT Ransley1*, Colm Durkan1, and Ashwin A. Seshia1 1 Cambridge University Nanoscience Center, Cambridge, CB3 0FF, UNITED KINGDOM (*Corresponding author: Tel : +44-1223 ... 0 2 2 2 3 129.0 12 2 1 a L wEh dx dx ud wh E V L E ...
In this article, we describe nanometer scale characterization of piezoelectric thin films of Lead... more In this article, we describe nanometer scale characterization of piezoelectric thin films of Lead-Zirconate-Titanate (PZT). Using the electric field from a biased conducting atomic-force microscopy (AFM) tip, we show that it is possible to form and subsequently image ferroelectric domains. Using a sphere-plane model for the tip-sample system we calculate the distribution of electric potential, field and polarization charge, and find good agreement with the experimental values. We also discuss the effects of surface contaminants on domain formation.
An analysis of polycrystalline Au thin-film interconnects of widths ranging from 850 to 25 nm, an... more An analysis of polycrystalline Au thin-film interconnects of widths ranging from 850 to 25 nm, and lengths ranging from 1 microm to 20 nm which have been electrically stressed to the point of failure is presented. A new method for testing failure of interconnects is proposed, based on a quantity we call the failure current density. The mean time to failure for fixed current density and also the failure current density are seen to decrease with decreasing wire width contrary to expectations. The failure current density for a given wire width increases as the length decreases. An analysis of the temperature and stress profiles based on calculations of a simple model is presented which shows that the length dependence is due to thermal stresses rather than electromigration, and the width dependence is due to enhanced electromigration due to surface diffusion.
The authors report the electrical characterization of gold and gold-palladium nanowires failed by... more The authors report the electrical characterization of gold and gold-palladium nanowires failed by electromigration. Nanogaps 1–2nm in size are reliably made from metal nanowires by controlling the electromigration failure process, opening up the possibility of using these metal nanowires with nanogaps for molecular conduction studies and large-scale molecular junction device fabrication. Nanogaps are formed by applying a voltage sweep to the wires at a ramp rate of 4mV∕s. The interplay between Joule heating and electromigration means that reliable nanogaps can be formed without the need of a feedback circuit, rendering the technique relatively simple to implement.
Page 1. CURRENT AT THE NANOSCALE An Introduction to Nanoelectronics Colm Durkan Page 2. ... Page ... more Page 1. CURRENT AT THE NANOSCALE An Introduction to Nanoelectronics Colm Durkan Page 2. ... Page 4. CURRENT AT THE NANOSCALE An Introduction to Nanoelectronics ColmDurkan University of Cambridge, UK ICP Imperial College Press Page 5. ...
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