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Conference paperCawley P, 2012, , 38th Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE), Publisher: AMER INST PHYSICS, Pages: 99-100, ISSN: 0094-243X
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Conference paperRibichini R, Cegla F, Nagy PB, et al., 2012, , 38th Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE), Publisher: AMER INST PHYSICS, Pages: 955-962, ISSN: 0094-243X
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- Citations: 5
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Conference paperPtaszek G, Cawley P, Almond D, et al., 2012, , 38th Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE), Publisher: AMER INST PHYSICS, Pages: 491-498, ISSN: 0094-243X
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- Citations: 1
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Journal articleJackson MD, Leinov E, 2012, , International Journal of Geophysics, Vol: 2012, ISSN: 1687-8868
We find that the thin double layer assumption, in which the thickness of the electrical diffuse layer is assumed small comparedto the radius of curvature of a pore or throat, is valid in a capillary tubes model so long as the capillary radius is >200 times thedouble layer thickness, while the thick double layer assumption, in which the diffuse layer is assumed to extend across the entirepore or throat, is valid so long as the capillary radius is >6 times smaller than the double layer thickness. At low surface chargedensity (<10 mC · m−2) or high electrolyte concentration (>0.5 M) the validity criteria are less stringent. Our results suggest thatthe thin double layer assumption is valid in sandstones at low specific surface charge (<10 mC · m−2), but may not be valid insandstones of moderate- to small pore-throat size at higher surface charge if the brine concentration is low (<0.001 M). The thickdouble layer assumption is likely to be valid in mudstones at low brine concentration (<0.1 M) and surface charge (<10 mC·m−2),but at higher surface charge, it is likely to be valid only at low brine concentration (<0.003 M). Consequently, neither assumptionmay be valid in mudstones saturated with natural brines.
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Journal articleRajagopal P, Drozdz M, Skelton E, et al., 2012,
On the use of absorbing layers to simulate the propagation of elastic waves in unbounded isotropic media using commercially available Finite Element packages
, NDT and E International, Vol: TBC -
Conference paperGalvagni A, Cawley P, 2012, , Conference on Health Monitoring of Structural and Biological Systems, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X
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- Citations: 3
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Journal articleRajagopal P, Skelton EA, Choi W, et al., 2012,
A generic hybrid model for bulk elastodynamics, with application to ultrasonic non-destructive evaluation
, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, Vol: 59, Pages: 1239-TBC -
Journal articleJones RE, Simonetti F, Lowe MJS, 2012,
Use of microwaves for the detection of water as a cause of corrosion under insulation
, Journal of Nondestructive Evaluation, Vol: 31, Pages: 65-76 -
Journal articleJackson MD, Gulamali MY, Leinov E, et al., 2012, , SPE Journal
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Conference paperBrierley N, Tippetts T, Cawley P, 2012, , 38th Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE), Publisher: AMER INST PHYSICS, Pages: 1824-1831, ISSN: 0094-243X
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- Citations: 4
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Journal articleMilne K, Cawley P, Nagy PB, et al., 2011, , JOURNAL OF NONDESTRUCTIVE EVALUATION, Vol: 30, Pages: 225-236, ISSN: 0195-9298
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- Citations: 25
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Journal articleXi X, Cegla FB, Lowe M, et al., 2011, , ULTRASONICS, Vol: 51, Pages: 1014-1025, ISSN: 0041-624X
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- Citations: 32
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Journal articleRibichini R, Cegla F, Nagy PB, et al., 2011, , IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL, Vol: 58, Pages: 2571-2581, ISSN: 0885-3010
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- Citations: 155
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Journal articleLovstad A, Cawley P, 2011, , NDT & E INTERNATIONAL, Vol: 44, Pages: 553-562, ISSN: 0963-8695
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- Citations: 70
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Journal articleHuthwaite P, Simonetti F, 2011, , JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA, Vol: 130, Pages: 1721-1734, ISSN: 0001-4966
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- Citations: 93
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Journal articleGulamali MY, Leinov E, Jackson MD, 2011, , Geophysics, Vol: 76, Pages: F283-F292, ISSN: 1942-2156
The injection of cold water into a hydrocarbon reservoir containingrelatively warmer, more saline formation brine may generateself-potential anomalies as a result of electrokinetic,thermoelectric, and=or electrochemical effects. We havenumerically assessed the relative contributions of these effectsto the overall self-potential signal generated during oil productionin a simple hydrocarbon reservoir model. Our aim was todetermine if measurements of self-potential at a production wellcan be used to detect the movement of water toward the well.The coupling coefficients for the electrochemical and thermoelectricpotentials are uncertain, so we considered four differentmodels for them. We also investigated the effect of altering thesalinities of the formation and injected brines. We found thatthe electrokinetic potential peaked at the location of the saturationfront (reaching values of 0.2 mV even for the most salinebrine considered). Moreover, the value at the production wellincreased as the front approached the well, exceeding the noiselevel ( 0.1 mV). Thermoelectric effects gave rise to largerpotentials in the reservoir (10 mV), but values at the wellwere negligible ð Þ .0:1 mV until after water breakthroughbecause of the lag in the temperature front relative to the saturationfront. Electrochemical potentials were smaller in magnitudethan thermoelectric potentials in the reservoir but were measurableð Þ > 0:1 mV at the well because the salinity front wasclosely associated with the saturation front. When the formationbrine was less saline (1 mol=liter), electrokinetic effects dominated;at higher salinities (5 mol=liter), electrochemicaleffects were significant. We concluded that the measurement ofself-potential signals in a production well may be used to monitorthe movement of water in hydrocarbon reservoirs duringproduction, but further research is required to understand thethermoelectric and electrochemical coupling coefficients in partiallysatu
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Journal articleClarke T, Cawley P, 2011, , STRUCTURAL HEALTH MONITORING-AN INTERNATIONAL JOURNAL, Vol: 10, Pages: 247-259, ISSN: 1475-9217
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- Citations: 41
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Journal articleGalvagni A, Cawley P, 2011, , JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA, Vol: 129, Pages: 1869-1880, ISSN: 0001-4966
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- Citations: 38
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Conference paperDuxbury D, Lowe M, Russell J, 2011,
Effects of variation in phased array element performance
When phased array probes are used for ultrasonic inspection it is necessary to ensure that consistent performance is achieved. If Full Matrix Capture (FMC) is used to record inspection data the most appropriate way of doing this is to assess transducer performance on an element by element basis rather than assess a specific beam.The rationale for this approach is that any beam can be synthetically produced from FMC data, so it is not logical to couple probe calibration with a particular beam. This paper presents a model based study that aims to place specifications on element performance. The effect of element sensitivity, phase, and non-functioning elements has been investigated using an array beam model, based on Huygen's principle, to carry out Monte Carlo simulations. This has revealed that the dominant result of variations in element performance is the introduction of beam artefacts, such as the creation of side lobes. Results will be presented from simulations of a number of beam types at several centre frequencies that show that focused beams are more resistant to artefacts than plane beams, and the effect of element phase is dependant on probe bandwidth. General guidelines for acceptable variations between elements will also be presented. © (2011) by the British Institute of Non-Destructive Testing. All rights reserved.
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Journal articleLowe M, Saffari N, Lhemery A, et al., 2011, , Journal of Physics Conference Series, Vol: 269, ISSN: 1742-6588
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